<P> The central Philippine Fault Zone consisting of the Guinyangan, Masbate, and Central Leyte faults are the most seismically active regions transecting the islands of Bondoc to Leyte . The northern and southern extensions of the Philippine Fault Zone experience infrequent earthquakes and often described as locked segments which are capable of larger magnitude earthquakes . The largest (M7. 0) and most destructive earthquakes are generated along the Guinyangan fault every 30 to 100 years with slip rates of 20--33 mm / year as determined by GPS and historical records . Moderate earthquakes (M3. 0 - 5.0) are observed along the Masbate fault with frequent aftershocks indicative of continued displacement and regional slip of 5--35 mm / year . The northern and southern segments of the Central Leyte fault experiences different seismic activity dependent on regional geology . While the Southern Central Leyte fault experiences moderate seismic events, the Northern Central Leyte fault creeps at approximately 25 mm / year . Historical data on the PFZ is limited due to the faults geographical location predominantly offshore, lack of complete paleoseismic data and lack of permanent Global Positioning System (GPS) that can trace movements over long periods of time . </P> <Ul> <Li> Valley Fault System </Li> <Li> Macolod Corridor - broad left - lateral fracture zone . </Li> <Li> Lubang - Verde Passage Fault System - located offshore between Batangas peninsula and Mindoro Island, following the northwest - southeast alignment of Verde and Lubang islands (thus the name) and essentially strike - slip (left - lateral) fault . </Li> <Li> Mindoro / Aglubang Fault - break in slope between mountainous western Mindoro and the flat lands of eastern . </Li> <Li> Sibuyan Sea Fault - located offshore north of Masbate; using bathymetric (SeaMarc) and paleomagnetic data gathered in the northern section of the Sibuyan Sea, Sarewitz and Lewis (1991) were led to conclude that the Sibuyan Sea Fault is relayed with the Verde Passage Fault, both left - lateral faults, by an aborted spreading center under a transtensional tectonic regime . </Li> <Li> Legaspi Lineament - long SE - trending linear feature emanating from Pasacao in the Ragay Gulf area, passing through Lake Bato then to Legaspi City and considering its morphological prominence and seismic activity, it deserves to be elevated in category from a less significant lineament to a fault . </Li> <Li> Tablas Lineament - tectonic boundary between the North Palawan microcontinental block and the western edge of the Philippine Mobile Belt . It trends northerly as it separates Busuanga peninsula from the Antique Range in Panay Island, and passess offshore northwards east of Tablas Island . The present geodynamic setting of the Philippines obliges the Tablas Lineament to operate as a right - lateral strike - slip fault . Structure appears to connect with the Negros Trench southwards . </Li> <Li> Mindanao Fault - a prominent NW - trending linear fracture zone on the western third of Mindanao Island and has 2 distinct segments, including that which separates the Daguma Range from the Cotabato Basin corresponding to the Cotabato Fault segment . This segment is highly linear and has features suggestive of normal faulting although it may have been a left lateral strike slip fault during its early history . The Quaternary Mt . Parker volcano is located at the western end of this fault and, on radar images, seems to be cut by the fault and terraces formed by Quaternary limestone mark the Daguma Range . These, together with the young morphology of incised river valleys, suggests a young age for the fault along which the Daguma Range was uplifted . Although Quaternary in age, it still has to be ascertained whether the fault is active or not (Quebral, 1994). The Sindangan Fault segment represents the northern continuation of the fault towards northern Zamboanga . Focal mechanism solutions of earthquakes offshore and narrow shear zones transecting recent gravel deposits suggest active left - lateral faulting (Pubellier and others, 1991). </Li> <Li> Offshore Cebu - Bohol faults (?) - occasional occurrence of low to moderate magnitude, shallow - seated earthquakes between Cebu and Bohol, some capable of causing significant damage to infrastructure, is the subject of current discussions on the possible existence of active faults in the region . Such earthquake generators are most likely offshore, as there have so far been no indications of active faulting within the islands of Cebu and Bohol . Active fault studies are spearheaded by PHIVOLCS . </Li> </Ul> <Li> Valley Fault System </Li> <Li> Macolod Corridor - broad left - lateral fracture zone . </Li>

What are the active fault lines in the philippines