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? ***
