Velocity Model in Taiwan Kuo-Liang WEN 1,2 , Che-Min LIN 2 , - - PowerPoint PPT Presentation

▶
velocity model in taiwan
SMART_READER_LITE
LIVE PREVIEW

Velocity Model in Taiwan Kuo-Liang WEN 1,2 , Che-Min LIN 2 , - - PowerPoint PPT Presentation

Sep 30, 2023 495 likes •747 views

Taipei, Taiwan 2016/8/15~17 Construction of the Shallow Shear-wave Velocity Model in Taiwan Kuo-Liang WEN 1,2 , Che-Min LIN 2 , Chun-Hsiang KUO 2 , Chun-Te CHEN 3 , Jyun-Yan HUANG 2 1. Department of Earth Sciences, National Center University,

slide-1
SLIDE 1

Construction of the Shallow Shear-wave Velocity Model in Taiwan

Kuo-Liang WEN1,2, Che-Min LIN2, Chun-Hsiang KUO2, Chun-Te CHEN3, Jyun-Yan HUANG2

  • 1. Department of Earth Sciences, National Center University, Taiwan
  • 2. National Center for Research on Earthquake Engineering, Taiwan
  • 3. Institute of Earth Sciences, Academia Sinica, Taiwan

Taipei, Taiwan 2016/8/15~17

slide-2
SLIDE 2

Introduction

High Seismicity in Taiwan

Strong site characteristics of the thick and soft Quaternary sediments

 Taipei Basin, Ilan Plain, Western Coastal Plain, Pingtung Plain

2 (Fisher et al., 2002)

slide-3
SLIDE 3

1986/11/15 Hualien Eq. ML=6.8

V IV

IV

III II

slide-4
SLIDE 4

台北縣中和市員山路之華陽市場，原為三層多柱少牆鋼筋混凝土的市場建築 物，由於2、3層改為住家後砌築了許多磚造外牆與隔間牆，使得建築物成為 上剛下軟的結構，加上過大的超載，在耐震上十分不利。在此次地震襲擊下， 幾乎大部份一、二樓的支柱折斷，造成12人死亡，數十人受傷的慘劇。

3F

slide-5
SLIDE 5

台北市復興南路一段某大廈，一樓剪力牆腳及牆邊構材部份被壓碎，鋼 筋暴露且扭曲變形，牆面呈斜向之剪力龜裂，一、二樓間之混凝土樓板 破裂並下陷。

14F

slide-6
SLIDE 6

6

Depth contour to the basement top from deep drilling. (Central Geol. Surv.)

slide-7
SLIDE 7

Introduction

The resolutions of shallow part (within a depth of 1 or 2 km) of existing 3D tomography velocity models are insufficient

A integrated and detail shallow velocity model of Taiwan is essential for ground motion prediction and simulation in the future

7 (Chen et al., 2016)

Additional shallow model

(Lin, 2009)

slide-8
SLIDE 8

8

Near-surface Data of Engineering Geological Database for TSMIP (EGDT)

slide-9
SLIDE 9

9

Near-surface Data of Engineering Geological Database for TSMIP (EGDT)

(Kuo et al., 2012)

447 stations

slide-10
SLIDE 10

Receiver Function Analysis of TSMIP Stations

 RF was applied on the high-frequency acceleration

seismograms recorded by TSMIP stations to estimate the Vs profiles

10

TAP010

(Lin et al., 2014)

slide-11
SLIDE 11

Receiver Function Analysis of TSMIP Stations

(Lin et al., 2014)

slide-12
SLIDE 12

Receiver Function Analysis of TSMIP Stations

Bottom of Sungshan Formation

Taipei Basin

Top of Tertiary Basement

Ilan Plain

Top of Tertiary Basement

 RF is sensitive to a boundary

with high velocity contrast

 RF analysis has been applied at

almost 400 TSMIP stations

 Providing a rough and

preliminary model for further studies Kaohsiung & Pingtung Area

Vs > 0.5 km/sec Vs > 1.0 km/sec

(Lin et al., 2016) (Lin et al., 2014) (Lin, 2003)

slide-13
SLIDE 13

Microtremor Array

13

0.5 1 1.5 2 2.5 3 3.5 4 1 2 3

slide-14
SLIDE 14

Microtremor Array

 Compared with EGDT and deep borehole data

(Kuo et al., 2016)

slide-15
SLIDE 15

 Compared with seismic structural maps

15

Microtremor Array

(Lin et al., 2009)

slide-16
SLIDE 16

Microtremor Array

16

ESG5 poster: P102B (Chen et al.)

 About 150 microtremor array

measurements have been conducted in Taiwan

 Arrays with different layouts can

provide velocity information of diverse depths or resolutions

slide-17
SLIDE 17

Modeling of Microtremor H/V Spectral Ratio (HVSR)

17 

A dense microtremor single-station survey of more than 4000 sites has been conducted to evaluate the detail site response all over Taiwan using the HVSR analysis

The measurement intervals are mostly 2 km, and 1 km for some metropolitan regions.

(Huang, 2009)

slide-18
SLIDE 18

18

 Theoretical SH-wave transfer function of Haskell matrix (Haskell,

1960) shear-wave velocity model inverted by RF agree with the

  • bserved microtremor H/V spectral ratios at TSMIP stations

 The theoretical SH-wave transfer function can be used to model the

microtremor H/V spectral ratios to estimate the S-wave velocity profiles for all sites

Modeling of Microtremor H/V Spectral Ratio (HVSR)

(Lin et al., 2014)

slide-19
SLIDE 19

19

GA-Haskell method based on the combination

  • f the Haskell matrix and Genetic Aalgorithm

(GA) models the microtremor HVSR to estimate the Vs velocity profile

The fitness function of GA-Haskell is defined by linear correlation coefficient and dominant frequency.

Modeling of Microtremor H/V Spectral Ratio (HVSR)

      

  

    

i i i i i i i

y y x x y y x x r

2 2

2 . 3 . 1 8 . 2 1                      

HV HV SH

F F F r f

slide-20
SLIDE 20

20

Modeling of Microtremor H/V Spectral Ratio (HVSR)

Taipei Basin

Sungshan Formation & HVSR dominant frequencies (Lin et al., 2014)

slide-21
SLIDE 21

21

Modeling of Microtremor H/V Spectral Ratio (HVSR)

Ilan Plain

Engineering bedrock (Vs =600 m/sc)

Western Plain

Soft soil – Alluvium boundary Alluvium – Pleistocene boundary Pleistocene – Miocene basement boundary

ESG5 poster: P112B (Lin et al.) ESG5 poster: P102B (Chen et al.)

slide-22
SLIDE 22

Z1.0 for GMPE

22

1 10 100 1000 100 1000 Z1.0 [m] Vs30 [m/s]

EGDT RF H/V Array LK16_TW

slide-23
SLIDE 23

Summary

3D Tomography Models EGDT, other downhole and surface geology data Near- Surface ~2km Receiver Function

  • 800 TSMIP stations

Microtremor Array

  • About 150 sites

HVSR Modeling

  • More than 4000 sites

 Refer to geology, seismic and other geophysical surveys

  • A detail and integrated shallow shear-wave velocity model for Taiwan
slide-24
SLIDE 24

24

Thank you for your attention!

Taipei, Taiwan 2016/8/15~17