Post on 30-Oct-2014
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Reservoir Induced
Seismicity
Induced Seismicity
Many human activities are known to induce or increase seismic activity (Simpson,1986): Fluid injection for various purposes:
waste disposal,
solution mining,
geothermal power generation, and
secondary oil recovery;
Deep underground mining;
Removal of large volumes of rock during quarrying;
Fluid extraction in petroleum production; and
Impoundment of large reservoirs behind high dams (Simpson, 1986).
A dam is a structure which prevents the flow of
water and accumulates it in a reservoir
Impoundment facility
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Needs for Dam Construction
1. Drinking and domestic water supply
2. Flood control
3. Irrigation
4. Industrial water supply
5. Hydroelectric energy production
6. Retention and control of sediments
and Inland navigation, Improvement of water quality, Fish Farming, Recreation facilities
REGION THEORETICAL
POTENTIAL (TWh)
TECHNICAL
POTENTIAL (TWh)
AFRICA 10118 3140
N. AMERICA 6150 3120
LATIN AMERICA 5670 3780
ASIA 20486 7530
OCEANIA 1500 390
EUROPE 4360 1430
WORLD 44280 19390
Continent Wide distribution
COUNTRY POWER
CAPACITY (GWh)
INSTALLED
CAPACITY (GW)
TAJIKISTAN 527000 4000
CANADA 341312 66954
USA 319484 79511
BRAZIL 285603 57517
CHINA 204300 65000
RUSSIA 160500 44000
NORWAY 121824 27528
JAPAN 84500 27229
INDIA 82237 22083
FRANCE 77500 77500
Top ten countries (in terms of capacity) The Indian Scenario
The potential is about 84000 MW at 60% load factor spread across six major basins in the country.
Pumped storage sites have been found recently which leads to a further addition of a maximum of 94000 MW.
Annual yield is assessed to be about 420 billion units per year though with seasonal energy the value crosses 600 billion mark.
The possible installed capacity is around 150000 MW
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The proportion of hydro power increased from 35%
from the first five year plan to 46% in the third five
year plan but has since then decreased continuously to
25% in 2001.
The theoretical potential of small hydro power is 10071
MW.
Currently about 17% of the potential is being
harnessed
About 6.3% is still under construction.
India’s Basin wise potential
Rivers Potential at 60%LF
(MW)
Probable installed
capacity (MW)
Indus 19988 33832
Ganga 10715 20711
Central Indian
rivers
2740 4152
West flowing 6149 9430
East flowing 9532 14511
Brahmaputra 34920 66065
Total 84044 148701
Region wise status of hydro development
REGION POTENTIAL
ASSESSED
(60% LF)
POTENTIAL
DEVELOPED
(MW)
%
DEVELOPED
UNDER
DEVELOPMENT
NORTH 30155 4591 15.2 2514
WEST 5679 1858 32.7 1501
SOUTH 10763 5797 53.9 632
EAST 5590 1369 24.5 339
NORTH
EAST
31857 389 1.2 310
INDIA 84044 14003 16.7 5294
Major Hydropower generating units
NAME STATA CAPACITY (MW)
BHAKRA PUNJAB 1100
NAGARJUNA ANDHRA PRADESH 960
KOYNA MAHARASHTRA 920
DEHAR HIMACHAL
PRADESH
990
SHARAVATHY KARNATAKA 891
KALINADI KARNATAKA 810
SRISAILAM ANDHRA PRADESH 770
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Installed Capacity
REGION HYDRO THERMAL WIND NUCLEAR TOTAL
NORTH 8331.57 17806.99 4.25 1320 27462.81
WEST 4307.13 25653.98 346.59 760 31067.7
SOUTH 9369.64 14116.78 917.53 780 25183.95
EAST 2453.51 13614.58 1.10 0 16069.19
N.EAST 679.93 1122.32 0.16 0 1802.41
INDIA 25141.78 72358.67 1269.63 2860 101630.08
Region wise contribution of Hydropower
REGION PERCENTAGE
NORTH 30.34
WEST 13.86
SOUTH 37.2
EAST 15.27
NORTH-EAST 37.72
INDIA 24.74
Small Hydro in India
STATE TOTAL CAPACITY (MW)
ARUNACHAL PRADESH 1059.03
HIMACHAL PRADESH 1624.78
UTTAR PRADESH &
UTTARANCHAL
1472.93
JAMMU & KASHMIR 1207.27
KARNATAKA 652.51
MAHARASHTRA 599.47
Sites (up to 3 MW) identified by UNDP
STATE TOTAL
SITES
CAPACITY
NORTH 562 370
EAST 164 175
NORTH EAST 640 465
TOTAL 1366 1010
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Hydroelectric Power Plants in India
Baspa II Binwa Gaj Nathpa Jakri
Rangit Sardar Sarovar
ACCORDING to the SIZE of the DAM
1. Large (Big) dam
2. Small dam
International Commision on Large Dams, (ICOLD) assumes a dam as big when its height is bigger than 15m.
