Watch out for ‘The Big One’ (Second of Two Parts)

By Henrylito D. Tacio
Perhaps no other natural disaster can cause so much damage so suddenly and in so little time as earthquakes.  It is surprising that nobody wants to talk about earthquakes in earthquake-prone Philippines.
When asked if a big earthquake that hit Baguio in 1990 will happen in Davao City, a woman in her late forties just said: “God forbid.”  Then, she made a sign of a cross.
The woman was not alone.  A survey conducted by this writer showed that most people in Davao City and nearby towns are ill-prepared should earthquake happen any time of the day.
“It’s one issue Filipinos would rather not talk about or do something about,” wrote award-winning journalist Carolyn O. Arguillas.  “Until it’s too late.  (Earthquake) is one issue that we should not avoid but confront head-on.”

Intensity scale
Earthquakes send shock waves through the earth.  The amplitude of these seismic waves indicates the force of an earthquake and is measured on a scale devised by Charles Franci Ritcher known as the Richter scale.
However, the Philvolcs has been using since 1996 a different intensity scale which “based on relative effect to people, structure, and objects in the surroundings.”  Let’s take a closer look at them:
I. Scarcely perceptible: It is perceptible to people under favorable circumstances.  Delicately-balanced objects are disturbed slightly.  Still water in containers oscillates slightly.
II. Slight felt: It is felt by few individuals at rest indoors.  Hanging objects swing slightly.  Still water in containers oscillates slightly.
III. Weak: It is felt by people indoors especially in the upper floors of buildings.  Vibration is felt like the passing of a light truck.  Dizziness and nausea are experienced by some people.  Hanging objects swing moderately.  Still water in containers oscillates moderately.
IV. Moderately strong: It is felt generally by people indoors and some people outdoors.  Light sleepers are awakened.  Vibration is felt like the passing of a heavy truck.  Hanging objects swing considerably.  Dinner plates, glasses, windows and doors rattle.  Floors and walls of wood-framed buildings creak.  Standing motor cars may rock slightly.
V. Strong: Generally felt by most people indoors and outdoors.  Many sleeping people awakened.  Some are frightened; some run outdoors.  Strong shaking and rocking are felt throughout the building.  Hanging objects swing violently.  Dining utensils clatter and clink; some are broken.  Small, light and unstable objects may fall or overturn.  Liquids spill from filled open containers.  Standing vehicles rock noticeably.  Shaking of leaves and twigs of trees is noticeable.
VI. Very strong: Many people are frightened, many run outdoors.  Some people lose their balance.  Motorists feel like driving with flat tires.  Heavy objects and furniture move or many be shifted. Small church bells may ring.  Wall plaster may crack.  Very old or poorly built houses and man-made structures are slightly damaged, though well-built structures are not affected.  Limited rockfalls and rolling boulders occur in hilly to mountainous areas and escarpments.  Trees are noticeably shaken.
VII. Destructive: Most people are frightened and run outdoors.  People find it difficult to stand in upper floors.  Heavy objects and furniture overturn or topple.  Big church bells may ring.  Old or poorly built structures suffer considerable damage.  Some well-built structures are slightly damaged.  Some cracks may appear on dikes, fish ponds, road surfaces or concrete hollow block walls.  Limited liquefaction, lateral spreading and landslides are observed.  Trees are shaken strongly.
VIII. Very destructive: People are panicky.  People find it difficult to stand even outdoors.  May well-built buildings are considerably damaged.  Concrete dikes and foundations of bridges are destroyed by ground settling or toppling. Railway tracks are bent or broken.  Tombstones may be displaced, twisted or overturned.  Utility posts, towers, and monuments may tilt or topple.  Water and sewer pipes may be bent, twisted or broken.
Liquefaction and lateral spreading cause man-made structures to sink, tilt or topple.  Numerous landslides and rockfalls occur in mountainous and hilly areas.  Boulders are thrown out from their positions particularly near the epicenter.  Fissures and fault rupture may be observed.  Trees are violently shaken.  Water splashes or slops over dikes or banks of rivers.
