Gaku Kimura is a Professor Emeritus at The University of Tokyo and an Adviser at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). He holds a Dr. Sc. in Geology and Mineralogy from Hokkaido University (1981). With a career spanning over four decades, Dr. Kimura has held prestigious academic positions at Osaka Prefecture University, Tokyo University of Marine Science and Technology, and notably served as a Professor at The University of Tokyo from 1997 to 2016. His leadership in geosciences is widely recognized: he has served as President of both the Geological Society of Japan (2006-2008) and the Japan Geoscience Union (JpGU, 2008-2012), and as a Council Member of the Science Council of Japan (2014-2020). Dr. Kimura’s contributions to marine geology and geophysics include serving as Co-Chief Scientist for the Ocean Drilling Program (ODP) Leg 170 and Chair of the Chikyu IODP Board. His excellence has been honored with awards such as the Geological Society of Japan Prize (2012) and the Tokyo University of Marine Science and Technology President’s Award (2017). He is a Fellow of the Japan Geoscience Union (2023~).
Ongoing Subduction and Orogeny in Japan and Nankai Trough
The Japan Arc and Nankai Trough constitute one of the most dynamic geotectonic settings globally, shaped by the ongoing oblique subduction of the Philippine Sea Plate beneath the Eurasian Plate. This study synthesizes multi-source geophysical data, including seismic tomography, marine gravity surveys, and crustal deformation monitoring, to investigate the spatiotemporal patterns of subduction processes and their coupled orogenic responses in the region. Key findings reveal that the subducting Philippine Sea Plate exhibits significant variations in slab geometry—from flat subduction beneath southwest Japan to steep dipping offshore the Nankai Trough—directly controlling the distribution of seismicity, volcanic activity, and crustal shortening. The Nankai Trough, in particular, is characterized by episodic megathrust earthquakes and slow slip events, which are closely linked to the dehydration of subducted sediments and the mechanical interaction between the slab and the overriding plate. Meanwhile, orogenic processes across the Japan Arc manifest as active mountain building, with crustal thickening and exhumation of metamorphic complexes driven by plate convergence and slab roll-back. Integrating these observations, this presentation discusses the dynamic mechanisms underlying the co-evolution of subduction zone processes and orogeny in the region, highlighting their implications for hazard assessment and our understanding of convergent margin tectonics worldwide. The results provide critical insights into how plate interactions modulate surface deformation and geohazard potential in active continental margins.