由深源远震体波记录反演华北北部地壳上地幔速度结构
|
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。
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 ac 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 were given, and based on this, the outline of Moho surface was given.
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 ac 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 were given, and based on this, the outline of Moho surface was given.
引文
1Langton，C．A．andHelmberger，D．V，AProcedureformodelingshallowsources，Geophys．J．R．Astron．Soc．42，117—130，1975．2Richards，P．G，Theapparentattenuagionofascatteringmedium，Bull，SeismSocAmer，23，1983．3朱碚定，李幼铭．利用深源远震记录波形研究台站区域的介质结构．地球地理学报，1985，28（1）：16～254朱碚定，李幼铭，张立敏，束沛镒，梁尚鸿．川南、滇北地区台网区域壳幔介质分层结构的初步研究．地球物理学报，1986，29（3）：245—2545李祥，包东健，陈原平，束沛镒，朱磅定．内蒙古中部地区壳幔介质分层结构．华北地震科学，1987，5（4）：58—656姚殿义，于利民，李铁祖，束沛镒，李幼铭．利用合成地震图研究东北地区壳幔介质结构．地震学报，1991，13（4）：471—4797国家地震局《深部物探成果》编写组．中国地壳上地幔地球物理探测成果．北京；地震出版社，1986．
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心