Probabilistic Seismic Hazard Analysis of Kathmandu Valley

I

ABSTRACT

Probabilistic Seismic Hazard Analysis (PHSA) is a technique commonly used for the

assessment of seismic hazard of any region or any place. This technique incorporates

uncertainties associated in the size, location and rate of recurrence of earthquakes. Such

uncertainties are identified, quantified and combined together to give a clear concept of the

seismic hazard. This research work utilizes the basic methodology for PSHA in order to

approximately calculate the seismic hazard of the Kathmandu Valley.

In the process of calculating seismic hazard, an attempt has been undertaken to

complete earthquake catalog to assess the seismic hazard potential, particularly, in close to

Kathmandu Valley, which consists of a number of earthquake sources. For the purpose of

keeping only main earthquake events in catalog, declustering is done to remove spatially and

temporally dependent events by the windowing procedure based on the algorithm given by

Gardner and Knopoff (1974). Refined catalog containing independent events is examined and

found to follow the Poissonian distribution.

Six aerial sources are used in this study. Characterization and identification of these

sources were done by plotting the refined catalog in the map of Nepal, which are similar to the

earthquake sources as given by Pandey et. al. (2002)

The maximum possible magnitudes of the identified sources are calculated based on Wells and

Coppersmith’s formula (Wells and Coppersmith, K.J., 1994) and the attenuation model selected

for the study is that given by Youngs et. al. (Youngs et. al. 1997) for the subduction zone.

The final result of this work depicts a maximum Peak Ground Acceleration (PGA) value

of 510 gal (1 gal = 1 cm/sec2) and the minimum PGA obtained is 425 gal at the bed rock level,

and the maximum PGA value of 730 gal and minimum PGA value of 620 gal at the soil site

condition. These ground acceleration values are calculated for 10% probability of exceedance

in 50 years i.e. for the return period (RP) of 475 years.

II

TABLE OF CONTENTS DECLARATION ............................................................................... Error! Bookmark not defined.

CERTIFICATION ............................................................................. Error! Bookmark not defined.

ACKNOWLEDGEMENTS ................................................................ Error! Bookmark not defined.

ABSTRACT ..................................................................................................................................... I

LIST OF ABBREVIATION ............................................................................................................... V

LIST OF FIGURES ............................................................................................................................ VII

LIST OF TABLES ................................................................................................................................ X

1. INTRODUCTION .................................................................................................................... 1

1.1 Background ................................................................................................................ 1

1.2 Scope of the Study ..................................................................................................... 1

1.3 Objective of the Study ............................................................................................... 2

2.0 SEISMICITY OF THE REGION ............................................................................................. 3

2.1 Past Destructive Earthquakes ................................................................................... 7

3.0 LITERATURE REVIEW ........................................................................................................ 9

3.1 Previous Studies ........................................................................................................ 9

3.1.1 Global Seismic Hazard Assessment Program (GSHAP) ....................................... 9

3.1.2. National building code of Nepal ...................................................................... 10

3.1.3. Department of Mines and Geology, Nepal ...................................................... 10

3.1.4. Study of Potential Magnitude of Impending Earthquakes in the Himalaya .... 11

3.2 Some Other Literatures Reviewed .......................................................................... 12

4.0 PROBABILISTIC SEISMIC HAZARD ANALYSIS ................................................................... 16

4.1 Identification of Seismic Sources ............................................................................ 17

4.2 Characterization of Seismicity or Temporal Distribution of Earthquake Sources .. 17

III

4.3 Prediction of Ground Motion by Using Attenuation Relationship .......................... 19

4.4 Probability Computation ........................................................................................ 19

5.0 METHODOLOGY ............................................................................................................. 21

5.1 Earthquake Catalog ................................................................................................. 22

5.1.1 Introduction: ..................................................................................................... 22

5.1.1.1 Historical Catalog and Seismicity (1255 – 1910 A.D.) .................................... 22

5.1.1.2 Instrumental Catalog and Seismicity (1911-2012 A.D.) ................................. 23

5.2 Unifying Magnitudes ............................................................................................... 23

5.3 Declustering ............................................................................................................. 24

5.4 Catalog Completeness ............................................................................................. 25

5.5 Seismic Source Zone ................................................................................................ 27

5.6 Gutenberg – Richter Coefficients (a, b) ................................................................... 29

5.7 Maximum Magnitude for the Sources .................................................................... 35

5.8 Mean Annual Rate of Exceedance (ν) ..................................................................... 37

5.9 Attenuation Relationship ........................................................................................ 38

6.0 DATA INPUT .................................................................................................................... 41

6.1 Crisis 2007 Program: A tool for Seismic Hazard Analysis ....................................... 41

6.2 Input Options ........................................................................................................... 41

6.2.1 Input Maps ........................................................................................................ 41

6.2.2 Input Grid of Sites ............................................................................................. 42

6.2.3 Input Source Geometry .................................................................................... 43

6.2.4 Input Source Seismicity..................................................................................... 44

6.2.5 Input Attenuation Data ..................................................................................... 45

6.2.6 Input Spectral Ordinates ................................................................................... 46

IV

6.2.7 Input Global Parameters ................................................................................... 47

7.0 RESULTS AND ANALYSIS ................................................................................................. 49

7.1 Rock Site Condition ................................................................................................. 49

7.2 Soil Site Condition ................................................................................................... 56

8.0 CONCLUSION AND RECOMMENDATIONS ...................................................................... 61

9.0 REFERENCES ................................................................................................................... 62

10.0 ANNEX – 1....................................................................................................................... 64

11.0 ANNEX – 2.……………………….………………...................................…………..………………………...78

V

LIST OF ABBREVIATION a, b Guttenberg – Richter coefficients

DSHA Deterministic Seismic Hazard Analysis

E. Region Epicentral Region

g Acceleration due to gravity

GSHAP Global Seismic Hazard Assessment Program

IS Indian Standard

ISC International Seismological Centre

Km Kilometer

L Length

Lat Latitude

Lon Longitude

M Magnitude

MBT Main Boundary Thrust

MCT Main Central thrust

MFT Main Frontal thrust

mb Body wave magnitude

Mmax Maximum Magnitude

M0 Threshold Magnitude

Ms Surface wave magnitude

Mw Moment Magnitude

NBC Nepal Building Code

NSC National/Nepal Seismological Centre

PGA Peak Ground Acceleration

PHA Peak Horizontal Acceleration

PSHA Probabilistic Seismic Hazard Analysis

R Source to site distance

RP Return Period

rrup Closet distance to rupture (km)

VI

T Time Period

t Number of years

Tn Natural Period of vibration, (sec)

λm, ν Mean annual rate of exceedance

σ Standard Deviation

σMw Standard Deviation of Moment Magnitude

VII

LIST OF FIGURES

Figure 2.1 Destructive Earthquakes (M>=6) which occurred in the region (Annex 1)

(modified after ISC, 2012) -----------------------------------------------------------------------4

Figure 2.2 Approximated rupture area and magnitudes of destructive Himalayan

Earthquakes in the Himalaya Region ---------------------------------------------------------5

Figure 2.3 Figure 2.3.: Seismicity (M>=4) of the region. (Ojha et. al 2013) -----------------------6

Figure 2.4 Intensity distribution of 1833, North Kathmandu Earthquake (Bilham, 1995) -----8

Figure 2.5 Intensity distribution of 1934, Bihar-Nepal Earthquake (Bilham, 1995) -------------8

Figure 3.1 Seismic Hazard Map of Nepal by ASC (India), using Global Seismic Hazard

Program (GSHAP) database. The PGA values correspond to 10% chance of

exceedance in 50 years (~500 year return period). ---------------------------------------9

Figure 3.2 Seismic Hazard Map of Nepal (NBC-105). -------------------------------------------------10

Figure 3.3 Probabilistic Seismic Hazard Map of Nepal (Pandey et. al., 2002). ---------------------

--------11

Figure 3.4 View of the India-Asia collision showing estimated potential slip at different parts

of the Himalayan Stretch. (Source: Bilham, R. et. al., 2001). -------------------------12

Figure 4.1 Four steps of a probabilistic seismic hazard analysis (Kramer, 1996) ---------------16

Figure 5.1 Flow chart for the seismic hazard analysis. -----------------------------------------------21

Figure 5.2 Cumulative frequency of earthquakes considered for the given number of

earthquakes per year (dots represent the observed value and dashed lines

represent the approximate exponential function; Poisson distribution) ----------26

Figure 5.3 Earthquake sources (DMG 2002) ------------------------------------------------------------27

Figure 5.4 Gutenberg-Richter recurrence relationship curve for source zone 2 ---------------29

VIII






Figure 6.1 Map and cites file selection of Kathmandu Valley ---------------------------------------42

Figure 6.2 Sites of Computation of Hazard --------------------------------------------------------------43

Figure 6.3 Geometry of the Seismic Sources ------------------------------------------------------------44

Figure 6.4 Source Seismicity data of the Earthquake Sources --------------------------------------45

Figure 6.5 It shows the Built in attenuation models along with fault locations, soil type and

model properties. -------------------------------------------------------------------------------46

Figure 6.6 Intensities for each spectral ordinate -------------------------------------------------------47

Figure 6.7 Global parameters (integrations parameters, fixed return periods and distance

for deaggregation) -------------------------------------------------------------------------------48

Figure 7.1 Seismic hazard map for the Kathmandu valley having 10 % probability of being

exceeded in 50 years (rock site condition) Maximum PGA – 508 gal and Minimum

PGA – 425 gal -------------------------------------------------------------------------------------49

Figure 7.2 Uniform Hazard Spectra for the coordinates X = 85.41969, Y = 27.41038 for 10 %

probability of being exceeded in 50 years (rock site condition) Maximum PGA –

508 gal ---------------------------------------------------------------------------------------------50

IX


probability of being exceeded in 50 years (rock site condition) Minimum PGA –

425 gal ---------------------------------------------------------------------------------------------51


probability of being exceeded in 50 years (rock site condition) ----------------------52






probability of being exceeded in 50 years (soil site condition) having Maximum

PGA – 730 gal -------------------------------------------------------------------------------------55

Figure 7.8 Seismic hazard map for the Kathmandu valley having 10 % probability of being

exceeded in 50 years (Soil site condition) having Maximum PGA – 730 gal and

Minimum PGA – 620 gal -----------------------------------------------------------------------56


probability of being exceeded in 50 years (soil site condition) having Minimum

PGA – 620 gal -------------------------------------------------------------------------------------57


probability of being exceeded in 50 years (soil site condition) -----------------------58





X

LIST OF TABLES

Table 2.1 Four great earthquakes which ruptured the Himalayan Range over the last one

hundred years --------------------------------------------------------------------------------------4

Table 2.2 Historical earthquakes which reportedly destroyed the Kathmandu valley in the

past (source: Chitrakar and Pandey, 1986) -------------------------------------------------7

Table 5.1 Window algorithm for aftershock -----------------------------------------------------------25

Table 5.2 Source Coordinates (Longitudes, Latitudes) ----------------------------------------------28

Table 5.3 Source Coordinates (km) ----------------------------------------------------------------------28

Table 5.4 Quantitative distribution of instrumental records of last approximately 100 years

within considered magnitude intervals ----------------------------------------------------29











Table 5.10 Mean Maximum magnitude for the sources ----------------------------------------------35

Table 5.11 Maximum and Minimum magnitude for the sources -----------------------------------36

Table 5.12 Coefficient for attenuation relations for rock site (after, Young’s et. al. 97) ------38

XI

Table 5.13 Coefficient for attenuation relations for soil site (after, Young’s et. al. 97) -------39

Table 6.1 Grid of sites for the study area (Kathmandu Valley) ------------------------------------43

Table 11.1 Different PGA for both rock and soil site condition of the Kathmandu valley-----78

Table 11.2 Intensity (gal) V/S Exceedance rate for coordinates X=85.41969, Y=27.41038---79

Table 11.3 Intensity (gal) V/S Exceedance rate for coordinates X=85.5462, Y=27.78348----80

Table 11.4 Intensity (gal) V/S Exceedance rate for coordinates X = 85.34357, Y = 27.5143--81


Table 11.6 Intensity (gal) V/S Exceedance rate for coordinates X = 85.4432, Y = 27.6977---83



Table 11.9 Intensity (gal) V/S Exceedance rate for coordinates X = 85.3435, Y = 27.5122----86



1

1. INTRODUCTION

1.1 Background

Nepal is located in one of the seismically very active parts of the world. Among the

natural disasters, earthquake is the most devastating which can cause plenty of damages in

terms of loss of human life and property, in a few seconds. On average, 10,000 (e.g. Bhattarai

G. K. (2010) people die each year due to earthquakes, while annual economic losses are in

billions of dollars and often a large percentage of the gross national product of the country is

affected (Elanashai, 2008). With high annual population growth and one of the highest urban

densities in the world, Kathmandu Valley and other part of Nepal are clearly seen to face the

earthquake risk. It is also obvious that the next large earthquake to strike near Kathmandu

Valley would cause significantly greater loss of life, structural damage, and economic hardship

than in the past earthquakes.

To reduce such a loss from the impending earthquakes, the task of earthquake

engineering professionals is to work for earthquake resistant design of structures. Hence, it is

felt that for every region, site specific design ground motion parameters should be available

during the time of analysis, design and construction of earthquake resistant engineering

structures.

1.2 Scope of the Study

It is evident that without considering the reality that Nepal is an earthquake prone

country and without careful examination of available earthquake precautions together with the

new, innovative prevention and/or prediction techniques, severe damages and losses of lives

will be unfortunately expected in the future as well. So first of all, the awareness of the

earthquake hazard and its drastic probable consequences should be known to the people.

As we know, effect of earthquake depends on the local geology and site conditions in

addition to magnitude and distance from earthquake source. Available codes in practice used

for earthquake resistant design of buildings clusters different regions into a uniform single

zone. This is not reasonable to categorize different seismic sites under one seismic region

2

without study of hazard level of individual area. In order to accurately estimate earthquake

loadings in structures during earthquake, site specific study of seismic hazard and ground

response analysis is necessary.

