CAGAYAN
MANILA, MARCH 27, 2012
(BULLETIN) By JULIO PEREZ JR. — A magnitude 4.3 earthquake rocked
the province of Cagayan early evening Sunday.
According to the Philippine Institute of Volcanology and Seismology
(Phivolcs), the quake that was recorded at 6:23 p.m. was tectonic in origin.
Phivolcs added that there was no reported damage or injury.
In its earthquake information No. 2 issued at 7:14 p.m., the
epicenter of
the quake was traced some eight kilometers (kms)
northeast of Santa Ana in
Cagayan.
Phivolcs added that the earthquake was felt in Santa Ana at Intensity III.
It also said that no aftershocks are expected.
VIDEO: TOURISTS DESTINATION: STA ANA CAGAYAN,
PHILIPPINES
FROM http://www.phivolcs.dost.gov.ph/
EARTHQUAKES IN THE PHILIPPINES TODAY
NDRRMC holds nationwide-earthquake drill Tuesday,
06 March 2012 14:05
As a way of re-evaluating government's response to disasters and assessing
its evacuation and response plan, the National Disaster Risk Reduction and
Management Council (NDRRMC) conducted the First Quarter Nationwide Earthquake
Drill on March 1 at Camp Aguinaldo, Quezon City.
Simultaneously done in government and non-government offices, and selected
schools and establishments around the country, the earthquake drill started at 9
am and featured the Sounding of Alarm, Evacuation Process, Response Phase, and
the Courtesy Bow.
Armed Forces of the Philippines (AFP) Chief of Staff Lt. Gen. Jessie Delloso,
said that "the earthquake drill is a timely activity and is a means to
strengthen capability and enhance awareness on how to respond to a relatively
strong calamity, particularly earthquake."
Philippine Institute of Volcanology and Seismology (PHIVOLCS) Director Dr.
Renato U. Solidum said: "that [Feb. 6, 2012 magnitude 6.9 earthquake in Negros]
will not be the last… Each region or province in the country could have its own
earthquake scenario…Therefore, each region, province, and community in the
Philippines must prepare, and continue doing this earthquake drill."
Visualizing a 7.2 magnitude earthquake that would cause Metro Manila a
widespread devastation, the drill also highlighted the procedures that the
response groups use in times of disasters and the static display of equipment
and capacities of the Philippine Army, Philippine Air Force and Air Responses,
National Development Support Command, CGEA Station Hospital and Fire Station,
Philippine Navy, National Capital Region Command, NDRRMC Emergency Operations
Center, Bureau of Fire Protection, and AFP Reserve Command.
DND Secretary and NDRRMC Chairperson Voltaire Gazmin commended the Bayanihan
spirit and unity among the national and local government units and volunteer
groups who took part in showcasing the Philippine survival and safety measures
as reflected in the drill.
The earthquake drill, which is part of the NDRRMC's four-point plan on
disaster preparedness specifically on public information, education,
communication and disaster response, has been conducted quarterly since 2006.
What is happening at Negros Oriental, Cebu and nearby islands?
At 11:49 AM on 6 February 2012, a moderate size earthquake of magnitude 6.9
shook Negros, Cebu and nearby islands.
Aftershocks of lesser magnitude followed a few minutes after the main shock.
23 hours later, 896 aftershocks have been recorded by the PHIVOLCS seismic
monitoring network. The main shock and ensuing aftershocks have epicenters on
the eastern coast of Negros Oriental, near the municipality of Tayasan.
It is a shallow earthquake, with focal depth of 10 kilometers. Although there
are identified active faults in the island, such as the Central Negros Fault,
further investigation needs to be done to determine the fault responsible for
this earthquake. Intensity reports showed that municipalities of Tayasan,
Vallehermoso, Guihulngan and Dumaguete City (Negros Oriental) felt the strongest
ground shaking at PEIS VII (destructive ground shaking).
Furthermore, the surrounding areas of La Carlota City and La Castellana
(Negros Occidental), Tanjay and Manjud (Negros Oriental), Argao, Dalaguete,
Barili, Cebu City (Cebu) and Clarin (Bohol) felt the ground shaking at PEIS VI
(very strong ground shaking).
There were reports of felt intensities as far as 200 kilometers away from the
epicentral area. The strong ground shaking, especially in the epicentral area,
caused damage to or collapse of weak structures, liquefaction in low-lying soft
grounds, and landslide in steep slopes.
There were also reported sea disturbance in some coastal areas.
Moderate-magnitude earthquakes have also affected Negros Island in the past! On
5 May 1925, a magnitude 6.8 earthquake occurred at Southern Negros. The towns of
Bais, Tanjay, Tolong and Siaton felt the strongest intensity of ground shaking
at PEIS VI to VII.
