East Java also decided to join Indonesia. East Java province borders the Java Sea in the north, the Strait of Bali in the east, the Indian Ocean in the south, as well as the Central Java province in the west. The length of the east-west stretch of about 400 km. The width of the stretch of the north-south in the west about 200 km, but in the eastern part of narrower by about 60 km. Madura is the largest island in East Java, separated from the mainland Java by the Strait of Madura. Bawean Island is located about 150 km north of
Japan Trench within the Japan Trench consist mainly of highly localized clay-rich material. The subducting Pacific Plate creates basins along the ocean floor of the Japan Trench, accommodating the deposition of fine-grained turbidites and interseismic sediment deposits through turbidity currents. These turbidites preserve the sediment deposits as a geologic record of past large earthquakes by indicating the change in sediment deposition through sediment gravity flow. The small deep-sea basins with high sedimentation rates found along the Japan Trench fault line pose favorable environmental conditions for the studying of turbidite paleoseismology. During an exploration to the Japan Trench on January 1, 1999, a