If the height of the dam is between 10m and 15m and matches the following criteria, then ICOLD accepts the dam as big:
If the crest length is bigger than 500m
If the reservoir capacity is larger than 1 million m3
If the flood discharge is more than 2000 m3/s
If there are some difficulties in the construction of foundation
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ACCORDING to HEIGHT of DAM
High Dam or Large Dam If the height of the dam is bigger than 100m
Medium Dam If the height of the dam is between 50m and
100m
Low Dam or Small Dam If the height of the dam is lower than 50m
ENVIRONMENTAL IMPACTS of
RESERVOIRS
Loss of land
Habitat Destruction : The area that is covered by the reservoir is destroyed, killing
whatever habitat existed there beforehand.
Loss of archeological and histrorical places
Loss of mineral deposits
Loss of special geological formations
Aesthetic view reduction
Sedimentation
Change in river flow regime and flood effects
Reservoir induced seismicity
Change in climate and plant species
Benefits of Dam Environmental Benefits of Dam
• No operational greenhouse gas emissions
• Savings (kg of CO2 per MWh of electricity):
– Coal 1000 kg
– Oil 800 kg
– Gas 400 kg
• No SO2 or NOX
Non-environmental benefits
– Flood control, irrigation, transportation, fisheries and
– Tourism.
Dam Uses
Direct Water Usage
Private / Domestic - Household purposes, Drinking water and
landscape irrigation
Commercial - Restaurants, hotels, golf courses, etc.
Irrigation – Crop use. Water needs at the scale that large dams
provide most often feed industrial farming practices.
Livestock – Use for animal raising as well as other on-farm needs
Industrial – Cooling water (power generation, refineries, chemical
plants), processing water (manufacturing; pulp and paper, food, high
tech, etc.)
Mining – hydraulic mining, various processes, settling ponds
General public supply – Firefighting, public parks, municipal office
buildings
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Dam Uses
Indirect Uses
Hydroelectric Power – Power generation is one of the most
common purposes for the construction of large dams. It is promoted
as a totally “clean” form of electricity.
Flood Control – Dams even out the peaks and lows of a rivers
natural flow cycle by calming seasonal flooding, then storing that
water for gradual release year round.
Transportation – Dam locks are used to move ships past large
dams. This in conjunction with flood control make transportation
feasible on rivers that were traditionally wild.
Disadvantages
The loss of land under the reservoir.
Interference with the transport of sediment by the
dam.
Problems associated with the reservoir.
Climatic and seismic effects.
Impact on aquatic ecosystems, flora and
fauna.
Climatic and Seismic effects
It is believed that large reservoirs induce have the potential to induce earthquakes.
In tropics, existence of man-made lakes decreases the convective activity and reduces cloud cover. In temperate regions, fog forms over the lake and along the shores when the temperature falls to zero and thus increases humidity in the nearby area.
Reservoir-Induced Seismicity There is a correlation between the creation of a large
reservoir, and an increase in seismic activity in an area
The physical weight of unnatural reservoirs can cause seismic activity. While not the direct cause of earthquakes, the weight of reservoirs can act as a trigger for seismic activity.
Although not much direct research is available on the subject, the proposed explanation is that “when the pressure of the water in the rocks increases, it acts to lubricate faults which are already under tectonic strain, but have been prevented from slipping by the friction of the rock surfaces”.
