Why PH is a quake-prone country

Why PH is a quake-prone country

The Magnitude 7.0 temblor damaged a lot of buildings in the province of Abra like the featured image above courtesy of PNA.

As we write this piece, our countrymen up north, particularly in Abra, are in a rung of anxiety, looking hopeful but helpless after a powerful 7.1 magnitude earthquake struck Luzon past breakfast time Wednesday which sent tremors of lesser magnitude through the national capital region.

Initial reports have said one was killed in Benguet, another in Abra, and one more in another province, with at least 60 people initially reported as injured.

A total of 227 aftershocks were recorded before sundown Wednesday, with reports that 14 national roads in the Cordillera and the Ilocos Regions are currently impassable.

Churches – like the bell towers of Bantay in Ilocos Sur and the Laoag Cathedral as well as the old stone church in Sarrat town in Ilocos Norte were all destroyed, according to Senator Imee Marcos, who comes from Ilocos Norte.

A reassuring report has said President Ferdinand Marcos Jr. has announced his plan to visit the quake-hit areas Thursday, with a focus on Abra, home to nearly 250,000, to avoid disruptions to the delivery of local government units’ service to earthquake victims following his order to immediately dispatch rescue and relief teams to the landlocked province.

Interior Secretary Benhur Abalos said 173 buildings were damaged and 58 landslides were reported, with 44 of the 60 injured in Abra.

A hospital in Abra was also evacuated after the building partially collapsed but there were no casualties reported there.

The Philippines is prone to natural disasters and is located on the seismically active Pacific “Ring of Fire,” a string of volcanoes and fault lines that arcs around the edge of the Pacific Ocean.

This horseshoe-shaped belt encompasses 452 volcanoes and is home to over 75 percent of the world’s active and dormant volcanoes.

The Ring of Fire causes the country to have frequent seismic and volcanic activity. Many earthquakes of smaller magnitude occur very regularly due to the meeting of major tectonic plates in the region. The largest was the 1918 Celebes Sea earthquake with Mw.8.3.

Earthquakes are frequent and there are an average of 20 typhoons each year, some triggering deadly landslides.

The Wednesday earthquake reminded old hands of a 45-second major shock that rumbled in Luzon on July 16, 1990, with an estimated moment magnitude of 7.7 and maximum Mercalli intensity of 9 and produced a 125 km-long ground rupture that stretch from Dingalam, Aurora to Kayaba in Nueva Vizcaya.

Baguio suffered the most damage – the earthquake collapsed 28 buildings, damaged roads, and caused landslides that blocked Kennon Road and Marcos Highway, the two main roads to access Baguio from the capital.

The epicenter was in Nueva Ecija, which ruptured rice lands and submerged the coastal areas of La Union and Pangasinan.

The following are the top 10 strongest earthquakes in the Philippines that caused major destructions and casualties:

  1. Magnitude 8.0 earthquake in Mindanao (August 17, 1976)

A magnitude 8.0 earthquake took place near Mindanao and Sulu a little past midnight on August 17, 1976, that was felt as far as the Visayas. It was then followed by a massive 4 to 5 meters high tsunami covering 700 kilometers of coastline bordering the island. Because it was dark, the people were caught by the raging water which claimed 8,000 lives, injured 10,000, and left 90,000 more, homeless.

  1. Magnitude 7.8 earthquake in Northern and Central Luzon (July 16, 1990)

A total of 2,412 people died and at least ₱10 billion worth of damages to public and private properties were reported after a magnitude 7.8 earthquake struck Northern and Central Luzon at around 4:00 p.m. on July 16, 1990.

Hyatt Terraces Plaza, Nevada Hotel, Baguio Hilltop Hotel, Baguio Park Hotel, and FRB Hotel, all in Baguio collapsed trapping and burying people alive.

Although the epicenter was recorded in Nueva Ecija, it caused more damage in the City of Pines. And the quake that just lasted for about a minute was one of the tragedies in the country that would never be forgotten.

