2011-AGU-Chan
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Transcript of 2011-AGU-Chan
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8/3/2019 2011-AGU-Chan
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Chung-Han Chan Yih-Min Wu Po-Shen LinChin-Tung ChengDepartment of Geosciences, National Taiwan University, Taiwan Geotechnica
Earthquake forecasting and probabilistic seismic hazard assessment through a smoothing Kernel and the ra
Contact : [email protected]
Two examples show that consequent earthquakes took placed in thet rate increase regionsGood correlation between background
seismicity rate and consequent events
Overview
Similar seismicity patterns during different periods in the Taiwan region
Catalog is acquired by the Central Weather Bureau Seismic Network (CWBSN).Catalog is declustered according to the method by Burkhard and Grnthal [2009].
Declustered events during 1940-2005 Non-declustered events during 2006-2010
I n t e r f a c e r e g i o n
I n t r a s l a b r e g i o n
I n t e r f a c e
r e g i o n
I n t r a s l a b
r e g i o n
E u r a s i a
n p l
a t e
E u r a s i a
n p l
a t e
M5 events
R
y
u
k
y
u
T
r
e
n
c
h
8 c m / y r .
R y u k y u T r e n c h
8 c m / y r .
30 km
LongitudinalValleyFault
(plateboundary)
Hualien city
Crustal eq.
Interface eq
Intraslab eq.
Crustal eq.
Interface eq
Intraslab eq.
Hualien city
Crustal eq.
Interface eq
Intraslab eq.
Crustal eq.
Interface eq
Intraslab eq.
Declustered eq.
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Estimated seismicity density rate for M5.0 ( x10 -6/yr/km 2) Seisimicity rate changes by the events during 2006-2010
30 km
- 10 % - 5% - 1% - 0. 5% - 0 .1 % 0 .0 + 0. 1% + 0. 5% + 1% + 5% + 10 %
Smoothing Kernel only
Smoothing Kernel +rate/state friction law
Molchan diagram
0% 20% 40% 60% 80% 100%
Fraction of failureto predict
Fraction of space occupied by alarm
0%
20%
40%
60%
80%
100%
Positivecorrelation
Negativecorrelation
N o c o r r e l a t i o n
A smoothing Kernel function and the rate-and-state model are employed for forecasting the spatio-temporalof the seismicity density in Taiwan. Through using an integration of these two approaches, the application wbe capable of providing a seismicity forecast with a high accuracy. The proposed me thodology, with verified for rate estimation, could provide a suitable basis for application in short-term propobilistic seismic hazard a
Seis. rate change atdifferent time points
Combination of the two modelshas a better forecasting ability
According to the rate-and-state friction model, the Coulomb stress change imparted by each earth-quake results in seismicity rate change.Slip dislocation model of each event is acquired by the scaling law by Yen and Ma [ BSSA , 2011].For Coulomb stress change calculation, spatial variable receiver fault and maximum stress changeamong seismogenic layer (proposed by Catalli & Chan [accepted by GJI ]) are considered.
Background seismicity rate is evaluated by asmoothing Kernel in the neighboring region of the declustered earthquakes during 1940-2005.
Higher seismicity rates along the east coastand southwestern Taiwan.
Eq. 6
Eq. 4
P h i l i p p i n e S e a p l a t e
P h i l i p p i n e S e a p l a t e
Eq. 6
Eq. 4
Eq. 6
Eq. 4
Earthquake 4:
Dec. 26, 2006
ML7.0
Earthquake 6:
Jul. 23, 2007
ML5.8
Declustered eq.
Distribution of seismicity during 2006-2010 compare with different fore-cast models through the Molchan diagram.
The smoothing Kernel shows a good forecasting ability. A better forecast-ing ability is obtained when the rate/state law are further integrated.
Significant seismic hazard increases are evaluated when earthquakes takeplace in vicinity, even through with small magnitudes.
According to the rate-and-state friction model, larger and longer hazardperturbations are expected when large earthquakes occur.
After eq. 4 After eq. 6Seis. rate change atdifferent time points
Eq. 1
Eq. 2
Eq. 5
Eq. 1
Eq. 2
Eq. 5
Areaforcalculation
Philippine
Japan
China
Areaforcalculation
Hualien city
Hualien city
Events during2006-2010
Events during2006-2010
Events after eq. 4 Events after eq. 6