The purpose of this study is to perform a probabilistic seismic hazard assessment for the

Kathmandu Valley. The principle aim of this study is to provide the seismic hazard curves and

the hazard maps for the study area in terms of Peak Ground Acceleration’ for 10% probability of

exceedance, for different time periods of 50, 100, 500 years and different site classifications.

1.3 Objective of the Study

• Complete earthquake catalog

• Compute seismic hazard curves for different return period for Kathmandu Valley

• Find uniform hazard seismic response spectra for different return periods at both rock

and soil conditions

3

2.0 SEISMICITY OF THE REGION Earthquake data is very important in the study of tectonics and seismic hazard

assessment for any region or site. Such data comes from historical earthquakes recorded in

chronicles, inscriptions, macroseismic reports and instrumental records. Historical data is very

scanty in the case of Nepal. Instrumental data are also very limited because instrumental

monitoring of earthquakes in Nepal started only 25 years ago. The other data comes from the

catalog of the International Seismological Centre (ISC), UK which reports instrumental data

after 1960.

Historical destructive earthquakes, their impacts as well as the threats of future

earthquakes have been studied by well known scientists, e. g. Roger Bilham et. al.(2004) and

Khattri, K. N. (1987, 1992). They have collected and compiled historical earthquake data in the

Himalayan Region (Annex 1). This table (Annex 1, Fig. 2.1) shows the activity of major

earthquakes since 1505. Epicenters of earthquakes which occurred before 1900 were

estimated by corresponding authors after the interpretation of macroseismic data (e.g.,

destruction data).

In the last century, the Himalayan Range has hosted four destructive great earthquakes

(Table 2.1), killing many people and destroying economy of the region. The region between the

1905 Kangra Earthquake (M7.8) and 1934 Bihar-Nepal Earthquake (M8.1) (Fig 2.2) has not

produced any great earthquake (M>8.0) possibly at least since the last five hundred years. This

stretch of the Himalaya has been identified as ‘seismic gap’ by Khattri (1987, 1992) and stands

as a potential site for future great earthquake(s).

4

Table 2.1: Four great earthquakes which ruptured the Himalayan Range over the last one hundred years

Year Location Magnitude

1897 Shillong 7.6

1905 Kangra 7.8

1934 Bihar-Nepal 8.1

1950 Assam 8.5

Figure 2.1: Destructive Earthquakes (M>=6) which occurred in the region (Annex 1) (modified

after ISC, 2012)

The study area (Kathmandu Valley) falls in the western extremity of the source region

that produced the 1934 great earthquake. It is believed that this region has to wait for some

5

hundreds of years before it gets matured to produce great earthquake (M>8.0) again, but we

should not ignore the possibility that this region has collected some energy in the last about 80

years (after the 1934 Bihar-Nepal Earthquake) and this energy might be equivalent to one

~M7.0 earthquake at the present (Fig. 2.2).

Figure 2.2.: Approximated rupture area and magnitudes of destructive Himalayan Earthquakes

in the Himalaya Region.

Instrumentally recorded seismicity data for earthquakes having magnitude greater than

or equal to 4.0 after 1964 AD are available from International Seismological Centre, UK.

Department of Mines and Geology, Government of Nepal has been running a network of

seismic stations since 1995. The detection threshold of the network is local magnitude (ML) for

any earthquake that occurs in Nepal (Pandey et. al., 1999). The monitoring of local seismicity

by DMG has revealed an exceptional picture of seismic activity in the Nepal Himalaya. A

continuous belt of seismic activity has been observed at the front of the Nepal Himalaya

(Pandey et. al. 1995, Pandey et. al., 1999).

The microseismic activity in the Nepal Himalaya is characterized by shallow focus (10

km<depth<25 km) earthquakes (Pandey et. al., 1995, 1999). Comparatively, shallow focus

earthquakes are more destructive than deeper ones. The epicentral region of the 1988

6

earthquake is an exception all along the Himalaya, where the focal depth of earthquakes ranges

up to upper mantle (~58 km, Chen et. al. 2004). The seismicity belt is narrow (~50 km) in the

east of 820 E and is divided into two sub-parallel belts in the west of 820 E.

Figure 2.3.: Seismicity (M>=4) of the region. (Ojha et. al 2013)

The belt of intense microseismic activity in central Nepal coincides with the front of the

Higher Himalaya and close to the Main Central Thrust (MCT) (Annex-2). This belt correlates

well with the zone of maximum vertical uplift revealed by spirit leveling data (Jackson et. al..,

1994) and maximum gradient of horizontal GPS velocities (Bettinelli et. al., 2006). The

microseismic activity is interpreted to reflect the strain accumulation (Pandey et. al., 1999), in

the Himalaya, in the interseismic period. The belt further correlates with the location of

geometrical ramp, inferred to join the locked portion and creeping part of the MHT.

7

2.1 Past Destructive Earthquakes

The Kathmandu Valley has been reported to have experienced/been destroyed by many

earthquakes in the past. Records of past destructive earthquakes date back up to 1255 AD

(Chitrakar and Pandey, 1986). Specifically, Kathmandu Valley has been destroyed by 9 major

earthquakes since 1255 (Table 2.2). However, detail information about such earthquakes is not

available.

The North Kathmandu Earthquake (1833, ~M7.6) and the Bihar-Nepal Earthquake (1934, M8.1)

destroyed the Kathmandu Valley severely. The study area (Kathmandu Valley) falls in Intensity

Zone VIII (Bilham, R., 1995) of the 1833 AD earthquake (Fig. 2.4). This intensity value

corresponds to a PGA of about 300 gal (Trifunac and Brady’s relation, 1975). Similarly, the 1934

Bihar-Nepal earthquake produced an intensity of about IX to VIII at the Kathmandu Valley (Fig.

2.5) and equivalent to a PGA of about 400 gal.

Date Latitude Longitude Magnitude Intensity (MMI)

in Kathmandu

1255 --- --- --- X

1408 --- --- --- X

1681 --- --- --- IX

1810 --- --- --- IX

1833 28 85 7 X

1833 27 85 7 IX

1833 27 84 7 VIII

1866 27.7 85.3 7 X

1934 26.5 86.5 8.3 IX-X

Table 2.2: Historical earthquakes which reportedly destroyed the Kathmandu valley in the past (source: Chitrakar and Pandey, 1986)

8

Fig. 2.4: Intensity distribution of 1833, North Kathmandu Earthquake (Bilham, 1995)

Figure 2.5: Intensity distribution of 1934, Bihar-Nepal Earthquake (Bilham, 1995)

9

3.0 LITERATURE REVIEW

3.1 Previous Studies

A number of scientists have worked on the seismicity and seismic hazard of the region. Some of them are as follows:

3.1.1 Global Seismic Hazard Assessment Program (GSHAP)

Global Seismic Hazard Assessment Program (GSHAP), a UN initiative, has published

seismic hazard map of the region. Using GSHAP database, Amateur Seismological Centre

(www.asc-india.org), Pune, India has reproduced seismic hazard map of Nepal (Fig. 3.1). The

values are at a hard rock site having 10% chance of exceedance in 50 years. As per this map, the

study area (Kathmandu Valley) falls in a high hazard zone and the predicted PGA is above 400

gal for the Kathmandu Valley.

Figure 3.1.: Seismic Hazard Map of Nepal by ASC (India), using Global Seismic Hazard Program (GSHAP) database. The PGA values correspond to 10% chance of exceedance in 50 years (~500 year return period).

10

3.1.2. National building code of Nepal

Beca Worly International, New Zealand in association with other consultants in Nepal

and abroad prepared seismic hazard map (Fig. 3.2.) and conducted risk assessment for Nepal

(Building Code Development Project, 2004). They used attenuation relationship of Kawashima

(1984) that defines structural response (5%) damping expected at a given distance from a given

magnitude earthquake. It was the first work of its kind carried out in Nepal. As per the report,

most of the part of Kathmandu Valley falls in high hazard zone having zoning factor 1.0.

Figure 3.2.: Seismic Hazard Map of Nepal (NBC-105).

3.1.3. Department of Mines and Geology, Nepal

Department of Mines and Geology, Government of Nepal has published a probabilistic

seismic hazard map of Nepal (Pandey et. al., 2002, Fig. 3.3). The map shows contour lines of

PGA levels with 10% chance of exceedance in 50 years (return period of ~500 years) on hard

11

bed rock. According to this map the project area is expected to experience a PGA of about 250

gal with 10% chance of exceedance in 50 years (~500 years return period).

Figure 3.3.: Probabilistic Seismic Hazard Map of Nepal (DMG, 2002).

3.1.4. Study of Potential Magnitude of Impending Earthquakes in the Himalaya

A study has been carried out to estimate the potential crustal slip deficit in the

Himalaya, which is a kind of study to estimate magnitude potential of impending destructive

earthquake in the region. Bilham et. al. (2004) estimated strain accumulation in the Himalayan

region since the last 500 years and did estimate of the possible slips due to known destructive

great earthquakes in the same duration of time. He inferred that the amount of possibility

accumulated strain is far larger than that released during the same span of time. Thus, it can

easily be interpreted that some parts of the Himalaya are waiting for great earthquakes. Fig. 3.4

shows areas of past destructive earthquakes with available potential slip at the present.

12

Figure 3.4: View of the India-Asia collision showing estimated potential slip at different parts of the Himalayan Stretch. (Source: Bilham, R. et. al., 2001).

3.2 Some Other Literatures Reviewed

Bilham R, (2004), research for the Historical Studies of Earthquakes in India gives some

of the major earthquake events for the Nepal Himalaya. He has collected and compiled

historical earthquake data in the Himalayan Region.

The research of Chitrakar G. R. and M. R. Pandey (1986) Geologist and Senior

Seismologist of Department of Mines and Geology gives the table of historical earthquakes of

Nepal compiled from different books and articles.

13

E.M. Scordilis, (2006), gives the Empirical global relations of converting surface wave

magnitude (Ms) and body wave magnitude (mb) to moment magnitude. For the purpose of

unifying magnitude the relation given by Scrodilis is used in this study.

Gardner, J. K., and L. Knopoff (1974), removes the aftershocks for the Earthquakes in

Southern California by the windowing procedure based on the algorithm (Gardner and Knopoff)

and checked whether the sequence of earthquakes in Southern California, with aftershocks

removed, Poissonian?

Parajuli et. al. (2008) study gives the probabilistic hazard estimate throughout Nepal

considering historical earthquakes, intra plate slip and faults. Also a typical case probabilistic

spectra is plotted for Pokhara city. For the city, design earthquakes for three probabilities of

exceedance are simulated which can be useful to design new structures and retrofit of existing

structures.

Pandey et. al. (2002) has performed Probabilistic Seismic Hazard Analysis to prepare

Seismic Hazard Map of Nepal by using commercial software “CRISIS 99” prepared by Institute

de Ingenieria UNAM, Mexico. They have divided whole region of Nepal into ten Arial sources

and twenty four liner sources with approximately 40 km length of each. For the purpose of

calculation of peak ground acceleration they have used attenuation relationship proposed by

Young’s et al (1997). Their work is limited within the PGA on bed rock. They have left the work

about amplification of ground motion due to geological condition or local soil effect. Hence, in

this thesis work site specific hazard curves and spectral curves are calculated and plotted for

both hard rock and soft soil sites.

Raghu Kanth et. al. (2005) have carried out the probabilistic seismic hazard analysis for

the site of Mumbai. The state-of-the-art in the seismic hazard analysis used in the work has

produced the result in terms of peak ground acceleration and uniform hazard spectra for return

period of 500 and 2500 years. Attenuation relation developed for the regions of India has been

14

used. The local soil effects are considered in the attenuation relation. The work considers only

line sources and is silent about areal sources located in this part of Peninsular India.

A detailed PGA hazard map with 10% annual probability of exceedence in 50 years was

worked out by Khattri et al in 1984. These authors used the attenuation relation developed by

Algermissen and Perkins (1976) for use in USA. Bhatia et al (1999) presented a PGA hazard map

with 10% annual probability of exceedance in 50 years using the attenuation relation of Joyner

and Boore (1981).

Iyengar and Ghosh (2004) carried out PSHA for Delhi city on a grid size of 1 km x 1 km.

Nearly 300 years of past data was used to determine the regional seismic recurrence relations.

The maximum potential magnitude of the Himalayan faults has been underestimated in this

study. There are other limitations regarding the type of site considered and choice of the

attenuation relation.

Young’s et. al. (1997) has presented attenuation relationship for peak ground

acceleration and response spectral acceleration for subduction zone interface and intraslab

earthquakes for moment magnitude M5 or greater and for distances of 10 to 50 Km. On the

paper Seismological Research Letters they have published two sets of attenuation relations for

peak ground acceleration and spectral acceleration each for rock site and soil site for

subduction zones.

Khatiwada (2009) has prepared seismic hazard map of Nepal. In his report the

maximum level of shaking in eastern Nepal at bed rock level is 0.65g. He has performed

probabilistic seismic hazard analysis considering ten aerial sources defined by National

Seismological Centre, Nepal. In his work he has not considered the linear sources proposed by

National Seismological Centre, Nepal. Attenuation effects of distant sources are also not

considered his work.

15

Bhattarai G. K. (2010) has determined the Peak Ground Acceleration (PGA) and uniform

hazard spectra for two different return periods of nearly 500 and 2500 years for both rock and

soil sites of Biratnagar. The PGA of 0.29g is obtained at the rock site. The maximum spectral

acceleration for return Period of 500 years is calculated as 0.50g at rock site.

Maskey et. al. (2004) has concluded that among the different attenuation relationships

prepared for different regions their suitability depends not only on one law but also in

magnitude range and source to site distance. For example where attenuation relationship

cannot be developed due to lack of complete set of earthquake catalogue, for Nepal it is

accepted to use attenuation relationships proposed by Young’s et al (1997), Donovan (1973)

and Cornell (1979) which give way the PGA values nearer to the values equivalent to the

recorded intensities during the past earthquakes of 1833, 1934 and 1988.

