GEOLOGIC SETTING AND SEISMIC DATA
The Nankai Trough is the subduction boundary between the Shikoku Basin and the Southwest Japan Arc（Fig.1）［6，7］.The Shikoku Basin is part of the Philippine Sea plate，which is subducting to the northwest Japan at a rate of 2～4cm/yr［6，7］，approximately normal to the plate margin.Active sediment accretion is presently taking place at the Nankai Trough.
Line NT62-2was acquired by Cruise FM3506with the R/V Fred Moore in July 1987（Fig.1）.The seismic signals were received with a 96-channel hydrophone array with 16.67m group interval，sampled at 2ms.Record length is 11.262s.Source to near trace offset is 162.6m.Source was a 6-gun 17436cm3array made of six air guns of various chamber size.Some shots of raw seismic data of NT62-2are missing because of operation mistakes.The seismic data have been processed several times before to study the structure of the accretionary prism on the subduction margin［2，6，7］.Details of the acquisition and previous processing have been described in Moore et al.［2］.(https://www.daowen.com)
Fig.1 Locations of NT62-2and drilling sites of Deep Sea Drilling Project（DSDP）and Ocean Drilling Project（ODP）（wauer depth contoured in meters）
