Killer earthquakes in PH history

FOLLOWING the magnitude 7.8 earthquake that struck the southern region of Turkey on Monday, the Philippine Volcanology and Seismology Institute (PHIVOLCS) raised the possibility that the country will also encounter such a destructive temblor.

According to PHIVOLCS’ officer-in-charge Teresito Bacolcol, there is always a “possibility” of a magnitude 7.8 earthquake in the country, as it had already happened in the Philippines in 1990.

The magnitude 7.8 earthquake in Luzon was considered the country’s strongest earthquake that has ever hit the country, based on PHIVOLCS’ instrumental records.

Bacolcol said that the country has “several faults” that are being monitored today that are also capable of creating a very strong earthquake similar to that of Turkey.

“We have several active segments in the Philippines; it’s more than a hundred segments,” he said in a public briefing.

The longest is the Philippine fault, which is 1,200 kilometers from Davao to Luzon.

“And in fact, it just moved last week – magnitude 6.0 earthquake in Davao – that was the Philippine fault also,” he said.

But in case a more destructive earthquake hits the country, the agency said the government is “more prepared than before” since Filipinos regularly participate in earthquake drills. 

He underscored the importance of regularly conducting these activities to help save lives. 

“Kailangan natin mag-participate diyan regularly kasi it becomes habit-forming. So, when we regularly participate in earthquake drills, we develop this culture of preparedness and it becomes part of our reflex,” he said. 

In case you are not aware, here are some of the most destructive earthquakes that have struck the Philippines:

Casiguran Earthquake, August 2, 1968

The town of Casiguran in the province of Aurora was shaken severely by an earthquake on August 2, 1968, at 4:19 a.m. It registered an intensity of VIII on the Rossi-Forel Intensity Scale. the Philippines has been hit by several devastating earthquakes, but this one stood out as the most powerful and catastrophic at that time, according to Phivolcs.

Some 270 people lost their lives, and 261 more were injured during the earthquake. The six-story Ruby Tower in Binondo, Manila collapsed, and several prominent buildings in the Escolta and Binondo areas of Manila experienced varied levels of structural damage.

As a result of the quake, Phivolcs noted that a tsunami was also noticed and recorded in Japan.

Moro Gulf Earthquake, August 17, 1973

On August 17, 1973, a powerful magnitude 8.1 earthquake in Mindanao caused a tsunami that wrecked about 700 kilometers of shoreline abutting Moro Gulf in the North Celebes Sea. 

This earthquake, tagged the tremendous tsunamigenic earthquake in Mindanao, was caused by the Cotabato trench, a lesser-known Philippine trench system. 

The earthquake and tsunami devastated Cotabato’s cities and provinces, especially Pagadian City, it said.

Surveys during the incident found that the tsunami caused 85 percent of deaths, 65 percent of injuries, and 95 percent of missing people were due to the said tsunami. After the tide calmed, thousands of people were dead, homeless, or missing, and millions of pesos were lost in property damage, Phivolcs said

Losses include residential, commercial, and banca properties that support hundreds of families.

Laoag Earthquake, August 17, 1983

The province of Ilocos Norte was struck by an earthquake that registered a magnitude of 5.3 on the Richter Scale and an intensity of VII on the Rossi-Forel Scale on August 17, 1983. 

The tremor was felt up to a distance of approximately 240 miles (400 kilometers) from the epicenter. This was the most severe earthquake to strike Northwestern Luzon in the past 52 years. It is possibly the second-greatest seismic event to have struck Laoag City and its immediate surroundings in the course of the city’s history, Phivolcs said.

This earthquake resulted in the deaths of 16 individuals and injuries to 47 others, according to Phivolcs.

Bohol Earthquake, February 8, 1990

A shallow-seated tectonic earthquake with a magnitude 6.8 rocked Bohol in 1990, causing panic, damage to residences and infrastructure, and geologic disruptions. 

Its epicenter was 17 kilometers east of Tagbilaran City near the towns of Jagna, Duero, and Guindulman in the lower Northeast quadrant of the island, with a Rossi-Forel intensity of VIII. 

As per records from Phivolcs, over 180 houses, structures, and churches were toppled, including two centuries-old churches.

There were reports that six people died, and over 200 were injured. The event displaced 46,000 individuals and left 7,000 homeless. Estimated property damage is P154 million, it noted.

Panay Earthquake, June 14, 1990

Records from Phivolcs showed that on June 14, 1990, a magnitude 7.1 earthquake struck Panay Island. As a result of the quake, eight people lost their lives, and 41 others were injured. 

The epicenter of the earthquake was located in the province of Culasi, Antique. According to the calculations, the depth of the quake is 15 kilometers. It was caused by the movement of faults in the collisional zone off Panay Island’s western coast.

Luzon Earthquake, July 16, 1990

An earthquake with a magnitude of 7.8 devastated the Philippines on July 16, 1990, causing extensive damage in the provinces of La Union, Pangasinan, Nueva Ecija, and Baguio City, as well as in Metro Manila, the Cordillera Administrative Region, and the Bicol Region. 

The earthquake, according to Phivolcs, caused a ground rupture 125 kilometers long and ran along the Digdig portion of the Philippine Fault. The intense ground shaking that lasted for 45 seconds was responsible for several structural disasters, one of which was the collapse of the Hyatt Hotel in Baguio City. There were around 1,200 fatalities as a result of the quake.

Palimbang Earthquake, March 6, 2002

The earthquake took place around 5:15 in the morning on March 6, 2002, and the epicenter, as determined by PHIVOLCS, was in the area of Isulan, Sultan Kudarat. 

PHIVOLCS said the earthquake was caused by subduction along the Cotabato Trench. 

It was responsible for the deaths of eight individuals and the injuries to 41 others. 

It had an impact on 7,684 families, four cities, and 17 municipalities across the provinces of Sultan Kudarat, Sarangani, North Cotabato, and South Cotabato. 

The earthquake damaged 17 public buildings, four road networks, seven bridges, 36 school buildings, 29 business premises, one mega dike, and seven bridges. The amount of damage was P4.175 million.