International Support: Satellite Imagery Aids Taiwan's Post-Quake Assessment

The powerful magnitude 7.2 earthquake that struck Hualien, Taiwan, on April 3, 2023, sent shockwaves throughout the nation and generated concern across the international community. The Taiwan Space Agency (TASA) promptly arranged for its FORMOSAT-5 satellite to acquire images of the affected areas along Taiwan’s east coast three hours after the seismic event. By analyzing the pre- and post-earthquake imagery, experts were able to assess the extent of the damage. Additionally, through the Sentinel Asia mechanism, TASA received valuable remote sensing data from Japan, Thailand, and India, which significantly aided Taiwan’s disaster response and reconstruction efforts. TASA reported that FORMOSAT-5 passed over Taiwan just three hours after the earthquake, and an emergency command was issued to alter the mission and capture images of the affected regions on the east coast. However, due to the satellite’s two-day revisit time and limitations caused by cloud cover, TASA submitted an emergency disaster request to Sentinel Asia, seeking additional remote sensing imagery from member countries. Taiwan subsequently received pre- and post-earthquake satellite data from Japan, Thailand, and India. The Sentinel Asia framework, as noted by TASA, encompasses various satellite imagery providers, including the Japan Aerospace Exploration Agency (JAXA), the Geo-Informatics and Space Technology Development Agency (GISTDA) of Thailand, and the Indian Space Research Organisation (ISRO). Notably, Axelspace, a Japanese space startup, voluntarily contributed relevant imagery to Taiwan despite not being a member of Sentinel Asia. Several countries and institutions also provided damage assessment and analysis reports based on the satellite imagery acquired by these satellite data providers. These contributions came from institutions like JAXA, the Geospatial Information Authority of Japan (GSI) and the Earth Observatory of Singapore (EOS). TASA pointed out that the received imagery, which included both optical satellite remote sensing and synthetic aperture radar (SAR) data, enabled the identification of areas with significant surface deformation, thereby enhancing Taiwan’s understanding of the disaster’s impact. Specifically, the Differential Interferometric SAR (DInSAR) data generated from single look complex (SLC) data acquired by JAXA’s ALOS-2 SAR satellite, combined with the post-disaster map provided by EOS, proved crucial in detecting topographic changes and damage to buildings. TASA confirmed that the geospatial data and analysis reports generated from FORMOSAT-5 and various international partners would be submitted to the Central Emergency Operation Center and subsequently shared with the National Science and Technology Center for Disaster Reduction to identify collapsed buildings and landslides, as well as to locate potential landslide dams. The data will also be utilized for analysis and research by the Academia Sinica’s Institute of Earth Sciences and the Agency of Rural Development and Soil and Water Conservation of the Ministry of Agriculture. Sentinel Asia, an initiative under the Asia-Pacific Regional Space Agency Forum (APRSAF), is a multilateral cooperative program focused on providing and utilizing satellite observation resources for disaster preparedness and humanitarian assistance. The program comprises 29 member nations and several international organizations. Taiwan’s National Space Organization (TASA’s predecessor) joined Sentinel Asia in 2010 as a Data Provider Node (DPN), and in 2022, it expanded its role to become a Data Analysis Node (DAN). TASA previously provided emergency disaster relief imagery services internationally with FORMOSAT-2 and continues to do so with its successor, FORMOSAT-5.