Phivolcs quells rumors of tsunami threat after magnitude 7.2 earthquake

MANILA, Philippines – The Philippine Institute of Volcanology and Seismology (Phivolcs) reiterated its announcement that the agency has canceled its earlier tsunami advisory “as there is no longer a tsunami threat.”

Science Undersecretary Renato Solidum Jr, concurrent Phivolcs director, told media Saturday morning, April 29, that the cancellation was issued as early as 6:59 am, Saturday.

Rumors of the tsunami risk have been spreading online. There have also been persistent questions from online users about the tsunami warning even after Phivolcs had lifted it. A telecom also sent a text message about the warning minutes after the cancellation, causing confusion among subscribers.

At 5:03 am, shortly after a magnitude 7.2 earthquake struck Sarangani town in Davao Occidental, Phivolcs issued a tsunami advisory for coastal communities fronting the Celebes Sea.

“The first tsunami waves will arrive between 4:28 am to 5:23 am, (2017/04/29) and may not be
the largest,” the initial Phivolcs warning read.

The affected areas included Sarangani town, Davao Occidental, South Cotabato, Davao Oriental, and Sultan Kudarat, where sea level disturbances were expected.

According to Phivolcs, the occurrence of sea level disturbance was confirmed by records of the Sarangani sea level monitoring station that showed a drop of about 30 centimeters (cm) and a maximum rise of about 10 cm wave height relative to normal sea level. The continuing sea level fluctuations in the area associated with the strong earthquake will no longer exceed this recorded wave height, Solidum said. 

“Hindi namin inaasahan na hihigit ito sa isang metro (We don’t expect the wave height to exceed a meter),” Solidum said.

There is no need to evacuate unless the earthquake caused cracks to or damaged houses and buildings, he said. 

No volcanic earthquakes

During the press briefing on Saturday morning, Solidum also noted that there are two volcanoes in the area – Parker and Makaturing.

However, according to the Phivolcs chief, no volcanic earthquakes were recorded by the network of instruments around these volcanoes as of 8 am, April 29.

The quake was tectonic in origin and had a depth of 57 kilometers, Phivolcs said. As of 7 am, April 29, there had been 36 recorded aftershocks and 4 plotted aftershocks with magnitude that ranged from 2.8 to 4.1

It was felt at Intensity V in General Santos City; Koronadal City; Santa Maria, Jose Abad Santos, Don Marcelino, Balot Island, Davao Occidental; Polomolok, Tupi, South Cotabato; Alabel, Malapatan, Glan, Sarangani; and Palimbag, Sultan Kudarat

The strong quake was also felt in the following areas:

Intensity IV – Davao City; Cotabato City; Zamboanga City
Intensity III – Cagayan De Oro City
Intensity II – Kidapawan City

– Rappler.com