[M-IS09] Interdisciplinary studies on pre-earthquake processes

[MIS09-07] Seismo-ionospheric precursors in GIM TEC and ion parameters observed by FORMOSAT-5/AIP associated with the 3 April 2024 M7.4 Hualian earthquake

*Jann-Yenq LIU^1,2,3, YUN-CHENG WEN², FU-YUAN CHANG^1,2, Chi-Yen LIN^1,2, Yuh-Ing CHEN¹ (1.Center for Astronautical Physics and Engineering, National Central University, Taiwan, 2.Department of Space Science and Engineering, National Central University, Taiwan, 3.Center for Space and Remote Sensing Research, National Central University, Taiwan)

Keywords:2024 Hualien earthquake, total electron content, FORMOSAT-5, seismo-electric field

On 3 April 2024, at 07:58:12 LT (23:58:12 UTC on 2 April), a Mw 7.4 earthquake struck Hualien, Taiwan (23.84N, 121.60; Depth: 40 km). At least 19 people were killed and over 1,100 were injured in the earthquake. It is the strongest earthquake in Taiwan since the 1999 M7.7 Chi-Chi earthquake. The global ionosphere map (GIM) of total electron content (TEC) over the epicenter anomalously and significantly increase on 3-5 March 2024, day 30-28 before the 2024 Hualien earthquake, which generally agrees with characteristics of GPS TEC related to 289 magnitude M5.0 equal and greater earthquakes in Taiwan during 1990-2023. To find possible physical mechanisms causing the GIM TEC increase anomalies before the 2024 Hualien earthquake, the equatorial ionization anomaly of TEC along the Taiwan longitude during March and April of 2024 and plasma quantities of the ion density and ion velocity measured by advanced ionospheric probe (AIP) onboard FORMOSAT-5 satellites are examined. It is found that seismo-electric fields around the epicenter area before the earthquake are essential.