UPDATE:
Date and Time: 29 Oct 2019 - 09:04 AM
Magnitude = 6.6
Depth = 007 kilometers
Location = 06.78N, 125.04E - 025 km S 71° E of Tulunan (Cotabato) pic.twitter.com/Uh5wcU5cw4

— PHIVOLCS-DOST (@phivolcs_dost) October 29, 2019

MANILA (UPDATE) -- The earthquake that struck parts of Mindanao on Tuesday morning was upgraded to a Magnitude 6.6, the Philippine Institute of Volcanology and Seismology said.

“Yung damages before pwedeng mag deteriorate kung walang intervention na nagawa kaagad,” said Erlington Olabere, Phivolcs Science Research Specialist 2.

(Damages from the previous quake could deteriorate if no intervention was done.)

The epicenter was located off Tulunan town in Cotabato province, where an earthquake earlier this month killed at least 3 people.

• Magnitude 6.3 quake hits North Cotabato, nearby areas

Initially recorded at magnitude 6.4, Phivolcs said Tuesday’s tremor struck at 9:04 a.m. and was tectonic in origin. It had a depth of 7 kilometers.

The U.S. Geological Survey also measured the quake at Magnitude 6.6.

Prelim M6.6 Earthquake Mindanao, Philippines Oct-29 01:04 UTC, updates https://t.co/kDbAGfp6MR

— USGS Big Quakes (@USGSBigQuakes) October 29, 2019

The earthquake was felt at the following intensities:

Intensity VII - Tulunan at Makilala, Cotabato; Kidapawan City; Malungon, Sarangani

Intensity VI - Davao City; Koronadal City; Cagayan de Oro City

Intensity V - Tampakan, Surallah at Tupi, South Cotabato; Alabel, Sarangani

Intensity IV - General Santos City; Kalilangan, Bukidnon

Intensity III - Sergio Osmeña Sr., Zamboanga del Norte; Zamboanga City; Dipolog City; Molave, Zamboanga del Norte; Talakag, Bukidnon

Intensity I - Camiguin, Mambajao

With the upgrade to main shock, the previous strong quake in the same area last October 16 now becomes a foreshock.

“In terms of magnitude, magiging foreshock yung (magnitude) 6.3 kasi mas mababa ang magnitude,” Olabere said.

(In terms of magnitude, the previous 6.3 now becomes a foreshock because it has a lower magnitude.)

Olabere explained that in reference, they are related as both are strong quakes that occurred in almost the same general area.

They however are still studying if the new event was due to movement of the same fault that caused the October 16 quake.

Phivolcs said it has recorded more than 900 aftershocks after the October 16 quake.

"Mas malakas ito kumpara sa nakaraang lindol," said Tulunan Mayor Reuel Limbungan, referring to the Magnitude 6.3 quake last October 16 that damaged barangay halls, health centers, and senior citizens’ halls.

Several students from the Daig Elementary School in the same town were injured during the quake. The mayor has sent rescue team to the area.

The mayor has suspended all classes and work in all public and private offices in Tulunan Tuesday to allow authorities to check all infrastructure in the town.

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"Walang pasok sa school at munisipyo, kahit pribado wala muna. Mga ospital we will check and get the patients out, nag iikot kami," he told radio DZMM.

The quake was also felt in Davao City, causing residents to flee their homes, an ABS-CBN Regional Network Group report said.

Employees in several office buildings also conducted duck, cover and hold before evacuating their workplaces.