Phivolcs explains why Pampanga was hit hardest by Luzon quake
by Robie de Guzman | Posted on Tuesday, April 23rd, 2019
MANILA, Philippines – The center of the magnitude 6.1 earthquake that rattled parts of Luzon on Monday was traced in Castillejos, Zambales, but the province of Pampanga recorded the hardest hit.
The Philippine Institute of Volcanology and Seismology (Phivolcs) explained that aside from being a neighbor of Zambales, the province sits on soft sediment and alluvial soil.
Alluvial, in geology, means made up of or found in the materials that are left by the water of rivers, floods among others. An area with softer soil is prone to strong shaking during an earthquake.
Although the temblor was not considered major, Phivolcs said, it was felt by many because it was a bit shallow.
Monday’s earthquake had a depth of 21 kilometers.
“Kaya nagkaroon ng damages sa Pampanga, bukod sa malapit siya sa episentro ng lindol ay malambot yung area na yan. Alluvial area po yung Pampanga kaya malakas yung shaking na mararamdaman,” said Phivolcs Senior Science Research Specialist Melchor Lasala.
(Pampanga recorded heavy damages because aside from being near the quake’s epicenter, the province has soft soil. It is an alluvial area so the shaking was amplified.)
Among the areas that suffered heavy damages were Porac, Angeles and Lubao.
The National Disaster Risk Reduction and Management Council (NDRRMC) on Tuesday reported 16 fatalities in the quake, 15 of which were from Pampanga.
Five people were killed in the collapse of a four-story supermarket in Porac, seven in different barangays in Porac, two in Lubao and one in Angeles.
The earthquake that struck Castillejos, Zambales on Monday was also felt in Metro Manila, parts of Bataan, Tarlac City, Batangas and Cavite.
Phivolcs said it has yet to identify if the recent quake in Luzon originated from an existing active fault in Zambales.
“Yung dalawang fault system na tinitingnan namin yung Iba Fault at East Zambales Fault,” Lasala said.
(We are looking at two fault systems, the Iba and East Zambales fault.)
Lasala added that the movement felt on Monday was called “strike slip”.
“‘Pag strike slip may dalawa tayong slab yung fault—yung left at yung right. Sa behavior, horizontal yung movement niya. ‘Yung isa papunta sa kaliwa yung isa sa papunta sa kanan,” Lasala explained.
Strike-slip faults are vertical (or nearly vertical) fractures where the blocks have mostly moved horizontally, according to the United States Geological Survey (USGS) earthquake glossary.
If the block opposite an observer looking across the fault moves to the right, the slip style is termed right lateral; if the block moves to the left, the motion is termed left lateral.
Phivols also believes that the magnitude 6.1 quake that jolted Zambales will not trigger a movement of the West Valley Fault as it is 100 kilometers away from the epicenter traced in the Castillejos town.
According to a 2004 study, the West Valley Fault runs through the cities of Marikina, Pasig and Muntinlupa. It is capable of generating a magnitude 7.2 quake that could kill up to 34,000 people and injure 100,000 others. — Robie de Guzman (with details from Rey Pelayo)
by Marje Pelayo | Posted on Tuesday, July 16th, 2019
MANILA, Philippines – Want to know potential hazards within your area?
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Tuesday (July 16) launched a web application dubbed as ‘Hazard Hunter’ which provides the public with information on the possible dangers that may happen in a specific area like earthquake, flood or even volcanic eruption.
‘Hazard Hunter’ is a web-based application that can be accessed on desktop, laptop or in smart phones.
A welcome message will lead you to the Hazard Hunter official page.
You will be asked to proceed until you see the full map of the Philippines.
Click on the menu bar then several options on the type of hazards that may be present in your area will appear – seismic for earthquakes, volcanic for volcanoes and hydro-meteorological for flood and storm-related hazards.
Click on the type of hazard then select an area by pointing the cursor to the place of inquiry on the map.
Double click on the area of choice.
The system will immediately load the results that will flash on the right side of the screen.
For instance, Baseco compound in Manila has a population of about 60,000 people.
Based on the app’s reading, Baseco is about 12 kilometers away from the West Valley Fault.
