台湾海峡大容量气枪震源海陆联测初探  

A preliminary exploration into onshore-offshore seismic experiment by using large volume air-gun source in Taiwan Strait

作　　者：姚道平 张艺峰 闫培 李普春 王笋 郭晓然 

机构地区：[1]厦门地震勘测研究中心,中国福建厦门361021

出　　处：《地震学报》2016年第2期167-178,328,共12页Acta Seismologica Sinica

基　　金：国家自然科学基金(41474071);中国地震局行业专项(2015419015)共同资助

摘　　要：本文利用在我国台湾海峡采用大容量气枪震源开展海陆联测获得的广角地震测线HX9,采用二维射线追踪法反演得到了HX9剖面的地壳二维速度结构和地壳界面形态,初步探明了福建—台湾海峡海陆过渡带的深部构造.结果表明:HX9剖面的地壳内存在两个速度间断面,即C界面和莫霍面,其中:C界面为上、下地壳的分界面,是一个小的速度不连续面,速度变化值达0.08—0.16km/s;而地壳底部的莫霍面则有较大的速度反差,变化值达1.02—1.29km/s,莫霍面上、下的速度分别为6.75—6.97km/s和8.00—8.07km/s.沿剖面的地壳界面形态总体起伏不大,陆域上、下地壳的厚度和界面变化趋势均相似,从陆域到海域呈微倾斜变化趋势,表现为减薄陆壳的特征.莫霍面陆域埋深约为31.6km,向福建东南沿海逐渐减薄至27.4km左右.This paper revealed the 2-D crustal velocity structure and interface morphology by inversion of the 2-D ray tracing method along the survey line HX9 conducted by onshore-offshore seismic experiment using the large volume air-gun source in Taiwan Strait, preliminary ascertaining the deep crustal structures of the sea-land transition zone between Fujian land and Taiwan Strait. The results show that there are two velocity discontinuities in the earth＇s crust, i.e., C and Moho interfaces. C interface, as a demarcation between the upper crust and lower crust, is a small velocity discontinuity, with the velocity rang- ing 0.08-0. 16 km/s; whereas for the Moho interface at the bottom of crust, there is a large velocity difference being 1.02-1.29 km/s. The velocity above the Moho interface is 6.75-6.97 km/s, and that beneath the Moho interface is 8.00-8.07 km/s. Along the profile, the overall crustal interface morphology is less volatile. The thickness and its variation tendency in the upper crust are similar to those lower crust of continental area. However, the crustal interface has slightly tilted trends from land to sea, suggesting the characteristic of thinned continental crust. The Moho interface is about 31.6 km deep in the continental area, and gradually thins to about 27. 4 km in the southeast coast of Fujian.

关 键 词：大容量气枪震源 台湾海峡 海陆联测 深部构造 

分 类 号：P315.2[天文地球—地震学]