Not 'The Big One':<br>Earthquakes that caused much destruction in PH since 1968

• On Aug. 2, 1986, a 7.3-magnitude earthquake shook Casiguran, Aurora, which killed 270 and injured 261 persons.
• A 7.8-magnitude earthquake hit parts of Luzon on July 16, 1990, killing 1,200 people, and causing at least P10 billion in property damages.
• A 7.2-magnitude earthquake shook Bohol Island, including the Visayas Region, in 2013, which killed 200 and damaged P2 billion in properties.

A destroyed residential house caused by a 7.0-magnitude earthquake that hit parts of Northwestern Luzon last July 27. (Photo courtesy of Abra Province)

Filipinos are again reminded to prepare for the "Big One" with the 7.0-magnitude earthquake that struck parts of Northwestern Luzon on July 27.

The "Big One" is a term associated with the effects of high-magnitude earthquakes that may occur not only in the Greater Metro Manila area but also in several regions or provinces nationwide susceptible to natural disasters.

Based on the Phivolcs Earthquake Intensity Scale (PEIS), an earthquake is considered destructive when "people find it difficult to stand on upper floors and some well-built structures are slightly damaged."

Here's a list of destructive earthquakes that struck the country from 1968 to 2022, gathered from the records of the Philippine Institute of Volcanology and Seismology (Phivolcs):

August 2, 1968: Casiguran Earthquake
On Aug. 2, 1986, a 7.3-magnitude earthquake struck the town of Casiguran, Aurora, at 4:19 a.m. According to the Phivolcs, the earthquake resulted in 270 casualties and 261 people were injured.

The agency recorded damages of several major buildings in the Binondo and Escolta, Manila areas.

March 17, 1973: Ragay Gulf Earthquake
A magnitude 7.0 earthquake rocked Caluag, Quezon, on March 17, 1973, resulting in the total destruction of 98 houses and partial destruction of 270 other structures. In Sumulong, approximately 70 percent of the school buildings were damaged. The extent of the natural disaster reached Lopez, a municipality in the province.

A damaged bridge caused by a 7.0-magnitude earthquake that hit parts of Northwestern Luzon last July 27. (Photo courtesy of Abra Province)

August 17, 1976: Moro Gulf Earthquake
On Aug. 17, 1976, at 12:11 a.m., an earthquake with a magnitude of 8.1 occurred in the island of Mindanao, resulting in a tsunami that destroyed over 700 kilometers of Moro Gulf's coastline border in the North Celebes Sea.

Phivolcs’ record said that the earthquake mostly affected cities and provinces found in Cotabato. At the same time, the tsunami brought destruction to provinces bordering the gulf, especially on the shores of Pagandian City.

"According to surveys during the event, the tsunami was responsible for 85 percent of deaths, 65 percent of injuries, and 95 percent of those missing," the report said.

August 17, 1983: Laoag Earthquake
On Aug. 17, 1983, the province of Ilocos Norte experienced a 5.3-magnitude earthquake at 8:18 p.m. The natural disaster caused the death of 16 people, and injuries of 47 persons.

As per Phivolcs, "a number of concrete buildings either totally crumbled or sustained major structural damage beyond rehabilitation" within the region, particularly in Laoag City.

Feb. 8, 1990: Bohol Earthquake
A magnitude 6.8 earthquake rocked the island of Bohol on Feb. 8, 1990, at 3:15 p.m. The natural disaster was felt in Tagbilaran City and the towns of Jagna, Duero, Guindulman, Garcia Hernandez, Loboc, Valencia, and Anda, including the neighboring islands of Cebu and Camiguin, and other areas in northern Mindanao.

As per the agency's record, there were six fatalities and 200 injured. The natural disaster also displaced around 46,000 people, and 7,000 individuals became homeless. A total of P154 million worth of properties were destroyed.

June 14, 1990: Panay Earthquake
On June 14, 1990, at 3:41 p.m., a 7.1-magnitude earthquake hit Panay Island, which injured 41 people and resulted in eight casualties.

