宁夏区域震源参数特征研究

摘要

利用宁夏区域数字地震台网记录的发生于宁夏区域2008～2014年210个ML2.0～4.9地震波资料,采用Brune模式,将台站获取的速度记录进行几何扩散校正、介质衰减校正及仪器校正,对速度谱在频率域积分得到震源位移谱,使用遗传算法计算拐角频率及零频极限,进而计算震源半径、地震矩等小震震源参数,并系统分析各参数特征及其相互关系.结果显示,地震矩范围为10111～1015 N·m,震源破裂半径为60～766 m,拐角频率为1.6～22.2 Hz,地震应力降范围为0.01～7.63 MPa,视应力范围为0.01～3.11MPa,地震矩、拐角频率、矩震级及里氏震级等震源参数之间表现出一定的对数线性或半对数线性关系.%According to seismic wave data recorded by the regional digital seismic network of Ningxia regions,we get the Fourier spectrum with use of the Fourier transform,after speed records of stations geometrical diffusion correction,dielectric attenuation correction,and instrument correction using the Brune model.The Fourier spectrum is integrated to obtain the source displacement spectra in the frequency field,then the corner frequency and zero frequency.Using the radius of the epicenter,the earthquake moments and other small local earthquake source parameters are acquired using genetic algorithms.Finally,we systematically analyze the characteristics of source parameters and the relationship between the various parameters.The paper researches 210 earthquakes of Ningxia regions with ML2.0～4.9,occurring between 2008 and 2014.The results are as follows:the range of seismic moment is 1011～1015 N·m,the range of source radius is 60～766 m,the corner frequency is 1.6～22.2 Hz,seismic stress drop is in the range of 0.01～7.63 MPa,and apparent stress is in the range of 0.01～3.11 MPa.Some log-linear or semi-logarithmic linear relationships are shown between seismic moment,corner frequency,Richter magnitude,moment magnitude,and other source parameters.