Seismogenesis of Badong Earthquake (M s 5.1)in Three Gorges Reservoir Area and Infrasound Anomaly
Li Xianrui
Zeng Zuoxun
Zhou Qiang
He Chicheng
Liu Jiangping
Zhao Juan
Pan Lili
Abstract：On 1 6 December,2013,an earthquake of M s 5.1 occurred in the Badong County,the Three Gorges reservoir area, China.Using the EIGEN-6C2 model,the satellite 8-638 order gravity anomalies in this area were studied.The results show that there is a regional low gravity anomaly beneath Badong area at 10 km,which may imply that rock density this area of is lower than its surroundings.Meanwhile,the profiles of crustal velocity structure of this area indicate the existence of two low-velocity layers at depth of 5-9 km and 10-1 5 km respectively.We believe that the upper layer is closely related to the reservoir seep-age and the lower layer may result from the upwelling of the mantle hydrothermal fluid.The low-density layer and the two low-velocity layers provide an evidence for the existence of a possible ductile layer.The occurrence of Badong earthquake is due to the long-term energy accumulation and abrupt release at the deep crust,thus it is a tectonic earthquake.The low-velocity anom-aly in the upper crust caused by reservoir seepage decreased the threshold value of fault activities and the change of water load of this reservoir might trigger the Badong earthquake.By comparing the infrasound with seismic waves,we conclude that the infrasound anomalies recorded by the infrasound monitor array are local infrasound.
Keywords：Badong earthquakesatellite gravity anomalydeep structural conditionreservoir-triggered earthquakeinfrasound anomalyearthquake
Publication Date：2014-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：14( 1793-1806 )