[1]ZHANG Pei,ZHOU Cong,Wang Wenqing,et al.Study on the Seismic Wave Velocity Variation around the Anninghe-Zemuhe Fault Zone by Ambient Noise Cross-correlation[J].Journal of Seismological Research,2024,47(04):493-502.[doi:10.20015/j.cnki.ISSN1000-0666.2024.0045
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Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
47
Number of periods:
2024 04
Page number:
493-502
Column:
Public date:
2024-08-20
- Title:
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Study on the Seismic Wave Velocity Variation around the Anninghe-Zemuhe Fault Zone by Ambient Noise Cross-correlation
- Author(s):
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ZHANG Pei1; 2; ZHOU Cong1; Wang Wenqing1; Chai Xuchao1; LIU Geng1; SHI Kexu1
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(1.The Second Monitoring and Application Center,China Earthquake Administration,Xi'an 710054,Shaanxi,China)(2.Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)
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- Keywords:
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ambient noise; the Xichang array; the Anninghe-Zemuhe fault zone; wave-velocity variation
- CLC:
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P315.2
- DOI:
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10.20015/j.cnki.ISSN1000-0666.2024.0045
- Abstract:
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We presented the 6-year continuous changes of the seismic wave velocity from 2013 to 2018 around the Anninghe-Zemuhe fault zone.The continuous waveforms recorded by the Xichang array consisting of 23 broadband stations,and ambient noise correlation techniques were used to calculate the wave velocity changes in five different period bands.A significant characteristic of the seasonal variation of the wave velocity changes was observed in the period band of 1-3 s:from June to October each year,the relative wave velocity changes(dv/v)showed a trend of slow decreasing,and the error of the speed change was small.The relative speed change from January to May showed the characteristics of random change with larger errors.Referring to the local meteorological data,we speculated that the wave velocity changes may be related to the pore pressure changes caused by seasonal precipitation.The velocity changes in the 3-8 s period band were discretely distributed,while velocity changes in the period bands 6-15 s and 8-20 s were weaker and fluctuated near the zero line,this indicated that the middle and lower crustal media were in a relatively stable state.In the focal area of the Shimian MS4.5 earthquake,we had also detected wave velocity reduction at some paired-station in the 1-4 Hz frequency band.Although there were frequent small earthquakes in Shimian region,no surface rupture had been spotted yet.It is more likely that the opening or closing of shallow cracks induced by ground motions contributes to the changes in wave velocity.