摘要
中国及全球大陆不同构造域广泛存在壳内低速层.壳内低速层不仅与地壳表层金属、非金属矿床、油气资源及地壳变形密切相关,而且也是一些重大地震和活动断裂的发育场所.一般认为,地壳低速层反映了地壳物质的含水、热状态和部分熔融等信息,其研究对探讨地壳结构及其动力学演化有重要意义.本文总结了利用深地震测深资料的震相走时、振幅、相位信息识别壳内低速层的5种典型方法：1）Pg震相走时中断;2）低速层顶、底界面反射波走时曲线近似平行;3）30°～ 60°入射角范围内低速层顶界面反射转换波强于反射纵波;4）低速层底界面反射波强于顶界面;5）低速层顶界面反射波极性反转等.研究实例表明,以上方法为利用深地震测深资料揭示壳内低速层提供了有效途径。
Crustal low velocity layers are distributed in different tectonic regions in China's Mainland and other tectonic regions in the world. Crustal low velocity layers are not only strongly linked with metal and nonmetal deposit, oil and gas resource, crustal deformation, but also associated with some major earthquakes and active faults development places. It is generally thought that crustal low velocity layers contain information of fluid existing, partial melting and thermal condition. Thus, there is of great significance for exploring crust structure and its geodynamic evolution. This paper summarized five typical methods that using travel time, amplitude and phase characteristics to identify crustal low velocity layer in deep seismic sounding data： 1） termination of Pg phase; 2）approximate parallel between travel time curves of reflection from top of low velocity layer and from bottom of low velocity layer; 3） stronger P-to-S converted reflection than P-to-P reflection from top of low velocity layer in 30 - 60 degree incidence angle; 4）stronger reflection from bottom of low velocity layer than from top of low velocity layer ; 5） polarity reversal reflection from top of low velocity layer. Research examples show that these methods provide effective ways to identify crustal low velocity layer in deep seismic sounding data.
出处
《地质科学》
CAS
CSCD
北大核心
2015年第4期1244-1260,共17页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
中国地震局公益性行业科研专项（编号：20140823）、国家“深部探测技术与实验研究”专项课题（编号：SinoProbe-02-02）和国家自然科学基金项目（编号：41374062,41274070）资助.
关键词
低速层
深地震测深
地壳结构
Crustal low velocity layer；Deep seismic sounding；Crustal structure
