MANILA (4TH UPDATE) — A magnitude 6.8 earthquake struck off Southern Mindanao on Friday, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.

The quake was initially registered at magnitude 7.2 before Phivolcs revised the data.

The undersea tectonic quake occurred at a depth of 72 kilometers and 34 km northwest of Sarangani Island in Davao Occidental at around 4:14 p.m.

Phivolcs recorded the following instrumental intensities:

• Intensity V - Matanao, Davao del Sur; Jose Abad Santos, Davao Occidental; Maasim, and Malapatan, Sarangani; Banga, Lake Sebu, Polomolok, and Tampakan, South Cotabato
• Intensity IV - Magsaysay, Davao del Sur, Davao City; Don Marcelino, Davao Occidental; City of Kidapawan, Cotabato; Kiamba, SaranganiI; Norala, and Tantangan, South Cotabato; Bagumbayan, Columbio,
• Esperanza, Isulan, Kalamansig, Lebak, and President Quirino, Sultan Kudarat
• Intensity III - Zamboanga City; Nabunturan, Davao de Oro; M'lang, Cotabato; Lambayong, Sultan Kudarat
• Intensity II - Molave, Zamboanga del Sur; City of Malaybalay, Bukidnon; Kapatagan, Lanao del Norte; Balingasag, and Initao, Misamis Oriental; Cagayan de Oro City; Carmen, and Pikit, Cotabato
• Intensity I - San Lorenzo, Guimaras; City of Talisay, Cebu; City of Dapitan, Liloy, and Sindangan, Zamboanga del Norte; Talakag, BUKIDNON; Tubod, Lanao del Norte; Alamada, Cotabato; City of Cabadbaran, Agusan del Norte; City of Bislig, Surigao del Sur

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No tsunami threat

In a separate advisory, Phivolcs said it has not detected a tsunami threat following the earthquake.

"No destructive tsunami threat exists based on available sea-level data... [T]here is no tsunami threat to the Philippines from this earthquake," Phivolcs said.

However, it added that "earthquakes of this size may generate unusual sea level disturbances that may be observed along coasts near earthquake epicenter of Davao Occidental."

Malacañang, in a statement, said President Ferdinand Marcos, Jr., who is currently in the US, has already instructed government agencies to "take action" on the quake.

"The President has instructed every relevant government agency to promptly take action to ensure the safety and well-being of those affected," the Palace said.

Damage

In a statement, the Civil Aviation Authority of the Philippines (CAAP) said some airports in the affected areas only had minor damage.

The terminal building of General Santos Airport sustained some minor damage, with hairline cracks noted on some of the airport’s columns.

Meanwhile, Davao International Airport, Cotabato Airport, and Mati Airport reported no damage.

The Philippine Red Cross (PRC) said it has mobilized staff in the quake-hit areas.

The PRC General Santos City-Sarangani Province chapter provided first aid and medical attention to students in Holy Trinity Junior High and Golden State College, and other affected communities students affected by the earthquake.

According to reports from the PRC Davao Del Sur Chapter, the earthquake caused power outages in Digos City.

Alberto Olarte Sr. National High School in Sarangani and two malls in Koronadal and General Santos City had collapsed ceilings and broken glass while a construction crane in Davao City with a block of cement also collapsed, according to PRC.

In an interview with Teleradyo Serbisyo, Phivolcs director Toto Bacolcol said the quake was located in the Cotabato trench.

"Every now and then gumagalaw po ito pero yung pinakamalakas niya is noong Aug. 17, 1976, ito po ay may 8.1 magnitude and around 3,000 people yung casualties," he said.

• Safety first: What to do when a deadly quake strikes

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