As of now, it is not accurately possible to predict which large dams will produce RIS or how much activity will be produced. Earthquakes that are produced as the result of dams are not usually major, but they still pose a major threat to dam stability and the safety of people living downstream.
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Of all causes, reservoir impoundment has produced the largest earthquakes.
There is evidence linking earth tremors and reservoir operation for more than 70 dams.
Reservoirs are believed to have induced five out of the nine earthquakes on the Indian peninsula in the 1980s which were strong enough to cause damage.
Reservoir induced seismicity (RIS) is well documented but relatively poorly understood.
The mechanisms of RIS are not sufficiently well understood to predict accurately which dams will induce earthquakes or how strong the tremors are likely to be.
Most of the strongest cases of RIS have been observed for dams over 100 metres high - but dams just half this height are also believed to have induced quakes.
Reservoirs filling can Increase the frequency of earthquakes in areas of
already high seismic activity and
Cause earthquakes to happen in areas previously thought to be seismically inactive.
Reservoir induced seismicity
Depth of the water
The volume of the water
Type of local geology and the region’s historic seismic stress patterns.
Increase the frequency of earthquakes.
An increased rate of activity in RIS cases occurs within 10-15 kilometers of impounded reservoirs.
The effect of RIS can be rapid (following the initial filling of the reservoir) or delayed (occurring later in the life of the reservoir).Minor cases of RIS can occur immediately during the filling periods.
Reservoir Filling
Groundwater discharge to a flooded valley is usually inhibited
as a reservoir fills.
Recharge continues unaffected by flooding.
Flooded
Natural
Dams are generally
constructed in groundwater
discharge areas (because
aquifers predominantly
discharge to river valleys).
Reservoir heads are
generally greater than the
aquifer heads.
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Transient Readjustment
The flow regime adjusts by filling groundwater storage
until a new steady state is established.
Where the water table was near the surface, new
discharge zones become established. (e.g. Flathead
Reservoir, Mt.)
Flow direction reversals in the subsurface are likely to
occur.
Flooded
Natural
Reversal
New Springs
Valley Bottom Stability
Reservoir impoundments can also lead to stability problems.
Beneath the reservoir, increased pore-pressures are partially
compensated by the total stress increase due to the water loading.
Downstream of the impoundment, pore-pressures are increased to
similar levels with no total stress compensation.
Post-Reservoir Head
Pre-Reservoir Head
Zone of potential uplift and slope failure
Aquitard
Aquifer
Valley Wall Stability
Pore-pressures can reactivate bedrock shears, faults and gouge
(mylonitic) zones
Increased uplift pressure can cause heave of the valley floor.
Bedrock slide blocks and landslides can be reactivated or initiated by
large changes in pore-pressures in valley walls.
Regional Aquifer
Slide Debris
Slide Block
Water Table
Piezometric Surface
River
Effects of Dams
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Effects on Faults Rock effect
Fault effect Evidence
For most well-studied cases of RIS, the intensity of seismic activity increased within around 25 km of the reservoir as it was filled.
The strongest shocks normally occurred relatively soon - often within days but sometimes several years - after the reservoir reached its operating level.
After the initial filling of the reservoir, RIS events normally continued as the water level rose and fell but usually with lower frequency and magnitude than the initial events.
The pattern of RIS is, however, unique for every reservoir.
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Interpretation of Evidence
The evidence is consistent with a mechanism involving stress-relief.
The early events release the initial stresses more quickly the nearer they are to the critical level for slip.
Later changes in stress trigger less violent releases as the fault plane weakens (c,f approaches residual ) with each successive event.
Another Perspective Seismologists have published a list of about 100 cases of RIS.
These cases show that after the completion of a dam, the reservoir area experienced earthquakes of micro-level magnitude - 2.0 or 3.0 on the Richter scale.
Dense seismic networks have increased the detection potential and increased the number of cases cited as instances of RIS.
The earthquakes that the Indian peninsula has so far experienced may not be attributable to dams.
Construction of dams should be done in such a way as to withstand anticipated seismic activity and minor stress adjustments are inevitable.
Seismicity of India
The map shows
the location of
the Koyna and
Killari
earthquakes in
the largely
aseismic Indian
penninsula.
The recent M7.9
Gujarat quake is
also shown.
