Broad Band Crust/Upper Mantle Studies Around New Zealand

9418343 WU本项目与美国南加州大学Thomas Henyey和David Okaya已经资助的大陆动力学项目有关，该项目名为“现代大陆-大陆碰撞造山带的地球物理研究：新西兰南阿尔卑斯山”（简称主项目）。主要项目集中在南岛，包括陆上反射样带、陆上/海上折射/广角反射样带和以当地地震活动和远震为中心的被动地震研究。最后一个组成部分是在南岛部署宽带仪器，以记录当地地震和远震的震源机制、SKS各向异性和直接在南岛下的深部地幔结构。该项目旨在通过在南岛以东的查塔姆岛部署监测站，提供更广泛的区域覆盖；靠近奥克兰，北岛；在澳大利亚东南部，与澳大利亚国立大学Brian Kennett教授合作；在南岛，总共有11-12个监测站。这些监测站将部署14个月，其中部分部署与主要项目的部署重叠。需要解决的具体问题是：(1)与新西兰造山运动相关的岩石圈变形的横向程度是多少？它是否涉及到造山带两侧的地幔物质流动？(2)南岛以西发现的上地幔各向异性的确切性质是什么？它是否与新西兰造山运动有关，还是与太平洋板块下流向新西兰西北部有关？(3)查塔姆隆起和豪勋爵隆起的深层结构是什么？是否存在深层的横向差异驱动着地幔动力学？(4)南岛地下是否存在高速（高密度）带？它们的横向范围是什么？＊＊＊

9418343 WU This project is related to an already funded Continental Dynamics project directed by Thomas Henyey and David Okaya of the University of Southern California (USC), titled "Geophysical Investigation of a modern Continent-Continent Collisional Orogen: The Southern Alps, New Zealand" (referred to as the main project). The main project concentrates on the South Island, with an onshore reflection transect, onshore/offshore refraction/wide angle reflection transect and a passive seismic study using local seismicity and teleseisms as the center pieces. The last component involves a six months deployment of broad band instruments on the South Island to record local earthquakes and teleseisms for focal mechanisms, SKS anisotropy and deep mantle structures directly under the South Island. This project aims to provide a broader regional coverage by deploying stations on Chatham Island east of South Island; near Auckland, North Island; in Southeast Australia, in cooperation with Prof. Brian Kennett of Australian National University; and on the South Island, for a total of 11-12 stations. The stations would be deployed for 14 months, with part of the deployment overlapping with that of the main project. The specific questions to be addressed are: (1) What is the lateral extent of the lithospheric deformation associated with the New Zealand orogeny? Does it involve flow of mantle materials on both sides of the orogen? (2) What is the precise nature of the upper mantle anisotropy that has been discovered to the west of the South Island? Is it related to the New Zealand orogeny or to flow under the Pacific plate to the northwest of New Zealand? (3) What are the deeper structures under the Chatham Rise and the Lord Howe Rise? Are there deep lateral differences that drive mantle dynamics? (4) Are there high velocity (and high density) zones under the South Island? What is their lateral extent? ***