  1. Magnitude 7.5 earthquake in Luzon (November 30, 1645)

The magnitude 7.5 earthquake that crushed Luzon on November 30, 1645, at about 8:00 pm was called the “most terrible earthquake” in Philippines history. The Epicenter of the said quake was in Nueva Ecija caused by the San Manuel and Gabaldon Faults.

The extent of the tremor was felt as far as Cagayan Valley. It has caused many landslides which buried many people alive and destroyed many buildings and churches including Manila Cathedral.

At that time, only Spanish are counted so the recorded number of casualties was only 600 while the injured was 3,000.

  1. Magnitude 7.3 earthquake in Casiguran (August 2, 1968)

Most of the people in Casiguran, Aurora was still fast asleep when a magnitude 7.3 earthquake struck at 4:19 a.m. on August 2, 1968.

It was another deadly and shocking seismic activity in the country. And the City of Manila got the most severe damage. Many buildings were either damaged or destroyed totally.

The said event was also called the Ruby Tower earthquake after the said six-story building located in Binondo collapsed, and caused the death of 260 people. A total of 268 people died that day and 261 more were injured.

  1. Magnitude 7.2 earthquake in Bohol (October 15, 2013)

I can still remember how people panicked on the morning of October 15, 2013. It was around 8:12 a.m. when a strong earthquake was felt here in Tacloban City. Only to find out after the lights came back that what we have experienced was nothing compared to the damage it caused in Bohol which was the epicenter of the magnitude 7.2 earthquake.

The quake affected most of Central Visayas, particularly Bohol and Cebu. It was felt in the whole area of Visayas and reached as far as Masbate Island in the north and Cotabato in Southern Mindanao.

According to the National Disaster Risk Reduction and Management Council (NDRRMC), a total of 222 people died, 8 went missing and 976 others were injured. An estimated 73,000 structures were damaged wherein more than 14,500 of them were destroyed totally.

  1. Magnitude 7.1 earthquake in Mindoro (November 15, 1994)

November 15, 1994, at around 3:15 a.m., a magnitude 7.1 earthquake rocked Mindoro. A gigantic 8.5 meters (28 ft) tsunami then followed which devastated the islands of Baco and Calapan, Mindoro.

A total of 7,566 houses were washed out and some 78 people died because of that tragedy.

  1. Magnitude 6.9 earthquake in Central Visayas (February 6, 2012)

A total of 51 people died, 62 still missing and 112 were injured when a 6.9 earthquake in Central Visayas, particularly Negros and parts of Mindanao on February 6, 2012.

It caused a landslide that buried a barangay, damaged 15,483 houses, and total damage of ₱ 383 million to infrastructures and buildings was recorded.

  1. Magnitude 7.5 earthquake in Central and Southern Mindanao (March 5, 2002)

A magnitude 7.5 earthquake resulted in the death of 15 people and injured around a hundred more in Central and Southern Mindanao on March 5, 2002.

The said quake originated near the Cotabato Trench which was followed by a tsunami. But it was the flood that was generated by landslides and falling debris that caused damage to an estimated 800 buildings.

  1. Magnitude 6.5 quake in Ilocos Norte (August 17, 1983)

The magnitude 6.5 quake in Ilocos Norte on August 17, 1983, happened around 8:18 p.m. and resulted in 16 casualties and 47 people got injured.

It caused damage to various establishments such as schools, buildings, malls, residences, etc. There were also landslides and sand boils that followed the event.

  1. Magnitude 7.6 earthquake happened near Guiuan, Eastern Samar (August 31, 2012)

A very strong earthquake with a magnitude of 7.6 happened near Guiuan, Eastern Samar on August 31, 2012 that was felt as far as Mindanao.

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) issued a tsunami warning Level 3, but it was lifted 5 hours later.

The quake caused damage on homes, bridges, and other infrastructures. There were also power interruptions in the affected areas. But despite the intensity only one person was reported dead and one injured because of the landslide in Cagayan de Oro City.
Deadliest earthquakes

(With reports from FAQ.ph/ai/mtvn)

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