Solid Earth Sciences (S)
Session Sub-category Complex & General(CG)
Session ID S-CG50
Title Earthquakes, Tsunamis, Seismotectonics, and Hazard Potential of the Ryukyu Trench and Okinawa Trough
Short Title Ryukyu Trench and Okinawa Trough
Main Convener Name Kenji Satake
Affiliation Dept. Earth Sciences, National Central University, Taiwan
Co-Convener 1 Name Mamoru Nakamura
Affiliation Faculty of Science, University of the Ryukyus
Co-Convener 2 Name CHANG PINGYU
Affiliation National Central University, Taiwan
Co-Convener 3 Name J. Bruce H. Shyu
Affiliation National Taiwan University
Session Language
E
Scope
Along the Ryukyu trench between Kyushu and Taiwan, the Philippine Sea plate subducts beneath the Eurasian Plate with a rate of approximately 8 cm/year. Unlike the neighboring Nankai Trough, the history of great interplate earthquakes is not well known, except for the enigmatic 1771 Meiwa earthquake, which caused more than 10,000 casualties due to tsunami. The Hualien earthquake on April 3, 2024 (M 7.4) originated from this plate boundary, causing the worst earthquake damage to Taiwan since the 1999 Chi-chi earthquake. The Hualien earthquake also prompted a tsunami warning in Ryukyu Islands, Japan.
The Okinawa Trough, which is located on the northwest side of the Ryukyu Arc, is currently in the early stages of back-arc rifting. Associated with the rifting, seismic swarm activity and hydrothermal activity are also active within the trough. However, the mechanism of the Okinawa Trough's extension is still unknown.
The geodetic measurements on the Ryukyu islands indicate that the plate coupling is very weak, while recent offshore geodetic measurements indicate coupled patches along the megathrust. Slow earthquakes have been observed along the Ryukyu trench. 
In order to exchange current knowledge on the Ryukyu trench and stimulate further collaboration between Taiwan and Japan, we propose a joint session between Chinese Geoscience Union in Taiwan (TCGU) and JpGU.  This session solicits recent studies on earthquakes, tsunamis or seismotectonics.  Possible topics include, but not limited to, studies of the 2024 Hualien earthquake and its tsunami, recent geophysical observations of slow or regular earthquakes, studies of past earthquakes in the region, Probabilistic Seismic Hazard Assessments of the region. 
Presentation Format Oral and Poster presentation
Joint Session with CGU
Invited Authors Kuo-Fong Ma (Institute of Earth Sciences, Academia Sinica, Taiwan)
Yushiro Fujii (International Institute of Seismology and Earthquake Enginnering, Building Research Institute)
Mamoru Nakamura (Faculty of Science, University of the Ryukyus)
Ryoya Ikuta (Faculty of Science, Shizuoka University)
Cheng-Hung CHEN (Department of Geosciences, National Taiwan University)
Pei-Ru Jian (Department of Geosciences, National Taiwan University)
Time Presentation No Title Presenter
Oral Presentation May 28 PM1
13:45 - 14:00 SCG50-01 Earthquakes, Tsunamis, Seismotectonics, and Hazard Potential of the Ryukyu Trench and Okinawa Trough - Introduction Kenji Satake
14:00 - 14:15 SCG50-02 A Comparative Analysis of the November 14, 1986, and April 2, 2024, Hualien, Taiwan earthquakes: Seismic Source Characteristics and Regional Impacts Kuo-Fong Ma
14:15 - 14:30 SCG50-03 Spatiotemporal Patterns of the April 2, 2024, Hualien Earthquake Sequence and Finite Fault Solutions of Significant Aftershocks Yopi Ruben Serhalawan
14:30 - 14:45 SCG50-04 Tsunami simulation for the Hualien, Taiwan earthquake (M7.4) on April 3, 2024 Yushiro Fujii
14:45 - 15:00 SCG50-05 Source mechanism and early warning of volcanic tsunamis Tony Song
15:00 - 15:15 SCG50-06 Develop new numerical method CGM to simulate landslides and enhance the description of turbidity suspension phenomena Cheng-Hao Yeh
Oral Presentation May 28 PM2
15:30 - 15:45 SCG50-07 Decadal-Scale Changes in Very Low-Frequency Earthquake Activity in the Southwestern Ryukyu Trench Mamoru Nakamura
15:45 - 16:00 SCG50-08 Lack of inter-plate coupling along the southern end of the Ryukyu trench deduced from GNSS-A geodetic measurements Ryoya Ikuta
16:00 - 16:15 SCG50-09 The Offshore Seismogenic Structure Database in Northeast Taiwan Cheng-Hung CHEN
16:15 - 16:30 SCG50-10 The New Ryukyu Area CMT (RACMT) Catalog: Implications for Ryukyu Subduction Zone Rupture Behavior Pei-Ru Jian
16:30 - 16:45 SCG50-11 Long-term vertical deformations in the Ryukyu subduction zone, Japan Sophie Debaecker
16:45 - 17:00 SCG50-12 Analysis of Subsurface Fault Systems Using Audio-Magnetotelluric Surveys in the Western Ilan Plain , the tip of the extension of Okinawa Trough CHANG PINGYU
Presentation No Title Presenter
Poster Presentation May 28 PM3
SCG50-P01 Analysis of Spatiotemporal variation of the earthquake swarms in the Okinawa Trough by using Matched filter method Yuji Abe
SCG50-P02 Improved sedimentary layer model including the accretionary prism in the fore-arc region of Ryukyu arc, Japan Masanao Komatsu
SCG50-P03 Reconstructing relative sea-level changes on Kikaijima Island from coral microatolls: Implications for megathrust earthquake potential along the Ryukyu Trench Junki Komori
SCG50-P04 Coupled Dynamics of Internal Waves and Submarine Landslides in the Formation of Nepheloid Layers Che-Han Chang