|
By Paul M. Icamina, Special reports editor
IT is just after sunset, and the ground shakes violently. A jolt
pushes you forward, up, down and sideways, and the ground motion
grows more violent for the longest minute of your life.
There is a booming sound. Screams are heard from
houses. Glasses break. Trees and utility poles sway violently. Then
the power goes off.
You run outside where the road is heaving like
waves. Then the shaking stops and you get up with knees shaking.
Cries and wails add to the panic and confusion
everywhere. Houses have collapsed, roads are cracked, water and
sewage gush from broken pipes.
You hurry home to find it in shambles and the
family scared but safe. The mobile phone has no signal and the
landline is off.
But the radio works, and you hear the first
news: “A devastating earthquake, with magnitude 7.2 generated by
the nearby Western Marikina Valley Fault, has hit Metro Manila. Weak
to strong after shocks are expected …”
This is not science fiction but a worse-case
scenario by the most extensive study yet of what a magnitude 7
earthquake may do to Metro Manila.
The study was done by the Japan International
Cooperation Agency, Philippine Institute of Volcanology and
Seismology and the Metro Manila Development Authority.
One of Asia’s most densely populated areas,
Metro Manila’s 13 cities and four towns packed in 636 square
kilometers is home to about 10 million (when the study was made
between 2000 to 2004).
The metro population is expected to grow to 25
million by 2015 in a highly urban sprawl that will spread by then to
1,500 square kilometers.
Since Metro Manila is the country’s only mega
urban center of government, finance, commerce and social activities
(it generates 35 percent of GDP), the study observes, “the impact
of a large earthquake will greatly affect the nation … national
functions will be paralyzed, and in the worst case, the earthquake
will lead to chaos and disruption of the national economy.”
Faults
Many earthquake faults surround the megapolis:
the Western Valley Fault System (Marikina Valley Fault), Philippine
Fault, Lubang Fault, Manila Trench (which runs off western Luzon)
and the Casiguran Fault.
Because of its proximity, the West Valley Fault,
which runs north to south along the west and east edges of Marikina
Valley, is considered the greatest threat. The 30-kilometer-long
northern half of the fault is only 10 kilometers east of central
Manila.
The five strongest earthquakes in Manila
occurred in 1658, 1771, 1863, 1880 and 1937. Two earthquakes—in
1677 and 1863—generated a tsunami around Manila Bay. Since 1900,
over 30 earthquakes have caused some damage.
Analyzing past earthquakes, the study selected
18 scenarios based on three epicenters originating from the West
Valley Fault, Manila Trench and Manila Bay. Ground motion,
liquefaction (when the soil turns liquid-like), slope stability and
tsunami height were factored in.
The fault has moved at least four times and
generated strong earthquakes in the last 1,400 years. The
approximate return period of these earthquakes is less than 500
years and no event along the West Valley Fault is known after the
17th century, says the study.
Its conclusion: “the active phase of the
Western Valley Fault is approaching.”
National crisis
A magnitude 7 earthquake will cause liquefaction
in coastal and floodplain lowlands, including the central district
of Makati, resulting in damage to roads, buildings and
infrastructure.
If the earthquake originates from the Manila
Trench (a fault line that runs off western Luzon, from Ilocos to
Mindoro), a tsunami 2 meters to 4 meters high may hit the Manila Bay
area one hour after. The Old Manila area—including low areas with
elevation less than 4 meters such as that in Malacañang and
Pandacan—will be hit.
Such an earthquake will result in 170,000 houses
collapsing, 340,000 residential buildings damaged, 34,000 persons
dead and 114,000 injured.
So many wooden buildings and hazardous
facilities will spread fires across 1,710 hectares. Fatalities: over
19,000.
“This human loss, together with properties and
economy losses, will be a national crisis,” the study warns.
The hardest-hit areas would be Navotas,
Manila’s Port Area and southeastern portion, Central Manila Bay
area, northeastern Quezon City, western Marikina, eastern Pasig, the
border between Manda-luyong and Makati and the Muntinlupa-Laguna Bay
area.
Overall, fires and evacuation will be most
intense around Navotas Bay, the North Port Area in Manila,
southeastern Manila and those surrounding the central Manila Bay
area. Building collapse and evacuation problems will be greatest in
northeastern Quezon City, western Marikina, eastern Pasig,
Muntinlupa-Laguna Bay area and the border between Mandaluyong and
Makati.
Fires will be a problem in the intersection
between Valenzuela, south Caloocan and western Quezon City.
Evacuation will be difficult in the fringes of
Metro Manila, especially in the northern Taguig and Las Piñas
sides. Western Metro Manila will be isolated by fire and destroyed
buildings. The northern and southern part will be separated by
rubbles, especially in the border between Mandaluyong and Makati.
All road networks along the Western Valley Fault
running east-west will be damaged while roads running north-south in
the fault area will be cluttered by collapsed buildings.
Surreal landscape
On Day 1, fires will break out in villages,
chemical plants, factories and hospitals. About 4,000 major water
distribution points will be damaged.
There is no electricity, telephone lines and
cell-phone networks are down; from 31 to 97 kilometers of
electricity and telecommunication lines will be affected.
About four out of 10 residential buildings will
collapse or be affected. Many schools and business establishments
will be heavily damaged or destroyed.
Some hospitals will be heavily damaged and many
patients will be evacuated. Hundreds, if not thousands, will be
trapped dead or injured.
Abandoned cars will litter the streets. Some
bridges will be down, many roads will be impassable and ambulances
cannot get through. The light rail systems will be at a standstill.
Within the next few hours, the National Disaster
Coordinating Council convenes but “not all member agencies have
representatives immediately available,” the study says.
By the second and third day, food and drinking
water will be scarce. Moderate to weak aftershocks will occur. There
will be no electricity, telephone communication and water. Back-up
power generators will be available only in critical offices.
Fires will spread unabated. Haze from burning
buildings will darken the horizon.
The President declares a state of calamity while
the police contain random acts of looting. The military is mobilized
for rescue, clearing of debris and construction of temporary
shelters and medical centers.
The homeless—that will swell to as much as
3.15 million—begin to occupy open spaces. Relief goods are
distributed while volunteer rescue teams arrive from abroad.
Many survivors rescued from collapsed buildings,
especially children, will suffer from shock. Bodies exhumed from the
rubbles will line the streets. Disease outbreaks threaten.
Some 33.555 million tons of debris from nearly
half a million damaged buildings will litter a surreal landscape.
The air has the smell of decay and death. The
Philippine flag, if it is raised, flies at half-mast.
|
