The Valley Fault System and formerly as the Marikina Valley Fault System is a group of dextral strike-slip fault which extends from San Mateo, Rizal to Taguig City on the south; running through the cities of Makati, Marikina, Parañaque, Pasig and Taguig. == Threat to Manila == The fault possesses a threat of a large scale earthquake with a magnit...