Manila Vulnerable to Major Earthquake

The 12.1 million-resident Metro Manila agglomeration, a shambolic collection of 16 cities grown together, is at risk of a 7.2 magnitude earthquake that could take more than 50,000 lives, cost as much as US$49 billion and wreck the economy, according to an exhaustive 56-page report by a Manila-based country risk firm.

Although there has been no major earthquake in the urban area since the 16th century, Metro Manila sits astride the West Valley Fault System, which runs 150 km from Bulacan in the north to Laguna in the south. Years of breakneck population growth, in-migration from outlying areas and a near-complete lack of planning or updating of disaster services have left the city at risk. The gigantic conurbation is also vulnerable to earthquakes from nearby and distant crustal faults, such as the Philippine Fault Zone, the Lubang Fault, the Casiguran Fault and the Manila Trench.

The report, by PSA Philippines Consultancy and titled “Metro Manila Earthquake Vulnerability Assessment 2019,” repeats many of the same concerns by the same political risk firm five years ago, in November of 2014. It appears little or nothing has been done to address the issues.

Lest skeptics think it couldn’t happen, the Philippines, close to the Ring of Fire, is vulnerable to temblors. In 1645, the City of Manila, one of the 16 cities that make up Metro Manila, was almost completely destroyed. Aftershocks continued for five days, with more than 600 Spaniards killed. The Manila Cathedral was completely destroyed.

More recently, a series of three earthquakes struck the North Cotabato region 1,450 km south of Manila on the island of Mindanao, affecting nearly 350,000 people, destroying 25,800 homes and damaging another 21,700. The earthquakes, at about 6.0 magnitude, continued for three weeks starting October 16.

PSA Philippines Consultancy, which prepared the report, titled Metro Manila Earthquake Vulnerability Assessment 2019, cautioned that information is subject to change, that public domain information could be unreliable and that the public domain sources may not be comprehensive or complete. Clients, according to the report, requested an assessment of risk to help prepare for a potential earthquake and its aftermath. But, the firm said, it is not a geoscience organization although it has advised on safety, security, and business continuity in the private sector in the Philippines for approximately 20 years.

Soil composition and building construction quality are likely to determine the extent of the damage, according to the report. Neither is encouraging. Metro Manila’s soil composition is mixed, with the coastal regions, in particular the northern shore of Laguna de Bay and the coast of Manila Bay itself are prone to liquefaction as coastal areas have been infilled for new construction.

“It remains unknown how many buildings across Metro Manila are compliant with the structural standards set by the National Building Code,” the report indicates, adding rather drily that “Non-compliance with national building standards is a major concern. Corruption in regulatory agencies and cost-cutting in construction materials and methods will have compromised the structural integrity of many existing buildings across the region.”

The report cites the 2009 response to Tropical Storm Ondoy, which hovered over Metro Manila for days, generating flooding up to waist high and in some areas up to six feet. Landslides and flooding left at least 246 people dead. The biggest lesson from Ondoy, however, was that the government was utterly incapable of responding to the emergency. Public and private roads were clogged by vehicles stuck in floodwater. Thousands of motorists and more than 500 passengers were stranded at the North Luzon Expressway. Power, communication and water connections disappeared.

Survivors, with little help from authorities, banded into community groups to help each other while those who lived in provinces or hade connections with people in the provinces returned to their hometowns.

“In the worst case, the government may declare martial law and looting will be widespread across the region. The reality may fall somewhere in between the two.”

Thus, according to PSA Consultants, “Emergency response will be delayed due to the lack of capacity in both manpower and resources and their inability to reach victims. 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.”

Important roadways and bridges are likely to collapse, raising the probability of a regional separation within the metropolis. Infrastructure and lifeline systems, including power grids, telecommunications networks, and water distribution infrastructure are also expected to be heavily damaged from the quake. An estimated 500 fires are expected across the entire urban areas, causing additional fatalities and property damage.

The city’s teeming slums, which stretch for miles, are expected to be hit hard by the damage and fires caused by electrical short circuits of haphazardly wired electrical conduits and by LPG and petroleum tank explosions. Fires could cover as much as 1,710 hectares and result in an additional 18,000 fatalities. The slums make up a full third of Metro Manila’s population, according to charitable agencies, possibly the most of any urban area in the world.

“Damage to water distribution pipelines will limit firefighting capabilities, cause an immediate shortage of potable-water and create localized flooding. It is estimated that 4,000 water supply points would be cut immediately with damage to reservoirs and water purification plants causing major long-term water shortages. The metropolis’ main source of water, Angat Dam, is vulnerable to damage in the event of an earthquake as part of the facility straddles the West Valley Fault System.”

The dam could fail, flooding the Angat River, its tributaries and low-lying areas in Metro Manila and Bulacan, destroying pipeline networks and cutting off water supply in various areas as well as likely causing If the distribution pipes are damaged, contaminant inflows to the pipes will pollute and facilitate the spread of water-borne diseases. With limited supplies of potable water many inhabitants would be exposed to drinking water from unsanitary sources, further magnifying the risks from communicable diseases.

Individuals are advised to prepare for a minimum of one week of self-sufficiency and personal safety. “As major roadways and bridges in Metro Manila may have collapsed or been damaged in the earthquake, relief efforts are expected to be delayed for at least this period. To prepare for this likelihood, individuals should purchase and maintain food and water supplies, medicines and first aid items that would last for at least one week.”

Businesses, the report advises, should “prepare for crisis response and have a business continuity plan in the case of a major earthquake. The crisis response should address the company’s response to the event, how this is managed, the immediate risks to the people and facilities and the from there the process required for controlling events and the delivery of aid and support.”