辽西兴城地区深反射地震剖面初步研究  

Study on deep seismic reflection profile in Xingcheng area of the western Liaoning Province

作　　者：姜弢[1,2] 徐学纯[3] 贾海青[1,2] 葛利华[1,2] 

机构地区：[1]教育部地球信息探测仪器重点实验室(吉林大学),长春130026 [2]吉林大学仪器科学与电气工程学院,长春130026 [3]吉林大学地球科学学院,长春130026

出　　处：《地球物理学报》2014年第9期2833-2845,共13页Chinese Journal of Geophysics

基　　金：深部探测技术与实验研究专项SinoProbe-09-06(201011083和201311197);高等学校博士学科点专项科研基金(20110061110053)联合资助

摘　　要：为了分析和研究辽西兴城地区深部地下结构,深部探测与实验研究专项SinoProbe在辽西进行了深反射地震实验研究.本文报告了在辽西东部进行的一次二维近垂直深反射地震实验结果,测线西起葫芦岛市西老爷庙村,东至兴城市区外首山附近的郭家店,方向约为北偏西33°,剖面全长21.93 km.在共中心点叠加剖面发现了5个主要反射波组,分别出现在双程走时6 s,6.5 s,7.5 s,8 s,10.4 s左右.论文对主要反射波组地球物理特征进行了描述、分析,并结合邻区深部地震资料研究成果,得出三点认识:一是研究区域地壳可分为上、下两层结构,上地壳内无明显反射层位,下地壳呈现"凹陷"特征;二是观测到来自莫霍面反射信号(10.4 s TWT),对应莫霍面深度约为30 km左右(速度按地壳平均速度6 km/s折算),莫霍面西深东浅,东部较西部约抬升600 m;三是本区域莫霍面可能由一组横向速度、厚度不一致的多个薄层构成.In order to study the crust structure in Xingcheng area,we did a deep reflection seismic experiment in the western Liaoning Province.This paper shows a 2D seismic profile in study area using a nearly vertical reflection method.The survey line starts from Xilaoye village in Huludao,and ends at Guojiadian near Shoushan,Xingcheng.The survey line is 21.93 km long and extended in 33° North West.We identified 5 main reflected waves,whose two way travel time is around 6 s,6.5 s,7.5 s,8 s,and 10.4 s,respectively.We described and analyzed geophysical characteristics of these reflected waves,and compared the data with other results from neighborhoods.Then we conclude that the crust in survey area is divided into upper and lower crust,and the upper crust has no obvious reflection,the lower crust shows ＂sunken＂ features10.4 s TWT signals from Moho are observed with high signal-to-noise ratio and good resolution,it tells us the depth of Moho here is roughly 30 km and Moho in the east end near Bohai is 600 m shallower than the other side;and Moho in the study area is composed of some thin layers with different velocity and thickness.

关 键 词：辽西 地震 反射 莫霍 

分 类 号：P541[天文地球—构造地质学] P315[天文地球—地质学]