 Luzon is part of the Philippine Mobile Belt, a fast deforming plate boundary zone (Gervasio, 1967) hemmed in between two opposing subduction zones, the west-dipping Philippine Trench-East Luzon Trench subduction zone, and the east-dipping north-south trending Manila Trench-Negros Trench-Cotabato Trench.The Philippine Sea Plate subducts under eastern Luzon along the East Luzon Trench and the Philippine Trench, while the South China Sea basin, part of the Eurasian plate, subducts under western Luzon along the Manila Trench.The North-Southeastern trending braided left-lateral strike-slip Philippine Fault System traverses Luzon, from Quezon province and Bicol to the northwestern part of the island.