Study on the Influence of Ground Motion Field of Scenario Earthquake in Mining Area of Huating,Gansu

The study of distribution of strong ground motion is one of the crucial tasks in earthquake engineering.Near-fault strong ground motion is the basis for establishing building codes for the field of earthquake engineering and it has significant applicability in the field of earthquake engineering.It is important to estimate a suitable building code for an industrial area,and even for a mining area,which may be located in or near potential sources of earthquakes.Several studies have focused on the physics of strong ground motion during an earthquake.Results of such studies have demonstrated a strengthening phenomenon of earthquake activity and the outputs of cool mines in Huating region,Pingliang City,Gansu province,from 2001 onward.The acceptable conclusion is that this strengthening phenomenon is caused by mining in Huating region.In this study,we analyze the earthquake activity of Huating region in Gansu province on the basis of earthquake data from 2001 onward that were downloaded from earthquake networks centers of Gansu province and the China earthquake networks center.Specifically,the mining-induced earthquake data from 2001 to 2008are based on the catalog and study results of earthquake networks centers of Gansu province,and the mining-induced earthquake catalog from 2009 to 2013is based on the results of the China earthquake networks center.As an example,the distribution of strong ground motion around the Liupanshan southern segment fault was predicted under simulated earthquake activity that included recent earthquake trends in the northern segment of the north-south seismic belt.A special finite fault source model was constructed for this simulated earthquake located on the Liupanshan southern segment fault.Further,the strong ground motion,including acceleration and velocity,near the causative fault was calculated using the finite fault source model.Next,the characteristics of these simulated accelerations and velocities were studied and their respective peak values were calculated.As another useful and essential example,the near-fault ground motion distribution of Changchun City was predicted under a setting earthquake.After the occurrence of an Ms 6.0earthquake on the Jianshanzi-Kalun fault,the influence range of potentially destructive ground motion lied near the fault,and the distribution of this influence range was along the fault.The peak acceleration reached 200cm/s2.Based on these results,we considered an M7earthquake to occur on the Liupanshan southern segment fault,whose influence range was along the fault;the variation in the peak acceleration along the fault of the Liupanshan eastern segment of the west Qinling seismic gap was up to 1 500cm/s2.The study area included three mining regions:the Huating region,Ningxian south mining region,and Ningxian middle mining region.The Huating region is located near the eastern boundary of the Liupanshan eastern segment of the west Qinling seismic gap,almost 30km.The peak ground acceleration in Huating region is 100cm/s2,and those in the Ningxian south and Ningxian middle mining regions are 50cm/s2 each.The numerical modeling developed in this study has high potential for applicability in the estimation or prediction of ground motion for earthquake engineering.Furthermore,the numerical algorithm could also be used to generate a near-real-time shaking map at the implementation level if the current finite fault inversion technique is applied.