INVERSE OF VELOCITY STRUCTURE OF UPPER MANTLE OF CRUST IN NORTHERN PART OF NORTH CHINA BY BODY WAVE RECORDINGS OF DEEP FOCUS DISTANT EARTHQUAKES
摘要: 重点研究的地区为河北省北部包括京津地区,以及山西、内蒙的部分地区,在此区选取了29个台站;在向东延伸的背景区,选取了6个台站。利用这些台站的深源远震体波记录资料,通过选取介质结构模型,计算理论地震图,与观测图进行拟合,以确定地震台下介质结构的可接受模型。在拟合时,对每个地震台站都选择若干次深源远震的体波记录作为观测图。对每个地震台站一般都算出60个不同模型的理论图。实际上做出的结果比地壳深,为大约80km(即大致相当于岩石层或称岩石圈)厚度内的地壳上地幔介质结构,它们大都由10层左右的介质组成。通过波形拟合共给出了上述35个台站下的壳幔介质分层结构。并由此给出了Moho面的轮廓。Abstract: The studied area is the northern part of Hebei province, including Beijing-Tianjin region and some regions in Shansi prevince and the Inner Mongolia Autonomous Region.29 seismic stations were selected in this area and 6 selected in the east-extending background area.By the body wave of deep focus distant earthquakes from those stations and by selecting the medium strucgure medel, the theoretical seismograms were calculated,which were fitted with the observed seismograms so as to define an acceptable model for the medium structures under the seismic stations.In titting,for each seismic station,the body wave recordings of deep focus distant earthquakes were selected for several times to be as observed seismograms.Urually,for each seosmic station,the theoretical seismograms of 60 different models were calculated.In fact,the obtained result is deeper than the crust,being the medium structure of upper mantle of the crust in the depth of about 80 kms (that is, roughly corresponding to the lithostrome or called lithosphere),they all consist of about 10 layers of media.By wave form fitting, the medium stratified structures of the mantle under above mentioned 35 seismic stations wete given, and based on this,the outline of Moho surface was given.
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