August 2, 2014

Earthquakes in the Philippines

Are you thinking of buying a condominium unit in one of Manila's new gleaming high rises?

Before doing so, you must realize Manila is mostly sitting on historic layers of alluvial soil.  This means places along Manila Bay and parts along Laguna De Bay are highly prone to liquefaction.  Liquefaction comes from the word "liquid" - that is the ground soil behaves like liquid when shaken tremendously as in an earthquake.  Liquefaction causes a building to resonate and possibly collapse or bend over.

An earthquake fault line, the West Valley or Marikina Valley Fault runs north to south from Marikina to parts of Quezon City, Pasig City, parts of Makati and Taguig City, almost parallel to the C-5 circumferential road.  There were local media reports the fault is showing signs of waking up, watch: West Valley Fault.

Although building structural codes addressing earthquake tolerance in the Philippines are in place, the codes are said to be up to only magnitude 6.0.  The Ruby Tower in Binondo, Sta. Cruz, Manila collapsed in 1968 after magnitude 7.2 epicentered in Casiguran, Quezon province (now Aurora) 240 km northeast.  Furthermore who can tell whether government inspections are done diligently?

What if you have or bought a place already whether detached housing or in a condo tower?  You may consider a structural audit (contact the Association of Structural Engineers of the Philippines) and if necessary engage for a seismic retrofit.  It will cost you but it increases the chance of saving a life.

Some informative sites regarding earthquakes in the Philippines, click on hyperlink

The Philippines Earthquake History

Metro Manila | Liquefaction Hazard Map

Latest Philippine Earthquake Information
PHIVOLCS Earthquake Bulletins of latest seismic events in the Philippines are listed below. The event parameters (hypocenter, time and magnitude) are determined using incoming data from the Philippine National Seismic Network
Philippine Standard Time (PST)  is eight hours ahead of Coordinated Universal Time (UTC). (PST = UTC + 8H) UTC is the time standard for which the world regulates clocks and time.
Earthquakes in this list with their date and time underlined in blue have reported felt intensities. Intensity ratings are based on the PHIVOLCS Earthquake Intensity Scale

Earthquake: Metro Manila Braces For The Big One! (List of Buildings above or close to the West Valley/Marikina Valley Fault)
By Essential Green Environmental Solution world-wide blog

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