[S-CG56] Science of Slow and Fast Earthquakes

Tue. May 26, 2026 9:00 AM - 10:30 AM Convention Hall (CH-B) (International Conference Hall, Makuhari Messe)

Chairperson:Kita Saeko(IISEE, Building Research Institute, National Research and Development Agency, Japan), Hosokawa Takahiro(Kochi University)

Growing evidence of geophysical observations has demonstrated that earthquake faults host a broad spectrum of slip modes from slow to unstable fast slip, which may lead to complexity in the nucleation process, rupture behavior, and slip and energy distribution. This discovery has boosted up vigorous discussions about the connection between slow and fast earthquakes including large earthquakes. How and when does a slow earthquake become a fast earthquake? What geological and geophysical structural differences distinguish slow earthquakes from fast ones? To answer these fundamental questions, it is particularly important to proceed further global and interdisciplinary research through the integration of geophysics, seismology, geodesy, geology, and physics. Advancements in measurement technology, the application of information science and statistical methods to seismic big data, and the utilization of high-performance computing are required as key ingredients in accelerating the integration. In addition, various subduction zone phenomena, including earthquakes, volcanic eruptions, and surface processes , often occur as a cascading series of events, necessitating a system-wide, integrative approach. This session encourages presentations shedding light on geophysical observations, data analysis, field studies, laboratory experiments, numerical modeling, and theoretical studies, as well as comparative investigations across onshore fault zones and multiple subduction systems. We also welcome contributions from cutting-edge science and technology fields that explore development of novel measurements, data-driven analysis, and large-scale computation that are relevant to our understanding of slow and fast earthquakes and other subduction zone phenomena. This session is organized by the JpGU Science of Slow and Fast Earthquake Focus Group and the SZ4D initiative.

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9:00 AM - 9:15 AM

[SCG56-07] Electromagnetic constraints on fluids, plate coupling, and megathrust earthquake behavior

★Invited Papers

*Samer Naif¹, Yinchu Li¹, Darcy Cordell², Kerry Key³, Steve Constable⁴, Rob L Evans⁵, Donna J Shillington⁶, Anne Bécel⁷ (1. Georgia Institute of Technology, 2. Athabasca University, 3. Deep Blue Geophysics, LLC, 4. Scripps Institution of Oceanography, 5. Woods Hole Oceanographic Institution, 6. Northern Arizona University, 7. Lamont-Doherty Earth Observatory)

9:15 AM - 9:30 AM

[SCG56-08] Resistivity heterogeneity along the plate boundary in the Nankai Trough off Kumano

*Manaka Kuroda¹, Hiroshi Ichihara¹, Tada-nori Goto², Takafumi Kasaya³, Hisanori Iwamoto⁴, Yusuke Ohta³, Keiichi Tadokoro¹, Yuya Akamatsu³, Kazuya Shiraishi³, Ryo Miura³ (1. Nagoya University , 2. University of Hyogo, 3. Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 4. Nippon Marine Enterprises (NME))

9:30 AM - 9:45 AM

[SCG56-09] Seimological, structural and geomechanical effects of Seamount Subduction from Seismic Reflection and Refraction imaging in Hyuga-nada, Japan

*Rie Nakata^1,2, Yanxue Ma², Kimihiro Mochizuki², Masataka Kinoshita², Yoshitaka Hashimoto⁴, Yohei Hamada³ (1. Lawrence Berkeley National Laboratory, 2. Earthquake Research Institute, University of Tokyo, 3. JAMSTEC, 4. Kochi University)

9:45 AM - 10:00 AM

[SCG56-10] Seismic velocity and anisotropy structure of the Hyuga-nada forearc, southwest Japan, revealed by 3D active-source tomography

*Ryuta Arai¹, Kazuya Shiraishi¹, Yasuyuki Nakamura¹, Gou Fujie¹, Seiichi Miura¹, Ayako Nakanishi¹, Tsutomu Takahashi¹, Shuichi Kodaira¹, Kimihiro Mochizuki² (1. Japan Agency for Marine-Earth Science and Technology, 2. Earthquake Research Institute, The University of Tokyo)

10:00 AM - 10:15 AM

[SCG56-11] Mechanical properties of crystalline host rocks at potential long-term borehole monitoring site in eastern Taiwan

*Szu-Ting Kuo¹, Kuo-Ying Peng¹, Lun-Wei Wei¹, Chien-Chung Ke¹ (1. Advanced Geology Research Center, Sinotech Engineering Consultants Inc.)

10:15 AM - 10:30 AM

[SCG56-12] Slow Earthquake Fossils in a Collisional Orogen: Multi-scale Geological Evidence from High-Strain Shear Zones in Eastern Taiwan

*Gong-ruei Ho¹, Thomas Yeo², Ya-Chu Tseng³, En-Chao Yeh³, Kuan-Yi Hsu¹, Hsing-En Hsieh⁴ (1. Department of Geology, National Museum of Natural Science, 2. Graduate School of Science and Technology, University of Tsukuba, 3. Department of Earth Sciences, National Taiwan Normal University, 4. Department of Geography, National Taiwan Normal University)

Session information