DAVAO CITY – Hundreds of families living along the coastline of Sultan Kudarat have initiated a preemptive evacuation due to fear of tsunami following the magnitude-5.7 earthquake that jolted the province at 1:05 a.m. Wednesday, Jan. 28.

In a report from the Philippine Institute of Volcanology and Seismology (Phivolcs), the earthquake’s epicenter was 55 kilometers southwest of Kalamansig town with a depth of 19 kilometers.

Phivolcs has not released a tsunami threat advisory following the tremor.

But as aftershocks are expected, Gov. Datu Pax Ali Mangudadatu has ordered the suspension of work and classes until further notice.

“Residents of both municipalities are advised to remain alert, avoid staying in damaged or unstable structures, and prepare for possible aftershocks,” Mangudadatu said.

The governor said work suspension is only applicable for coastal towns of Kalamansig, Lebak and Palimbang.

Mangudadatu said that these measures were adopted to minimize exposure to risk while ensuring that appropriate response actions are in place during the period of continuing seismic activity.

He advised his constituents to exercise caution, stay indoors when possible, and avoid coastal and structurally vulnerable areas.

The governor encouraged residents to continuously monitor official announcements for updates and further instructions.

Mangudadatu said that fishing activities in coastal areas in the province are temporarily prohibited following the series of seismic activities.

The earthquake was felt at Intensity 4 in Palimbang and Lebak; Intensity 3 in Esperanza in Sultan Kudarat and Norala in South Cotabato; and Intensity 2 in M'lang and Pikit in Cotabato, Maitum and Malungon in Sarangani, and Tantangan, Banga, Tupi, Surallah, Tampakan, Santo Nino, and Koronadal City in South Cotabato.

It was felt at Intensity 1 in Kadingilan, Bukidnon; Maasim and Alabel, Sarangani; Zamboanga City in Zamboanga del Sur; and Santa Maria in Davao Occidental.

After the main shock at 1:05 a.m., dozens of aftershocks have been recorded, ranging from magnitudes 1.1 to 5.2.

Last week, classes and work were suspended in the province due to a magnitude-5.2 earthquake on Jan. 20 with an epicenter 43 kilometers southwest of Kalamansig.

The Municipal Disaster Risk Reduction and Management Office in the towns of Kalamansig, Lebak, and Palimbang have confirmed that some residents in coastal barangays have initiated preemptive evacuations due to fear of tsunami.

A personnel of the MDRRMO in Kalamansig said that the tremor triggered a preemptive evacuation in 10 coastal barangays.

“Nobody ordered them to evacuate,there was no tsunami advisory but maybe they were just scared that a stronger earthquake might come and might trigger a tsunami,” the MDRRMO personnel said.

Kalamansig Municipal Social Welfare and Development Office head Roshelo Caluyo said that about 3,000 to 4,000 families have evacuated to safer grounds.

Caluyo added that it was just an approximate figure as validation is still ongoing as of this posting.

“This is just an approximate figure because in one coastal barangay alone, more than 600 families have evacuated. And we also have some bigger barangays including the town proper,” he said.

In Lebak, an MDRRMO personnel said that she could not provide the number of families that initiated a preemptive evacuation as validation is still ongoing.

She added that most of these families were from six coastal towns of municipality.

But the Philippine Coast Guard Station Sultan Kudarat reported that about 350 families from the coastal barangay of Tibpuan have temporarily sought shelter in designated evacuation centers in Barangays Pasandalan and Poloy-Poloy in Lebak.

In Palimbang, MDRRMO chief Engr. Yasser Tuanadatu said that only 90 families from Barangay Kiponget have initiated a preemptive evacuation.

Tuandatu said that residents initiated the preemptive evacuation even with the tsunami threat advisory.

“Most of the residents in Kiponget have experienced the tsunami in the 1976 earthquake,” he added, referring to the Moro Gulf earthquake and tsunami on Aug. 17, 1976.

Phivolcs records showed that the earthquake measured magnitude-eight with a depth of 20 kilometers.

The powerful tremor triggered a destructive tsunami that left an estimated 5,000 to 8,000 fatalities.

Tuanadatu said that the local government has suspended classes as a precautionary measure.

“We have two-story classroom buildings here. And if there will be aftershocks, it might cause panic and stampede,” he said.

Since Jan. 19, the Phivolcs has recorded a total of 765 swarm earthquakes around Kalamansig.

More than with magnitudes ranging from 1.4 to 5.2were plotted or located.

But only 30 were felt, according to Phivolcs.

The swarm was generated by the Cotabato Trench, noting that such activity reflects the gradual release of built-up stress in a tectonically active area, the Phivolcs said.