CRISIS 2007 is a computer program that computes seismic hazard using a probabilistic model

that considers the rates of occurrence, attenuation characteristics and geographical distribution

of earthquakes

CRISIS 2007 was developed at Instituto de Ingeniería, UNAM, Mexico. It has been written by:

M. Ordaz, A. Aguilar and J. Arboleda

Derechos Reservados, 1987-2007)

16

4.0 PROBABILISTIC SEISMIC HAZARD ANALYSIS

Probabilistic Seismic Hazard Analysis is a four step process according to Kramer (1996)

as written in Geotechnical Earthquake Engineering namely:

• Identification and characterization of earthquake sources

• Development of seismicity or temporal distribution of earthquake recurrence model of

each source

• Use of predictive relationship to find ground motion parameter by any possible size of

earthquake

• Combination of probability of earthquake location, size and ground motion parameter

to find total probability of exceedance of specified level of ground motion.

This method of seismic hazard analysis is very similar to that proposed by panel on

seismic hazard analysis. This method of seismic hazard analysis does not restrict on taking

seismic source as annular zone as proposed by Cornell (1968).

Figure 4.1: Four steps of a probabilistic seismic hazard analysis (Kramer, 1996)

17

The first methodology applied to the most of the probabilistic seismic hazard analyses

was defined by Cornell in 1968 but in fact, the basic steps have not been challenged since then.

The method adopted in this research is according to the method described by Kramer (2007)

which is similar in much respect to the seismic hazard analysis developed by Cornell (1968).

These steps can be grouped into four categories as:

4.1 Identification of Seismic Sources

It is the first step in seismic hazard analysis which involves identification of all

earthquake sources capable of producing significant ground motion at the site. Source

characterization includes definition of source type and geometry. The sources of earthquakes

can be point source, linear source and or areal source. There can be many earthquake sources

having potential threat to cause damage in different regions of the country, some of them

being known and some being unknown. Identification of seismic sources requires some

detective works that may include interpretation and observation of earthquakes occurring at

and around the site. Study on historical earthquakes and interpretation of geological and

tectonic evidences in Nepal is quite a complex work. Regarding historical earthquakes and

instrumental earthquakes from the past an earthquake catalog is prepared during this research

work consisting of independent events that occurred in Nepal from 1255 to 2012 A.D.

4.2 Characterization of Seismicity or Temporal Distribution of Earthquake

Sources

Geometric characteristics of an earthquake source are incorporated into the source to

site distance and magnitude calculation. The spatial characteristics are considered in the form

of spatial uncertainty and size and time uncertainty. In seismic hazard analysis it is included by

considering the distribution of earthquakes within sources, the distribution of earthquake size

for each source, and finally distribution of earthquakes with time. After identifying all possible

earthquake sources that may produce the strong level of shaking at site, it is calculated the

18

uncertainty related with the magnitude and distances between the source and site. It is implied

that earthquakes are equally likely to occur at any point within the source zones.

The distribution of earthquake size in a given period of time is expressed by Guttenberg -

Richter Recurrence Law (1994) and is given by the relation:

𝑙𝑙𝑙𝑙𝑙𝑙10𝜆𝜆𝜆𝜆 = 𝑎𝑎 − 𝑏𝑏𝜆𝜆 (4.0)

Here, 𝜆𝜆𝜆𝜆 is the mean annual rate of exceedance of magnitude m, 10a is the mean yearly

number of earthquakes of magnitude greater than or equal to zero, and b (b value) describes

the relative likelihood of large and small earthquakes. A lower b value means that out of the

total number of earthquakes, a larger fraction occurs at the higher magnitudes, whereas a

higher b value implies a larger fraction of low magnitude events in the catalogue. The (a, b)

values characterized the seismicity of the region. Although the b value varies from region to

region, it lies in the range from 0.6 < b < 1.1. Detailed calculation for the determination of G-R

relation is discussed in the chapter below.

In probabilistic seismic hazard analysis, it is considered that there is equal probability of

occurrence of every level of earthquake size in between lower level of threshold magnitude and

maximum magnitude of every source. For engineering significance, an earthquake of size

below magnitude 4 is not considered as strong motion. Thus, the probability for each range of

magnitudes above 4 and below the maximum magnitude are calculated.

The cumulative density function and probability density function for the Guttenberg - Richter

law with upper and lower bounds are expressed as:

FM(m) = P[M < 𝜆𝜆\𝜆𝜆0 ≤ 𝜆𝜆 ≤ 𝜆𝜆𝜆𝜆𝑎𝑎𝑚𝑚

=1 − exp[−β(m − m0)]

1 − exp[−β(mmax − m0)] (4.1)

19

fM(m) =βexp[−β(m− m0)]

1 − exp[−β(mmax − m0)] (4.2)

Where, FM(m) and fM(m) are cumulative and probability density function. β is earthquake

recurrence parameter and equals to 2.303b, m is magnitude considered, m0 is minimum

magnitude and mmax is maximum predicted magnitude for the given source.

4.3 Prediction of Ground Motion by Using Attenuation Relationship

Predictive relationship also known as attenuation relationship usually expresses ground

motion parameters like peak ground acceleration, spectral displacement or spectral

acceleration as function of magnitude and source to site distance and sometimes in other

variables too. Attenuation relationship is articulated as: Y= f(M, R, Pi) , where Y is ground

motion parameters of interest, M is the magnitude of earthquake ,R is the source to site

distance and Pi is source path and local soil effect which may or may not be considered.

Generally with attenuation relationship, uncertainty associated with the expression i.e.

standard deviation is also specified.

These attenuation relationships are based on the regional values. Hence, there are

many types of attenuation relationships. These relationships are nearly obtained empirically by

least-square regression on a particular set of strong ground motion parameter. In context of

Nepal, where systematic recording of earthquake data only begin from the early of nineties of

decades, we still need to wait to develop the suitable attenuation relationship. In order to

develop the attenuation relationship for a particular region, it requires a lot of seismic data,

which are lacking now.

4.4 Probability Computation

Final step in the method of probabilistic seismic hazard analysis is to find the total

probability of exceedance of specified level of peak ground acceleration. In this method of

20

PSHA uncertainties in earthquake size, location and ground motion prediction is combined to

obtain the total probability. In all number of sources, if the magnitude is divided in to j no. of

intervals and source to site distance is divided into k no. of intervals and attenuation

relationship is used to find peak ground acceleration in each interval of magnitude and

distance, the combined probability of particular ground motion parameter Y expressed as mean

annual rate of exceedance to minimum value of ground motion parameter y is expressed as:

λy ∗ = � fM(m) ∗� fR(r) ∗� dm dr nR

k=1

(4.3) nm

j=1

ns

i=1

where, λy* is the annual rate of exceedance of peak ground acceleration y* occurring at source

from 1 to number nS in between magnitudes of total nM number at source to site distances of

ranges from 1 to nR number. νi is the annual rate of exceedance of minimum threshold

earthquake (M=4) at source i derived using G-R recurrence relationship as represented by

equation (4.0) in which λ (m=4) = ν, and P[Y>y*/mj, rk] is the probability of exceedance of

specified peak ground acceleration Y to the value y* obtained using attenuation relationship for

given magnitude m and distance r at each of interval of one to j number and k number

respectively. Probability of exceedance of acceleration is calculated using normal distribution

function.

fM (m) is the function of magnitude probability as given by truncated G-R relationship with

upper and lower bound as expressed in equation (4.1 and 4.2).

After getting the values of λy* for different values of y* the plot between these values against

mean rate of exceedance is made to draw hazard curves. Total hazard at a particular site is

obtained after adding the contribution from all the seismic sources. Thus hazard curves of

given ground motion parameter i.e. spectral acceleration at different periods and also peak

ground acceleration (PGA) i.e. spectral acceleration at 0s period for rock and soil sites are

drawn.

21

5.0 METHODOLOGY

A detailed flow chart of the adopted methodology of this research work is presented in figure 5.1.

Figure 5.1: Flow chart for the seismic hazard analysis

Data Collection

Historical Earthquakes Instrumental Earthquakes

Seismic Data Compilation

Unifying Magnitude

Identification of Seismic Sources

Declustering fore shocks and after shocks

Check for completeness Determination of Gutenberg

Parameters (a, b)

Selection Attenuation Relationships

Seismic Hazard Analysis

Seismic Hazard Map

Preparation of Earthquake Catalog

Earthquake Distribution in the Region

Data Input (CRISIS 2007 2007)

22

5.1 Earthquake Catalog

5.1.1 Introduction:

A complete earthquake catalog is required for the purpose of quantification of seismic

hazard and understanding risk. However, seismic risk assessment done without a complete

catalog is always susceptible. Past seismicity not only indicates where destructive earthquakes

occurred but it also gives a statistical basis to analyze the prediction of future ground motions

probabilistically. An attempt has been implemented to compile all available earthquake events

(historical and instrumental) in the Nepal Himalaya in order to produce a complete catalog of

earthquakes in the context to contribute for the seismic hazard studies of the Nepal.

Earthquake events from available published source for the area between 20o to 35o N and 78o

to 92o E is taken for the preparation of catalog. In order to take account of completeness of

earthquake data from different sources, the earthquake catalog is divided as: Historical Catalog

and Instrumental Catalog.

5.1.1.1 Historical Catalog and Seismicity (1255 – 1910 A.D.)

Historical catalog consists of historical earthquakes taken from intensities estimated

from felt reports and historical documents. These felt reports are usually contemporary

newspaper or diary reports, different literatures and some of them are remembered accounts.

The records of the preinstrumental (historical) seismicity can be used to identify the

potential earthquake sources by means of the historical accounts of the ground shaking effects

which could confirm the occurrence of the past earthquakes and sometimes estimate their

geographic distributions of the intensity. Although the maximum intensity may be used to

assess the epicentral location and the magnitude of a specific earthquake event, the accuracy

of this location found by this method depends strongly upon the population density and the

rate of the earthquake recurrence. However, the geographic distribution of the historic

epicenters still provides a good evidence for the existence of the earthquake source zones, at

least it can be used to evaluate the rate of recurrence of the earthquakes or simply the

‘seismicity’ in some areas (Kramer, 1996).

23

5.1.1.2 Instrumental Catalog and Seismicity (1911-2012 A.D.)

Instrumental catalog used in this work consists of earthquakes reported by International

Seismological Centre (ISC). Although the instrumental records of the large earthquakes have

been available since about 1910 (lots of them before 1960 are incomplete or of uneven

quality), they represent the best, the most significant information for the evaluation of the

earthquake sources. The most important disadvantage of using these records is the short

period of time when compared with the average time interval between the large earthquakes.

But, still the alignment of the instrumentally located epicenters or even hypocenters together

with the analysis of the aftershocks can help in the subjects of the detection and the

delineation of the earthquake source zones.

After the interpretation of the geological, geophysical and seismological data obtained

by many tools, the characterization of an earthquake source first demands the consideration of

the spatial characteristics of this source, the distribution of the earthquakes within that source,

the distribution of the earthquake sizes for each source then the distribution of these

earthquakes with time. It is evident that these characteristics should involve specified, required

uncertainties (Kramer, 1996).

5.2 Unifying Magnitudes

The collected earthquake data consists of different magnitude scales and intensities

which are finally converted into moment magnitude in order to keep uniformity in

completeness by using the empirical relationships given by Johnston, A.C. (1996b) and E.M.

Scordilis (2006). Following are the empirical relationships used to convert intensities and

magnitudes of earthquake given by Johnston, A.C. (1996b) and E.M. Scordilis (2006).

24

Conversion of Ms to Mw – Relationship given by E.M. Scordilis (2006)

a) MW =0.67(±0.005)MS + 2.07(±0.03), (5.1)

3.0 ≤ MS ≤ 6.1

b) MW =0.99(±0.02)MS + 0.08(±0.13), (5.2)

6.2 ≤ MS ≤ 8.2

Conversion of mb to Mw – Relationship given by E.M. Scordilis (2006)

c) MW =0.85(±0.04)mb + 1.03(±0.23), (5.3)

3.5 ≤ mb ≤ 6.2

Conversion of Intensities to Mw – Relationship given by Johnston, A.C. (1996b) d) log Mo = 19.36 + 0.481*Imax + 0.0244*Imax^2 (I < Imax < XII); (5.4)

Mw = 2/3*log Mo - 10.7 (5.5)

5.3 Declustering

Declustering is the method of filtering the overlap events. As the available earthquake

data consists for shock, main shock and aftershock, it is difficult to identify main shock or

background event. Hence, after converting reported magnitude (Ms or Mb) and intensity into

moment magnitude (Mw), all the dependent events (for shock and aftershock) were removed

by the windowing procedure based on algorithm given by Gardner and Knopoff (1974).

Table 5.1 shows the window algorithm for aftershock.

25

M L (KM) T(Days)

0 0 0

2.5 19.5 6

3 22.5 11.5

3.5 26 22

4 30 42

4.5 35 83

5 40 155

5.5 47 290

6 54 510

6.5 61 790

7 70 915

7.5 81 960

8 94 985

Table 5.1: Window algorithm for aftershock

A listing of selected values for the windows is given in above table; the computational routine

uses an interpolation among the values listed. As an example, any earthquake within 510 days

after a magnitude M = 6.0 earthquake, and with epicenter within 54 km of the epicenter of the

M = 6 shock, was identified as an aftershock. For M>6.4, the slope of the T (M) window is less

than for M<6.4 to conform with improved estimates of the shape of the envelope. (Gardner

and Knopoff 1974)

5.4 Catalog Completeness

Residual catalog obtained after declustering the dependent events, containing independent

earthquakes is finally prepared. The earthquake distribution map of complete catalog is shown

in figure 2.3 above in section 2. Earthquake catalog is prepared neglecting magnitude less than

4 because earthquakes with magnitude less than 4 contributes very less in seismic hazard

26

assessment. In this work a total of 2275 main shocks are presented for the period of 1255 to

2012 A.D.

It is examined that the prepared earthquake catalog follows Poissonian distributions as

depicted in the Figure 5.2. In this figure the horizontal axis represents number of earthquakes

per year as obtained by dividing the catalog completion duration into nearly 100 intervals in a

duration of 1911 to 2012 A. D. The vertical axis represents the cumulative frequency of

exceedance of number of earthquakes.

