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 kilometers (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 epicenters.”
Bacolcol and other authorities expressed fears that the second nighttime earthquake could further weaken or collapse structures already undermined by the first one.
President Ferdinand Marcos Jr., facing his latest natural disaster after a recent deadly quake and back-to-back storms, said the potential damage was being assessed and rescue teams and relief operations were being prepared and would be deployed when it was safe to do so.
Quake toll The first quake was centered at sea about 43 kilometers (27 miles) east of Manay town and was caused by movement in the Philippine Trench at a depth of 23 kilometers (14 miles), government seismologists said.
At least seven people were killed, including two patients who died of heart attacks at a hospital during the first earthquake and a resident who was hit by debris in Mati city in Davao Oriental, Ednar Dayanghirang, regional director of the government's Office of Civil Defense, told The AP.
Three villagers died and several others were rescued with injuries by army troops and civilian volunteers in a landslide set off by the first quake in a remote gold-mining village in Pantukan town in Davao de Oro province near Davao Oriental, Dayanghirang said.
Another resident died because of the first quake in the port city of Davao, disaster mitigation officials said without providing other details. They added that a few hundred residents were injured in the city.
Damage assessment Office of Civil Defense deputy administrator Bernardo Rafaelito Alejandro IV said that several buildings sustained cracks in their walls, including an international airport in Davao city, but it remained operational without any flights being canceled.
“I was driving my car when it suddenly swayed and I saw power lines swaying wildly. People darted out of houses and buildings as the ground shook and electricity came off,” Jun Saavedra, a disaster-mitigation officer of Governor Generoso town in Davao Oriental, told The AP.
Schools evacuated “We've had earthquakes in the past, but this was the strongest,” Saavedra said, adding that the intense ground swaying caused cracks in several buildings, including a high school, where about 50 students were brought to a hospital by ambulance after sustaining bruises, fainting or becoming dizzy because of the first quake.
Governor Generoso is a town about 100 kilometers (60 miles) south of Manay, where school classes in all levels were also suspended.
Children evacuated schools in Davao city, which has about 5.4 million people and is the biggest city near the epicenter, about 250 kilometers (155 miles) west of Davao Oriental province.
Tsunami fears The Pacific Tsunami Warning Center in Honolulu said that small waves were detected on the coasts of the Philippines and Indonesia before the threat passed about two hours after the first quake. It said that small sea fluctuations may continue.
A tsunami warning that set off evacuations in six coastal provinces near Davao Oriental was later lifted without any major waves being detected, Bacolcol said.
Indonesia’s Meteorology, Climatology and Geophysics Agency said that small tsunami waves were detected in North Sulawesi province with heights ranging from 3.5 to 17 centimeters (1.3 to 6.7 inches) in Melonguane, Beo, Essang and Ganalo in Talaud Islands districts.
History of quakes and storms The Philippines is still recovering from a Sept. 30 earthquake with a 6.9 magnitude that left at least 74 people dead and displaced thousands of people in the central province of Cebu, particularly in Bogo city and outlying towns.
The archipelago also is lashed by about 20 typhoons and storms each year, making disaster response a major task of the government and volunteer groups.
Also Friday, an earthquake with a preliminary magnitude of 6.0 struck Friday off the coast of Papua New Guinea. The US Geological Survey said that it was centered in the Bismarck Sea 414 kilometers (257 miles) northeast of Lae, the South Pacific island nation’s second-most populous city.
Lae police official Mary Jane Huafilong said that no damage was reported.
