Details

Autor(en) / Beteiligte

• Zhou, Yijian
• Yue, Han
• Zhou, Shiyong
• Fang, Lihua
• Zhou, Yun
• Xu, Lisheng
• Liu, Ziming
• Wang, Teng
• Zhao, Li
• Ghosh, Abhijit

Titel

Microseismicity along Xiaojiang Fault Zone (Southeastern Tibetan Plateau) and the characterization of interseismic fault behavior

Ist Teil von

• Tectonophysics, 2022-06, Vol.833, p.229364, Article 229364

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The Xiaojiang Fault (XJF) Zone locates in the southeastern of Tibetan Plateau and defines the boundary between the South China and Sichuan-Yunnan blocks. Historical large earthquakes were hosted on the XJF, though its seismic hazard in the near future is under debate. In this study, we utilize portable broad-band seismic network to unravel the microseismic activities along XJF, and to further investigate the fault structures and their properties. Adopting PALM, a newly developed earthquake detection algorithm, we obtained ~13,000 relocated events. The micro-seismicity reveals widespread off-fault structures showing conjugate geometry, while the major faults present low seismicity. The fault branches conjugate to the main-fault present intensive microseismicity, which hosts repeating events and presents high b-value. Regional GPS stations reflect slips are mostly concentrated along the XJF, while the slip rate on off-fault branches correlates with seismic activities on these structures. Combining with other recent seismological and magnetotellurics evidences, we suggest a low strength on these off-fault structures, which may partially release tectonic stress loading and serve as a barrier for future big earthquakes. On the XJF, the microseismic events are clustered on the fault junctions with low b-value. A special set of clusters between 25°N to 25.5°N show an along-strike variation of depth from 10 to 25-km, imaging the boundary between creeping and locked fault portions. We revisit the seismic hazard problem of XJF, and conclude that XJF is at the late stage of inter-seismic period. •We obtained a high-resolution interseismic catalog (2016–2019) for the Xiaojiang Fault Zone.•Widespread microseismicity are detected on off-fault structures, but the major fault shows low seismicity.•The major Xiaojiang fault is strongly locked with low b-value, and could be at a late stage of interseismic loading.•The off-fault structures generate intense microseismicity, repeaters, and high b-values, indicating a weak crustal strength.