Two powerful offshore earthquakes struck the same region in the southern Philippines hours apart on Friday, with the first 7.4 magnitude temblor killing at least seven people, setting off landslides and prompting evacuations of coastal areas nearby because of a brief tsunami scare.
The second one had a preliminary 6.8 magnitude and also sparked a local tsunami warning by authorities. It was caused by movement in the same fault line, the Philippine Trench, at a depth of 37 kilometres (23 miles) off Manay town in Davao Oriental province, Philippine Institute of Seismology and Volcanology chief Teresito Bacolcol said.
“The second one is a separate earthquake, which we call a doublet quake,” Bacolcol told the Associated Press. “Both happened in the same area but have different strengths and epicentres.”
Bacolcol and other authorities expressed fears that the second night-time earthquake could further weaken or collapse structures already undermined by the first one.
Tsunami warnings were issued in several countries and people in nearby coastal areas were urged to move to higher ground after the quake off the island of Mindanao.
President Ferdinand Marcos Jr said the potential damage was being assessed and rescue teams and relief operations would be deployed when safe to do so.
The Philippine Institute of Volcanology and Seismology said it was expecting damage and aftershocks from the earthquake, which was centred in the sea about 62km south-east of the town of Manay in Davao Oriental province. It was caused by movement in a fault at a depth of 10km.
Schools were evacuated in Davao city, the biggest city near the epicentre, about 250km west of Davao Oriental province.
The Pacific Tsunami Warning Centre in Honolulu said hazardous waves were possible within 300km of the epicentre. It said waves up to 3m above normal tides were possible on some Philippine coasts, while smaller waves were possible in Indonesia and Palau.
Office of Civil Defence deputy administrator Bernardo Rafaelito Alejandro IV warned that tsunami waves could hit six coastal provinces near Davao Oriental up to two hours after the earthquake struck at 9.43am local time.
He asked people to immediately move to higher ground or further inland away from coastal areas.
“We urge these coastal communities to be on alert and immediately evacuate to higher grounds until further notice,” Mr Alejandro said. “Owners of boats in harbours and those in the coastal areas … should secure their boats and move away from the waterfronts.”
Indonesian authorities issued a tsunami warning for north-eastern regions of Papua and North Sulawesi, about 275km from the epicentre. Indonesia’s Meteorology, Climatology, and Geophysics Agency said in a statement that residents in the area should be aware and stay away from beaches and riverbanks.
The Philippines is still recovering from a September 30 earthquake with a magnitude of 6.9 that left at least 74 people dead and displaced thousands in the central province of Cebu.
The country is often hit by earthquakes and volcanic eruptions because of its location on the Pacific “Ring of Fire” − an arc of seismic faults. It is also lashed by about 20 typhoons and storms each year.
