Baluyos: Earthquake and earthquake preparedness-A A +A
Sunny Side Up
Thursday, October 17, 2013
THE magnitude 7.2 earthquake that hit the Visayas region last October 15 left hundreds dead and injured and (many still missing), thousands of families homeless, crumbled historical structures especially churches, and destroyed buildings and structures and claimed billions in damages.
Why and how earthquakes occur? Philippine Institute of Volcanology and Seismology (Phivolcs) Chief Science Research Specialist Ma. Mylene Martinez Villegas* said that the earth is made up of three layers, namely, crust, mantle and core.
The outermost layer, crust, can be brittle and break into several smaller pieces.
Villegas added that the theory of Plate Tectonics which emerged and developed in the 1960s explains that the earth’s outer layer called “lithosphere’ is broken into several pieces known as tectonic plates that are more relative to each other.
Earthquake, Villegas stated, is a feeble shaking to violent trembling of the ground produced by sudden displacement of rocks or rock materials below the earth’s surface.
There are two types of earthquakes: tectonic and volcanic.
Tectonic earthquakes are those generated by the sudden displacement along faults in the solid and rigid layer of the earth. The earthquake that recently hit the Visayas region in the Philippines is tectonic in origin.
On the other hand, an earthquake induced by rising lava or magma beneath active volcanoes is called volcanic earthquake, and this is the type of earthquake that usually generates tsunamis.
There are two ways by which the strength of an earthquake is measured: magnitude and intensity.
Magnitude is the measure of energy released and is determined based on instrumentally-derived information (through a seismograph).
Magnitude correlates with the amount of total energy released at the earthquake’s point of origin and is reported as Arabic numbers, for example, magnitude 5.3 or 7.2.
Intensity, on the other hand, is the description of how weak or strong the shaking is.
Intensity is generally higher near the epicenter (reported as Roman numerals, e.g., I - Scarcely Perceptible to X - Completely Devastating) and this is measured by a) what people see and feel; b) severity and extent of damage to buildings or structures; c) condition of ground failure and presence of other earthquake hazards associated during the event.
Focus is the point within the earth during which is the center of energy released during an earthquake, while epicenter is the point on the surface of the earth directly above the focus.
The Philippine Institute of Volcanology and Seismology (Phivolcs) of the Department of Science and Technology (DOST) is the national government agency mandated to monitor and study earthquake and volcanoes in the Philippines.
It is mandated to study earthquake generators and raise awareness and preparedness of the public regarding the hazards associated with earthquakes.
Phivolcs, along with other DOST agencies and their partner-agencies, continues to conduct trainings and disaster preparedness.
DOST also trains science and mathematics teachers and they are expected to share their knowledge and skills in their own schools and community, and most of all, to their students and family members.
Here are some tips on what to do during an earthquake:
When inside the house/building
When a strong shaking starts:
Protect yourself. Stay away from objects that may fall such as cabinets, shelves, ceiling fans, etc.
Get under a sturdy table/desk and do the ‘DUCK, COVER AND HOLD.” Stay put until the shaking stops.
As soon as the shaking stops:
Look quickly for damage in and around your home.
Check yourself for injuries and get a first aid.
Report life-threatening emergencies.
Extinguish small fires. Fire is the most common hazard after an earthquake.
Clean up spilled medicines, bleach, gasoline and other flammable liquids immediately.
Open closets and cabinet doors carefully as contents may have shifted.
If there is an aftershock, DROP, COVER AND HOLD ON.
If your home/building is not safe, get out immediately.
Walk, do not run. Do not push. Do not talk.
Watch out for fallen power lines or broken gas lines and stay out of damaged buildings.
Keep animals under your direct control.
Monitor/listen to radio for updates/reports/instructions.
Return home only when authorities say it is safe to do so.
If you are outside
Move to an open area. Get away from power lines, posts, walls and other structures that may fall or collapse.
Stay away from buildings with glass panes.
If you are driving, pull over to an open, safe area.
If you are in a mountain or near a steep hill slope, move away from steep escarpments that may be affected by landslides.
If you are along the shore, run away from the shore toward higher ground.
If there is something positive about what happened on October 15, it was because it was a holiday in the Philippines, as our Muslim brothers and sisters celebrated the Eid Al-Adha, thus, there was no classes, no work.
The number of casualties could have been bigger as some of those damaged by the earthquake were office and school buildings.
An earthquake is one natural disaster that may strike anytime, thus, it is very important to be well-prepared.
Disaster preparedness reduces death, injuries, damage to properties and infrastructures.
Published in the Sun.Star Cagayan de Oro newspaper on October 18, 2013.