Deep Earthquakes From the Pre-Digital ERA

WPC 2‘B Z R#X#|x HP LaserJet IIIP HPLSIIIP.PRS x@，\，|@Courier 10cpi Courier 10cpi(粗体)？X，x 6 X@8；X@？X，d x‘B；X|H H 8 2 Y9218907 X`高p x(#%‘0*，.81 3 5@8：H？甲型H8OKAL H8H H@H H‘本研究旨在研究安通爪哇高原的地震构造，海底火成岩活动的最大表现者。由PASSCAL仪器组成的四个地震台将在密克罗尼西亚群岛丘克、波恩佩、科斯雷和瑙鲁部署两年。所罗门俯冲带的震源将被用来调查高原上面波的频散，以测量深度为200公里的地震结构。同时，针对该区地壳和上地幔的结构各向异性，还将进行多项体波实验。预计这项工作将回答诸如地壳的确切厚度、深部地壳的性质、高原地幔(盖子和下伏低速带)的结构以及上地幔各向异性的程度和方向等问题。这些参数反过来又制约着白垩纪高原侵位的环境和机制。***

WPC 2 ' B Z R # X #| x HP LaserJet IIIP HPLSIIIP.PRS x @ , \ , | @Courier 10cpi Courier 10cpi (Bold) ? x x x , x 6 X @ 8 ; X @ ? x x x , d x ` B ; X | H H 8 2 Y 9218907 X ` h p x (# % '0* , .81 3 5@8 : H? A H 8 Okal H 8 H H @H H ' This research is to study the seismic structure of the Ontong Java Plateau, the largest expression of igneous activity of the ocean floor. Four seismic stations composed of PASSCAL instruments will be deployed for two years on the Micronesian islands of Chuuk, Pohnpei, Kosrae and Nauru. Earthquake sources in the Solomon subduction zone will be used to investigate the dispersion of surface waves over the plateau to measure seismic structure to depths on the order of 200 km. Concurrently, a number of body wave experiments will be conducted targeting the structural anisotropy of the crust and upper mantle in the area. The work is expected to provide answers to such questions as the exact thickness of the crust, the nature of the deep crust, the structure of the mantle (lid and underlying low velocity zone) of the plateau, and the extent and direction of anisotropy in the upper mantle. In turn, these parameters will put constraints on the environment and mechani sm of emplacement of the plateau in the Cretaceous. ***