[1]LIU Li-fang,SU You-jin,LIU Jie,et al.Study on Temporal and Spatial Features of Stress Drop for Low-to-moderate Earthquakes in Sichuan and Yunnan Region[J].Journal of Seismological Research,2010,33(03):314-319.
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Study on Temporal and Spatial Features of Stress Drop for Low-to-moderate Earthquakes in Sichuan and Yunnan Region
Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
33
Number of periods:
2010 03
Page number:
314-319
Column:
Public date:
2010-03-01
- Title:
- Study on Temporal and Spatial Features of Stress Drop for Low-to-moderate Earthquakes in Sichuan and Yunnan Region
- Keywords:
- stress drop; generalized inversion technique; low-to-moderate earthquake; Longmenshan Mountain Fault Belt; Yunnan; Sichuan
- CLC:
- P315.63
- DOI:
- -
- Abstract:
- The observational S-waveform data are corrected by removing influential factors including the propagation route,site effects,instrument response and noise.Then,we obtained source spectra for the medium-small earthquakes.Based on Brune source model and by means of generalized inversion technique,we determined the stress drop(Δσ)of 2 121 earthquakes with ML2.0-5.3 in Yunnan region and those of 323 earthquakes with ML3.0-5.1 in Sichuan region,and we analyzed temporal and spatial features of the medium-small earthquakes in Yunnan and Sichuan Region.The results show that in Yunnan region the stress drop(Δσ)is 0.03-57.55 MPa.The earthquakes with Δσ≥10.0 MPa(higher stress drop)is 4.8% of the total,and the annual average of stress drop is 2.30-5.05 MPa.In Sichuan region,the stress drop is 0.19-47.47 MPa.The earthquakes with Δσ≥10.0MPa(higher stress drop)is 21.7%,and the annual average of stress drop is 5.11-8.72MPa.The earthquakes with Δσ≥10.0MPa(higher stress drop)mainly distribute from the Northwest to Northeast of Yunnnan region and along the boundary of Yunnan and Sichuan,especially in Longmenshan Mountain Fault Belt.The earthquakes with Δσ≥10.0 MPa in Longmenshan Mountain Fault Belt is 35.8%,and the annual average varies from 5.20 MPa to 12.09 MPa.The increase in the events with high stress drop from 2004 to 2007 reflects the high tectonic stress before the MS8.0 Wenchuan,Sichuan earthquake.
- References:
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Last Update:
2010-03-23