8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 1/46
S E O F T R A V E L S E O F T R A V E L I M E T O M O G R A P H Y I N S T R O N G I M E T O M O G R A P H Y I N S T R O N G O T I O N S I M U L A T I O N O T I O N S I M U L A T I O N
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 2/46
CONTENTS
• Introduction• Travel time tomography
• Strong motion simulation using Semi-Empiricalapproach
• Case study- 1• Case study- 2
• Conclusion
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 3/46
Introduction
• The word ‘tomography’ means ‘slice picture’ ( from the Greekword ‘tomos’ meaning ‘slice’ ).• It was first used in medical imaging.• Seismologist use ‘tomography ’ word to describe the imaging of
2-D slices only.
• Tomography involve gathering projection data from multipledirections and feeding the data into a tomographicreconstruction software algorithm processed by a computer.
• In the present day, seismic travel time tomography is the one of the robust technique which is used in determining theappropriate velocity model.
•
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 4/46
Velocity ModelRay Tracing (Forward Modeling)
Seismic Data (Travel time)
Seismic Data (Travel time) Seismic Data (Travel time)Tomographic inversion (Inverse Modeling)
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 5/46
.
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 6/46
bjectives of PresentWork
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 7/46
ravel Time Tomography
Ø Introduction
•
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 8/46
t(ray) = ∫s(x,z) dl
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 9/46
∆t = D∆S
Ø Forward Modeling Vs Inversion
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 10/46
Ø Ray Tracing
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 11/46
Ø Problem StatementT = Dn×m ×Sm
Ø Experiment Data vs. Model Data
Treal = Dreal ×Sreal
Tmodel = Dmodel ×Smodel
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 12/46
Dreal = Dmodel = D
ØThe Damped least Squares Problem
mest = GT × dest
mest= (GTG + λ Ι )−1Γ Τ δ
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 13/46
S=||d-Gm||2 + λ ||m||2
•
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 14/46
sing
-emi empirical Approach
• Introduction
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 15/46
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 16/46
Ø Similarity relationships of earthquake
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 17/46
Ø Methodology
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 18/46
•
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 19/46
(a) white gaussian noise (b) filter representing basic spectral shape
(c) filtered white noise (d) envelope of accelerogram
(e) multiplication of the envelope with filteredwhite noise
(f) summation of all accelerogram (g) the simulated acceleration record
( after Joshi, 2004)
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 20/46
-ase Study 1
Ø Introduction
•
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 21/46
1 : Pre-Tertiary rocks
2 : Mainly sedimentary rocks of lower tomiddle Miocene age
3 : Mainly volcanic rocks of lower to Middle Miocene age
4 : Mainly sedimentary rocks of upper Miocene to Pliocene age
5 : Mainly volcanic rocks of upper Miocene to Pliocene age
6:
Neogene intrusive
rocks7 : Mainly sedimentary rocks of Pliocene to
lower Pleistocene age8 : Mainly volcanic rocks of Pliocene to
lower Pleistocene age9 : Mainly sedimentary rocks of middle to
late Pleistocene10 : Mainly volcanic rocks of middle to late
Pleistocene
11: holocene sediments
(After Kakimi et al., 1982))
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 22/46
Ø Initial Model
•
Velocity(km/s) Thickness of thelayers(km)
2.8 0-8
2.9 8-22
3.5 22-35
(Courtesy: Junichi Nakajima, Toru Matsuzawa,and Akira Hasegawa et al., 2001)
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 23/46
Ø Data
(Courtesy: http://www.kik.bosai.go.jp-sitemap)
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 24/46
Figure: Diagram explainingthe format of Kik-net data
(Courtesy:http://www.kik.bosai.go.jp-sitemap)
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 25/46
Figure: Diagram showing the hypocenter of Events1 and 2 and location of various stationswhere it was recorded. (Courtesy: http://www.kik.bosai.go.jp)
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 26/46
Figure 4.6: Diagram showing the hypocenter of Event 4 and location of various stationswhere it was recorded. (Courtesy: http://www.kik.bosai.go.jp, modified)
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 27/46
Ø Result
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 28/46
36.7
37
Event 1 Event 2
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 29/4636 7
37
36.7
37
Event 4 Event 3
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 30/46
Velocity(km/s) Thickness of thelayer(km)
1.72 0-8
2.78 8-22
3.5 22-35
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 31/46
v e
l o c
i t
y
depth
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 32/46
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 33/46
2.6
2.8
3
2.5
3
Figure (a): resolution matrix of inversion of the data
Figure (b): covariance matrix of inversion of the data
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 34/46
-ase Study 2
Ø Introduction
Ø Data
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 35/46
•
Station code Latitude Longitude PGA Epicentraldistance(km)
Station name NIGH 11 37.169 138.747 57.1515 24 KawanishiGNMH 09 36.618 138.91 3.45243 40 TakayamaFKSH 07 37.007 139.378 7.27059 55 HinoemataFKSH 21 37.339 139.317 7.93994 65 Tadami
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 36/46
Figure: Diagram showing the hypocenter of Event and location of various stationswhere it was recorded. (Courtesy: http://www.kik.bosai.go.jp)
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 37/46
•
Modelling Parameter
Rupture length L = 3.4kmWidth D = 3.0kmDip = 450
Depth = 14km
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 38/46
Ø Result
•
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 39/46
Figure: Comparison of the observed acceleration records at variousstations with the synthetic records
CONCLUSION
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 40/46
CONCLUSION
•
REFERENCES
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 41/46
REFERENCES
•
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 42/46
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 43/46
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 44/46
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 45/46
8/6/2019 Use of Travel Time Tomography in Strong Motion Simulation
http://slidepdf.com/reader/full/use-of-travel-time-tomography-in-strong-motion-simulation 46/46