July 16, 1990: Luzon Earthquake
A 7.8-magnitude earthquake hit parts of Luzon on July 16, 1990, with a 125 km-long ground rapture that stretched from Dingalan, Aurora, to Kayapa, Nueva Vizcaya. The record showed that about 1,200 people died from the natural disaster, and at least P10 billion worth of buildings, infrastructures, and properties were damaged.

Nov. 15, 1994: Mindoro Earthquake
On Nov. 15, 1994, a 7.1-magnitude earthquake occurred in the province of Mindoro at 3:15 p.m. This resulted in a tsunami, causing the death of 78 people. According to the record, without the tsunami, casualties would have only been 29. It brought significant damage to properties in the shoreline communities in northern Mindoro.

March 06, 2002: Palimbang Earthquake
On March 6, 2002, a 6.8-magnitude earthquake hit Palimbang, Sultan Kudarat, at 5:15 a.m. The records of Phivolcs said that eight persons died and 41 were injured, citing a report from the Office of Civil Defense (OCD).

The earthquake affected 7,684 families in the provinces of Sultan Kudarat, Sarangani, North Cotabato, and South Cotabato, including four cities and 17 municipalities. The earthquake resulted in P4-million damage to infrastructure.

Feb. 15, 2003: Masbate Earthquake
A 6.2-magnitude earthquake rocked the province of Masbate on Feb. 15, 2003, at 7:01 p.m. The quake was felt on the island of Masbate and in the regions of Bicol, Leyte, Panay, Cebu, Negros, and Romblon. Roads were damaged, while buildings, houses, and schools had cracks on their structures.

Oct. 15, 2013: Bohol Earthquake
On Oct. 15, 2013, a 7.2-magnitude earthquake shook Bohol Island, including the Visayas Region, at around 8:12 a.m., causing damage to houses, buildings, and infrastructure amounting to P2 billion. Records showed over 200 deaths and 600,000 families affected.

2019: Cotabato Earthquakes
A series of earthquakes were felt in Cotabato province on Oct. 16, a 6.3-magnitude earthquake hit the area at 7:37 p.m.; on Oct. 29, a 6.6 and 6.1-magnitude earthquakes were felt at 9:04 a.m. and 10:42 a.m., respectively; and on Oct. 31, a 6.5-magnitude earthquake rocked the province at 9:11 a.m.

The Cotabato province and nearby areas also suffered from severe damage in infrastructure and landslides were recorded near the epicentral region in Makilala, Kidapawan City, and Tulunan in Cotabato and in Magsaysay and Bansalan in Davao del Sur.

Dec. 15, 2019: Davao del Sur Earthquake
On Dec. 15, a 6.9-magnitude earthquake hit Davao del Sur. Aside from the province’s vicinity, strong ground shaking was also felt in provinces and cities of Cotabato, South Cotabato, Sarangani, Maguindanao, Davao del Sur, Davao del Norte, Bukidnon, Lanao del Sur, and Agusan del Sur, among others.

July 27, 2022: Northwestern Luzon Earthquake
A 7.0-magnitude earthquake hit parts of Luzon, including Metro Manila, on July 27 at 8:43 a.m., Phivolcs's earthquake bulletin reported.

A damaged building located in Mudiit, Dolores, Abra, caused by a 7.0-magnitude earthquake that hit parts of Northwestern Luzon last July 27. (Photo courtesy of Abra Province Facebook page)

Phivolcs said the earthquake was mostly felt in Bucloc and Manabo in Abra. Other areas that experienced “very strong” shaking were Vigan City, Sinait, Bantay, and San Esteban in Ilocos Sur; Laoac in Pangasinan; and Baguio City.

As of July 29, the death toll has risen to 10, as reported by the National Disaster Risk Reduction and Management Council (NDRRMC). On July 30, the agency recorded a total of 228,238 earthquake-affected individuals from 639 barangays in Cordillera Administrative Region (CAR), Ilocos (Region 1), and Cagayan Valley (Region 2).