Why did Taiwan have little damage despite a strong earthquake?

Located on the Pacific Ring of Fire and regularly exposed to earthquakes, Taiwan is carefully prepared to respond to this type of natural disaster.

On April 3, Taiwan suffered a 7.4 magnitude earthquake, the strongest in the past 25 years. At least 9 people were killed and hundreds were injured. Buildings and roads were damaged and dozens of workers in quarries were trapped. Experts say strong earthquakes are not uncommon in Taiwan , but damage to the island's 23 million residents is relatively limited thanks to good preparation.

The building at the intersection of Bac Tan and Khang Lac streets, Hualien district, leaned to one side and lost the first floor. (Photo: AFP).

According to assessments, this relatively low level of damage contrasts with damage caused by strong earthquakes in many other areas.

In 2011, an earthquake occurred in Christchurch, New Zealand, killing 165 people. The 2015 Nepal earthquake killed nearly 10,000 people. The 2005 earthquake in Pakistan killed nearly 90,000 people, and the 2010 earthquake that hit the island of Hispaniola killed 300,000 Haitians.

" Taiwan's earthquake preparedness is among the most advanced in the world . The island has enforced strict building codes, deployed an advanced seismic network and conducted public education campaigns. widespread consensus on earthquake safety ," said seismologist Stephen Gao, a professor at the Missouri University of Science and Technology.

Photos and videos show buildings leaning in Hualien, eastern Taiwan. The structures lean into the street, surrounded by a few rubble and rubble, but still quite intact, while cranes and rescue workers move around. In some cases, air conditioners are still mounted on windows and many windows are still intact.

This case may be "asthenosphere collapse" , according to Christie Rowe, an expert in earthquake geology at McGill University, Canada. "This is one of the most common types of structural damage during earthquakes and often causes total loss of the structure ," Rowe told the National Post.

Taiwan restricted soft floor design after the 1999 earthquake disaster , but these are probably old buildings without reinforced lower floors. However, because the rest of the building's structure is sturdy enough, even if a soft floor collapse occurs, the frame remains intact. A steel frame building, even if the ground floor collapses, can still be strong enough to stand almost upright. Meanwhile, Rowe said, buildings made of brick or stone will be completely destroyed.

Taipei 101, the tallest building in Taiwan, stood firm in the 7.4 magnitude earthquake on April 3. (Video: X)

There are three factors that determine the extent of damage from an earthquake, according to Rowe.

1. The first is seismic intensity - the amount of energy the earthquake releases. The earthquake in Haiti in 2010 had a magnitude of 7.0, while the earthquake in Taiwan on April 3 was 7.4 magnitude and the earthquake in Nepal was 7.8 magnitude.
2. Second is geology. "The influence of location on the level of damage is equally great, even greater ," said Rowe. For example, if a city is built on solid rock, it will suffer less damage during an earthquake. Seismic waves passing through the ground after an earthquake will have smaller amplitudes in bedrock than in flooded soil, meaning the shaking that hits a building on the surface will be lighter.
3. Third is the construction method. Modern, innovative buildings are more likely to withstand an earthquake. They can bend flexibly, but are less likely to fall.

Many countries set building codes to ensure new buildings can withstand earthquakes. But many of the buildings are old and have not been reinforced or improved. Taiwan is located in an earthquake-prone area and since 1974, the island has included anti-earthquake regulations in its building codes. These regulations have also been updated and strengthened several times since then (Other regulations existed before 1974).

"Taiwan has had very high construction standards for a very long time ," said Rowe. He said that although earthquakes have caused damage to Taiwan in the past, that level is still nothing compared to the damage that other countries will suffer in the same earthquake.

In addition, Taiwan has developed an advanced earthquake warning system and its people have an "incredible culture of earthquake knowledge". "They know what to do, they know how to help each other. Everyone is prepared, from what needs to be done at home to in school, in the city, in large-scale infrastructure, everything is covered." quite close coordination ," said Rowe.

Why does Taiwan have many earthquakes?

Pacific Ring of Fire, an area where earthquakes frequently occur. (Photo: Universal Images Group Editorial).

Taiwan is located along the Pacific Ring of Fire, a seismic fault line surrounding the Pacific Ocean, where most of the world's earthquakes occur, according to the Washington Post. This region is particularly prone to tremors because the accumulated strain from the interaction between two tectonic plates, the Philippine plate and the Eurasian plate, can lead to sudden release in the form of earthquakes.

The fault in the Taiwan earthquake was a reverse fault , meaning one side of the fault moved over the other side. Under the ocean, water moves strongly, which can cause tsunamis.

Taiwan's mountainous landscape can increase ground shaking, leading to landslides. Several such landslides occurred on Taiwan's east coast, near the epicenter of the April 3 earthquake, near eastern Hualien county. Rock and soil fell into tunnels and highways, crushing vehicles and killing several people.