we should be prepared for this.. simbako lang intawn.
Vibrations worry command post | Sun.Star
Vibrations worry command post
Thursday, September 25, 2014
WITHIN two weeks, the Cebu City Command Control Center (C3) monitored an average of 25 tremors a day.
These became so frequent that Cebu City Councilor Dave Tumulak wrote Director Renato Solidum last Sept. 3 to ask what the Philippine Institute of Volcanology and Seismology (Phivolcs) thought of the events.
In his letter, Tumulak requested an investigation and an explanation, “for us to understand and be relieved from this apprehension that something bad is happening.”
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Phivolcs assigned a seismic intensity meter to the C3, allowing it to monitor daily seismic activity since it began operating last February.
Tumulak, the Cebu City Disaster Risk Reduction Management Council (CDRRMC) presiding officer and C3 spokesperson, was alarmed when numerous seismic movements were felt between Aug. 27 and Sept. 8.
The intensities were between one and three.
Solidum’s reply did not entirely relieve Tumulak of his fears.
“After careful review of the transmitted intensities and compared to the records of nearby seismic stations, the recorded and displayed values by the installed device are not real earthquakes but are transient vibrations that trigger the device,” Solidum replied.
Also, the seismic activity recorded in the C3 did not show up in the Philvolcs’ base in Lapu-Lapu City.
Solidum explained transient vibrations can be caused by vehicular traffic and the operation of heavy machinery or construction work.
“These ambient vibrations can also be generated by either strong winds, moving components of a building or supporting structures,” he also wrote.
But why were the multiple tremors felt only in the last week of August and first week of September?
Tumulak said he will send a tracer letter to Solidum at the Philvolcs central office in Quezon City about this question.
He mentioned some research done in Japan, which reportedly showed that major earthquakes were preceded by “slower earthquakes” or movements that registered low intensities.
In the two weeks when a number of vibrations were recorded in the city, four days had 31 such incidents: Aug. 27 and 30, Sept. 3 and 5.
Most events were only registered at intensity one and two.
But intensity three was recorded at 10:48 a.m. last Aug. 27, at 4:33 p.m. last Aug. 28 and at 5:33 p.m. last Sept. 2.
Solidum also stated in his letter that the intensity meter installed at C3 is still under development.
“Modifications and updates to achieve optimum configuration for each device are still being made and will soon be implemented to ensure the performance of its goal and purpose,” said Solidum.
Since earthquakes cannot be predicted, unlike typhoons, Tumulak said the public should be prepared anyway.
“The people should be vigilant. Always prepare emergency kits, improve the stability of the house, be aware of one’s escape route and have an emergency plan in both the workplace and the house,” said Tumulak.
In time for the celebration of Cebu Press Freedom Week and Kapisanan ng mga Brodkaster ng Pilipinas (KBP) Month, Tumulak wrote KPB leaders to promote disaster awareness and preparedness in their daily radio and television broadcasts, as part of their corporate social responsibility.
Cebu City Command Control Center (C3) monitored an average of 25 tremors a day in Cebu
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