[1]YANG Jianwen,YE Beng,GAO Qiong,et al.Study of the Wave Velocity Changes in the Focal Area of the Tonghai MS5.0 Earthquake and the Mojiang MS5.9 Earthquake by Ambient Noise[J].Journal of Seismological Research,2021,44(04):529-540.
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Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
44
Number of periods:
2021 04
Page number:
529-540
Column:
Public date:
2021-11-10
- Title:
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Study of the Wave Velocity Changes in the Focal Area of the Tonghai MS5.0 Earthquake and the Mojiang MS5.9 Earthquake by Ambient Noise
- Author(s):
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YANG Jianwen1; 2; YE Beng1; 2; GAO Qiong1; 2; WANG Jun1; 2; CHEN Jia1; 2
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(1.Dali Center of China Earthquake Science Experimental Site,Dali 671000,Yunnan,China;2.Field Scientific Observation and Research Station on Crustal Tectonic Activities in Dali,Northwest Yunnan,Dali 671000,Yunnan,China)
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- Keywords:
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ambient noise; waveform cross-correlation; the empirical Green's function; wave velocity change
- CLC:
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P315.3
- DOI:
-
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- Abstract:
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Based on the ambient noise cross-correlation method,we extract the travel time shift of the direct Rayleigh-wave of the daily empirical Green's function and the referential empirical Green's function of 14 station pairs to study the characteristics of the wave velocity changes in the source region of the Tonghai MS5.0 earthquake and the Mojiang MS5.9 earthquake by using continuous seismic data recorded by the broadband stations of the Yunnan Digital Seismic Network from January 2017 to December 2019.The results show that the seismic velocity are changed in the source region by the Tonghai MS5.0 earthquake and the Mojiang MS5.9 earthquake in 2018 to a certain extent.Before and after the two earthquakes,the travel time shift of the Rayleigh wave of the station pairs passing through the epicenters and their vicinity shows obvious abnormal characteristics about 20 days before the earthquakes,and the travel-time changes are synchronous in the short term but there are some differences between the amplitude and the lasting-time of the anomaly of the two earthquakes.The abnormal travel-time shift of the station pairs is V-shaped or double V-shaped,and both earthquakes occurred before the appearance of the first V-shape.The average travel-time shift of multi-station pairs show that the seismic velocity changes in the source region caused by the Tonghai MS5.0 and the Mojiang MS5.9 earthquakes both last about 260 days.The anomaly of the Tonghai earthquake last longer than the one of the Mojiang earthquake,but in the early stage the travel-time shift is more obvious and the lasting-time of the anomaly caused by the Mojiang earthquake is longer than those caused by the Tonghai earthquake.