The focal mechanisms of 62 moderate-small earthquakes since 1980 in the"Huoshan seismic window"region are calculated with the method developed recently by Snoke,combining the use of the first motion of P,SV ...The focal mechanisms of 62 moderate-small earthquakes since 1980 in the"Huoshan seismic window"region are calculated with the method developed recently by Snoke,combining the use of the first motion of P,SV and SH waves with their amplitude ratios.Based on these abundant focal mechanisms,the mean tectonic stress field in the"Huoshan seismic window"region is inverted with the average stress tensor method,and the result shows that the"Huoshan seismic window"region is horizontally compressed in the near EW direction and horizontally dilated in the near NS direction,which is in accord with statistical results of focal mechanism parameters.We estimate the difference(also referred to as consistency parameterθ)between the force axis direction of the focal mechanism solution and the mean stress tensor,then further analyze the variation characteristics ofθversus time,and the relationship with moderately strong earthquakes in the east China region.The result indicates thatθin the"Huoshan seismic window"region is in good correspondence with moderately strong earthquakes in the East China region.Whenθis lower than the mean value,corresponding moderately strong earthquakes may occur in the East China region.展开更多
The Anqing MS4.8 earthquake occurred on January 19, 2011, with the epicenter lying in the foreland deformation belt along the Yangtze River of the lower Yangtze block. After the earthquake, the field work team surveye...The Anqing MS4.8 earthquake occurred on January 19, 2011, with the epicenter lying in the foreland deformation belt along the Yangtze River of the lower Yangtze block. After the earthquake, the field work team surveyed and collected building damage data, calculating and obtaining more accurate intensity distributions. The focal mechanism of the main shock was calculated tentatively using digital seismic wave data from provincial digital seismic networks using the FOCMEC program and the first motions of P, SV and SH waves with their amplitude ratios. Using the location results of the main shock and aftershocks by the Anhui seismic network, combining the three-dimensional crust velocity structure imaging results of the focal region by seismic tomography, and referring on intensity distribution of the elliptic major axis' predominant direction, we conclude by comprehensive analysis that the NE-trending Susong-Zongyang fault is possibly the causative fault of the Anqing earthquake.展开更多
基金funded by the Youth Program of Earthquake Scientific Research Fund of Anhui Province(20120704)Contract Subject of Earthquake Administration of Anhui Province(201210)
文摘The focal mechanisms of 62 moderate-small earthquakes since 1980 in the"Huoshan seismic window"region are calculated with the method developed recently by Snoke,combining the use of the first motion of P,SV and SH waves with their amplitude ratios.Based on these abundant focal mechanisms,the mean tectonic stress field in the"Huoshan seismic window"region is inverted with the average stress tensor method,and the result shows that the"Huoshan seismic window"region is horizontally compressed in the near EW direction and horizontally dilated in the near NS direction,which is in accord with statistical results of focal mechanism parameters.We estimate the difference(also referred to as consistency parameterθ)between the force axis direction of the focal mechanism solution and the mean stress tensor,then further analyze the variation characteristics ofθversus time,and the relationship with moderately strong earthquakes in the east China region.The result indicates thatθin the"Huoshan seismic window"region is in good correspondence with moderately strong earthquakes in the East China region.Whenθis lower than the mean value,corresponding moderately strong earthquakes may occur in the East China region.
基金funded by the Key Research Program of "Tracking the Southern Section of the Tancheng-Lujiang Fault Zone and Study on the Earthquake Risk in Its Vicinity among 2011 National Seismic Risk Zones " (2011013301)the Youth Projects of Earthquake Research Fund of Anhui Province,2011 (20110403)
文摘The Anqing MS4.8 earthquake occurred on January 19, 2011, with the epicenter lying in the foreland deformation belt along the Yangtze River of the lower Yangtze block. After the earthquake, the field work team surveyed and collected building damage data, calculating and obtaining more accurate intensity distributions. The focal mechanism of the main shock was calculated tentatively using digital seismic wave data from provincial digital seismic networks using the FOCMEC program and the first motions of P, SV and SH waves with their amplitude ratios. Using the location results of the main shock and aftershocks by the Anhui seismic network, combining the three-dimensional crust velocity structure imaging results of the focal region by seismic tomography, and referring on intensity distribution of the elliptic major axis' predominant direction, we conclude by comprehensive analysis that the NE-trending Susong-Zongyang fault is possibly the causative fault of the Anqing earthquake.
