海南岛及近海波速比特征初步研究  

Preliminary Study on the Wave Velocity Ratio(v_P/v_S) in Hainan Island and Offshore Areas

作　　者：张慧[1] 李志雄[1] 李盛[1] ZHANG Hui,LI Zhixiong,LI Sheng(Earthquake Administration of Hainan Province , Haikou 570203, Hannah, Chin)

机构地区：[1]海南省地震局,海南海口570203

出　　处：《地震工程学报》2018年第3期524-534,共11页China Earthquake Engineering Journal

基　　金：海南省地震局科研任务(HDKJ201608)

摘　　要：基于"广义重复地震"的思路,收集整理1990—2015年海南岛及近海地震丛发区事件,利用单台单震法呈现海南台网至海南岛及近海显著地震丛发区的波速比特征,初步探讨研究区地壳介质物性信息。结果表明:(1)地震丛至单台的整体平均波速比低于理想体的1.732,2008年前后各台站的平均波速比及波速比随时间变化特征有明显差异,这可能与2007—2008年研究区地震活动较长时间平静后的应力调整以及2008年汶川地震应力传递作用有关;(2)地下介质的破碎程度及流变性影响波速比:地下岩石破碎程度高,介质流变性强可能会造成台站波速比相对高值,如QXL台、DOF台、CHM台、NAD台、SLL台等;(3)琼中南隆起区地下介质较致密、稳定,除特殊介质区的NAD台、CHM台、DOF台,其他台站波速比呈现相对低值;(4)2008年前后各地震丛发区视速度特征有差异,地震活动也存在明显不同,研究区可能处于应力调整状态;铺前—清澜断裂东西两侧呈现完全不同的视速度,主要影响来自岩性的不同以及火山地区热物质上涌等热作用过程。The observation of the earthquake cluster from 1990 to 2015 in Hainan Island and its coastal areas was collected based on the idea of a ＂generalized repeat earthquake＂.This study investigates the wave velocity ratio（vP/vS）of the earthquake cluster zone to different stations around using the single station-single earthquake method and preliminarily analyzes the physical properties of the subsurface medium in the study area.The results showed that：（1）The average wave velocity ratio of the earthquake cluster to the single station was lower than 1.732.Before and after 2008,significant differences were found in the variation characteristics of the average velocity ratio and the velocity ratio with time,which may be related to the stress adjustment after the long-period seismic activity in the study area during2007—2008 and to the stress transfer of the 2008 Wenchuan earthquake.（2）The vP/vSratio was affected by the crushing degree and the rheological property of the subsurface medium.A high rupture degree of underground rocks and a strong rheological property of the medium may cause a relatively high velocity ratio of stations,such as the QXL,DOF,CHM,and NAD stations.（3）The underground medium in the uplift area of the central-southern Hainan was compact and stable.Aside from the NAD,CHM,and DOF stations in the special medium area,the wave velocity ratio of the other stations showed relatively low values in this area.（4）Before and after 2008,differences in the apparent velocity features and the seismic activities in different seismic cluster zones were found,which may indicate that the study area was in a state of stress adjustment.The different apparent velocities in the east and west sides of the Puqian—Qinglan fault were mainly affected by different lithologies and the thermal process in volcanic areas.

关 键 词：海南岛及近海 波速比 地下介质 

分 类 号：TU17[建筑科学—建筑理论]