地震工程学报Issue(4)：1019-1025,7.DOI:10.3969/j.issn.1000-0844.2014.04.1019
唐山4.8级地震前后视应力变化研究
Variations in Apparent Stress Prior to and after the Tangshan M S 4.8 Earthquake
摘要
Abstract
On May 28,2012,an earthquake of MS 4.8 occurred in Tangshan,and was followed by earthquakes of MS 4.0 and MS 3.5 in Baodi.Data from this series of earthquakes (Tangshan MS 4.8, and the Baodi MS 4.0 and MS 3.5 earthquake series,from January 201 1 to June 2013),recorded by the Digital Seismic Network in Tianjin,were used to calculate the apparent stress in this region. First,the multi-window FFT was used to obtain the observed spectrum,and then after extracting the instrument response it was corrected for geometry spreading and attenuation.For geometry spreading correction,Gail’s three section geometry spreading model was used.The frequency-de-pendent Q value was used for inelastic attenuation correction.A genetic algorithm was applied to determine the pair of f C andΩ0 of Brune’sω2 model,which yields the least deviation between the theoreticalω2 model and the corrected spectral.The seismic moment (M 0 )was calculated fromΩ0 ,and ES was obtained by integrating the corrected spectral with limited bandwidth compensa-tion.Apparent stress was calculated from M 0 and ES.Furthermore,the time distribution of appar-ent stress and the average value of apparent stress are presented.The results are as follows:First, a high apparent stress appeared before the MS 4.8 earthquake and its peak value appeared at the mainshock;then,the apparent stress decreased after the MS 4.8 earthquake.The size of the appar-ent stress accurately reflects the state of the stress field in the hypocenter region.Therefore,it can be used as the basis for determining the seismic trend.Second,the apparent stress before and after the MS 4.8 earthquake is generally positively correlated.The apparent stress increases with magni-tude,but,on the whole,the apparent stress value is greater before the MS 4.8 earthquake than af-ter.关键词
唐山 4.8 级地震/视应力/数字地震台网/辐射能量/地震矩Key words
Tangshan MS 4.8 earthquake/apparent stress/digital seismic network/radiated energy/seismic moment分类
天文与地球科学引用本文复制引用
李赫,刘双庆,刘文兵,王熠熙,尚先旗,谭毅培,胡培元,高也..唐山4.8级地震前后视应力变化研究[J].地震工程学报,2014,(4):1019-1025,7.基金项目
地震科技星火计划(XH14002Y) （XH14002Y）
2014年度震情跟踪专项青年工作任务(2014020306) （2014020306）
天津市地震局局内课题(20131008) （20131008）
