September 20, 2014 Earthquake: Barangay Luayon, Philippines

Felt (V PIVS) at Kidapawan and Makilala; (IV PIVS) at Matalam and M'lang; (III PIVS) at Davao; (II PIVS) at General Santos and Koronadal.

Tectonic Summary

Seismotectonics of the Philippine Sea and Vicinity

The Philippine Sea plate is bordered by the larger Pacific and Eurasia plates and the smaller Sunda plate. The Philippine Sea plate is unusual in that its borders are nearly all zones of plate convergence. The Pacific plate is subducted into the mantle, south of Japan, beneath the Izu-Bonin and Mariana island arcs, which extend more than 3,000 km along the eastern margin of the Philippine Sea plate. This subduction zone is characterized by rapid plate convergence and high-level seismicity extending to depths of over 600 km. In spite of this extensive zone of plate convergence, the plate interface has been associated with few great (M>8.0) ‘megathrust' earthquakes. This low seismic energy release is thought to result from weak coupling along the plate interface (Scholz and Campos, 1995). These convergent plate margins are also associated with unusual zones of back-arc extension (along with resulting seismic activity) that decouple the volcanic island arcs from the remainder of the Philippine Sea Plate (Karig et al., 1978; Klaus et al., 1992).

(above from reference #13456)

Several earthquakes that struck parts of North Cotabato on Saturday, September 20 - the highest recorded at magnitude 5 - damaged 82 houses and a church, and caused minor injuries on a boy, local authorities said. Cynthia Ortega, Provincial Risk Reduction and Management Council action officer of North Cotabato, said that Barangay Luayon in Makilala town was the most badly hit, with 82 houses damaged by the tremor, 15 of which were destroyed. A church was also reportedly damaged by the earthquake. (reference #11095)