1)Zhongwei Seismostation of Earthquake Administration of Ningxia Hui Autonomous Region,Zhongwei 7550002)Institute of Geophysics,CEA,Beijing 1000813)Earthquake Administration of Zhejiang Province,Hangzhou 310013
Abstract Using the Brune model (1970) and the digital seismic wave data of Ningxia and the adjacent regions, which was recorded by Ningxia seismic network, we transferred the recorded velocity spectrum into hypocenter displacement spectrum by geometry diffusion correction, dielectric attenuation correction and instrumental correction. The corner frequency and zero frequency were calculated by using genetic algorithm,further,the hypocentral parameters including hypocentral radius and seismic moment were calculated and the relationships among them were analyzed systematically. 186 earthquake events from ML1.7 to ML4.4 which occurred from June, 2003 to December,2007 were studied. The estimated results show that the relations between seismic moment, bodywave magnitude, rupture radius and corner frequency are near loglinear or semi-loglinear. Seismic stress drop and apparent stress show little obvious correlation with hypocenter radius, but display positive correlation with seismic moment. Compared with other regions, there are lower stresses released in the studied region.
