Geophysical Features on Subducting Seamounts at the Junction of Japan and Kuril Trenches

Using Potential Anomalies and Admittance Functions

Abstract

The R/V KAIREI of Japan Marine Science and Technology Center (JAMSTEC) has surveyed juncture of the Japan Trench and the Kuril Trench, focusing on geophysical investigations of the northern edge of the Pacific plate, including bathymetry, gravity, and total and three-component geomagnetics along MCS/OBS track lines and box survey lines during Leg KR00-04. The purposes of this study are: (1) to obtain geophysical and geological observations of subduction zones at the northern Japan Trench region; (2) to reveal a fine scale shape of subducted seamounts and its vicinity area from the view of sub-bottom topography, gravity, and magnetics; and (3) to understand the northern edge of the Pacific plate kinematically. Magnetic lineations aligned WSW-ENE directection can be clearly seen oceanward to landward slope of the Pacific plate. The location of Erimo Seamount and its vicinity area are strong geomagnetic intensity with 1000 nT of Peak ?Peak. We also investigate the compensation mechanism of subducting seamount using admittance functions.