Abstract
We documented regional and local variations in basement relief, sediment thickness, and sediment type in the Shikoku Basin, northern Philippine Sea Plate, which is subducting at the Nankai Trough. Seismic reflection data, tied with ocean drilling program drill cores, reveal that variations in the incoming sediment sequences are correlated with basement topography. We mapped the three‐dimensional seismic facies distribution and measured representative seismic sequences and units. Trench‐parallel seismic profiles show three regional provinces in the Shikoku Basin that are distinguished by the magnitude of basement relief and sediment thickness: Western ( 600 m sediment thickness), Central (>1500 m relief, ∼2000 m sediments), and Eastern (