Seismogenic structure and stress triggering of the Tangshan Guye MS 5.1 earthquake in 2020
On July 12nd,2020,the MS 5.1 earthquake occurred in Guye,Tangshan.This paper primarily investigates the fault geometry and slip properties,as well as the stress triggering of subsequent after shocks.The main conclusions are as follows:① Regarding the seismogenic structure,based on the precise seismic relocation results of the Guye earthquake,the improved fuzzy clustering analysis method was used to calculate the fault geometry and spatial distribution of the fault.The strike of the fault is 230.2°,and the dip angle is 86.2°.Based on the focal mechanism,the tectonic stress field of the region was obtained,and project the tectonic stress field onto the seismogenic fault plane,the slip angle of the fault was-177.2°.② In terms of stress triggering,thepaper derives the earthquake rupture model based on empirical formulas,the fault length is 3.9 m and width is 4.4 m,and a fault slip is 0.02 m;Based on the rupture model and PSGRN/PSCMP software packages,we calculated the earthquake stress triggering on MS 4.3 aftershock and other aftershocks.The results shows that the triggering by the main shock on aftershocks varies at different depths,with the highest proportion of stress triggering on aftershocks at the depth of 12 km.When calculating the triggering of the MS 5.1 earthquake on the MS 4.3 earthquake,we found that the magnitude 4.3 earthquake was located in the area where the Coulomb stress change caused by the MS 5.1 earthquake was positive,indicating that the earthquake was triggered by the MS 5.1 event.The research results of this paper have certain significance for studying and understanding the seismogenic structure and seismic risk in Tangshan area.
Guye MS 5.1 earthquakefault plane fittingstress fieldstress triggering
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