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Performance of the CWA Earthquake Early Warning System for the 2024 ML 7.2 Hualien Earthquake, Taiwan

Description: 

On April 3, 2024 at 7:58:9.9 am (Taiwan local time), an ML 7.2 earthquake struck the eastern coast of Hualien County at a depth of 15.5 km, causing strong shaking with the maximum intensity of 6+ on the seismic scale of Central Weather Administration, Taiwan (CWA) near the epicenter. It also generated intensity 5- in northern Taiwan and intensity 4 for most of Taiwan island. The 2024 Hualien earthquake is the largest damaged earthquake after the 1999 Chi-Chi earthquake. Unfortunately, tens of people died, thousands were injured, and hundreds of buildings collapsed or seriously damaged not only near the epicenter, but in the metropolis in northern Taiwan island. Furthermore, the shaking triggered large scale landslides in the Taroko National Park and along the important highways, the #9 Suhua and #8 Central Cross-Island Highway in northern Hualien County.

The earthquake early warning (EEW) system operating by CWA issued the first warning for an M 6.2 earthquake at 9 s after the origin time of the earthquake to parts of central and eastern Taiwan. The system issued an updated warning for an M 6.8 earthquake at 15 s after the event origin time. The warning regions extended to parts of northern, southern, and entire central Taiwan. In this study, we evaluate the performance of the EEW system based on the warning time which is the time difference between the first warning issue and arrival of the maximum peak ground velocity phase from the strong motion network, then taking away another 5 s for broadcasting. We recognize that public had the warning times of 10 s, 5 s, 7 s, and 7 s near the epicenter, in the Hualien City, in the Taroko National Park, and in the #9 Suhua Highway, respectively. There was no blind zone in the source region for the earthquake. The EEW system indeed plays a key role to prevent life loss and numbers of injuries in the 2024 Hualien earthquake in the source area.

Session: The 3 April 2024 Magnitude 7.4 and 6.4 Earthquakes and Aftershock Sequence Near Hualien City, Eastern Taiwan - I

Type: Oral

Date: 5/3/2024

Presentation Time: 10:30 AM (local time)

Presenting Author: Yen-Yu

Student Presenter: No

Invited Presentation: 

Authors