Figure 5.2: Cumulative frequency of earthquakes considered for the given number of earthquakes per year (dots represent the observed value and dashed lines represent the approximate exponential function; Poisson distribution)

27

5.5 Seismic Source Zone

The first step of seismic hazard analyses is the definition of the earthquake sources that

could most probably affect the site of interest at which the seismic hazard will be calculated. In

fact, the characterization of seismic source zones depends on the interpretation of the

geological, geophysical and seismological data obtained by many tools such as tectonic theory,

seismicity, surface geological investigations and subsurface geophysical techniques (Reiter,

1990)

Operations required to characterize the sources may be the segmentation of MHT using

seismological and geological symptoms, assignment of magnitude on the basis of arc length or

surface area, assignment of mean return period, and adaptation of characteristic fault model

(Pandey et al, 2002). Therefore, this all study was not possible in the limited time frame of this

research work. Hence, the Characterization of earthquake sources is taken from the research

conducted by Pandey et al (2002). Total six earthquake source is taken for this research work

as shown in figure 5.3.

Figure 5.3: Earthquake sources (DMG 2002)

28

The discontinuity in the tectonic boundary of the study area has been divided into a total of six

quadratic, Areal sources and the geographic coordinates of their corners are shown in table 5.2.

And the table 5.3 represents the same in terms of the metric coordinates (kilometer). Source

coordinates are converted to kilometer by multiplying Latitude with 111.11 and Longitude by

99.

Source

Node 1 Node 2 Node 3 Node 4

Long Lat Long Lat Long Lat Long Lat

1 87.98 26.82 88.98 26.59 89.24 27.22 88.26 27.56

2 87.06 26.85 87.93 26.71 88.21 27.51 87.44 27.55

3 85.46 27.15 86.94 26.71 87.36 27.48 85.97 27.92

4 84.36 27.46 85.47 27.15 85.93 27.96 84.96 28.29

5 82.73 27.74 84.4 27.44 84.97 28.29 83.59 28.63

6 81.34 28.46 82.6 27.62 83.42 28.45 82.16 29.26

Table 5.2: Source Coordinates (Longitudes, Latitudes)

Source

Node 1 Node 2 Node 3 Node 4

X1 (km) Y1 (km) X1 (km) Y1 (km) X1 (km) Y1 (km) X1 (km) Y1 (km)

1 8710.02 2979.97 8809.02 2954.41 8834.76 3024.41 8737.74 3062.19

2 8618.94 2983.30 8705.07 2967.75 8732.79 3056.64 8656.56 3061.08

3 8460.54 3016.64 8607.06 2967.75 8648.64 3053.30 8511.03 3102.19

4 8351.64 3051.08 8461.53 3016.64 8507.07 3106.64 8411.04 3143.30

5 8190.27 3082.19 8355.60 3048.86 8412.03 3143.30 8275.41 3181.08

6 8052.66 3162.19 8177.40 3068.86 8258.58 3161.08 8133.84 3251.08

Table 5.3: Source Coordinates (km)

29

5.6 Gutenberg – Richter Coefficients (a, b)

After characterizing the earthquake sources, logarithmic value of the rate of exceedance of earthquakes falling in the particular sources are plotted against the earthquake magnitude in order to find out the G-R parameters. The slope of the plotted curve represents the “b” value while the rate of earthquake exceeding 0 magnitudes represents the “a” value.

S.N.

Source Zone 1

Mw > No. of earthquakes No. of Earthquakes per year Log λ m

1 4 20 0.2 -0.699

2 4.5 11 0.11 -0.959

3 5 4 0.04 -1.398

Table 5.4: Quantitative distribution of instrumental records of last approximately 100 years within considered magnitude intervals

Figure 5.4.: Gutenberg-Richter recurrence relationship curve for source zone 1

y = -0.699x + 2.126R² = 0.978

-1.6

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0 2 4 6

log 1

0λm

Magnitude Value

Series1

Linear (Series1)

30

S.N.

Source zone 2


1 4 16 0.16 -0.796

2 4.5 12 0.12 -0.921

3 5 5 0.05 -1.301

4 5.5 1 0.01 -2



y = -0.798x + 2.537

-2.5

-2

-1.5

-1

-0.5

0

0 1 2 3 4 5 6

log 1

0λm

Magnitude Value

Series1

Linear (Series1)

31

S.N.

Source zone 3


1 4 36 0.36 -0.444

2 4.5 22 0.22 -0.658

3 5 8 0.08 -1.097

4 5.5 1 0.01 -2


Figure 5.6: Gutenberg-Richter recurrence relationship curve for source zone 3

y = -1.021x + 3.801

-2.5

-2

-1.5

-1

-0.5

0

0 1 2 3 4 5 6

log 1

0λm

Magnitude Value

Series1

Linear (Series1)

32

Source zone 4



y = -0.96x + 3.002

-2.5

-2

-1.5

-1

-0.5

0

0 1 2 3 4 5 6

log 1

0λm

Magnitude Value

Series1

Linear (Series1)

S.N. Mw > No. of earthquakes No. of Earthquakes per year Log λ m

1 4 20 0.2 -0.699

2 4.5 16 0.16 -0.796

3 5 4 0.04 -1.398

4 5.5 1 0.01 -2

33

S.N.

Source zone 5


1 4 48 0.48 -0.319

2 4.5 22 0.22 -0.658

3 5 8 0.08 -1.097

4 5.5 1 0.01 -2

5 6 1 0.01 -2

6 6.5 1 0.01 -2


Figure 5.8: Gutenberg-Richter recurrence relationship curve for source zone 5

y = -0.761x + 2.654

-2.5

-2

-1.5

-1

-0.5

0

0 2 4 6 8

log 1

0λm

Magnitude Value

Series1

Linear (Series1)

34

Source zone 6



y = -0.72x + 2.536

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0 1 2 3 4 5 6

log 1

0λm

Magnitude Value

Series1

Linear (Series1)

S.N. Mw > No. of earthquakes No. of Earthquakes per year Log λ m

1 4 42 0.42 -0.377

2 4.5 23 0.23 -0.638

3 5 8 0.08 -1.097

35

5.7 Maximum Magnitude for the Sources

Wells and Coppersmith (1994) have provided a formula for the calculation of maximum

magnitude for an areal source. The equation for reverse thrust is as follows:

Mw = 4.33 + 0.90 log A (5.6)

And the standard deviation is given as:

σMw = 0.25 (5.7)

Where, Mw = Maximum moment magnitude

A = Area of areal source in km2 for reverse fault.

The mean maximum magnitude for the sources are calculated and tabulated below:

Source Mean Maximum Magnitude (Mw)

1 7.9

2 7.8

3 8.1

4 7.8

5 8.3

6 8.2

Table 5.10: Mean Maximum magnitude for the sources

36

The maximum magnitude shown in the table 5.10 above is the mean magnitude, obtained from

the relationship given by Wells and Coppersmith (1994).

For the purpose of this research, Upper bound magnitude (M2) and Lower bound magnitude

(M1) is needed and is tabulated below.

Source Standard Deviation Lower Limit (M1) Upper Limit (M2)

1 0.25 7.65 8.15

2 0.25 7.55 8.05

3 0.25 7.85 8.35

4 0.25 7.55 8.05

5 0.25 8.05 8.55

6 0.25 7.95 8.45

Table 5.11: Maximum and Minimum magnitude for the sources

37

5.8 Mean Annual Rate of Exceedance (ν)

The mean annual rate of exceedance (ν) of an earthquake of minimum threshold magnitude

(m0 = 4) are obtained from Guttenberg – Richter relation (1994)

The relation for all six sources is given below:

Source zone 1: logλm = 2.126 − 0.699 M (5.8)





Source zone 6: logλm = 2.536 − 0.720M (5.13)

Assuming that earthquakes of magnitude less than 4.0 do not contribute to the seismic hazard,

the mean rates of exceedance of magnitude 4.0 events from each of the source zones are:

Source zone 1: ν = 102.126 – 0.699 (4.0) (5.14)

Source zone 2: ν = 102.537 – 0.798 (4.0) (5.15)

Source zone 3: ν = 103.801 – 1.021 (4.0) (5.16)

Source zone 4: ν = 103.002 – 0.96 (4.0) (5.17)

Source zone 5: ν = 102.654 – 0.761 (4.0) (5.18)

Source zone 6: ν = 102.536 – 0.72 (4.0) (5.19)

38

5.9 Attenuation Relationship

Most of the earthquakes occurring in Nepal are considered to be interface events due to

subduction/collision of Indian plate beneath the Eurasian plate. Hence, in this research work

attenuation relationship suitable for subduction zone proposed by Youngs et. al. (1994) is used.

For the rock site it is expressed by the following relation:

ln(y) = 0.2418 + 1.414M + C1 + C2(10 – M)3 + C3ln(rrup + 1.7818e0.554M) + 0.00607 H + 0.3846 ZT

(5.20)

Standard Deviation = C4 + C5M (5.21)

Where, y is spectral acceleration in g, M is moment magnitude, rrup is closest distance to

rupture (km), H is depth (km) and ZT coefficient for source type which is 0 for interface event

and 1 for intraslab event. The coefficients C1, C2, C3, C4 and C5 are given in the table below:

Periods C1 C2 C3 C4 C5

PGA 0.0 0.0 -2.552 1.45 -0.1

0.075 1.275 0.0 -2.707 1.45 -0.1

0.1 1.188 -0.0011 -2.655 1.45 -0.1

0.2 0.722 -0.0027 -2.528 1.45 -0.1

0.3 0.246 -0.0036 -2.454 1.45 -0.1

0.4 -0.115 -0.0043 -2.401 1.45 -0.1

0.5 -0.4 -0.0048 -2.36 1.45 -0.1

0.75 -1.149 -0.0057 -2.286 1.45 -0.1

1 -1.736 -0.0064 -2.234 1.45 -0.1

1.5 -2.634 -0.0073 -2.160 1.5 -0.1

2 -3.328 -0.008 -2.107 1.55 -0.1

3 -4.511 -0.0089 -2.033 1.65 -0.1

Table 5.12: Coefficient for attenuation relations for rock site (after, Young’s et. al. 97)

39

Similarly, for soil site the attenuation relationship is given by the following equation:

ln(y) = -0.6687 + 1.438M + C1 + C2(10 – M)3 + C3ln(R + 1.0978e0.617M) + 0.00648 H + 0.3846 ZT

(5.22)

Standard Deviation = C4 + C5M (5.23)

Where, y, M, H and ZT are the same as defined above and the coefficients C1, C2, C3, C4 and C5

are shown in the table below:

Periods C1 C2 C3 C4 C5

PGA 0 0 -2.329 1.45 -0.1

0.075 2.4 -0.0019 -2.697 1.45 -0.1

0.1 2.516 -0.0019 -2.697 1.45 -0.1

0.2 1.549 -0.0019 -2.464 1.45 -0.1

0.3 0.793 -0.002 -2.327 1.45 -0.1

0.4 0.144 -0.002 -2.23 1.45 -0.1

0.5 -0.438 -0.0035 -2.14 1.45 -0.1

0.75 -1.704 -0.0048 -1.952 1.45 -0.1

1 -2.87 -0.0066 -1.785 1.45 -0.1

Table 5.13: Coefficient for attenuation relations for soil site (after, Young’s et. al. 97)

The standard deviation of the predicted parameter like peak ground acceleration and spectral

acceleration are calculated in order to account for uncertainty related with scatter of seismic

data and randomness in rupture of seismic sources. From the probability distribution of

particular ground motion parameter, the probability that this parameter Y exceeds a certain

value, y*, for an earthquake of a given magnitude, m, occurring at a distance, r, is given by:

P[Y>y*/m,r]=1-FY (y*) (5.24)

40

Where, FY(y) is the value of the cumulative distribution function of Y at m and r. The value of

FY(y) depends on the probability distribution used to represent Y. In general, ground motion

parameters are usually assumed to be log normally distributed (the logarithm of the parameter

is normally distributed); however, the unbounded characteristics of that distribution can

attribute to a nonzero probability to unrealistic values of the ground motion parameters.

41

6.0 DATA INPUT

6.1 Crisis 2007 Program: A tool for Seismic Hazard Analysis

CRISIS 2007 is a computer program that computes seismic hazard using a probabilistic model

that considers the rates of occurrence, attenuation characteristics and geographical distribution

of earthquakes. Followings are main considerations made in this program in order to compute

seismic hazard:

• Earthquake occurrence modeled as a Poissonian process

• Earthquakes sources modeled as area sources.

• Dynamic integration procedure is allowed for fast computation of hazard in extended areas.

• Young’s Attenuation models is used to compute PGA at considered site

6.2 Input Options

6.2.1 Input Maps

In this option, the name and the path of the map file and the cities file were entered as shown

in figure 6.1. Kathmandu valley map has been entered for the seismic hazard computations as

it is the study area of this research work. The map and cities information is a helpful visual

reference but has not any influence on the computations.

mk:@MSITStore:C:\PROGRA~1\II-UNAM\CRISIS~1\CRISIS~1.CHM::/Ayuda%20CRISIS/Topicos/seismicity_models_used.htm�

mk:@MSITStore:C:\PROGRA~1\II-UNAM\CRISIS~1\CRISIS~1.CHM::/Ayuda%20CRISIS/Topicos/spatial_integration_procedure.htm�

mk:@MSITStore:C:\PROGRA~1\II-UNAM\CRISIS~1\CRISIS~1.CHM::/Ayuda%20CRISIS/Topicos/attenuation_tables.htm�

42

Figure 6.1: Map and cites file selection of Kathmandu Valley

6.2.2 Input Grid of Sites

This option allows to input the grid or list of sites for which seismic hazard will be computed.

Grid of sites: Compute for a grid, defined by its origin, longitude and latitude increments, and

number of lines in both directions. Hazard is computed at the nodes of this grid.

For the study, the grids of sites are given as follows table 6.1 and figure 6.2:

43

Longitude Latitude

Origin 85 27.4 Degrees

Increment 0.1 0.1 Degrees

No. of Lines 8 6

Table 6.1: Grid of sites for the study area (Kathmandu Valley)

Figure 6.2: Sites of Computation of Hazard

6.2.3 Input Source Geometry

Third option: Source Geometry allows entering the geometry of each seismic source. Source

vertex is used to give the coordinates of the vertex of the active sources. All the coordinates of

the six sources taken has been input on the vertex for the seismic hazard calculations. Rupture

area parameters has been taken from the relation given by Wells and Coppersmith, Reverse

Fault for all the seismic sources as shown in figure 6.3.