Gujarat
Killari
Koyna
Koyna Dam Earthquake
The area between the Koyna and the Warna dams, in the vicinity of the Shivaji Sagar and Vasant Sagar reservoirs, is unique for its ongoing, high level of seismic activity.
Seismicity at Koyna has close correlation with the filling cycles of the Koyna reservoir.
The 1967 Koyna event, in the watershed of the Krishna River in
Maharashtra state, is a classic example of earthquake activity triggered by reservoir.
The world's worst confirmed reservoir-induced earthquake was triggered by the Koyna Dam.
Nearly 200 were killed in the magnitude 6.3 tremor.
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Koyna Dam Background
The height of the Koyna-Dam is 103 m, reservoir volume is 2.78×109 m3.
Seasonal fluctuations of the lake level are typically 30 to 35 m and are dominated by monsoon rainfalls.
The site is now highly instrumented and the subject of active research
Since its first impoundment in 1962, more than 150 earthquakes of magnitude 4.0 have been recorded.
Events are mostly restricted to an area 40 × 25 km2 south of the Koyna-Dam.
This marks the area as probably the best in the world to study the phenomenon of reservoir induced/triggered seismicity (RIS).
Killari Event
The most puzzling event in Peninsular India is the Killari earthquake.
The devastating magnitude 6.4 earthquake struck Killari, Maharashtra in 1993, killing 10,000 people.
The event was totally unexpected as it was located in the Deccan Trap-covered stable Indian Shield. There was no record of any historical earthquake in the region.
The Killari earthquake is considered the most devastating SCR (Stable Continental Region) event in the world.
Some seismologists believe that the Killari event was triggered by a nearby (Tirna) reservoir.
Tirna Reservoir The Killari earthquake was about 10 km from the Lower
Tirna Reservoir.
The maximum water depth is about 20m, which is at the low end of the range of depths of reservoirs where induced seismicity has been documented.
The reservoir level was low at the time of the main shock, which is consistent with the expected negative effect of the loading by the reservoir on an underlying thrust fault.
Several other recent earthquakes in peninsular India appear to be located close to reservoirs.
Whether the Killari earthquake was triggered by the Lower Tirna reservoir is not known, but it cannot be ruled out at this time.
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Narmada Valley Indian seismologists have noted an increase in seismic activity in
the Narmada Valley over the past 20 years, which may be linked to reservoir impoundment.
In the Narmada Valley, a series of tremors were felt soon after the completion of the Sukta Dam.
A strong earthquake hit the Narmada Valley on May 22, 1997, killing around 50 people and injuring 1,000 in the city of Jabalpur in the state of Madhya Pradesh.
The epicentre of this magnitude 6.0 earthquake is believed to have been about 20-40 kilometers from Bargi Dam, which completed filling in 1990.
The recent earthquake has focused attention on the seismic risks faced by the large dams planned for the Narmada Valley, and on the risk of reservoir-induced earthquakes.
Seismic Hazard Assessment Seismic hazard assessments are an integral part of site
investigation for large dams and reservoirs.
In order to interpret the recorded seismicity of a region, a thorough review of the available previous seismicity and seismo-tectonic studies is performed.
The analysis is further deepened through the integration of three-dimensional velocity structures and inversion studies beneath this area.
The compilation of all these data makes it possible to define and gain considerable insight concerning the major seismic sources active in the region.
Some major/minor induced earthquakes
DAM NAME COUNTRY HEIGHT (m) VOLUME OF
RESERVOIR
(m3)
MAGNITUDE
KOYNA INDIA 103 2780 6.5
KREMASTA GREECE 165 4650 6.3
HSINFENGKIANG CHINA 105 10500 6.1
BENMORE NEW
ZEALAND
118 2100 5.0
MONTEYNARD FRANCE 155 240 4.9
M>5 Induced Earthquakes.
__________________________________________
Dam / Reservoir DP or Hydrocarbon Field
Magnitude Seismicity Induced Earthquakes
_____________________________________________________________
___________________________________
Gazli field, EIS 7.3 low horizontal midplate
Uzbekistan
Koyna, RIS 6.5 low horizontal midplate
India Coalinga field, EIS 6.5 high horizontal plate boundary
USA
Kremastaa, RIS 6.3 high vertical back arc extension
Greece
Hsinfengkiang, RIS 6.1 low horizontal midplate
China
Kettleman field, EIS 6.1 high horizontal plate boundary
USA
Montebello field, EIS 5.9 high horizontal plate boundary
USA
Oroville, RIS 5.9 low vertical Sierra Nevada foothills
USA
USA
Kariba, RIS 5.8 low vertical midplate
Zambia/Zimbabwee
Marathona, RIS 5.7 high n.a plate boundary
Greece
Aswana, RIS 5.5 low vertical midplate
Egypt
Eucumbene, RIS 5.5 low n.a midplate
Australia
Hoover, RIS 5.5 low vertical Colorado plateau
USA
Denver, IIS 5.5 low vertical Colorado plateau
USA
Caviaga, EIS 5.5 low horizontal midplate
Italy
Lake County, IIS 5.3 low horizontal midplate
USA
Monteynard, RIS 5.3 low vertical Alps foothills
France
El Reno, EIS 5.2 low horizontal midplate
USA
Snipe Lake, EIS 5.1 low horizontal midplate
Canada
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The most well-known are the instances
of seismicity induced by reservoirs
behind the Hoover and Oroville dams
in USA, Kariba dam on the Zambia–
Zimbabwe border, Nurek dam in
Tadzhikistan, Hsinfengkiang dam in
China and Koyna dam in India.
Dam! What a disaster
33 sure cases of reservoir-induced seismicity or M>4 (7 of them
were over 5.5)
Most know event is the Koyna Reservoir (India) earthquake in
1967. M=6.3 Over 200 fatalities and more than 1500 injured.
Heated debates on the responsibility of the Zipingpu reservoir in
the 2008 Sichuan (China) earthquake. Over 68000 fatalities and
has been felt all over China. During the initial impoundment,
notable number of earthquakes (M 3.5)
Dams and Earthquakes
Sichuan Earthquake May Be Dam-
Induced
Talembote Case History
The assessment of seismic hazard within the Talembote
area, Morocco, is a study of a dam located within the
actively deforming intermountain belt of the Rif region,
considered the most active zone in Morocco.
The historical seismic data available on Morocco extend
to about 11 centuries back in history.
Of more importance is the 20th century seismicity data,
which reveals the occurrence in 1909 of a M6.4 event
about 50 km away from the dam.
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Talembote Seismic Setting
Of particular importance are shallow surface features; mostly normal and strike-slip faults, which are identified as local faults that are running right next to the dam-site.
However, most of the seismic activity seems to be related to reverse faults along Rif-nappes connected to a detachment surface at about 20 km-depth.
This detachment runs right underneath the dam-site. The detachment zone may coincide with a low strength layer that decouples the overlying sediments from the basement of the African Plate.
As a result, there is a high level of small magnitude earthquakes.
Talembote Seismic Analysis
The analysis of seismic hazard of the site of the Talembote dam has shown that the Maximum Credible Earthquake (MCE) is in the order M6.8, risking to produce a maximum acceleration of 0.5g.
This event could possibly be generated once every ten thousand years by one of the faults passing in the immediate proximity of the dam.
When considering the much shorter design life for the dam-structure, it is normal to use an earthquake return period 7 or 8 times the 75-year design life.
An acceleration of 0.085 g, corresponds to a return period of 550 years. This acceleration is rounded to predict an operational basic earthquake of 0.1 g.
There are 19 cases of RIS in China, including the Xinfengjiang Reservoir which
was associated with a Ms 6.1 event in 1962. Most of the cases of RIS occurred in
South China and are predominantly in karst terrane. The cases of RIS in granitic
rocks, e.g., Xinfengjiang Reservoir appear to be caused by pore pressure
diffusion in fractured rocks. That lithology controls the location of seismicity is
illustrated by the example of RIS in Danjiangkou Reservoir. The temporal
association of RIS with filling showed that in some cases, shallow, small
earthquakes are associated with reservoir impoundment (Skempton’s effect).
Several examples illustrate that the chemical effect of water in dissolution is
responsible for RIS.
The presence of faults in the granitic core where the Three Gorges Project is
under construction, and the presence of outlying carbonate rocks upstream,
suggest the possibility of moderate earthquakes when the reservoir is
impounded.