Rupture process of the 16 July 2025 Mw 7.3 Sand Point, Alaska earthquake inferred from compressive sensing back projection and slip inversion

Wei Liu; Xiaofei Chen

doi:10.1007/s12583-026-0143-y

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Journal of Earth Science > 2026 > Accepted Manuscript

Wei Liu, Xiaofei Chen. Rupture process of the 16 July 2025 Mw 7.3 Sand Point, Alaska earthquake inferred from compressive sensing back projection and slip inversion. Journal of Earth Science. doi: 10.1007/s12583-026-0143-y

Citation:

Wei Liu, Xiaofei Chen. Rupture process of the 16 July 2025 Mw 7.3 Sand Point, Alaska earthquake inferred from compressive sensing back projection and slip inversion. Journal of Earth Science. doi: 10.1007/s12583-026-0143-y

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Rupture process of the 16 July 2025 Mw 7.3 Sand Point, Alaska earthquake inferred from compressive sensing back projection and slip inversion

doi: 10.1007/s12583-026-0143-y

Wei Liu^1,2,
Xiaofei Chen^{2,3,4
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1 College of Environment and Safety Engineering, Fuzhou University, Fuzhou, 350108, China;
2 Department of Earth and Space Sciences, Southern University of Science and Technology, Shenzhen, 518055, China;
3 Shenzhen Key Laboratory of Deep Offshore Oil and Gas Exploration Technology, Southern University of Science and Technology, Shenzhen, 518055, China;
4 Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology, Southern University of Science and Technology, Shenzhen, 518055, China

Funds:

This work is supported by National Natural Science Foundation of China (Grant Numbers 42304061 and 42494864), Shenzhen Key Laboratory of Deep Offshore Oil and Gas Exploration Technology (ZDSYS20190902093007855), and Guangdong Provincial Key Laboratory of Geophysical Highresolution Imaging Technology (2022B1212010002). This study is also supported by Center for Computational Science and Engineering at Southern University of Science and Technology.

Available Online: 17 Aug 2026

Abstract

Abstract

In recent years， the Shumagin region of the Alaska-Aleutian subduction zone has been active and suffered several M>7 earthquakes. Here we investigate the 2025 Mw 7.3 Sand Point earthquake by performing compressive sensing back projection analyses and slip inversions using seismic waveforms at teleseismic distances. Our results reveal that this earthquake ruptured eastward ～50 km from the epicenter within ～30 s， with most coseismic slip distributed at the depth range of 35-55 km and a maximum slip amount of ～1.6 m. This earthquake probably ruptured the pre-existing strike-slip fault within the downgoing Pacific plate， which might be related to the extinct Kula-Pacific midocean ridges. The high-frequency energy was radiated along the up-dip margin of the coseismic slip region， indicating rough structures at the shallow part of the pre-existing fault near the plate interface. We infer that this earthquake might be an aftershock of the 2020 Mw 7.8 Simeonof megathrust earthquake.
- the 2025 Mw 7.3 Sand Point earthquake,
- the Shumagin gap,
- back projection,
- finite fault inversion,
- earthquake rupture process