Subduction along the Sagami and Suruga Troughs, Central Japan

Abstract

There may be a subduction of the Philippine Sea Plate under the Eurasia Plate on the north side along the Sagami and the Suruga Troughs. This is demonstrated in multichannel and single channel seismic profiles in both troughs. The gentle and smooth basement on the Bonin Arc side declines toward the troughs overlaid with trough sediments, and the steep and ridged slope on the landward side of the troughs has been faulted and uplifted to make ridges and banks. It is presumed that there is an accretion associated with thrust faulting on the landward (west) side of the Suruga Trough. There is no remarkable accretion, however, on the landward (northeast) side of the Sagami Trough, where the banks and highs on the landward side may have been be formed by thrusting associated with the subduction of the Bonin Arc side under the highs.