Phivolcs warns of lake tsunami-like waves

Beware a possible tsunami-like wave or “seiche,” should an earthquake hit, the Philippine Institute of Volcanology and Seismology (Phivolcs) warned Muntinlupa on Wednesday, adding that a change in atmospheric pressure could cause this huge wave in enclosed bodies of water.

In a statement, Joan Salcedo, Phivolcs supervising science research specialist, noted that Laguna de Bay was “just on (Muntinlupa’s) eastern side” and that the “seiche” occurs only in lakes, bays, or gulfs after a seismic or atmospheric disturbance.

But public information officer Tez Navarro said the city has been “ready for all types of (possible) disasters” since 1999, when City Ordinance No. 98010 was passed, prompting them to “establish fault zones” where human activity was prohibited.

Following the Phivolcs’ release of updated and detailed maps that trace the 100-kilometer West Valley Fault traversing parts of Metro Manila and the adjoining provinces of Bulacan and Laguna, the city government has been “going to the grassroots and disseminating information to people near Laguna de Bay and the coastline,” the official said over the phone.

Navarro said a building of the Pedro Diaz High School located on the West Valley Fault was also temporarily evacuated so authorities can check its structural integrity.

The city official said Phivolcs Director Renato Solidum Jr. will meet with city and barangay (village) officials, homeowners and other stakeholders on June 1 to explain the dangers and preparations needed to cope with all possible disasters.

The Department of Education (DepEd), meanwhile, said it would build “temporary learning centers” for students who may be displaced because their schools traverse the West Valley Fault System.

“Once we have a better picture (of how many) students may be displaced because of the unsafe structures, the DepEd would have to find… other schools where the kids can be enrolled,” deputy presidential spokesperson Abigail Valte said in a press briefing.

The alternative, she added, is “to put up temporary learning centers to await construction of new classrooms, if necessary.”

Valte also reiterated the earlier announcement of DepEd Sec. Armin Luistro who said the department will not allow students to use buildings that have yet to be cleared by the Department of Public Works and Highways (DPWH).

In the latest edition of the Valley Fault System Atlas published by Phivolcs, five public schools were identified as being transected by the fault line: Barangka National High School in Marikina City, Alabang Elementary School, Pedro Diaz High School and Buli Elementary School in Muntinlupa City, and Anne Claire Montessori in Taguig City.

More than 100 other public schools also lie along the West Valley Fault Line, which could trigger a 7.2-magnitude earthquake.