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[1]LI Jiao,JIANG Jinzhong,WANG Guangming,et al.Focal Mechanism and Focal Depth Determination of the Two Tonghai,Yunnan,MS5.0 Earthquakes in 2018[J].Journal of Seismological Research,2021,44(02):133-144.

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Focal Mechanism and Focal Depth Determination of the Two Tonghai,Yunnan,M_S5.0 Earthquakes in 2018

Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume: 44 Number of periods: 2021 02 Page number: 133-144 Column: Public date: 2021-06-30

Title:: Focal Mechanism and Focal Depth Determination of the Two Tonghai,Yunnan,M_S5.0 Earthquakes in 2018

Author(s):: LI Jiao; JIANG Jinzhong; WANG Guangming; FU Hong; (Yunnan Earthquake Agency,Kunming 650224,Yunnan,China)

Keywords:: Tonghai earthquake; CAP method; sPn depth-phase; focal mechanism; focal depth

CLC:: P315.33

DOI:: -

Abstract:: Accurate earthquake parameters(e.g.focal mechanism and depth)are crucial for understanding the seismogenic mechanism.Based on waveforms of the 2018 Tonghai,Yunnan,M_S5.0 earthquakes recorded by more than 30 broadband seismic stations of the Yunnan Earthquake Networks,we invert their focal mechanisms and depths by using Cut-and-Paste(CAP)method and three different regional velocity models.We also employ sPn depth-phases recorded by different stations situated at the azimuth of ～300° to estimate the focal depth of the Tonghai M_S5.0 double earthquakes.The results are as follows:① Based on more broadband waveforms of near-earthquakes with better azimuth coverage,the obtained centroid depths(8 km and 7 km)of the two earthquakes inverted from different velocity models and frequency bands are more reliable.② By using sPn depth-phases at different stations with similar azimuth(～300°),we determine that the initial rupture depth of the two earthquakes are both about 10 km,which may indicate the rupture directivity(from bottom to top)of the earthquakes.③ According to the Double-difference relocation and our CAP inversions,we preliminarily infer that the Tonghai double earthquakes should occur on the same fault plane,whose parameters,strike/dip/rake,could be 20°/75°/-10°.

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Last Update: 2021-06-30