44

Figure 6.3: Geometry of the Seismic Sources

6.2.4 Input Source Seismicity

This option allows entering the information about the seismicity of each source. Occurrence

model is selected as Poisson model and the parameters defining Mu has been calculated from

the relation given by Wells and Coppersmith.

For the Poisson model, Threshold magnitude (Mo) is taken as Mw = 4. Mean annual rate of

exceedance, value of beta and the parameters defining Mu has been calculated and is discussed

in section 5. Figure 6.4 gives the source seismicity data of the source 1, and the same

procedure is repeated for other five seismic sources.

45

Figure 6.4: Source Seismicity data of the Earthquake Sources

6.2.5 Input Attenuation Data

This option allows entering information about the attenuation relations to be used in the

hazard analysis. In general, an attenuation relation describes the probabilistic link between

earthquake magnitudes, source to site distance, and intensity.

The attenuation relation used for this study is taken which is given by Youngs et. al. (1997) and

this is the built-in attenuations models given by Crisis 2007. The additional parameters such as

fault location is taken as intraslab and the soil type as rock as shown in figure 6.5.

46

Figure 6.5: It shows the Built in attenuation models along with fault locations, soil type and model properties.

6.2.6 Input Spectral Ordinates

This option allows entering the parameters for each spectral ordinate (or, in general, intensity

measure) for which seismic hazard will be computed. The total number of spectral ordinates is

the total number of different intensity measures for which hazard is to be computed.

Frequently, the different intensity measures refer to spectral ordinates for different structural

periods. In this case, spectral attenuation relations are needed.

The total number of spectral ordinates taken for the study is 10, the lower limit of intensity

level is taken as 1 and the upper limit of intensity level is taken as 2000 with unit gal. Actual

spectral ordinate is used for the control to move from one intensity measure to the other and

the values are taken as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 along with the values of structural period of

47

spectral ordinate 0, 0.05, 0.1, 0.15, 0.3, 0.5, 1, 2, 3, and 4 respectively. The total number of

levels of intensity for which seismic hazard will be computed is 20 as shown in figure 6.6

Figure 6.6: Intensities for each spectral ordinate

6.2.7 Input Global Parameters

This input option allows entering the information concerning the spatial integration procedure,

the fixed return periods for which map files are to be generated and the distance to be used for

M – R disaggregation. The integration parameters, fixed return periods and the option for the

distance for deaggregation is shown in figure 6.7.

48

Figure 6.7: Global parameters (integrations parameters, fixed return periods and distance for deaggregation)

49

7.0 RESULTS AND ANALYSIS All the data were validated with no errors found, execution was proceeded and the following results were obtained for the Probabilistic Seismic Hazard Assessment for the Kathmandu Valley.

7.1 Rock Site Condition

Figure 7.1: Seismic hazard map for the Kathmandu valley having 10 % probability of being exceeded in 50 years (rock site condition) Maximum PGA – 508 gal and Minimum PGA – 425 gal

50

Figure 7.2: Uniform Hazard Spectra for the coordinates X = 85.41969, Y = 27.41038 for 10 % probability of being exceeded in 50 years (rock site condition) Maximum PGA – 508 gal

51

Figure 7.3: Uniform Hazard Spectra for the coordinates X = 85.5462, Y = 27.78348 for 10 % probability of being exceeded in 50 years (rock site condition) Minimum PGA – 425 gal

52

Figure 7.4: Uniform Hazard Spectra for the coordinates X = 85.34357, Y = 27.51438 for 10 % probability of being exceeded in 50 years (rock site condition)

53


54


55

7.2 Soil Site Condition

Figure 7.7: Seismic hazard map for the Kathmandu valley having 10 % probability of being exceeded in 50 years (Soil site condition) having Maximum PGA – 730 gal and Minimum PGA – 620 gal

56

Figure 7.8: Uniform Hazard Spectra for the coordinates X = 85.4154, Y = 27.41038 for 10 % probability of being exceeded in 50 years (soil site condition) having Maximum PGA – 730 gal

57

Figure 7.9: Uniform Hazard Spectra for the coordinates X = 85.56228, Y = 27.76632 for 10 % probability of being exceeded in 50 years (soil site condition) having Minimum PGA – 620 gal

58

Figure 7.10: Uniform Hazard Spectra for the coordinates X = 85.34357, Y = 27.51223 for 10 % probability of being exceeded in 50 years (soil site condition)

59


60


61

8.0 CONCLUSION AND RECOMMENDATIONS The accuracy of a PSHA depends on the accuracy with which uncertainty in earthquake size,

location, recurrence and effects can be characterized. Although models and procedures for

characterization of uncertainty of these parameters are available, they are based on data

collected over periods of time that, geologically, is very short. State of the art technique in

engineering judgment must be applied to the interpretations of PSHA results.

The paucity of seismic data in this region is big problem in calculating seismic hazard and risk.

The data are collected from available sources especially from the work of ISC, USGS and DMG,

Nepal.

The Kathmandu valley where urban settlement is highly concentrated incorporates very big

structures like apartments, industries, government corporations and offices, and important

buildings like hospitals, school buildings, and most importantly unplanned dwellings needs

seismic risk evaluation in order to make decisions, planning and seismic risk reduction process.

This work gives an idea on present seismic hazard scenario of the considered site. The PGA

value of 508 gal (0.51g) for rock site condition and 730 gal (0.74 g) for soil site condition

indicates that it is very vulnerable to future earthquakes. These values obtained from this

research work can be used in design of structures in the region.

The PGA values obtained for the different soil site condition from this research work is very

much similar to the PGA values given by GSHAP for the region.

Identification of seismic sources zone need to be reviewed and further research is

recommended for determining the Gutenberg – Richter parameters (a, b) as it is highly

governing factor for the precise result in seismic hazard analysis.

Other limitation can be the selection of suitable attenuation relationship. We can develop our

own attenuation relationship for the particular region.

62

9.0 REFERENCES

1. Abrahamson N.A., State of the Practice of Seismic Hazard Evaluation, paper of Pacific

Gas and Electric Company, Mail Code N4C, PO Box 770000, San Francisco, CA 94177 USA

2. Bilham R. (2004), Historical Studies of Earthquakes in India, Annals of Geophysics, 1-26.

3. Bhattarai G. K. (2010). Probabilistic Seismic Hazard Assessment and Ground Response

Analysis of Biratnagar Sub-Metropolitan City, Eastern Nepal, Thesis Submitted at

Department of Earthquake Engineering, Khwopa Engineering College, Bhaktapur.

4. Chitrakar G. R. and M. R., Pandey (1986). Historical Earthquakes of Nepal, Bull. Geol.

Soc. Nepal, 4, 7-8.

5. Cornell C.A.1968. Engineering Seismic Risk Analysis. Bulletin of the Seismological Society

of America. Vol58. No.5. pp.1583-1606.

6. Gardner J. K. and L. Knopoff (1974). Is the sequence of earthquakes in Southern

California, with aftershocks removed, Poissonian?, Bulletin of the Seismological Society

of America 64, 1,363–1,367.

7. Gardner J. K. and L. Knopoff (1942). b Values for foreshocks and aftershocks in real and

simulated earthquake sequences, Bulletin of the Seismological Society of America, Vol.

72, No. 5, pp. 1663-1676.

8. Gupta I.D., 2002. The state of the art in Seismic hazard analysis, ISET Journal of

earthquake technology, paper no. 428, vol 39, no.4,2002,pp311-346.

9. International Seismological Center, data access, http://www.isc.ac.uk/.

10. Johnston, A.C. (1996b). Seismic moment assessment of earthquakes in stable continental

regions -II. Historic seismicity. Geophys. J. Int. 125, 639-678.

11. Khatiwada S. (2009). Construction of Probabilistic Seismic Hazard Map for Nepal, Thesis

Submitted at Department of Earthquake Engineering, Khwopa Engineering College,

Bhaktapur.

12. Kramer S.L. (2007), Geotechnical Earthquake Engineering, Pearson Education Inc.

13. Maskey P. N. (2005). Selection of Attenuation Laws for Estimation of Seismic Input in

Nepal. Journal of the Institute of Engineering Vol. 5, PP 75-85.

http://www.isc.ac.uk/�

63

14. McGuire R. K., (2004). Seismic Hazards and Risk Analysis, Oakland, Earthquake

Engineering Research Institute

15. National seismological centre, Department of Mines and Geology, Kathmandu, Past and

Historical Earthquake, http://www.seismonepal.gov.np/

16. Nepal National Building Code, NBC 105: 1994, Seismic Design of Buildings, Department

of Urban Development and Building Construction, Government of Nepal.

17. Ojha S., Bhattarai G.K. and Rajaure S. (2013). A Catalog for Nepal Himalaya Earthquakes

from 1255 to 2012 A.D., International Journal of Landslide and Environment, Vol. 1, No.

1, pp 5-6.

18. Pandey M. R., Chitrakar G.R., Kafle B, Sapkota S. N., Rajaure S., Gautam U. P., Seismic

Hazard Map of Nepal, September 2002, National Seismological Centre, Kathmandu

Nepal.

19. Parajuli Hari., Junji Kiyono, Yusuke Ono and Takahiro Tsutsumiuchi (2008). Design

Earthquake Ground Motions from Probabilistic Response Spectra: Case Study of Nepal,

Journal of Japan Association for Earthquake Engineering, Vol. 8, No. 4.

20. Raghu Kanth S.T.G., Iyengar R. N., 2006.Seismic hazard estimation for Mumbai city.

Current Science, Vol. 91, No. 11.

21. Reiter. 1990. Earthquake Hazard Analysis: Issues and Insights, Columbia University

Press, New York

22. Scordilis E.M. (2006). Empirical global relations converting MS and Mb to moment

.magnitude, Journal of Seismology, 10, 225-236.

23. Wells, D. L and Coppersmith, K. J. (1994), New empirical relationships among

magnitude, rupture length, rupture width, rupture area and surface displacement,

Bulletin of Seismological Society of America, Vol. 84, No. 4, pp. 974 – 1002.

24. Youngs, S.J. Chiou, W.J. Silva and J.R. Humphrey, Strong Motion Attenuation Relations

for Subduction Zone Earthquakes, Seismological Research Letters, Vo. 68, No. 1, pp-58-

73, January/February 1997.

http://www.seismonepal.gov.np/�

64

10.z0 ANNEX – 1

Earthquakes greater than Mw – 5, from 1255 – 2012 A.D.

