Morphological differences across the Shumagin-Semidi fault segments control slip behaviors and tsunami genesis in the Aleutian-Alaska subduction zone

Qiu, Qiang1,2,9; Li, Linlin3,4; Yang, Xiaodong1,2; Lin, Jian1,2,5,6; Chua, Constance Ting7,8

2024-09-01

10.1016/j.qsa.2024.100215

QUATERNARY SCIENCE ADVANCES   影响因子和分区

2666-0334

Rupture behaviors of a subduction megathrust define the slip type, the extent and the associated tsunami hazard. They are, however, difficult to be defined precisely due to limited fault-zone observations. Here, we integrate GNSS, tsunami-waveforms, seismic-profiles, and earthquake-cycle modeling to delineate the slip-extent of the 2020 M-w 7.8 Simeonof and the 2021 M-w 8.2 Chignik earthquakes in the Semidi segment; and to understand the possible structural and mechanical control on the distinct rupture behaviors of this segment and its neighboring Shumagin segment at the Aleutian-Alaska subduction zone. We show that both the Simeonof and Chignik earthquakes slipped a compact area at depth between similar to 20 and 40 km that is well constrained by the combination of GNSS and tsunami-waveform data. We explain the distinct slip behaviors associated with the Semidi and Shumagin segments by highlighting the morphological changes in the fault along the strike direction. Beneath the Shumagin Island, we identify a structural-mechanical boundary that separates the megathrust into Semidi (east) and Shumagin (west) two segments. Semidi is gentle and curved; while Shumagin is steep and planar. The Semidi segment produces spatially-heterogenous stress field, and generates partial, full, complex ruptures as indicated in modeled cycles and in historical seismic observations. Meanwhile the Shumagin segment, coincides with the ocean-continent transition boundary - the Beringian margin, tend to generate slow-slip-events, tremors, otherwise, generates small or moderate seismicity as indicated in the modeled cycles and in seismic records since 1750. Our findings indicate that Semidi is likely to rupture in a chaotic fashion with major or large earthquakes, resulting a greater tsunami hazard like the 1938 M-w 8.2 event. The tsunami potential in the Unimak segment may also remain high.

Aleutian -Alaska subduction zone Fault morphology differences Earthquake -cycle modeling Tsunamis Coseismic joint inversion

ESCI

英语

其他

National Natural Science Foundation of China[42076059] ; Chinese Academy of Sciences["Y4SL021","131551KYSB20200021"] ; Guangdong Provincial Research and Development Program in key areas[2020B1111520001]

Physical Geography ; Geology

Geography, Physical ; Geosciences, Multidisciplinary

WOS:001268103900001

ELSEVIER

Web of Science

1.Chinese Acad Sci, South China Sea Inst Oceanol, Innovat Acad South China Sea Ecol & Environm Engn, CAS Key Lab Ocean & Marginal Sea Geol, Guangzhou 511458, Peoples R China
2.CAS HEC, China Pakistan Joint Res Ctr Earth Sci, Islamabad 45320, Pakistan
3.Sun Yat Sen Univ, Sch Earth Sci & Engn, Guangdong Prov Key Lab Geodynam & Geohazards, Zhuhai 519082, Peoples R China
4.Southern Marine Sci & Engn Guangdong Lab Zhuhai, Zhuhai 519082, Peoples R China
5.Southern Univ Sci & Technol, Dept Ocean Sci & Engn, Shenzhen 518055, Peoples R China
6.Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA
7.Nanyang Technol Univ, Earth Observ Singapore, Singapore 639798, Singapore
8.Tohoku Univ, Int Res Inst Disaster Sci, Sendai 9808572, Japan
9.Xingang Xilu 164, Guangzhou 510301, Guangdong, Peoples R China

Qiu, Qiang,Li, Linlin,Yang, Xiaodong,et al. Morphological differences across the Shumagin-Semidi fault segments control slip behaviors and tsunami genesis in the Aleutian-Alaska subduction zone[J]. QUATERNARY SCIENCE ADVANCES,2024,15.

Qiu, Qiang,Li, Linlin,Yang, Xiaodong,Lin, Jian,&Chua, Constance Ting.(2024).Morphological differences across the Shumagin-Semidi fault segments control slip behaviors and tsunami genesis in the Aleutian-Alaska subduction zone.QUATERNARY SCIENCE ADVANCES,15.

Qiu, Qiang,et al."Morphological differences across the Shumagin-Semidi fault segments control slip behaviors and tsunami genesis in the Aleutian-Alaska subduction zone".QUATERNARY SCIENCE ADVANCES 15(2024).