S. F. Personius R.E. Rimando R.S. Punongbayan N. Tungol H. Mirabueno A. Rasdas A.R. Nelson 2000 <p><span>The first&nbsp;</span>¹⁴<span>C-based paleoseismic study of an active fault in the Philippines shows that a right-lateral fault on the northeast edge of metropolitan Manila poses a greater seismic hazard than previously thought. Faulted hillslope colluvium, stream-channel alluvium, and debris-flow deposits exposed in trenches across the northern part of the west Marikina Valley fault record two or three surface-faulting events. Three eroded, clay-rich soil B horizons suggest thousands of years between surface faulting events, whereas&nbsp;</span>¹⁴<span>C ages on detrital charcoal constrain the entire stratigraphic sequence to the past 1300–1700 years. We rely on the&nbsp;</span>¹⁴<span>C ages to infer faulting recurrence of hundreds rather than thousands of years. Minimal soil development and modern&nbsp;</span>¹⁴<span>C ages from colluvium overlying a faulted debris-flow deposit in a nearby stream exposure point to a historic age for a probable third or fourth (most recent) faulting event.</span></p> application/pdf 10.1785/0119990002 en Seismological Society of America Multiple large earthquakes in the past 1500 years on a fault in metropolitan Manila, the Philippines article