M 7.7 Earthquake in Mindanao, Philippines Triggers Tsunami Warning Due to Plate Subduction

The Meteorology, Climatology, and Geophysics Agency (BMKG) has stated that the magnitude 7.7 tectonic earthquake that shook the southern coast of Mindanao, Philippines, on Monday morning at 06:37 WIB was caused by plate subduction activity.

“Observing the location of the epicentre and the depth of the hypocentre, the earthquake that occurred is a shallow earthquake type resulting from plate subduction activity,” said Wijayanto, Director of Earthquakes and Tsunamis at BMKG, in a release shared via the ‘BMKG and Stakeholders’ communication group in Manado on Monday.

Source mechanism analysis indicates that the earthquake involved a thrust fault movement. The tremors were felt in Morotai City, North Halmahera, with an intensity of IV MMI, and in North Gorontalo Regency with an intensity of III-IV MMI. Significant vibrations (III MMI) were also reported in Batang Dua, Ternate, West Halmahera, Gorontalo, South Halmahera, East Halmahera, Parigi Moutong, Manado, Minahasa, Palu, Bitung, Boltim, and Central Halmahera.

As of now, there have been no reports of damage caused by the earthquake. However, modelling results indicate a potential tsunami, placing several regions under ‘Alert’ status, including Minahasa, Bolaang Mongondow, Manado, North Minahasa, South Minahasa, Buol, Sangihe Islands, Gorontalo, Talaud Islands, Minahasa Islands, Toli-toli, Palu, Donggala, Ternate, and Bitung.

Other areas, including Tidore, Bulungan, Nunukan, Halmahera, Tarakan, North Halmahera, East Kutai, South Minahasa, Bontang, and Berau, are under ‘Watch’ status.

In response to this potential threat, BMKG has recommended that residents in ‘Alert’ areas immediately move away from the coast to higher ground, while those in ‘Watch’ areas are advised to stay away from coastlines and riverbanks. As of 07:11 WIB, BMKG monitoring has detected two aftershocks, with magnitudes of M 6.7 and M 5.9.