When is the Big One? Earthquakes, calamities and other portents

When is the Big One? Earthquakes, calamities and other portents

THE Philippines sits on the Pacific Ring of Fire, a belt of countries around the Pacific Ocean that is prone to earthquakes and volcanic eruptions. Underground, it is lined with many fault lines, fissures and cracks. Its tectonic plates jostle against each other a few times each year. And there is always talk of the Big One, like a dark cloud in the air.

On April 3, the Philippines’ northern neighbor, Taiwan, was rocked by a magnitude 7.4 earthquake that was the island’s most powerful in 25 years. It lasted for a minute, but it tilted buildings, killed at least nine people and set off tsunami warnings in China, Japan and the Philippines. More than 1,010 people were injured.

Taiwan has strict building codes and a citizenry with long experience with earthquake drills. It has an expert earthquake response system that should be a model for countries like the Philippines. As of press time, aftershocks still rumble through the fault-riddled island.

On the other side of the Bashi Channel, the Philippines endures more than 10 tropical storms every year, aside from volcanic eruptions and daily earthquakes. According to the Philippine Institute of Volcanology and Seismology (Phivolcs), the country usually has more than 200 earthquakes, mostly minor ones. It’s a situation similar to Indonesia’s. When I was there, the university guest room moved, and I ran outside. A woman was sweeping dry leaves from the earth and just smiled when I told her, in my broken Bahasa, that there was an earthquake. She said they have that, every day.

Manila lies between two volcanoes that are still active. Mount Pinatubo in Zambales erupted in June 1991 after being dormant for 500 years. It was the second-biggest volcanic eruption of the 20th century, raising the earth’s temperature by 1 degree and darkening Southeast Asia’s skies for months. Taal Volcano, which lies at the bottom of a freshwater lake, is 50 kilometers south of Manila. Its eruption in January 2020 caused nearby residents to flee and scattered volcanic ash that reached the suburbs of Manila.

Last December 2, a 7.6 magnitude earthquake shook Mindanao, generating a small tsunami and many strong aftershocks. A magnitude 5.3 quake rattled Aras-asan, Caraga, on the northern tip of Mindanao on March 6, and two more 5-plus magnitude quakes shook the same area earlier that month. A 4.0 magnitude temblor jolted Sarangani Island on March 5.

The last major earthquake in Metro Manila happened in 1968. It had a magnitude of 7.6 and killed 207 people when a six-story building collapsed. More than 200 were injured. It turned out the engineers of the building did not follow the safety code, and earthquake response systems were unheard of then.

In a 2019 study, a Manila-based country risk firm (which asked not to be identified by name) said Metro Mania was at risk of another 7.2 magnitude earthquake. This would come from the West Valley Fault System, which cuts through the metropolitan area from Bulacan to Laguna, 11 kilometers to the south of the city center.

Phivolcs said the West Valley Fault System had caused at least two major earthquakes within the last 1,400 years. The ground beneath our feet in Metro Manila moves about every 400 years. The last such movement happened 355 years ago. Of course, earthquakes cannot be predicted 100 percent. But the pattern of evidence indicates something. Asia Sentinel said Phivolcs predicted that there might be a major quake “at some point during current lifespans.”

And it’s not just the West Valley Fault System, for other lesser crustal faults are found beneath our country. There are the Philippine Fault Zone, the Lubang Fault, the Casiguran Fault and the Manila Trench. The composition of their soil is mixed, with rocky and granite locations providing resistance to earthquakes. However, coastal regions, particularly the northern part of Laguna de Bay and the coast of Manila Bay, are prone to liquefaction.

What happens when the Big One comes?

“If the Big One, as the country-risk firm calls it, were to hit, international agencies predict an estimated 52,000 deaths and up to half a million injuries, with economic losses up to P2.5 trillion (approximately $44.7 billion),” Asia Sentinel said. The report also indicates that the government might not be completely equipped to deal with such a major calamity.

“Emergency response will be delayed due to the lack of capacity in both manpower and resources, and their inability to reach victims,” the report notes. “In the initial hours of the aftermath, confusion and delay in the relay of information is expected and may persist for some days. There are also few open spaces in the metropolis to accommodate the influx of short- and longer-term evacuees. Major infrastructure is expected to be severely damaged in the aftermath of the earthquake. Many important roadways and bridges are likely to collapse, raising the probability of a regional separation within the metropolis.”

In fairness to the government, it has upscaled its disaster management structure and resources after the major devastation wreaked by Typhoon “Yolanda” (Haiyan) in November 2013. That super typhoon killed at least 6,400 people and cost $3.5 billion in property damage. Subsequent floods, typhoons and landslides have seen improved communication and coordination that mitigated the impact on lives and livelihoods. Unfortunately, former president Rodrigo Duterte defunded Project Noah, but President Ferdinand Marcos Jr. is seen to restore it and the provision of geohazard maps to the country’s more than 1,500 towns and cities.

Be that as it may, the Philippines’ 2021 Disaster Management Reference Handbook notes that “informal settlements” still make up 45 percent of the urban population. They “are particularly at risk due to precarious infrastructure and will be vulnerable to negative impacts due to limited access to clean water and a lack of health care access.”

Moreover, the 2019 report said, “Power grids, telecommunications networks and water distribution infrastructure would be heavily damaged by the quake, with fires expected across the city, causing additional fatalities and property damage. After initial building collapses, further damage is expected from the breakout of an estimated 500 fires, with poorer areas expected to be hit hard by the damage and fires caused by electrical short circuits and LPG (liquefied petroleum gas) and petroleum tank explosions, charring as much as 1,710 hectares and resulting in an additional 18,000 fatalities.”

This seems like a recipe for catastrophe, but there is more. Water distribution pipes will be damaged, limiting firefighting capabilities. This will lead to lack of potable water and create localized flooding. About 4,000 water supply points would be cut immediately. Damaged reservoirs and water purification plants will cause major long-term water shortages.

The West Valley Fault System also cuts through Angat Dam, the major source of water for Metro Manila. Its damage would flood the Angat River, its tributaries and low-lying areas. Destroyed pipes could not deliver clean water, and water-borne diseases will rise. “Many inhabitants would be exposed to drinking water from unsanitary sources, further magnifying the risks from communicable diseases.”

What to do?

What, then, should we do in the face of what even insurance companies call acts of God?

We must have strict building codes and follow them. One model for this is Japan, where some buildings sit on movable steel balls. When an earthquake strikes, the tall buildings just sway from side to side and stop when the quake becomes still.

People are also advised to be self-sufficient for a week, with bags of canned food, medication, first-aid items, bottled water and flashlights. Relief efforts might be delayed for a week. They should also be familiar with best practices before, during and after an earthquake. Businesses are advised to prepare for crisis response and have a continuity plan ready to address the company’s response.

And the government, yes, the government should provide more green spaces — more “lungs” for the city — where people can congregate and settle down, even if the whole place has just seen a bit of doomsday.