Taiwan logs record seismic activty with 42 quakes surpassing M5.5 in 2024
Taiwan has recorded 42 earthquakes exceeding magnitude 5.5 on the Richter scale in 2024, marking the highest count since precision seismic monitoring began with the implementation of the Taiwan Strong Motion Instrumentation Program in 1991. The surge in seismic activity has been largely attributed to the April 3 Hualien earthquake, a powerful magnitude 7.4 event that struck 15 km (9.3 miles) south of Hualien City, causing extensive damage, 18 fatalities, and over 1 100 injuries.
Image credit: Shugu Liu / Office of the President (Taiwan). Captured on April 3, 2024
Taiwan has recorded 42 earthquakes exceeding magnitude 5.5 on the Richter scale in 2024, the highest count since the Central Weather Administration (CWA) began using precision instruments with the implementation of the Taiwan Strong Motion Instrumentation Program (TSMIP) in 1991.
Faults in Chiayi and Tainan have shown increased activity this year, with reports of earthquakes occurring frequently in these areas.
Hualien County experienced the highest number of national earthquake alerts this year, with a total of 64 alerts. Yilan County followed with 23 alerts, while Changhua County, ranked third, recorded 9 alerts.
“These data remind us that we need to always maintain awareness of earthquake disaster prevention and be prepared for disaster prevention,” CWA said. “No region should take it lightly!”
The rise in seismic activity, reported between November 14, 2023, and November 13, 2024, has been attributed largely to the “2024 Hualien earthquake,” the strongest seismic event in Taiwan since the 1999 Jiji earthquake.
The 2024 Hualien earthquake, commonly referred to as the 0403 earthquake, hit at 23:58 UTC on April 2 (07:58 LT on April 3), about 15 km (9.3 miles) south of Hualien City (population 99 500) with a magnitude of 7.4.
This seismic event caused extensive damage across eastern Taiwan and resulted in 18 fatalities and more than 1 100 injuries. The earthquake also generated a 1 m (3.3 feet) tsunami and triggered multiple landslides.
It released five times the annual average energy of earthquakes in Taiwan and initiated an extended aftershock sequence, with 1 746 recorded as of November 2024. Notable aftershocks include magnitudes of 6.4 and 6.1.
According to Wu Chien-fu, Director of the CWA Seismological Center, this event’s distinct energy release and seismic characteristics set it apart from previous significant earthquakes like the 1999 Jiji earthquake.
“The differences between these two major earthquakes are due to the distinct mechanisms behind their occurrence,” Wu explained.
The 1999 Jiji earthquake, also known as the 921 earthquake, struck central Taiwan on September 21, 1999, with a magnitude of 7.7. Its epicenter was located in Jiji Township, Nantou County, and the earthquake was triggered by the rupture of the Chelungpu Fault.
The Jiji earthquake caused extensive destruction across central Taiwan, leading to 2 415 fatalities, over 11 000 injuries, and leaving 100 000 people homeless. It was one of the deadliest earthquakes in Taiwan’s history.
The event caused severe infrastructure damage, including collapsed buildings, bridges, and roads, while widespread landslides significantly altered the landscape in mountainous areas. Surface ruptures extended for 100 km (62 miles) along the Chelungpu Fault.
The devastation led to significant changes in Taiwan’s approach to earthquake preparedness, including stricter building codes and the establishment of more advanced seismic monitoring systems.
At the end of August 2024, CWA updated its criteria for sending Presidential Earthquake Alerts using cell broadcast technology to include areas experiencing an intensity level of 3 or higher during earthquakes of magnitude 6.5 or greater. Previously, alerts were issued for intensities of 4 or above.
The change is aimed at providing earlier warnings, particularly for areas where seismic waves may amplify, such as in high-rise buildings. The adjustment comes in response to lessons learned from the 2024 Hualien earthquake, where initial forecasts underestimated the severity of its impact.
“Some earthquakes of lower magnitude produce long-duration, low-frequency waves that have a pronounced effect on high-rise buildings,” Wu said, adding that a level 3 (of 7) intensity at ground level can increase to level 4 on the ninth floor.
While some have expressed concerns about “alert fatigue,” Wu says that the frequency of alerts will remain manageable, with an average of only 1.4 additional alerts expected per year. The most noticeable change in number will be for people living in northern Taiwan who may be alerted more frequently.
Taking the city of Taipei (population 2.5 million) during the April 2024 M7.2 quake as an example, the greatest intensity was reached 16 to 17 seconds after the quake, which means that the current alert setup would send messages 2 to 3 seconds earlier.
References:
1 Earthquakes exceeding magnitude 5.5 on the Richter scale hit 14-year high – Taipei Times – December 7, 2024
2 Earthquake alerts’ scope to be broadened: CWA – Taipei Times – August 31, 2024
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“Thus says The Lord God: The earth is filled with violence, the whole world is corrupt! Madness has overcome the people, transgression is uplifted, and abominations of every kind are widely accepted; great wickedness proliferates throughout every tribe, tongue, people and nation unimpeded! Thus the earth is forsaken for a time, wherein I have turned to it My back. And so shall it remain, until the Great Day comes when I shall move swiftly against it…
And until this time and after, the earth shall tremble and shake, and bring forth calamity upon calamity, and famine and pestilence of every kind. For all this is but the beginning of sorrows, the first contractions of an expectant mother suffering to bring forth… Says The Lord.”
(From The Volumes of Truth, Volume Seven, excerpts from “The World Shall Be Shaken”)