Reestimation of slab dehydration fronts in Kuril-Kamchatka using updated global subduction zone thermal structures
Weiling Zhu,
Yingfeng Ji,
Lijun Liu,
Rui Qu,
Ye Zhu,
Chaodi Xie,
Lin Ding
Affiliations
Weiling Zhu
State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
Yingfeng Ji
State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Corresponding author
Lijun Liu
University of Illinois at Urbana-Champaign, Urbana, IL, USA
Rui Qu
State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
Ye Zhu
State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
Chaodi Xie
Geophysics Department, School of Earth Sciences, Yunnan University, Kunming 650500, China
Lin Ding
State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
Summary: Previous subduction thermal models are inconsistent with the values of forearc heat flow (50–140 mW/m2) and global P‒T conditions of exhumed rocks, both suggesting a shallow environment 200–300°C warmer than model predictions. Here, we revaluate these problems in Kuril-Kamchatka using 3D thermomechanical modeling that satisfies the observed subduction history and slab geometry, while our refined 3D slab thermal state is warmer than that predicted by previous 2D models and better matches observational constraints. We show that warmer slabs create hierarchical slab dehydration fronts at various forearc depths, causing fast and slow subduction earthquakes. We conclude that fast-to-slow subduction earthquakes all play a key role in balancing plate coupling energy release on megathrusts trenchward of high P-T volcanism.
