Intense tectonic movement causes strong tremors in southeast China: expert

The recent magnitude-7.3 earthquake in Hualien has been described as the most devastating earthquake to hit China's Taiwan region in 25 years.

The earthquake is closely related to the unique geographical conditions of China's Taiwan Island, said Gao Mengtan, a researcher at the Institute of Geophysics of China Earthquake Administration, in an interview with CGTN.

"The entire Taiwan region is located at the junction of the Philippine Plate and the Eurasian Plate, with the Philippine Plate subducting under the Eurasian Plate, causing very intense tectonic movements in the area and frequently triggering strong earthquakes," Gao told CGTN. "Statistical data from the past few decades shows that, on average, there's a strong earthquake of magnitude 7 or above every seven to eight years."

"Whenever such an earthquake occurs, it's crucial to be prepared for the possibility of strong aftershocks. In fact, following today's earthquake, there's already been an aftershock of magnitude-6," said Gao, noting that historically, after the magnitude-7.3 earthquake in 1951, there were four subsequent aftershocks each registering over magnitude-7.

He said it's essential to guard against the impact of follow-up earthquakes. "The major earthquake has already caused considerable damage to buildings, infrastructure and mountainsides," he said. "If a large earthquake subsequently occurs, the risk of buildings or mountains collapsing, landslides and rockfalls dramatically increases."

"As a result, to better implement emergency rescue efforts and guard life in the disaster area, special precautions must be taken against further damage to buildings and infrastructure, as well as the triggering of more secondary disasters," Gao said.

Gao also pointed out that in China's southeast coastal megacities, which have many tall buildings, the sensation of an earthquake can be stronger if people are higher up from the ground. This makes it possible for more people to feel the vibrations caused by a magnitude-7 earthquake occurring as far away as across the Taiwan Straits.

"Another factor is that the sedimentary plains' soil layers can amplify seismic waves, and many of the high rises in our southeastern coastal cities are built on these soil layers, resulting in the seismic sensation being doubly amplified," he told CGTN. "If the earthquake occurs in a place like Hualien, even if the magnitude is slightly higher, the vibrations felt in our coastal areas might be more intense but not enough to cause serious damage to our buildings and infrastructure."

(Cover via CFP.)