EVENTID DATE TIME LAT LON AUTHOR Mw E. REGION

00001 00/00/1255 - - - G.R. C / M. R. P 7.0 -

00002 00/00/1408 - - - G.R. C / M. R. P 7.0 -

00003 6/00/1505 - 29.5 83 Roger_bilham 8.2

Lo

Mustang/Nepal

00004 9/00/1555 - 33.5 75.5 Roger_bilham 7.6 Sri Nagar

00005 00/00/1681 - - - G.R. C / M. R. P 6.4 -

00006 7/00/1720 - 30 80 Roger_bilham 7.5 Uttar Pradesh

00007 9/00/1803 - 31.5 79 Roger_bilham 8.1 Uttar Pradesh

00008 00/00/1810 - - - G.R. C / M. R. P 6.4 -

00009 6/27/1819 - 30.5 80.5 Norconsult 6.2 -

00010 8/00/1833 - 27.7 85.7 Roger_bilham 7.7 Nepal

00011 5/23/1866 - 27.7 85.3 G.R. C / M. R. P 7.0 Kathmandu

00012 1/9/1869 - 25.5 91.5 Norconsult 7.1 -

00013 3/00/1885 - 34.1 74.6 Roger_bilham 6.4 Sri Nagar

00014 6/08/1897 - 24.5 91 Norconsult 7.6 -

00015 4/00/1905 - 33 76 Roger_bilham 7.8 Kangra

00016 2/00/1906 - 31.5 77.5 Roger_bilham 6.4 Bashahr

00017 8/6/1908 - 30 83 Norconsult 6.4 -

00018 10/14/1911 11:24:00 PM 31 80.5 PAS 6.8 -

00019 3/6/1913 11:04:00 AM 30 83 PAS 6.4 -

00020 8/28/1916 6:39:42 AM 29.9 80.5 Roger_bilham 7.3 Uttaranchal

00021 7/8/1918 10:22:07 AM 24.5 91 PAS 7.6 -

00022 9/9/1923 10:03:43 PM 25.25 91 PAS 7.1 -

00023 10/8/1924 8:32:57 PM 30 90 PAS 6.5 -

00024 6/4/1926 6:50:58 AM 35 89.5 PAS 6.0 -

00025 7/00/1926 - 30.3 80 Roger_bilham 6.5 Uttaranchal

00026 6/2/1927 4:37:34 PM 23.5 81 PAS 6.5 -

65


00027 7/2/1930 9:03:42 PM 25.5 90 PAS 7.1 -

00028 6/18/1931 12:58:29 PM 30.5 84 PAS 5.8 -

00029 3/4/1932 11:20:48 PM 33.5 81 PAS 5.8 -

00030 3/27/1932 8:44:40 AM 24.5 92 PAS 5.8 -

00031 11/9/1932 6:30:09 PM 26.5 92 PAS 5.8 -

00032 3/6/1933 1:05:35 PM 26 90.5 PAS 5.8 -

00033 1/15/1934 8:43:18 AM 27.6 87.1 Roger_bilham 8.1 Nepal - Bihar

00034 10/19/1934 8:58:16 PM 34 82 PAS 5.8 -

00035 12/15/1934 1:57:37 AM 31.25 89.25 PAS 7.1 -

00036 1/3/1935 1:50:08 AM 30.5 88 PAS 6.5 -

00037 3/5/1935 10:15:53 PM 29.75 80.25 PAS 6.1 -

00038 3/21/1935 12:04:02 AM 24.25 89.5 PAS 6.2 -

00039 5/21/1935 4:22:31 AM 28.75 89.25 PAS 6.2 -

00040 2/11/1936 4:48:00 AM 27.5 87 PAS 5.8 -

00041 5/27/1936 6:19:19 AM 28.5 83.5 Roger_bilham/PAS 7.0 West Nepal

00042 10/20/1937 1:23:43 AM 31 78 PAS 5.8 -

00043 11/15/1937 9:37:34 PM 35 78 PAS 6.5 -

00044 1/29/1938 4:13:08 AM 27.5 87 PAS 5.8 -

00045 9/3/1940 2:40:32 PM 31 91.5 PAS 5.8 -

00046 10/4/1940 4:35:52 AM 30 92 PAS 6.1 -

00047 1/21/1941 12:41:48 PM 27 92 Roger_bilham/PAS 6.8 Shillong

00048 8/1/1941 3:48:00 AM 33 85.25 PAS 5.8 -

00049 10/17/1944 6:36:54 PM 31.5 83.5 PAS 6.8 -

00050 10/29/1944 12:11:32 AM 31.5 83.5 PAS 6.8 -

00051 6/4/1945 12:09:06 PM 30.3 80 Roger_bilham/PAS 6.5 Uttaranchal

00052 6/00/1945 - 32.8 76.1 Roger_bilham 6.3 Chamba

00053 7/00/1947 - 28.8 93.7 Roger_bilham 7.3 Assam

00054 8/00/1950 - 28.7 96.6 Roger_bilham 8.5 Assam-Tibet

00055 11/18/1951 9:35:47 AM 30.5 91 PAS 8 -

00058 2/18/1964 4:35:14 PM 27.4 91.18 ISC 5.5 -

66


00059 3/27/1964 9:16:04 PM 27.13 89.36 ISC 5.3 -

00060 4/13/1964 1:56:55 AM 27.52 90.17 ISC 5.5 -

00061 4/15/1964 6:37:45 AM 21.6 88.07 ISC 5.5 -

00062 5/24/1964 11:18:36 AM 30.04 82.18 ISC 5.4 -

00063 9/26/1964 3:59:26 PM 29.96 80.46 ISC 6 -

00064 10/6/1964 8:40:17 PM 29.4 80.98 ISC 5.5 -

00067 10/25/1964 10:42:48 AM 27.9 88.6 ISC 5.1 -

00068 11/9/1964 3:23:39 PM 29.53 86.04 ISC 5.4 -

00070 12/20/1964 12:45:20 AM 29.35 81.1 ISC 5.5 -

00071 1/12/1965 5:26:10 AM 27.4 87.84 ISC 6 -

00074 4/20/1965 7:28:42 PM 33.86 82.1 ISC 6 -

00075 6/1/1965 12:09:32 AM 28.59 83.06 ISC 5.5 -

00076 6/14/1965 4:50:23 AM 32.09 87.62 ISC 5.6 -

00078 8/3/1965 2:12:04 PM 33.31 91.13 ISC 5.5 -

00080 11/14/1965 11:33:45 PM 34.5 80.2 USCGS 5.1 -

00083 2/24/1966 1:36:16 PM 26.35 91.44 ISC 5.1 -

00084 3/6/1966 6:17:07 PM 31.49 80.5 ISC 6.1 -

00085 3/17/1966 10:57:57 PM 31.6 82.76 ISC 5.1 -

00089 6/27/1966 5:41:19 PM 29.71 80.89 ISC 6.1 -

00090 6/27/1966 10:22:10 PM 29.62 80.83 ISC 6.1 -

00091 8/5/1966 3:03:00 AM 32.76 79.61 ISC 5.5 -

00093 8/15/1966 12:24:41 PM 28.67 78.93 ISC 5.8 -

00094 10/20/1966 5:05:32 PM 33.55 78.7 ISC 5.1 -

00095 11/5/1966 9:46:22 PM 28.22 83.87 ISC 5.2 -

00096 11/7/1966 2:27:13 AM 33.94 80.89 ISC 5.1 -

00098 1/30/1967 11:48:54 AM 25.4 90.54 ISC 5.1 -

00099 2/00/1967 - 33.6 75.3 Roger_bilham 5.6 Anantnang

00100 3/2/1967 4:29:44 PM 28.7 86.38 ISC 5.5 -

00103 9/6/1967 6:32:16 AM 24 91.9 ISC 5.2 -

00104 9/15/1967 11:13:06 AM 27.42 91.86 ISC 6 -

67


00106 11/14/1967 8:34:47 PM 24.05 91.61 ISC 5.2 -

00107 12/18/1967 1:15:38 AM 29.46 81.71 ISC 5.3 -

00108 12/30/1967 5:56:28 AM 31.67 86.73 ISC 5.3 -

00109 1/5/1968 10:37:19 AM 30.41 79.25 ISC 5.3 -

00111 2/11/1968 7:59:00 PM 34.15 78.7 ISC 5.4 -

00112 5/27/1968 12:39:50 AM 29.76 80.51 ISC 5.2 -

00113 5/31/1968 5:20:41 AM 29.91 79.92 ISC 5.3 -

00114 6/12/1968 10:01:31 AM 24.83 91.94 ISC 5.5 -

00115 8/18/1968 2:42:22 PM 26.42 90.62 ISC 5.4 -

00116 10/28/1968 7:23:12 PM 27.57 86.03 ISC 5.2 -

00117 12/27/1968 12:04:03 AM 24.12 91.61 ISC 5.4 -

00118 3/3/1969 4:44:53 AM 30.04 79.84 ISC 5.4 -

00119 3/5/1969 9:25:44 AM 29.46 81.02 ISC 5.3 -

00120 6/1/1969 2:06:34 PM 25.72 91.77 ISC 5.1 -

00121 6/22/1969 6:47:25 PM 30.5 79.4 ISC 5.5 -

00123 11/5/1969 4:09:06 AM 27.66 90.24 ISC 5.3 -

00124 11/11/1969 8:49:56 AM 26.6 91.8 ISC 5.3 -

00125 12/5/1969 1:30:47 PM 29.13 80.95 ISC 5.2 -

00127 2/12/1970 10:52:28 PM 29.24 81.57 ISC 5.5 -

00129 2/26/1970 8:14:09 AM 27.62 85.7 ISC 5.3 -

00131 7/21/1970 5:35:50 PM 27.94 84.81 ISC 5.1 -

00132 7/25/1970 10:16:40 PM 25.72 88.58 ISC 5.4 -

00134 8/28/1970 7:38:21 AM 24.78 91.55 ISC 5.2 -

00136 2/2/1971 5:00:02 PM 23.714 91.662 ISC 5.6 -

00137 5/3/1971 9:40:53 PM 30.79 84.328 ISC 5.5 -

00138 6/6/1971 2:21:43 AM 28.041 85.585 NEIS 5.2 -

00141 10/24/1971 4:24:15 PM 28.299 87.191 ISC 5.1 -

00142 10/29/1971 9:05:05 PM 34.132 86.436 ISC 5.2 -

00144 12/4/1971 6:26:46 AM 27.925 87.946 ISC 5.5 -

00145 2/4/1972 11:07:37 AM 30.345 84.469 ISC 5.4 -

68


00146 2/20/1972 3:48:27 PM 34.47 80.375 ISC 5.1 -

00147 3/15/1972 8:29:18 PM 30.526 84.432 ISC 5.4 -

00148 4/8/1972 1:10:08 AM 29.666 89.417 NEIS 5.1 -

00149 4/21/1972 5:50:59 AM 34.985 81.149 ISC 5.1 -

00150 4/28/1972 10:31:49 AM 31.337 84.922 ISC 5.3 -

00151 7/22/1972 3:12:40 PM 31.377 91.414 ISC 5.6 -

00152 8/17/1972 7:53:30 PM 30.747 78.421 ISC 5.5 -

00153 8/21/1972 12:34:21 AM 27.228 88.023 NEIS 5.4 -

00154 9/6/1972 5:15:11 AM 32.493 78.511 ISC 5.3 -

00157 1/2/1973 7:17:43 PM 31.173 88.085 ISC 5.4 -

00160 3/22/1973 9:20:14 AM 28.118 87.149 ISC 5.3 -

00163 8/1/1973 11:22:46 PM 29.589 89.168 ISC 5.2 -

00164 9/8/1973 4:03:36 AM 33.295 86.822 ISC 5.7 -

00166 10/16/1973 1:25:17 PM 28.358 82.989 ISC 5.3 -

00168 11/21/1973 10:46:58 PM 34.626 81.111 ISC 5.4 -

00170 2/24/1974 8:08:39 AM 30.965 78.469 ISC 5.2 -

00171 3/3/1974 12:49:30 PM 30.745 86.318 ISC 5.6 -

00175 3/24/1974 7:32:52 AM 27.664 86.003 ISC 5.6 -

00181 9/27/1974 11:37:55 AM 28.594 85.512 ISC 5.7 -

00182 10/13/1974 4:18:45 PM 34.761 87.227 ISC 5.4 -

00185 12/23/1974 6:21:17 AM 29.324 81.384 ISC 5.5 -

00189 1/19/1975 1:04:39 AM 32.385 78.496 ISC 6.3 -

00191 1/31/1975 10:26:20 AM 28.087 84.766 ISC 5.3 -

00194 4/24/1975 12:28:51 AM 27.438 87.044 ISC 5.2 -

00196 6/24/1975 9:50:32 AM 27.742 87.497 ISC 5.1 -

00199 8/27/1975 11:53:04 PM 34.797 80.432 ISC 5.1 -

00200 9/6/1975 4:33:54 AM 29.214 81.948 ISC 5.4 -

00201 9/8/1975 9:14:45 AM 31.587 84.726 ISC 5.2 -

00204 11/21/1975 11:17:16 PM 26.957 86.54 ISC 5.2 -

00205 11/26/1975 3:58:07 AM 28.148 87.801 ISC 5.3 -

69


00206 12/28/1975 8:38:57 AM 32.147 87.671 ISC 5.2 -

00210 5/10/1976 3:22:19 AM 29.327 81.458 ISC 5.5 -

00212 6/23/1976 12:44:00 PM 21.18 88.621 ISC 5.3 -

00213 7/12/1976 5:24:51 PM 34.254 85.629 ISC 5.1 -

00215 7/23/1976 2:46:32 AM 31.722 83.683 ISC 5.1 -

00218 9/14/1976 4:49:03 PM 29.808 89.568 ISC 5.6 -

00219 10/23/1976 9:29:54 PM 28.63 86.238 NEIS 5.4 -

00220 1/6/1977 2:10:44 AM 31.246 87.979 ISC 5.3 -

00223 2/19/1977 4:13:16 PM 34.628 81.291 ISC 5.4 -

00224 2/19/1977 8:54:06 PM 31.797 78.432 ISC 5.6 -

00225 3/16/1977 1:34:57 AM 31.303 89.378 ISC 5.3 -

00226 3/27/1977 6:15:47 AM 32.672 78.661 ISC 5.4 -

00227 4/20/1977 10:56:38 AM 30.489 79.451 ISC 5.2 -

00231 11/4/1977 5:40:00 AM 29.504 81.3 ISC 5.1 -

00232 11/18/1977 10:20:50 AM 32.648 88.389 ISC 5.9 -

00237 2/10/1978 9:45:03 AM 28.033 84.698 ISC 5.5 -

00241 4/4/1978 4:28:25 AM 32.983 82.255 ISC 5.7 -

00245 8/8/1978 11:11:47 PM 32.268 83.1 ISC 5.4 -

00247 8/15/1978 8:33:28 AM 31.321 84.664 ISC 5.1 -

00251 10/4/1978 3:16:50 AM 27.822 85.935 ISC 5.5 -

00252 10/14/1978 7:57:40 AM 27.656 87.328 ISC 5.1 -

00254 11/30/1978 5:19:21 PM 32.718 85.67 ISC 5.2 -

00255 12/7/1978 10:00:12 PM 32.685 85.967 ISC 5.2 -

00261 1/28/1979 2:05:15 AM 24.874 91.02 ISC 5.2 -

00271 5/20/1979 12:53:40 AM 29.932 80.27 ISC 5.9 -

00274 6/19/1979 2:56:11 PM 26.742 87.482 ISC 5.5 -

00285 12/28/1979 6:25:27 PM 30.821 78.575 ISC 5.3 -

00288 2/20/1980 8:27:58 AM 32.89 90.225 ISC 5.1 -

00289 2/22/1980 1:08:49 PM 30.552 88.646 ISC 5.9 -

