Central Java ash makes Central Java highly fertile agriculture land. Paddy fields are extensive, except in the southeastern Gunung Kidul region partly due to the high concentration of limestone and its location in a rain shadow from the prevailing weather. The largest rivers are the Serayu in the west, which empties into the Indian Ocean, and the Solo which flows into East Java. On the eve of the World War II in 1942, Central Java was subdivided into 7 residencies (Dutch "residentie" or plural "residenties", Javanese "karésiḍènan" or "karésidhènan") which corresponded more or less with the main regions of this area. These
Sunda Trench the techniques used to determine the depth of the trench. The research contributed to an understanding of the subduction characteristic of the Pacific margins. Various agencies have explored the trench in the aftermath of the 2004 earthquake, and these explorations have revealed extensive changes in the ocean floor. The subduction of the Indo-Australian Plate beneath a bloc of the Eurasian Plate is associated with numerous earthquakes. Several of these earthquakes are notable for their size, associated tsunamis, and/or the number of fatalities they caused. Sunda Trench The Sunda Trench, earlier known as and sometimes still indicated as the Java Trench,