S23D-2771
Upper mantle structures beneath the South Pacific superswell region using broadband data from ocean floor and islands
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Takehi Isse1, Hiroko Sugioka2, Aki Ito3, Hajime Shiobara4, Dominique Reymond5 and Daisuke Suetsugu3, (1)Earthquake Research Institute, University of Tokyo, Tokyo, Japan, (2)JAMSTEC Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan, (3)JAMSTEC, D-EARTH, Yokosuka, Japan, (4)University of Tokyo, Bunkyo-ku, Japan, (5)Laboratoire de Géophysique Tahiti, CEA/LDG, Papeete, French Polynesia
Abstract:
We deployed temporary seafloor observation around the Society hotspot in the South Pacific superswell by TIARES project from 2009 to 2010. We determined three-dimensional shear wave velocity structures beneath the South Pacific superswell down to a depth of 200 km by analyzing fundamental Rayleigh wave records from permanent and temporary seismic network on island and seafloor in the Pacific Ocean. Spatial resolution around the Society hotspot is about 300 km, which is higher resolution than the previous studies. The data by TIARES project enabled to obtain such a high-resolution result. The obtained structures shows small slow anomalies are located nearby hotspots. The vertical profiles of anomalies are various. Anomalies nearby Samoa, Macdonald, Pitcairn, and Society hotspots continue down to at least 200 km, those nearby Arago and Rarotonga hotspots down to about 100 km, and that nearby Marquesas down to about 150 km. Recent broadband seafloor observation enables us to determine the size of anomalies nearby Society hotspot, whose size is about 300 km or less.