00291 3/13/1980 10:30:30 PM 34.29 87.822 ISC 5.2 -

70


00292 6/11/1980 3:11:20 AM 25.794 90.311 ISC 5.2 -

00293 6/22/1980 7:52:11 AM 30.133 81.765 ISC 5.4 -

00294 6/24/1980 12:33:01 PM 32.996 88.548 ISC 5.4 -

00295 7/29/1980 5:13:52 PM 29.629 81.091 Roger_bilham/ISC 6.5 W. Nepal

00299 10/8/1980 11:57:14 AM 31.426 87.718 ISC 5.3 -

00301 11/18/1980 9:18:55 PM 29.55 85.179 ISC 5.3 -

00302 11/19/1980 1:59:45 AM 27.402 88.797 ISC 6.1 -

00308 2/9/1981 6:04:48 AM 27.199 89.761 ISC 5.2 -

00309 3/19/1981 10:45:39 AM 26.293 90.475 ISC 5.1 -

00310 3/26/1981 3:26:29 PM 22.347 89.076 ISC 5.2 -

00312 5/13/1981 12:48:10 AM 32.578 82.358 ISC 5.3 -

00313 5/15/1981 5:29:01 AM 29.464 81.926 ISC 5.4 -

00314 5/28/1981 10:09:51 AM 31.829 78.436 ISC 5.5 -

00315 6/9/1981 2:50:42 PM 34.514 91.424 ISC 5.5 -

00321 8/31/1981 6:55:45 PM 34.601 78.989 ISC 5.1 -

00325 11/21/1981 1:39:07 PM 29.526 89.117 ISC 5.1 -

00327 1/22/1982 11:00:48 PM 30.891 89.867 ISC 5.5 -

00329 1/23/1982 8:22:29 AM 31.675 82.284 ISC 6.1 -

00338 7/6/1982 2:30:03 AM 25.881 90.31 ISC 5.3 -

00342 8/31/1982 9:13:25 PM 25.385 91.46 ISC 5.3 -

00351 11/18/1982 3:21:00 PM 26.376 91.753 ISC 5.1 -

00357 12/30/1982 7:26:03 PM 26.009 91.691 ISC 5.2 -

00358 1/27/1983 12:06:53 AM 29.042 81.343 ISC 5.2 -

00361 2/27/1983 2:09:25 PM 32.602 78.568 ISC 5.5 -

00364 5/31/1983 4:11:56 AM 34.593 79.665 ISC 5.3 -

00372 11/5/1983 5:38:40 PM 33.92 89.945 ISC 5.4 -

00381 2/19/1984 11:46:15 AM 29.843 80.544 ISC 5.4 -

00382 3/14/1984 4:27:05 PM 29.178 81.12 ISC 5.3 -

00383 3/14/1984 9:07:56 PM 34.23 79.631 ISC 5.4 -

00385 4/11/1984 6:29:37 AM 34.759 79.671 ISC 5.1 -

71


00386 4/15/1984 11:10:27 AM 31.747 82.244 ISC 5.3 -

00388 4/27/1984 8:32:08 PM 33.676 89.45 NEIS 5.2 -

00390 5/18/1984 5:53:49 AM 29.52 81.793 ISC 5.8 -

00391 5/21/1984 10:34:40 AM 23.657 91.508 ISC 5.5 -

00395 8/6/1984 5:18:02 AM 32.141 88.019 ISC 5.1 -

00398 9/30/1984 7:20:33 PM 25.436 91.507 ISC 5.3 -

00402 11/18/1984 2:03:55 PM 28.674 83.319 ISC 5.6 -

00407 1/7/1985 1:28:08 PM 27.14 91.958 ISC 5.6 -

00409 1/30/1985 10:49:49 PM 30.916 85.441 ISC 5.1 -

00411 2/15/1985 8:11:30 AM 34.352 82.493 ISC 5.2 -

00417 6/15/1985 12:16:33 PM 34.634 82.994 ISC 5.6 -

00434 12/25/1985 7:50:51 PM 32.13 89.712 ISC 5.1 -

00435 1/6/1986 12:31:42 AM 27.853 85.322 ISC 5.1 -

00437 1/10/1986 9:53:23 AM 28.653 86.563 ISC 5.7 -

00442 2/19/1986 9:17:35 AM 25.104 91.13 ISC 5.5 -

00444 3/2/1986 6:39:16 PM 32.424 89.289 ISC 5.1 -

00450 4/13/1986 10:44:19 PM 32.628 85.302 ISC 5.2 -

00453 6/20/1986 12:46:51 PM 31.216 86.824 ISC 6 -

00457 7/6/1986 7:30:13 AM 34.446 80.197 ISC 5.9 -

00459 7/16/1986 4:51:54 PM 31.051 78.002 ISC 5.8 -

00461 7/28/1986 2:13:35 AM 33.554 87.889 ISC 5.1 -

00462 8/20/1986 6:54:25 AM 34.565 91.642 ISC 5.7 -

00466 9/9/1986 1:37:47 AM 31.54 85.046 ISC 5.6 -

00467 9/11/1986 6:18:38 AM 32.563 78.491 ISC 5.1 -

00470 1/19/1987 8:21:09 PM 28.196 83.6 ISC 5.5 -

00475 4/18/1987 7:45:22 PM 22.528 79.241 ISC 5.1 -

00479 6/6/1987 2:28:44 PM 30.362 79.117 ISC 5.2 -

00482 8/9/1987 4:31:15 AM 29.466 83.739 ISC 5.7 -

00486 9/25/1987 11:14:37 PM 29.841 90.367 ISC 5.4 -

00487 9/27/1987 3:55:28 AM 34.139 80.659 ISC 5.1 -

72


00490 11/3/1987 5:57:59 PM 33.129 86.853 ISC 5.2 -

00496 2/6/1988 10:03:02 PM 24.668 91.562 ISC 6 -

00507 5/15/1988 1:32:18 AM 29.76 80.435 ISC 5.2 -

00509 5/30/1988 10:53:59 AM 33.422 88.598 ISC 5.1 -

00511 6/12/1988 8:15:40 PM 28.7 82.424 ISC 5.1 -

00515 7/5/1988 2:59:02 PM 28.114 91.242 ISC 5.1 -

00519 8/20/1988 9:42:24 AM 26.72 86.626 ISC 6.4 -

00525 9/27/1988 1:47:27 PM 27.192 88.367 ISC 5.3 -

00528 10/29/1988 3:49:58 AM 27.866 85.638 ISC 5.7 -

00530 11/5/1988 1:11:39 PM 34.352 91.846 ISC 6 -

00536 12/20/1988 5:16:42 PM 27.66 91.121 ISC 5.2 -

00539 2/3/1989 7:19:14 AM 30.187 89.944 ISC 5.6 -

00544 4/9/1989 6:43:26 AM 29.113 90.022 ISC 5.4 -

00548 5/22/1989 1:26:48 AM 27.381 87.858 ISC 5.3 -

00550 6/12/1989 10:48:29 AM 21.834 89.775 ISC 5.9 -

00556 1/9/1990 2:53:32 PM 28.154 88.109 ISC 5.9 -

00561 2/22/1990 2:17:45 PM 29.14 90.021 ISC 5.2 -

00571 5/20/1990 1:06:10 PM 28.449 83.224 ISC 5.1 -

00578 9/21/1990 9:52:03 PM 29.985 79.907 ISC 5.4 -

00581 10/14/1990 11:54:35 AM 30.802 86.364 ISC 5.1 -

00583 12/20/1990 9:16:16 PM 28.158 82.879 ISC 5.2 -

00585 2/2/1991 6:37:57 AM 25.508 91.171 ISC 5.3 -

00602 5/27/1991 2:12:15 PM 29.495 80.28 ISC 5.2 -

00613 9/26/1991 5:41:31 PM 25.591 90.267 ISC 5.1 -

00616 10/19/1991 7:44:02 AM 30.77 78.791 Roger bilham/ISC 6.8 Uttarkashi

00619 12/9/1991 9:46:34 PM 29.512 81.611 ISC 5.8 -

00621 12/23/1991 7:08:15 AM 33.898 88.887 ISC 5.5 -

00632 4/4/1992 10:37:30 AM 28.12 87.962 ISC 5.2 -

00644 6/2/1992 6:47:36 PM 28.938 81.904 ISC 5.5 -

00648 7/9/1992 1:30:58 PM 21.046 90.024 ISC 5.5 -

73


00650 7/30/1992 10:52:39 PM 29.566 90.18 ISC 6 -

00655 8/24/1992 10:16:52 PM 34.679 80.177 ISC 5.2 -

00661 12/12/1992 2:21:55 AM 25.475 91.388 ISC 5.3 -

00662 12/22/1992 7:02:45 AM 34.548 88.056 ISC 5.3 -

00663 1/2/1993 11:43:36 AM 29.153 81.127 ISC 5.1 -

00668 1/18/1993 11:07:48 AM 30.844 90.378 ISC 5.9 -

00670 2/15/1993 8:29:29 PM 25.892 87.511 ISC 5.2 -

00675 3/20/1993 7:53:42 PM 29.027 87.328 ISC 5.9 -

00688 7/6/1993 8:44:38 AM 31.985 82.277 ISC 5.1 -

00698 10/20/1993 7:33:03 AM 28.691 82.246 ISC 5.4 -

00716 7/17/1994 7:48:12 PM 29.279 81.37 ISC 5.2 -

00717 7/23/1994 12:29:03 AM 31.097 86.601 ISC 5.3 -

00729 12/8/1994 8:39:09 AM 30.665 79.619 ISC 5.1 -

00758 7/30/1995 12:23:33 AM 30.246 88.21 ISC 5.1 -

00770 10/21/1995 8:33:39 AM 31.386 78.96 NEIC 5.2 -

00791 1/26/1996 10:51:20 AM 30.875 91.509 ISC 5.3 -

00805 4/26/1996 4:23:07 AM 27.835 87.8 ISC 5.3 -

00816 7/3/1996 7:52:22 AM 30.106 88.191 ISC 5.8 -

00833 9/25/1996 3:26:41 PM 27.602 88.804 ISC 5.2 -

00857 12/30/1996 7:46:53 AM 27.495 86.769 ISC 5.1 -

00859 1/5/1997 5:08:34 PM 29.874 80.565 ISC 5.6 -

00862 1/12/1997 7:11:05 AM 26.53 91.25 BJI 5.1 -

00867 1/31/1997 6:35:18 AM 27.989 85.205 ISC 5.5 -

00884 5/15/1997 2:09:36 PM 34.261 89.867 ISC 5.1 -

00885 5/21/1997 6:50:27 PM 23.091 80.082 ISC 6 -

00897 7/18/1997 3:00:33 AM 26.826 91.797 ISC 5.2 -

00918 10/30/1997 5:18:13 AM 29.542 89.727 ISC 5.4 -

00919 11/3/1997 9:59:04 AM 29.036 85.392 ISC 5.6 -

00922 11/9/1997 12:01:35 AM 33.713 88.344 ISC 5.4 -

00936 11/27/1997 5:33:22 PM 27.56 87.308 ISC 5.3 -

74


00952 2/22/1998 8:26:50 PM 28.497 85.513 ISC 5.1 -

00982 6/27/1998 4:52:05 PM 27.683 85.688 ISC 5.1 -

00983 7/8/1998 9:32:56 PM 27.322 91.065 ISC 5.4 -

00985 7/20/1998 6:54:37 AM 30.175 88.245 ISC 5.5 -

00995 9/3/1998 5:43:02 AM 27.863 86.95 ISC 5.8 -

01014 11/26/1998 10:39:01 PM 27.692 87.86 ISC 5.4 -

01027 3/28/1999 11:29:58 AM 30.511 79.421 Roger bilham/ISC 6.4 Chamoli

01050 7/22/1999 11:09:19 PM 21.617 91.896 ISC 5.5 -

01051 8/1/1999 3:50:10 AM 28.369 86.789 NEIC 5.5 -

01055 8/28/1999 10:33:32 PM 22.915 89.795 NDI 5.2 -

01057 9/5/1999 7:55:13 AM 28.067 87.527 NDI 5.2 -

01061 9/20/1999 2:38:35 AM 27.241 87.978 NDI 5.3 -

01064 10/5/1999 4:41:06 PM 26.26 91.926 NDI 5.5 -

01106 6/17/2000 9:16:27 PM 32 78.408 ISC 5.1 -

01144 3/5/2001 7:08:26 AM 34.258 86.86 ISC 5.5 -

01164 4/28/2001 4:45:16 AM 28.766 87.131 ISC 5.5 -

01184 7/16/2001 2:22:06 AM 28.148 84.872 ISC 5.3 -

01186 7/26/2001 11:43:47 AM 21.327 79.671 DMN 5.3 -

01200 11/6/2001 5:15:34 AM 34.13 79.716 ISC 5.1 -

01201 11/6/2001 9:56:25 AM 27.393 91.966 ISC 5.4 -

01205 11/27/2001 4:39:47 AM 29.691 81.716 ISC 5.7 -

01207 12/2/2001 2:01:28 PM 27.218 88.179 ISC 5.3 -

01226 3/6/2002 6:57:27 AM 22.345 79.212 DMN 5.2 -

01257 6/4/2002 8:03:33 AM 30.566 81.42 ISC 5.6 -

01278 8/31/2002 10:21:13 AM 29.878 88.055 ISC 5.3 -

01316 1/16/2003 8:13:12 PM 29.959 88.109 ISC 5.3 -

01334 3/25/2003 8:28:21 AM 27.256 89.379 ISC 5.1 -

01347 5/27/2003 9:19:18 PM 30.556 79.337 ISC 5.3 -

01360 7/7/2003 10:10:14 AM 34.589 89.503 ISC 5.5 -

01406 2/10/2004 9:28:57 AM 32.614 83.262 ISC 5.1 -

75


01418 3/6/2004 5:39:03 PM 33.243 91.925 ISC 5.3 -

01419 3/7/2004 10:19:54 PM 31.65 91.221 ISC 5.5 -

01423 3/27/2004 5:03:16 PM 33.989 89.182 ISC 6.1 -

01478 10/26/2004 10:29:33 AM 31.036 81.082 ISC 6 -

01499 2/8/2005 12:47:14 PM 27.711 86.051 ISC 5.1 -

01505 3/26/2005 4:52:17 PM 28.194 87.861 ISC 5.1 -

01510 4/7/2005 4:16:29 PM 30.517 83.655 ISC 6 -

01538 8/20/2005 3:20:03 AM 31.277 88.086 ISC 5.3 -

01556 10/31/2005 3:35:12 PM 29.719 81.752 ISC 5.1 -

01557 10/31/2005 8:16:03 PM 28.496 84.901 ISC 5.3 -

01566 12/14/2005 2:23:37 PM 30.515 79.25 ISC 5.5 -

01577 2/3/2006 5:52:53 PM 27.289 86.397 ISC 5.1 -

01580 2/14/2006 7:55:24 AM 27.387 88.417 ISC 5.5 -

01582 2/15/2006 5:17:05 PM 33.661 81.329 ISC 5.1 -

01585 2/23/2006 7:19:37 AM 26.958 91.712 ISC 5.6 -

01596 4/19/2006 10:48:52 AM 31.586 90.446 ISC 5.4 -

01597 5/5/2006 3:29:43 PM 29.48 80.906 ISC 5.1 -

01609 7/9/2006 11:39:49 PM 32.372 86.661 NDI 5.1 -

01650 2/25/2007 11:34:19 PM 33.152 90.614 ISC 5.3 -

01667 5/5/2007 7:08:38 AM 34.269 82.034 ISC 5.9 -

01672 5/20/2007 6:32:50 AM 27.334 88.27 ISC 5.2 -

