INTRODUCTION

The geologic history and structure of the Nankai accretionary prism off SW Japan have been extensively investigated by geophysical survey and drilling work［1～7］.The Bottom Simulating Reflector（BSR）is commonly associated with the base of gas hydrate stability zones［8］.BSR has been known to occur within the Nankai accretionary prism，but there is little work on the role of seismic data processing in the delineation of BSR and the character of the distribution of BSR on the slope of the western Nankai Trough［1～7］.Marine multi-channel seismic reflection lines were acquired in 1987by Cruise FM3506.NT62-2of the cruise is now used to locate drilling sites of western transect of the Ocean Drilling Project（ODP）Leg 190in 2000and 196in 2001［2，6～7］.We use the original data of NT62-2provided by UTIG（University of Texas，Institute of Geophysics），make seismic data processing，and compare the appearances of gas hydrate BSR on different profiles.(https://www.daowen.com)