There were report of damaged buildings in Bais and Siaton, while in
Dumaguete, landslides along ridges and fissures along rivers and mangrove areas.
Why do earthquakes occur at Negros and Cebu Islands?
Negros and Cebu islands are located in a seismically active area in the
Philippines. Instrumental monitoring of earthquakes for the past century has
detected many small to large-magnitude earthquakes in Negros Island generated by
the Negros-Sulu Trench.
The Negros-Sulu Trench is an earthquake generator located offshore west of
the island, roughly parallel to the Philippine archipelago along its length, but
veers very close to land at the southern tip of Panay Island.
Another earthquake generator that affects the islands is the Philippine Fault
Zone, segments of which pass through the islands of Masbate, Leyte and Eastern
Mindanao, and which have also been the locus of small to large-magnitude
earthquakes. Other active faults on the islands are the Central Negros Fault and
Cebu Lineaments. Seismicity for these structures are low.
Can these present earthquakes indicate volcanic activity from Kanlaon
Volcano? No. The origin of the main shock and aftershocks are clearly tectonic.
However, there are also known volcanic activities, such as those of Pinatubo
Volcano, which some scientists suggested were influenced by an earlier
large-magnitude earthquake. PHIVOLCS is closely monitoring the situation.
PEIS – Philippine Earthquake Intensity Scale 2 Small magnitude less 4.9 or
less; moderate magnitude 5 to 6.9; large magnitude 7 and above
What can we expect from the current earthquake activity?
The current seismic trend indicates that the magnitude 6.9 earthquake on 6
February 2012 may be the main shock, and the succeeding small magnitude
earthquakes are the aftershocks.
The aftershock may continue for weeks to months, but diminishing in number
and strength as time passes. In this case, a stronger earthquake related to this
event is no longer expected to occur.
However, there is no absolute way to determine whether another large
earthquake would not follow the current activity. The present state of
technology in the world is not capable of reliably predicting earthquake
occurrences.
What should we do?
The best course of action is preparedness – we can minimize the damaging
effects of earthquakes if we prepare ourselves for the event. Because a
large-magnitude earthquake, from the Negros-Sulu Trench, the Philippine Fault
Zone, or from any of the known active faults in the Visayas, may affect Negros
and neighboring islands as a whole, it is always prudent to prepare for such an
eventuality.
The conduct of earthquake and tsunami evacuation drill, as well as adherence
to the building code are effective means to save lives and properties.
What can we expect in the event of a large-magnitude/high-intensity
earthquake?
Strong ground shaking may cause extensive damage to, or even the collapse of
houses, buildings, bridges, and other infrastructures. Collapsed structures
usually account for most of the casualties during a strong earthquake. Falling
objects may also cause injuries.
Aside from strong ground shaking, what other seismic hazards are
life-threatening?
Landslides, rock falls, and other types of mass movements may occur in
mountainous or hilly areas. Liquefaction may affect low-lying, water-logged
areas near the coast or at the banks of rivers.
In general, a strong earthquake occurring offshore may also generate tsunamis
– large sea waves – that may sweep coastal areas. There is practically not
enough lead time to warn for a locally-generated tsunami.
If a nearby earthquake source generated a tsunami, it may reach the shore in
as short a time as 3-5 minutes, and may sweep away nipa huts and boats along
with unprepared residents.
What is the role of PHIVOLCS?
PHIVOLCS operates and maintains a network of 64 seismic stations spread
across the Philippines.
Nine of these – the manned seismic stations of Negros Oriental (Sibulan),
Cebu (Lapu-lapu City), Panay Island (San Jose Buenavista, Roxas City, Kalibo),
Bohol (Tagbilaran City), as well as unmanned stations of Guimaras Island and
Leyte Island (Maasin City and Ormoc City) – are located in or around Negros and
Cebu islands.
Additional seismic data came from the Kanlaon Volcano Observatory in La
Carlota City, Negros Occidental. Data from the seismic stations are used to
determine the location, magnitude and other characteristics of the earthquakes
generated.
Aside from monitoring the occurrences of earthquakes, PHIVOLCS also conducts
hazards analyses and assessments, and make these information available to the
public. PHIVOLCS works hand-in-hand with other government agencies in mitigating
the damaging effects of earthquakes.
Chief News Editor: Sol
Jose Vanzi
© Copyright, 2012 by PHILIPPINE HEADLINE
NEWS ONLINE
All rights reserved
PHILIPPINE HEADLINE NEWS
ONLINE [PHNO] WEBSITE
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