Variation in the thermal and dehydration regime below Central America: Insights for the seismogenic plate interface

Rui Qu; Yingfeng Ji; Lijun Liu; Weiling Zhu; Ye Zhu; Chaodi Xie; Shoichi Yoshioka; Haris Faheem; Lin Ding

doi:10.1016/j.isci.2023.107936

Variation in the thermal and dehydration regime below Central America: Insights for the seismogenic plate interface

iScience. 2023 Sep 17;26(10):107936. doi: 10.1016/j.isci.2023.107936. eCollection 2023 Oct 20.

Authors

Rui Qu^{1

2}, Yingfeng Ji^{1

2}, Lijun Liu^{3

4}, Weiling Zhu^{1

2}, Ye Zhu^{1

2}, Chaodi Xie⁵, Shoichi Yoshioka^{6

7}, Haris Faheem^{1

2}, Lin Ding^{1

2}

Affiliations

¹ State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
² University of Chinese Academy of Sciences, Beijing 100049, China.
³ State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
⁴ University of Illinois at Urbana-Champaign, Urbana, IL, USA.
⁵ Geophysics Department, School of Earth Sciences, Yunnan University, Kunming 650500, China.
⁶ Research Center for Urban Safety and Security, Kobe University, Kobe, Japan.
⁷ Department of Planetology, Graduate School of Science, Kobe University, Kobe, Japan.

Abstract

Slow earthquakes predominant in Costa Rica indicate unstable faulting of segmented Central American megathrusts, but the recurrence of episodic tremors and slips reported to precede a giant earthquake remains still enigmatic. The underlying mechanism is related to the variation in the coupling along the heterogeneous subduction interface which is poorly understood. In this study, we used up-to-date 3D thermal modeling to provide insights into the along-strike variation in the thermal state and hydraulic distribution beneath the Central American subduction zone. Our results show that the subducted Cocos Plate is much warmer than previously estimated, and the slab geometry exhibits remarkable perturbations along the trench. We found that the regions of large dehydration rate along the slab are consistent with the seismicity occurrence depth beneath the Moho. Below the Nicoya Peninsula and the Guatemala-Nicaragua segment of megathrusts, fluids derived from subducted slab result in increased pore fluid pressures and subsequent recurrence of slow slip events and regular earthquakes.

Keywords: Earth sciences; Geology; Geophysics; Tectonics.