河北地区Pb震相识别及康拉德界面分析  

Identification of Pb Seismic Phase and Conrad Discontinuity in Hebei Area

作　　者：王莉婵 李雪英[1] 蔡玲玲[1] 王宁[1] 赵英萍[1] WANG Lichan;LI Xueying;CAI Lingling;WANG Ning;ZHAO Yingping(Hebei Earthquake Agency,Shijiazhuang 050021,China)

机构地区：[1]河北省地震局

出　　处：《华北地震科学》2019年第3期10-17,共8页North China Earthquake Sciences

基　　金：2017年河北省地震科技星火计划项目(DZ20170503010)

摘　　要：基于河北测震台网现用速度模型,利用走时方程计算得到河北地区Pb震相的盲区范围大致为70km左右,作为初至震相的起始震中距范围为90~120km,作为后续震相的起始震中距范围为135~150km;收集近年京津冀地区2.0级以上地震88条,根据Pb震相理论波形特征,以及理论波形与实际波形到时比对,最终识别到158个有效Pb震相,拟合速度为6.69km/s,康拉德界面埋深21km,并得到河北地区Pb震相实际波形特征,弥补了河北台网Pb震相空白;利用Pb震相的射线分布,分析认为康拉德界面在河北北部山区发育程度较好,南部次之,中部渤海湾盆地地区连续性最差。Based on the current using velocity model of Hebei Seismic Network,the range of earthquake distance that the Pb phase can be found is calculated with travel time equation.The blind zone of Pb phase is about 70 km,and the range of initial epicentre which the Pb phase can be found as the first phase is from90 to 120 km,and the range of initial epicentre which the Pb phase can be found as the later phase is from135 to 150 km.88 seismic waves were collected in this article to recognize Pb phase according to the theoretical waveform characteristics and the time comparison between the theoretical and actual waveform.Finally 158 effective Pb phase were recognized,and the velocity of Conrad discontinuity is 6.69 km/s,the depth of Conrad’s discontinuity is 21 km.We summarize the actual waveform characteristics of Pb phase in Hebei area and make up for the blank of Pb phase of Hebei Seismic Network.Based on the radiation distribution of Pb phase,it is found that Conrad’s discontinuity developed well in the mountainous area of northern Hebei,followed by the South,and the least continuous area in the central Bohai Bay basin.

关 键 词：Pb震相 走时方程 折合走时 PTD深度测定 康拉德界面 

分 类 号：P315.31[天文地球—地震学]