Raised potential earthquake and tsunami hazards at the North Sulawesi subduction zone after a flurry of major seismicity

Zheng, Tingting1,2,3; Qiu, Qiang1,2,3; Lin, Jian1,2,4,5; Yang, Xiaodong1,2,3

2023-02-01

10.1016/j.marpetgeo.2022.106024

MARINE AND PETROLEUM GEOLOGY   Impact Factor & Quartile

0264-8172

1873-4073

The North Sulawesi subduction zone (NSSZ) was ruptured by a series of large earthquakes (Mw >7) since 1990s, generally triggered small to moderate tsunamis in the surrounding seas and ocean. But the 2018 Sulawesi Mw 7.5 earthquake ruptured the west subduction zone and induced a large tsunami that displaced hundreds of people. These large earthquakes, especially the deeper thrust events, generated stress loading to the shallow megathrust that could rupture to excite exceptional tsunami hazard as observed in Sumatra, Japan and the other subduction zones. Whether the stress loading from downdip events can trigger future failure of a shallow tsunami earthquake and its ensuring tsunami hazard impact remains elusive. Here we investigate the potential of earthquake and tsunami by analyzing the historical earthquake characteristics, calculating Coulomb stress changes and simu-lating hundreds of hypothetical earthquake ruptures to assess the plausible tsunami hazard in the NSSZ. Our results show that a series of Mw 7+ downdip megathrust earthquakes have loaded most of the megathrust, especially the shallow portion (<10 km), with increased stress >10 kPa, implicating a high potential of future large earthquakes and ensuring outsize tsunamis. Our modeled tsunami wave heights vary between >0 and 43 m along the North Sulawesi coastlines. One intriguing fact is that the end point of the tsunami wave energy dissipation path gains a comparable tsunami impact as the region in the rupture zone for all the magnitude considered, highlighting a dual-pattern threatened regions in the Celebes Sea. Importantly, the thrust and fold belt structure in the wide outer wedge of the accretionary prism and the strong seafloor bathymetry variation offshore Sulawesi Island could serve an efficient wave-amplification tool that need to be considered in future hazard assessment. Our findings alert that the earthquake and tsunami hazard potential are largely raised by these downdip major earthquakes.

North-Sulawesi subduction zone The Celebes sea Tsunami hazard assessment Coulomb stress changes Slip models

SCI

English

Corresponding

National Natural Science Foundation of China["42006055","42076059","41890813"] ; Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering[GML2019ZD0205] ; Chinese Academy of Sciences["QYZDY-SSW-DQC005","133244KYSB20180029","Y4SL021","ISEE2021PY03","131551KYSB20200021"] ; State Key Laboratory of Marine Geology, Tongji University[MGK202011] ; Guangdong Provincial Research and DevelopmentProgram[2020B1111520001]

Geology

Geosciences, Multidisciplinary

WOS:000901543300002

ELSEVIER SCI LTD

GEOSCIENCES

Web of Science

1.Chinese Acad Sci, South China Sea Inst Oceanol, Innovat Acad South China Sea Ecol & Environm Engn, Key Lab Ocean & Marginal Sea Geol, Guangzhou 511458, Peoples R China
2.Southern Marine Sci & Engn Guangdong Lab Guangzhou, Guangzhou 511458, Peoples R China
3.CAS HEC, China Pakistan Joint Res Ctr Earth Sci, Islamabad 45320, Pakistan
4.Southern Univ Sci & Technol, Dept Ocean Sci & Engn, Shenzhen 518055, Peoples R China
5.Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA

Zheng, Tingting,Qiu, Qiang,Lin, Jian,et al. Raised potential earthquake and tsunami hazards at the North Sulawesi subduction zone after a flurry of major seismicity[J]. MARINE AND PETROLEUM GEOLOGY,2023,148.

Zheng, Tingting,Qiu, Qiang,Lin, Jian,&Yang, Xiaodong.(2023).Raised potential earthquake and tsunami hazards at the North Sulawesi subduction zone after a flurry of major seismicity.MARINE AND PETROLEUM GEOLOGY,148.

Zheng, Tingting,et al."Raised potential earthquake and tsunami hazards at the North Sulawesi subduction zone after a flurry of major seismicity".MARINE AND PETROLEUM GEOLOGY 148(2023).