Dual Mechanism Transition Controls Rupture Development of Large Deep Earthquakes

Creators: Jia, Zhe^{1, 2}; Fan, Wenyuan²; Mao, Wei^{3, 4}; Shearer, Peter M.²; May, Dave A.²

1. The University of Texas at Austin
2. Scripps Institution of Oceanography
3. University of Chinese Academy of Sciences
4. California Institute of Technology

Abstract

Deep earthquakes at depths below 500 km are under prohibitive pressure and temperature conditions for brittle failure. Individual events show diverse rupture behaviors and a coherent mechanism to explain their rupture nucleation, propagation, and characteristics has yet to be established. We systematically resolve the rupture processes of 40 large M>7 deep earthquakes from 1990 to 2023 and compare the rupture details to their local metastable olivine wedge (MOW) structures informed from thermo-mechanical simulations in seven subduction zones. Our results suggest that these events likely initiate from metastable olivine transformations within the cold slab core and rupture beyond the MOW due to sustained weakening from molten rock at the rupture tip. Over half of the M>7 earthquakes likely rupture beyond the MOW boundary and are controlled by both mechanisms. Rupturing outside the MOW boundary leads to greater moment release, increased geometric complexity, and a reduction in rupture length, causing greater stress drops.

Copyright and License

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Acknowledgement

The facilities of IRIS Data Services, and specifically the IRIS Data Management Center, were used for access to seismic waveforms recorded by global seismic networks II, IU, IC, G, GT, PS, the related metadata, and/or derived products used in this study. Our thermal model calculations were performed on the NSF ACCESS HPC clusters Stampede2 and Stampede3 at the Texas Advanced Computing Center (TACC) and Anvil at Purdue University. We thank Heidi Houston, Zhongwen Zhan, Lara Wagner, Alice Gabriel for helpful discussions. This work is supported by the United States Geological Survey Grant G22AP00011, and the Cecil and Ida Green Foundation. DM was supported by the National Science Foundation through Grant EAR-2121568 and OAC-2311208.

Data Availability

All seismic data used in this study are publicly available from the IRIS-DMC. All subevent and thermal models are shown in the Supporting Information S1 and are publicly available at zenodo (Jia et al., 2025).

Supplemental Material

Supporting Information S1 (PDF)

Original Version of Manuscript (PDF)

Peer Review History (PDF)

Author Response to Peer Review Comments (PDF)

First Revision of Manuscript (PDF)

Name	Size	Download all
AGU Advances - 2025 - Jia - Dual Mechanism Transition Controls Rupture Development of Large Deep Earthquakes.pdf md5:cb44d1c865982f9f4cdc83d3f91680e4	1.9 MB	Preview Download
2025av001701-sup-0001-supporting information sis01.pdf md5:7ae2eefe17e9f1ac6cbd2b34f0dc6b8d	23.1 MB	Preview Download

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes