Regional Strategyagainst Earthquake Motion

Based on Geotechnical Database

27 October 2011Esri European User Conference @ Madrid, SpainEsri European User Conference @ Madrid, Spain

Chang-Guk SUNJeong-Soo JEON

Sung-Ja CHOI

Korea Institute of Geoscience and Mineral Resources

CONTENTS

Introduction

Earthquake Ground Motion

GIS Framework for Geotechnical Information

Geotechnical DB and Spatial Information

Spatial Zonations as Regional Seismic Strategy

Conclusions

CONTENTS

IntroductionIntroduction

Earthquake Ground Motion

GIS Framework for Geotechnical Information

Geotechnical DB and Spatial Information

Spatial Zonations as Regional Seismic Strategy

Conclusions

Earthquake Hazards

Earthquake Ground Motion

Minor Minor hazardshazards

Seismic Seismic zonationszonationsiin ann an urban areaurban area

Dynamic Rupture(Source effects)

Wave Propagation(Path effects)

Site effects

Earthquake Earthquake ByByFault MovementFault Movement

Serious hazardsSerious hazards

in anin an urban areaurban area

Use GIS in Geotechnical Earthquake Engineering

Data

Software

Hardware

MethodUser MethodUser

� GIS provides a very effective way to capture, edit, manipulate,

analyze, synthesize and visualize the geotechnical data,

particularly in spatial domain with time.

Objectives of This Research Work

� For two inland urban areas, Gwangju and Daegu,

� Building the geotechnical DB composed of the existing borehole

drilling data and surface geo-knowledge data

� Implementing the GIS-based geotechnical information system for

spatial geotechnical (geo-) layers using the geotechnical DB

DaeguGwangju

spatial geotechnical (geo-) layers using the geotechnical DB

� Creating a variety of spatial zoning maps for quantifying the site

effects in terms of the site period within GIS-based tools

CONTENTS

Introduction

Earthquake Ground MotionEarthquake Ground Motion

GIS Framework for Geotechnical Information

Geotechnical DB and Spatial Information

Spatial Zonations as Regional Seismic Strategy

Conclusions

Earthquake Motion Related to Site Effects

� Site effects

• The phenomenon of seismic waves travelling into soil layers

• Strongly related to

• The impedance contrast; the differences in shear wavevelocity (VS) between the soil layers and the bedrock

• The thickness of soil layers; the depth to bedrock• The thickness of soil layers; the depth to bedrock

• Earthquake ground motions can be amplifiedat the predominant site period, TG

� Site period

• Single-layered soil over bedrock

• Multi-layered soil over bedrock

SG V

HT 4=

∑=

=n

i Si

iG V

DT

1

4

Depth to bedrockDepth to bedrock

Average Vs of soilAverage Vs of soil

Thickness of soil layersThickness of soil layers

Vs of soil layers Vs of soil layers

Current Site Classification Scheme in Most Codes

Soil Profile Type Generic Description

Average Soil Properties for top 30.48 m (30 m; 100 ft)of Soil Profile

(Vs30) (m/s) (blows/30cm) (kPa)

SA (Site Class A) Hard Rock > 1,500 - -

Vs N Su

Short-Period Mid-Period

Z = 0.11 Z = 0.07 Z =0.11 Z = 0.07

Ca Fa Ca Fa Cv Fv Cv Fv

0.09 0.82 0.05 0.71 0.09 0.82 0.05 0.71

∑=

=n

i Si

iS

V

dV

1

/3030Thickness of Thickness of soil and/or rock layer soil and/or rock layer to a depth of 30 mto a depth of 30 m

Vs of Vs of soil and/or rock layer soil and/or rock layer

SB (Site Class B) Rock 760 - 1,500 - -

SC (Site Class C)Very Dense and

Soft Rock360 - 760 > 50 > 100

SD (Site Class D) Stiff Soil 180 - 360 15 - 50 50 - 100

SE (Site Class E) Soft Soil < 180 < 15 < 50

SF (Site Class F) Soil Requiring Site-specific Evaluation

0.11 1.00 0.07 1.00 0.11 1.00 0.07 1.00

0.13 1.18 0.08 1.14 0.18 1.64 0.11 1.57

0.16 1.45 0.11 1.57 0.23 2.09 0.16 2.29

0.22 2.00 0.17 2.43 0.37 3.36 0.23 3.29

∫=5.0

1.0rock

soil

)(RS

)(RS

4.0

1(RRS) dT

T

T

R

RF

rock

soila ∫=

0.2

4.0rock

soil

)(RS

)(RS

6.1

1(RRS) dT

T

T

R

RF

rock

soilv

Modification of Site Classification Scheme

� Suggested by Sun (2010) and adopted in this study

Generic Description Site ClassCriteria Site Coefficients

VS30 (m/s) TG (s) Fa Fv

Rock B > 760 < 0.06 1.00 1.00

Weathered Rock and Very Stiff SoilC1 > 620 < 0.10 1.28 1.04

Weathered Rock and Very Stiff Soil

CC2 > 520 < 0.14 1.45 1.09

Intermediate Stiff SoilC3 > 440 < 0.20 1.65 1.13

C4 > 360 < 0.29 1.90 1.19

Deep Stiff Soil D

D1 > 320 < 0.38 2.08 1.23

D2 > 280 < 0.46 2.26 1.29

D3 > 240 < 0.54 2.48 1.36

D4 > 180 < 0.62 2.86 1.43

Deep Soft Soil E ≤ 180 ≥ 0.62 1.50 2.00

CONTENTS

Introduction

Earthquake Ground Motion

GIS Framework for Geotechnical InformationGIS Framework for Geotechnical Information

Geotechnical DB and Spatial Information

Spatial Zonations as Regional Seismic Strategy

Conclusions

GIS-Based Geotechnical Information System (GTIS)

General GIS

Data extraction

Geostatistical kriging interpolation

Spatial analysis

DatabaseGeotechnical analysis

GIS GIS tools tools utilized utilized for geotechnical for geotechnical

informationinformation

GIS GIS tools tools utilized utilized for geotechnical for geotechnical

informationinformation

AutoCAD LDDT

EVS-PRO

Surface coverage data

Geo-knowledge data

Database

Surface contour visualization

3D volume & section visualization

Visualization

Site period computation

Geo-layer thickness computation

Geotechnical analysis

5 general geotechnical (geo-) layers from a number of geo-knowledgeFill (FL); Alluvial Soil (AL); Weathered Soil (WS); Weathered Rock (WR); Bedrock (BR)

EVS-PRO

ArcGIS tools

Code programfor kriging

Procedure for Building GIS-Based GTIS

1st Selecting the extended area including the study area

2nd Compiling all available documentary information for geo-knowledge

3rd Determining local landform characteristics based on terrain analysis

4th Zoning the extended area with the geologic and geomorphic characteristics4th Zoning the extended area with the geologic and geomorphic characteristics

5th Collecting borehole drilling data in the extended area

6th Visiting the extended area to collect additional nearby surface data in field

7th Building a database of geotechnical information system based on geo-knowledge

8th Interpolating spatial geotechnical information for the extended area

9th Extracting spatial geotechnical information for the study area from the extended area

Apply Sophisticated GeostatisticalKriging

Defining the the nugget(CO), range(a), and sill values

Selecting the model function

Input the known data and the unknown locations

Calculating the semivariogram depending on the distance ◄ AIC technique

Calculating the spatial autocovariance using the relationship

Calculating the kriging weights using the inversion of matrix

Estimating the value at unknown location from

kriging estimator∑

=

×=n

ijji ZwyxZ1

* ),(α

αα

CONTENTS

Introduction

Earthquake Ground Motion

GIS Framework for Geotechnical Information

Geotechnical DB and Spatial InformationGeotechnical DB and Spatial Information

Spatial Zonations as Regional Seismic Strategy

Conclusions

Study Areas

39 º N

38 º N

37 º N

39 º N

38 º N

37 º N

125 º N 129 º N128 º N127 º N126 º N

� Representative metropolitanareas located in the southernregion of the Korean peninsula

• Vulnerable to earthquake-induced hazards

• Collecting more than 1,900

36 º N

35 º N

34 º N

36 º N

35 º N

34 º N

125 º N 129 º N128 º N127 º N126 º N

N

S

W E

Gwangju

Daegu• Collecting more than 1,900existing borehole drilling datafor each target area

• Acquiring about 300 surfacegeo-knowledge datafor each target area

Geotechnical DB Framework

FTP Server

SQL DB ServerDB Management Program

Client

DB Management Program

Client

Network (TCP/IP)

�� Structure of DB Structure of DB management management systemsystem

GwangjuDaegu

DB Management Program

�� Main Main interface interface of of client’s client’s DB DB management management program program developed developed with with ArcGISArcGIS EngineEngine

Main Functions of DB Management Program

�� Zoom in/out and Zoom in/out and data data quiryquiry

�� Input and Input and modification of modification of various types of various types of geotechnical geotechnical datadata

Distribution of Data in Geotechnical DB

� Extended area of Gwangju: 37.8 km (WE) x 26.6 km (SN)

Surface geo-knowledge data from site visit

Existing borehole drilling data

Administrative boundary (for study area)

Distribution of Data in Geotechnical DB

� Extended area of Gwangju: 37.8 km (WE) x 26.6 km (SN)Surface geo-knowledge

data from site visit

Existing borehole drilling data

Administrative boundary (for study area)

Spatial Geotechnical Layers Predicted Using DB

� Study area of Gwangju: Whole administrative area

FillAlluvial SoilWeathered SoilWeathered RockBed Rock

Spatial Geotechnical Layers Predicted Using DB

� Study area of Daegu: Whole administrative area

Fill Alluvial SoilWeathered SoilWeathered RockBedrock

Variation of Geotechnical Layers with Topography

� A representative section case in Daegu

E FLASWSWR

W

WE

WRBR

Spatial Distribution (Zonation) of Geotechnical Layers

� Alluvial soil layer in Gwangju

- Maximum thickness of approximately 40 m in the central plains

Spatial Distribution (Zonation) of Geotechnical Layers

� Alluvial soil layer in Daegu

- Maximum thickness of approximately 20 m along the river

Thickness of Alluvial Soil (m)

0.01.02.04.08.010.012.012.015.018.021.023.0

Spatial Distribution of the Depth to Bedrock

� Depth to bedrock in Gwangju

- Maximum depth of deeper than 40 m in the northern plains

Depth to Bedrock, H (m)

0.01.02.04.08.010.012.015.018.0

Spatial Distribution of the Depth to Bedrock

� Depth to bedrock in Daegu

- Maximum depth of about 30 m in plains and near the rivers

18.021.024.027.030.033.0

CONTENTS

Introduction

Earthquake Ground Motion

GIS Framework for Geotechnical Information

Geotechnical DB and Spatial Information

Spatial Spatial ZonationsZonations as Regional Seismic Strategyas Regional Seismic Strategy

Conclusions

Conceptual Flow for Seismic Zonation on Site Period

350 m/s

330 m/s

450 m/s

Spatial geo-layers information Representative VS for each geo-layer

Weathered soil

Alluvial soil

Fill

∑=

=n

i Si

iG V

DT

1

4

550 m/s

(1,000 m/s)

Computation and visual zonation of site perido (TG) within spatial GIS tool

Thickness of soil layer (Di) VS of soil layer (VSi)

Bed rock

Weathered rockFillAlluvial Soil

Weathered Residual Soil

Weathered RockBed Rock

Site Period for Earthquake Hazard Potential

� Site period in Gwangju

- 0.20 to 0.47 s (vulnerability for 2 to 5 storied buildings during

earthquake in the central and northern plains

Site Period for Earthquake Hazard Potential

� Site period in Daegu

- 0.10 to 0.33 s

(vulnerability for

1 to 4 storied

buildings during

earthquake) inSite

Period, TG (s)

0.000.010.02

0.040.08

0.100.12

0.150.18

0.210.240.27

0.300.33

earthquake) in

plains and valleys

� Site classes based on the site period in Gwangju

- Site classes C (C1 to C4) and D (D1 to D3) in plains

- Max. 1.90 for Fa and 1.19 for Fv ▷significant seismic amplification

Site Classes with Site Period for Seismic Design

B (1.00; 1.00)

C1 (1.28; 1.04)

C2 (1.45; 1.09)

C3 (1.65; 1.13)

C4 (1.90; 1.19)

Site Class (Fa; Fv)

Site Classes with Site Period for Seismic Design

� Site classes based on

site period in Daegu

- Site classes C

(C1 to C4) in plains

- Max. 1.90 for Fa and

1.19 for F

B (1.00; 1.00)

C1 (1.28; 1.04)

C2 (1.45; 1.09)

C3 (1.65; 1.13)

C4 (1.90; 1.19)

Site Class (Fa; Fv)

1.19 for Fv

▷significant seismic

amplification

Representative Site Classes for Rapid Response

� Site class averaged with administrative sub-unit in Gwangju

- Site classes C (C1 to C4) in most of sub-unit ▷ seismic amplification

B

C1

C2

C3

C4

SiteClass

Representative Site Classes for Rapid Response

� Site class averaged with

administrative sub-unit

in Daegu

- Site classes C (C1 to

C4) in most of sub-unit

seismic amplification

B

C1C2

C3

C4

SiteClass

▷ seismic amplification

CONTENTS

Introduction

Earthquake Ground Motion

GIS Framework for Geotechnical Information

Geotechnical DB and Spatial Information

Spatial Zonations as Regional Seismic Strategy

ConclusionsConclusions

Conclusions

� For two inland metropolitan areas, Daegu and Gwangju, in Korea,

the GIS-based geotechnical information system was implemented

for reliably predicting the geotechnical layers, preferentially

building the geotechnical DB composed of existing boring data

and surface geo-knowledge data.

� Based on the GIS-based geotechnical information system,

spatial zoning maps of the depth to bedrock and the site period,

TG, were created and presented as fundamental resources

for regional seismic strategy.

� Moreover, spatial zonation on site class was conducted based

on the TG distribution for preliminary seismic design.

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