No tsunami threat to PH following magnitude 7 quake, says Phivolcs

Raffy Cabristante, ABS-CBN News

Posted at Jul 27 2022 11:14 AM | Updated as of Jul 27 2022 06:04 PM

MANILA (3rd UPDATE) — The Philippine Institute of Volcanology and Seismology on Wednesday assured the public that there was no threat of a tsunami anywhere in the country following the powerful magnitude 7 earthquake that jolted Abra and other parts of Luzon.

"Kung wala po kaming ina-announce na magkaka-tsunami or tsunami warning, wala pong inaasahan," Phivolcs Director Undersecretary Renato Solidum said in a press conference.

(If we have not announced that there will be a tsunami or tsunami warning, we should expect none.) 

He explained that there was no expected tsunami as a result of the earthquake since its epicenter was on land. 

"Hindi po niya mapapaangat ang sea floor sa ocean para magdulot ng life-threatening tsunami," he said. 

(It cannot raise the sea floor to cause a life-threatening tsunami.) 

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In a separate press briefing, Solidum explained that the "unusual waves" reported in the coastal areas of La Union and Ilocos was a "minor seawater oscillation."

"This was not a tsunami po ‘no because a tsunami would be very high waves because of the uplift of the ocean floor due to an earthquake in the ocean," he said. 

"What happened was there was shaking of the island and the coastal water was shaken, so there was minor seawater oscillation, some of the waters actually entered some of the river."

However, he cautioned residents living along beaches or bays of possible water movements, although these are not huge tidal waves.

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THE ABRA RIVER FAULT 

The earthquake was caused by the movement of the Abra River Fault, Solidum said in a press briefing.

"Ibig sabihin yung fault dahil zone of weakness ay sinundan ito ng tubig at naging ilog at ang tawag nga natin sa ilog ay Abra River," he said.

(The fault is a zone of weakness, water followed it and became a river named "Abra River.")

Solidum described Wednesday's temblor as a "major earthquake." 

"Ganiyan naman po ang mga fault na nagdudulot ng major earthquakes. Matagal, daang taon ang huling kilos bago magpakawala ng malaki," he added.

(Faults that cause major earthquakes are like that. Their last activity dates back to a long time, hundred years before they release a strong energy.)

The quake was felt at a "destructive" Intensity 7 in the towns of Bucloc and Manabo in Abra. Phivolcs says this intensity could overturn heavy furniture, cause "considerable damage" on old or poorly built structures, and may make it difficult for people to stand in upper floors. 

Meanwhile, Intensity 6 was recorded in Vigan, Sinait, Bantay and San Esteban in Ilocos Sur; Laoac, Pangasinan; and Baguio City.

The quake was also felt at Intensity 5 in Manila, Malabon and Intensity 4 in the cities of Marikina, Quezon City, Pasig, and Valenzuela.

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AFTERSHOCKS 

The temblor may also cause other neighboring faults to move, Solidum said, citing as an example the 2019 series of earthquakes in the Cotabato-Davao del Sur area.

Aftershocks with up to magnitude 6 could be felt until 3 days following Wednesday's tremor, Solidum added.

"Although ine-expect natin ang aftershocks, di ganun kalakas kanina, mga magnitude 6 siguro, possible yung ibang faults sa paligid ay maaaring ma-trigger na kumilos," he said.

(Although we expect aftershocks that are not as strong like the tremor, around magnitude 6, it's possible it might trigger the other faults to move.)

Residents are advised to stay outside their homes and wait for local engineers to assess their building especially if it is visibly damaged, according to Michael Brillantes, local disaster officer of Langilang town in Abra.

—With a report from Vivienne Gulla, ABS-CBN News