01688 7/22/2007 9:26:18 AM 30.87 78.288 ISC 5.3 -

01698 8/11/2007 8:14:43 AM 27.388 87.733 ISC 5.2 -

01735 1/9/2008 1:25:52 PM 32.404 85.255 ISC 6.3 -

01788 7/26/2008 9:30:28 PM 24.743 90.513 ISC 5.1 -

01792 8/5/2008 4:13:50 PM 33.18 91.995 ISC 5.3 -

01801 8/25/2008 10:21:25 AM 30.628 83.358 ISC 5.1 -

01802 8/25/2008 3:02:15 PM 31.061 83.652 ISC 6.1 -

01808 9/4/2008 7:07:18 PM 30.242 80.382 ISC 5.3 -

01817 10/6/2008 1:14:53 PM 29.845 90.379 ISC 6.1 -

76


01841 12/8/2008 5:35:05 AM 29.99 82.085 ISC 5.5 -

01875 4/1/2009 8:43:42 PM 33.685 82.459 ISC 5.3 -

01897 6/4/2009 3:42:13 AM 32.766 81.672 ISC 5.3 -

01908 7/24/2009 7:11:28 AM 31.169 85.963 ISC 6 -

01923 9/21/2009 5:24:06 AM 27.369 91.46 ISC 6.1 -

01932 10/25/2009 11:31:40 PM 34.878 80.349 ISC 5.2 -

01939 11/7/2009 8:17:34 AM 29.539 86.045 ISC 5.8 -

01955 12/13/2009 11:11:02 AM 22.018 91.774 ISC 5.4 -

01968 2/26/2010 12:01:58 AM 28.507 86.776 ISC 5.7 -

01973 3/15/2010 11:26:11 PM 30.543 81.919 ISC 5.1 -

01975 3/18/2010 8:47:52 AM 34.343 81.679 ISC 5.1 -

02020 10/7/2010 3:25:44 AM 33.565 90.845 ISC 5.1 -

02025 10/17/2010 2:49:57 AM 28.602 85.679 ISC 5.2 -

02035 11/30/2010 1:38:22 AM 29.797 90.317 ISC 5.6 -

02042 12/29/2010 10:24:15 AM 30.875 86.517 ISC 5.5 -

02070 3/18/2011 9:27:49 PM 31.209 81.337 DMN 5.2 -

02078 4/4/2011 10:54:33 AM 29.698 80.754 NEIC 5.8 -

02080 4/9/2011 8:16:14 PM 32.099 81.988 DMN 5.5 -

02086 4/19/2011 12:21:17 AM 34.29 89.58 NEIC 5.3 -

02104 6/20/2011 12:36:26 PM 30.61 79.338 NEIC 5.2 -

02109 6/23/2011 12:00:39 PM 23.76 91.03 BKK 5.1 -

02117 8/1/2011 1:27:23 AM 33.739 87.574 NEIC 5.4 -

02131 9/18/2011 6:59:10 PM 27.73 88.155 NEIC 6.9

Sikkim - Nepal

Border

02147 11/19/2011 9:52:38 PM 31.301 90.761 DMN 5.1 -

02150 12/1/2011 11:55:09 AM 31.841 83.812 NEIC 5.4 -

02152 12/22/2011 9:16:50 PM 31.92 86.322 NEIC 5.1 -

02153 12/24/2011 1:57:41 AM 32.458 81.953 DMN 5.5 -

02155 12/28/2011 11:19:22 AM 31.188 79.59 DMN 5.5 -

02168 2/9/2012 12:10:18 AM 30.979 78.323 NEIC 5.4 -

77


02171 2/17/2012 2:12:50 PM 32.373 82.833 NEIC 5.5 -

02176 3/7/2012 1:37:02 PM 34.23 81.99 GFZ 5.1 -

02184 3/27/2012 3:03:46 AM 26.086 87.761 NEIC 5.3 -

02187 3/29/2012 5:06:18 PM 29.31 85.67 BKK 5.5 -

02199 4/30/2012 1:16:24 AM 24.81 89.032 DMN 5.5 -

02207 5/27/2012 2:43:08 PM 30.799 83.47 MOS 5.1 -

02214 6/9/2012 11:29:01 PM 28.4 84.126 NEIC 5.1 -

02219 7/3/2012 10:53:14 PM 29.914 88.011 NEIC 5.2 -

02225 7/22/2012 2:58:17 AM 29.951 88.041 NEIC 5.2 -

02232 8/23/2012 11:44:10 AM 28.47 82.69 NEIC 5.3 -

02245 10/8/2012 12:35:07 AM 31.832 78.444 NEIC 5.2 -

02250 10/18/2012 11:59:19 PM 23.84 81.24 GFZ 5.3 -

02273 12/27/2012 11:38:41 AM 31.953 81.902 DMN 5.2 -

BKK Thai Meteorological Department (THAILAND)

DMN Department of Mines and Geology, Ministry of Industry of Nepal (NEPAL)

GFZ Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences (Germany)

ISC International Seismological Centre (UNITED KINGDOM)

MOS Geophysical Survey of Russian Academy of Sciences (RUSSIA)

NDI India Meteorological Department (INDIA)

NEIC National Earthquake Information Center (U.S.A)

NEIS National Earthquake Information Service (U.S.A)

PAS California Institute of Technology (U.S.A)

USCGS United States Coast and Geodetic Survey (U.S.A)

78

11.0 ANNEX – 2

Coordinates PGA (gal) Site Condition Remarks

X = 85.41969, Y = 27.41038 508 Rock Maximum PGA in the Valley

X = 85.5462, Y = 27.78348 425 Rock Minimum PGA in the Valley

X = 85.34357, Y = 27.51438 451 Rock

X = 85.2578, Y = 27.70843 435 Rock

X = 85.44327, Y = 27.69771 430 Rock

X = 85.4154, Y = 27.41038 730 Soil Maximum PGA in the Valley

X = 85.56228, Y = 27.76632 620 Soil Minimum PGA in the Valley

X = 85.34357, Y = 27.51223 702 Soil

X = 85.42612, Y = 27.7213 635 Soil

X = 85.25672, Y = 27.69128 643 Soil

Table 11.1: Different PGA for both rock and soil site condition of the Kathmandu valley.

Intensity (gal) versus Exceedance rate for different coordinates stated above for both rock and soil site condition is given in below tables.

79

X=85.41969, Y=27.41038 (Rock site condition)

Intensity (gal) Exceedance rate (1/year for intensity at 0 sec)

1.00E+00 1.21E+00

1.49E+00 1.03E+00

2.23E+00 8.66E-01

3.32E+00 7.09E-01

4.95E+00 5.66E-01

7.39E+00 4.40E-01

1.10E+01 3.33E-01

1.65E+01 2.44E-01

2.45E+01 1.73E-01

3.66E+01 1.18E-01

5.46E+01 7.70E-02

8.15E+01 4.77E-02

1.22E+02 2.79E-02

1.81E+02 1.52E-02

2.71E+02 7.56E-03

4.04E+02 3.40E-03

6.02E+02 1.35E-03

8.99E+02 4.54E-04

1.34E+03 1.21E-04

2.00E+03 2.09E-05

Table 11.2: Intensity (gal) versus Exceedance rate for coordinates X=85.41969, Y=27.41038

80

X=85.5462, Y=27.78348 (Rock site condition)


1.00E+00 1.21E+00

1.49E+00 1.03E+00

2.23E+00 8.62E-01

3.32E+00 7.03E-01

4.95E+00 5.59E-01

7.39E+00 4.33E-01

1.10E+01 3.25E-01

1.65E+01 2.36E-01

2.45E+01 1.65E-01

3.66E+01 1.11E-01

5.46E+01 7.04E-02

8.15E+01 4.23E-02

1.22E+02 2.36E-02

1.81E+02 1.22E-02

2.71E+02 5.66E-03

4.04E+02 2.33E-03

6.02E+02 8.17E-04

8.99E+02 2.30E-04

1.34E+03 4.35E-05

2.00E+03 3.49E-06

Table 11.3: Intensity (gal) versus Exceedance rate for coordinates X=85.5462, Y=27.78348.

81

X = 85.34357, Y = 27.51438 (Rock site condition)


1.00E+00 1.21E+00

1.49E+00 1.03E+00

2.23E+00 8.64E-01

3.32E+00 7.06E-01

4.95E+00 5.63E-01

7.39E+00 4.39E-01

1.10E+01 3.32E-01

1.65E+01 2.44E-01

2.45E+01 1.73E-01

3.66E+01 1.18E-01

5.46E+01 7.70E-02

8.15E+01 4.76E-02

1.22E+02 2.76E-02

1.81E+02 1.49E-02

2.71E+02 7.33E-03

4.04E+02 3.24E-03

6.02E+02 1.26E-03

8.99E+02 4.09E-04

1.34E+03 1.03E-04

2.00E+03 1.56E-05

Table 11.4: Intensity (gal) versus Exceedance rate for coordinates X = 85.34357, Y = 27.51438.

82



1.00E+00 1.20E+00

1.49E+00 1.02E+00

2.23E+00 8.52E-01

3.32E+00 6.93E-01

4.95E+00 5.51E-01

7.39E+00 4.27E-01

1.10E+01 3.23E-01

1.65E+01 2.37E-01

2.45E+01 1.68E-01

3.66E+01 1.15E-01

5.46E+01 7.48E-02

8.15E+01 4.61E-02

1.22E+02 2.66E-02

1.81E+02 1.41E-02

2.71E+02 6.82E-03

4.04E+02 2.92E-03

6.02E+02 1.08E-03

8.99E+02 3.28E-04

1.34E+03 7.25E-05

2.00E+03 7.78E-06


83



1.00E+00 1.21E+00

1.49E+00 1.04E+00

2.23E+00 8.67E-01

3.32E+00 7.09E-01

4.95E+00 5.66E-01

7.39E+00 4.41E-01

1.10E+01 3.34E-01

1.65E+01 2.45E-01

2.45E+01 1.73E-01

3.66E+01 1.17E-01

5.46E+01 7.54E-02

8.15E+01 4.58E-02

1.22E+02 2.60E-02

1.81E+02 1.36E-02

2.71E+02 6.42E-03

4.04E+02 2.70E-03

6.02E+02 9.78E-04

8.99E+02 2.89E-04

1.34E+03 6.08E-05

2.00E+03 5.89E-06


84

X = 85.4154, Y = 27.41038 (Soil site condition)


1.00E+00 1.36E+00

1.49E+00 1.19E+00

2.23E+00 1.02E+00

3.32E+00 8.52E-01

4.95E+00 6.96E-01

7.39E+00 5.54E-01

1.10E+01 4.30E-01

1.65E+01 3.25E-01

2.45E+01 2.38E-01

3.66E+01 1.68E-01

5.46E+01 1.14E-01

8.15E+01 7.41E-02

1.22E+02 4.57E-02

1.81E+02 2.65E-02

2.71E+02 1.43E-02

4.04E+02 7.08E-03

6.02E+02 3.15E-03

8.99E+02 1.23E-03

1.34E+03 4.07E-04

2.00E+03 1.06E-04


85



1.00E+00 1.36E+00

1.49E+00 1.19E+00

2.23E+00 1.02E+00

3.32E+00 8.51E-01

4.95E+00 6.93E-01

7.39E+00 5.51E-01

1.10E+01 4.26E-01

1.65E+01 3.20E-01

2.45E+01 2.32E-01

3.66E+01 1.62E-01

5.46E+01 1.08E-01

8.15E+01 6.86E-02

1.22E+02 4.09E-02

1.81E+02 2.27E-02

2.71E+02 1.16E-02

4.04E+02 5.34E-03

6.02E+02 2.17E-03

8.99E+02 7.49E-04

1.34E+03 2.06E-04

2.00E+03 3.74E-05


86



1.00E+00 1.36E+00

1.49E+00 1.19E+00

2.23E+00 1.02E+00

3.32E+00 8.49E-01

4.95E+00 6.93E-01

7.39E+00 5.51E-01

1.10E+01 4.28E-01

1.65E+01 3.24E-01

2.45E+01 2.37E-01

3.66E+01 1.68E-01

5.46E+01 1.14E-01

8.15E+01 7.39E-02

1.22E+02 4.54E-02

1.81E+02 2.62E-02

2.71E+02 1.40E-02

4.04E+02 6.86E-03

6.02E+02 3.00E-03

8.99E+02 1.15E-03

1.34E+03 3.68E-04

2.00E+03 9.01E-05


87



1.00E+00 1.36E+00

1.49E+00 1.19E+00

2.23E+00 1.02E+00

3.32E+00 8.48E-01

4.95E+00 6.91E-01

7.39E+00 5.49E-01

1.10E+01 4.26E-01

1.65E+01 3.21E-01

2.45E+01 2.34E-01

3.66E+01 1.65E-01

5.46E+01 1.11E-01

8.15E+01 7.10E-02

1.22E+02 4.29E-02

1.81E+02 2.42E-02

2.71E+02 1.25E-02

4.04E+02 5.89E-03

6.02E+02 2.44E-03

8.99E+02 8.70E-04

1.34E+03 2.50E-04

2.00E+03 4.97E-05


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1.00E+00 1.36E+00

1.49E+00 1.18E+00

2.23E+00 1.01E+00

3.32E+00 8.38E-01

4.95E+00 6.81E-01

7.39E+00 5.40E-01

1.10E+01 4.18E-01

1.65E+01 3.16E-01

2.45E+01 2.31E-01

3.66E+01 1.64E-01

5.46E+01 1.11E-01

8.15E+01 7.22E-02

1.22E+02 4.43E-02

1.81E+02 2.54E-02

2.71E+02 1.34E-02

4.04E+02 6.43E-03

6.02E+02 2.73E-03

8.99E+02 1.00E-03

1.34E+03 3.00E-04

2.00E+03 6.48E-05


89

Fig: Geological cross section through the Nepal Himalaya at the true scale (after Upreti, 1999). MFT: Main Frontal Thrust, MBT:

Main Boundary Thrust, MCT: Main Central Thrust, STDS: South Tibetan Detachment System. Legend: 1. Tibetan-Tethys sequence, 2.

Higher Himalayan Sequence 3. Lesser Himalayan Sequence, 4. Higher Himalayan leucogranites, 5. Lesser Himalaya (Paleozoic), 6.

Siwalik, 7. Gangetic plain.

Probabilistic Seismic Hazard Analysis of Kathmandu Valley

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