Evidence on non-self-similarity source scaling in cluster earthquakes Yen-Yu Lin 1 , Kuo -Fong Ma 1 , Hiroo Kanamori 2 , Teh-Ru Song 3 , Nadia Lapusta 2 , Victor Tsai 2 1 Department of Earth Sciences, National Central University, Taiwan 2 Seismological Laboratory, California Institute of Technology, USA 3 Department of Earth Sciences, University College London, UK IES 2014/3/19
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Evidence on non-self-similarity source scaling in cluster earthquakes Yen-Yu Lin 1, Kuo -Fong Ma 1, Hiroo Kanamori 2, Teh-Ru Song 3, Nadia Lapusta 2, Victor.
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Evidence on non-self-similarity source scaling in cluster earthquakes
Yen-Yu Lin1, Kuo -Fong Ma1, Hiroo Kanamori2, Teh-Ru Song3, Nadia Lapusta2, Victor Tsai2
1Department of Earth Sciences, National Central University, Taiwan2Seismological Laboratory, California Institute of Technology, USA
3Department of Earth Sciences, University College London, UK
Tw=0.020~0.054 s (a constant for each cluster)Source dimension=40~110m
Q=202
Q=101
13
8 1/302.4 10wT M
Comparison to earthquake self-similarity empirical relation (9.2>M>6.5)
Source scaling for the clusters
(Duputel et al., 2013)
Clusters with the constant P-wave durations observations break down the earthquake self-similarity behavior.
Power of 0.04(1/20)~0.10(1/10)
Constant rupture speed “a characteristic length “
Rupture speed and source dimension
a constantwrup
rT
V It can be constrained by
source time function estimations.
0r M 0if rupV M
If α=1/3, earthquake self-similarity!But, selection of α can be arbitrary!- Any specified α could also be another possible model to explain
the unique observations.
Summary
- We discovered 3 clusters with constant P-phase durations (Pdur) for events Mw 0.5 to 2.0 in TCDPBHS records, which had been shown to be natural events from deformed zone of decollement.
- The constant P-phase durations observations in the clusters break down the earthquake self-similarity behavior of Tw ∝ Mo(1/3) as examined by both the empirical Green’s function and Futterman Q correction analyses based on assumption of a constant rupture speed.
- A potential model to explain the constant Pdur phenomenon is an existence of a characteristic length on the fault, limiting the duration of the source time function.
- The difference in high frequency component between smaller and larger events might be due to the heterogeneity of fault.
- If not characteristic length related, another possibility is the significant difference in rupture speed among the cluster events.