Thursday, March 24, 2011

Strong earthquake feared- 43 CL villages in danger of becoming 'liquified'

CITY OF SAN FERNANDO, Pampanga— At least 43 villages in Central Luzon, particularly those situated near coastal areas, could be transformed into “virtual liquid” areas if a strong earthquake hits the region.

The Region III office of the Mines and Geosciences Bureau here said an extraordinary phenomenon known as solid liquefaction could occur in these villages.

The MGB, however, said the phenomenon would only happen if there is also La Niña.
Orlando Pineda Sr., MGB senior geologist, said the phenomenon is known as solid liquefaction.

Pineda explained the shaking caused by an earthquake would increase water pressure that may contribute to massive earthquake problems in urban and other residential areas in the region.

The geologist said however, La Niña will not be the main cause of solid liquefaction. If there’s no earthquake, the same is not possible.

In Pampanga, all 23 coastal areas in the town of Sasmuan are prone to solid liquefaction.

Five coastal villages in Macabebe town are also feared to suffer the same situation, including Barangays Batasan, Candelaria, Consuelo, San Esteban and San Francisco.

Nine villages in Minalin also face danger of the unusual phenomenon.

These are Barangays Bulac, Sta. Catalina, Daue, San Francisco I, San Francisco 2, Manica, Sta. Rita, San Pedro and Saplad.

The towns of Macabebe and Minalin are situated in the fourth district of the province, which have always been the catch basins of flood waters coming from the northern part of the Pampanga and its adjacent provinces.

In Nueva Ecija, two barangays and a sitio (small village) in Laur town are also identified as prone to liquefaction.

These are Barangays Betania and Panaulo, and Sitio Pangarolong.

The MGB reports are based on a rapid geological assessment that the government agency has been conducting for the past 26 years.

The MGB has been working in coordination with other government agencies, like the National Mapping and Resource Information Authority, the Philippine Institute of Volcanology and Seismology and the Philippine Atmospheric, Geological and Astronomical Services Administration.

Soil liquefaction is a phenomenon whereby a saturated soil substantially loses strength and stiffness in response to an applied stress, usually by an earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid.

The phenomenon is most often observed in saturated, loose (low density or uncompacted, sandy soils.

This is because loose sand has a tendency to compress when a load is applied.

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