The two major fault zones that are most dangerous are the Sulu Trench in the Sulu Sea and the Cotabato Trench, a region of subduction that crosses the Celebes Sea and the Moro Gulf in Southern Mindanao.
The two major fault zones are the Sulu Trench in the Sulu Sea. The two major fault zones are the Sulu Trench in the Cotabato Trench. This Cotabato Trench crosses the Celebes Sea. This Cotabato Trench crosses the Moro Gulf in Southern Mindanao. These two major fault zones are most dangerous. The Cotabato Trench is a region of subduction.