OBH EXPERIMENT AND CRUSTAL STRUCTURE OF XISHA TROUGH,SOUTH CHINA SEA
OBH EXPERIMENT AND CRUSTAL STRUCTURE OF XISHA TROUGH,SOUTH CHINA SEA
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发表时间：
2000
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通讯作者：
Qiu Xue
中科院分区：
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作者：
Qiu Xue
作者分析了海底水听器(OBH)的数据，结果表明，该区新生代沉积层厚度为1~4公里，P波速度从基底顶部的5.5公里·S~(-1)增加到地壳底部的6.8公里·S~(-1)，下部地壳不存在高速层，前第三纪地壳厚度逐渐减小V P在莫霍面上的反差较大，从6.8 km·S-1跃升到8 km·S-1。西沙海槽两侧对称相似的地壳结构显示出新生代裂谷减薄陆壳的特征，几乎没有下地壳底侵。这与南海北部大陆边缘东部发现的那些有很大不同。
The authors analyzed the Ocean Bottom Hydrophone(OBH)data,which were available for the first time in the Xisha Trough of the South China Sea by the Sino Germany cooperation.The different seismic phases were identified and their travel time arrivals were modeled to study the P wave velocity and crustal structure of this area.The results show that the Cenozoic sedimentary layer on the top is 1—4 km thick .The P wave velocity increases from 5.5 km·s -1 on the top of the basement to 6.8 km·s -1 at the bottom of the crust.No high velocity layer appears in the lower crust.The pre Tertiary crustal thickness decreases gradually from 25 km on both sides to 8 km in the middle .The Moho interface is uplifted in the central part of the section.The V P has large contrast on the Moho and jumps from 6.8 km·s -1 to 8.0 km·s -1 .The symmetrical and similar crustal structure on the both sides of the Xisha Trough shows the characteristics of the thinned continental crust by Cenozoic rifting.There is little lower crust underplating,which is very different from those found across the eastern part of the continental margin in the northern South China Sea.