IX. Devastating: People are forcibly thrown to the ground.  Many cry and shake with fear.  Most buildings are totally damaged.  Bridges and elevated concrete structures are toppled or destroyed.  Numerous utility posts, towers and monuments are tilted, toppled or broken.  Water and sewer pipes are bent, twisted or broken.
Landslides and liquefaction with lateral spreading and sandboils are widespread.  The ground is distorted into undulations.  Trees are shaken very violently with some toppled or broken.  Boulders are commonly thrown out.  River water splashes violently or slops over dikes and banks.
X. Completely devastating: Practically all man-made structures are destroyed.  Massive landslides and liquefaction, large scale subsidence and uplifting of landforms, and many ground fissures are observed.  Changes in river courses and destructive seiches in lake occur.  Many trees are toppled, broken or uprooted.
Always be ready
“We believe that the key to saving lives and properties in times of natural calamities like typhoons, floods or earthquakes is preparedness,” says Secretary Mario G. Montejo of the Department of Science and Technology.  “So we must take a proactive role in making our communities safer and more resilient.”
This must be the reason why Philippine Institute of Volcanology and Seismology (Philvolcs) urged every Filipinos to evaluate the structural soundness of home, office and buildings they frequent.  “Determine the safest areas both inside and outside,” said a Philvolcs primer.
The primer also recommends that every home must be prepared for the eventuality. “Secure heavy furniture to prevent sliding or toppling over by affixing them to walls or floors with brackets or tying to grillwork.  Keep heavy objects on lowest shelves.  Check hanging objects (like ceiling fans, mirrors, heavy picture frames).  Affix bolts or hooks on cabinet doors especially those in the kitchen to prevent them from flying open and allowing breakable items to spill out.  Keep only very necessary chemicals and flammable liquids in unbreakable containers.  Store them on low shelves.”
The PHILVOCS primer also suggests setting up an earthquake readiness plan at home.  “Make sure your children, elderly members and house helpers are properly instructed on what to do. Practice drills with them.  Familiarize yourself with First Aid procedures.  Keep a manual handy in case you forget.  Make sure everyone knows the locations of and how to switch off the electrical and water mains.  At home (and at work), master the quickest, safest way out,” it says.
The primer also recommends preparing a small bag – no more than 5-6 kilograms – for each member of the family.  Among those that should be packed inside the bag are two changes of clothes, a blanket, a towel, basic toiletries, sturdy shoes, flashlight, batteries, a bottle of water, biscuits candy, a small radio, any medications for chronic ailment suffers, first aid kit, contact phone numbers and addresses.  Important papers (passport, recent medical records, bank books, insurance papers, etc.) must also be included.
What should a family do during an earthquake?  The primer says: “Stay calm. Call out instructions to children or others who seem to be in panic.”
If you happen to be inside a building that is structurally sound during an earthquake, you must stay there.  However, if you have doubts about the building, leave immediately by the safest, quickest route.
Once you are outside the building, look for an open area where you can stay.  But you must stay away from power lines, telephone poles, and trees.  If objects are falling, brace yourself in the doorway of a building.
If driving, pull over and stop.  You should not cross bridges, over or underpasses. If on a mountain road, pull over and stay clear of ridges.  If by the sea, move inland to higher ground.
After an earthquake, check yourself and other members of the family.  In addition, check for fire, chemical spills and act on them right away.  In case of doubt about leaks or damage, switch off all electric main fuses and turn off gas tanks.
If you must evacuate, take your small bag with you and leave message with a contact person as to where you are headed.  Do not go sightseeing.
Be prepared for aftershocks.  Do not enter damaged buildings because aftershocks can finish them off.
It is said, and you should heed this, that natural calamities like earthquake happen when you have forgotten about them.