Residents in Baseco may feel ground shaking of up to intensity 8 once the West Valley Fault moves in an event called the Big One.
The area is prone to liquefaction and could suffer from up to four-meter-high tsunami as it is near Manila Bay.
Based on the app, Baseco is less likely to be affected if ever the nearest active volcano, Mount Taal in Batangas, erupts.
Taal Lake is about 58 kilometers away from Baseco.
Baseco is a flood-prone area and floodwater can go as high as two meters and can take up to three days to subside.
During the onset of a severe tropical cyclone, the area could suffer from storm surge as high as 4 meters.
But there is no possibility of a landslide in the area.
The app also has detailed recommendations or suggestions for a plan of action during a specific hazard.
Science and Technology Undersecretary and PHIVOLCS OIC Renato Solidum believes ‘Hazard Hunter’ will enable the public to prepare and plan ahead of a natural disaster.
Government agencies will also be guided for appropriate actions to be taken to minimize or prevent the loss of lives and damage to properties.
“Hindi naman masama na may hazards diyan. What is important is that the hazard is recognized so that the developer can develop approaches to lessen the impact, to mitigate the possible impact,” Solidum noted.
Solidum said even his own house sits on a location that is hazard-prone but recognizing the dangers enabled him to plan for his and his family’s protection.
“Tinaasan ko yung bahay. Ginawa kong three floors para hindi ako mamatay sa baha (What I did was I elevated my house. I made it into three floors to keep me safe from the flood),” he said.
“Inayos ko yung foundation ng building para sa shaking ng liquefaction. So mga ganung klaseng real life application magagamit (ang Hazard Hunter) (I aligned the foundation of the building in case of shaking during liquefaction. During those real-life applications, [Hazard Hunter] can be useful),” he added.
Before the end of the year, PHIVOLCS plans to launch the mobile version of the website. – with details from Rey Pelayo
by Marje Pelayo | Posted on Wednesday, July 3rd, 2019
MANILA, Philippines – Newly-elected mayor Francisco Domagoso admits they are not ready in case a strong earthquake or the so called ‘Big One’ strikes the city.
“The City of Manila is not ready. On record. Sila ang may sabi noon, (That’s what they said),” Domagoso said referring to the local disaster risk reduction management officials following a meeting with them on his second day in office on Tuesday (July 2).
Mayor ‘Isko’ ordered the City Disaster Risk Reduction Management Office (CDRRMO) to draft a concrete disaster management plan or a detailed hazard map to prepare the city for potential dangers.
During the meeting, Domagoso discovered a lot of problems in terms of the city’s disaster preparedness and response.
The city lacks plans and programs for risk reduction management.
There are no measures in place to solve the decade long flood problems.
The city’s disaster response command center lacks equipment, the office looks shabby and neglected.
The CCTV cameras only cover areas within the city hall and Carriedo area.
Emergency personnel admitted they have no established emergency hotline and they usually use their personal numbers to contact the public in times of need.
The CDRRMO also lacks personnel and the city falls short in resources when it comes to health care.
According to the overall assessment report of the Department of the Interior and Local Government (DILG), the city is considered a ‘total failure’ when it comes to disaster preparedness and response.
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) noted the importance of prioritizing disaster resiliency in all of Manila especially its buildings and structures as it is a city prone to hazards.
“The biggest stumbling block would be the resilience of the structures. Iyon ang pinakaunang kailangang gawin. Ayusin ang mga pwedeng bumagsak na mga bahay (That’s the very first thing that needs to be addressed – fix the houses that are damage prone),” explained DOST Undersecretary and PHIVOLCS administrator Renato Solidum.
“Marami silang (There’s a lot of) hazards that need to be integrated in their preparedness,” he noted.
Mayor Domagoso warned to dismiss all concerned DRRMO officials if they will not act on the matter at the soonest possible time.
“I will fire you if you don’t admit that we are not ready,” Mayor Domagoso told them.
“You have to be honest with yourself. You can even challenge me at the Civil Service (Commission) if I fire you,” he concluded. – with reports from April Cenedoza
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