Central Java city and its surrounding regencies have formed a separate special region (equivalent to a province) since Indonesian independence, administrated separately. Located in the middle of the island of Java, the Central Java province is bordered by West Java and East Java provinces. A small portion of its south region is the Yogyakarta Special Region province, fully enclosed on the landward side by the Central Java province. To the north and the south, the Central Java province faces the Java Sea and the Indian Ocean. Central Java includes offshore islands such as Karimun Jawa Islands in the north, and Nusakambangan in
Ryukyu Trench margin right up to the northeastern Taiwan coastline, also without the existence of a dextral north-south trending fault. Ocean bottom seismography methods combined with earthquake studies of the Benioff zone constrain the dip angle of the Philippine Sea Plate along the Ryukyu trench. In the Northern part of the Ryukyu trench, the dip of the Philippine Sea Plate is shallow at shallow depth, reaching only about 11° in the first 50 km, and steeper at deeper depths, reaching 70° below about 70 km. In contrast, the slab dip in the central and southern parts of the Ryukyu trench is more