Potential failure mechanism of low-angle submarine landslides in shelf-slope break of Pearl River Mouth Basin, South China Sea

Abstract

Low-angle submarine landslides pose a greater threat to offshore infrastructure compared to those with steep sliding angles. Understanding the preparation and triggering mechanism of these low-angle submarine landslides remains a significant challenge. This study focuses on a deformed low-angle submarine landslide in the shelf-slope break of the Pearl River Mouth Basin, South China Sea, integrating sedimentology, geophysics, and geotechnology to investigate potential failure mechanisms. The architecture and deformation characteristics of the submarine landslide were elucidated by analyzing multibeam and seismic data. Within the context of the regional geological history and tectonic framework, this study focuses on the factors (e.g., rapid sedimentation, fluid activity, and earthquakes) that potentially contributed to the submarine slope failure. Furthermore, a series of stability evaluations considering the effects of rapid sedimentation and earthquakes was conducted. Our findings indicate that the most probable triggering mechanism involves the combined effects of sedimentation controlled by sea-level fluctuations, high-pressure gas activity, and seismic events. The high-pressure gas, which acts as a long-term preconditioning factor by elevating pore pressures and reducing shear resistance within the sediment, accumulated beneath the upper and middle sections of the low-permeability stratum that was formed during sea-level rise and ultimately evolved into the sliding mass. The overpressure generated by gas accumulation predisposed the submarine slope to instability, and a frequent or moderate earthquake ultimately initiated local failure. This study enhances the mechanistic understanding of low-angle slope failures in the shelf-slope break zone and provides critical insights for assessing marine hazard risks.

Keywords

Submarine landslides / Rapid sedimentation / Earthquake / High-pressure gas / Triggering mechanism

Acknowledgments

This work was supported by NSFC Shiptime Sharing Project (Nos. 42349302, and 42149905); and the Hubei Provincial Natural Science Foundation of China (No. 2024AFB515); and the National Natural Science Foundation of China (Nos. 42207173, 41831280, and 42176071); and the National Key R&D Program of China (No. 2024YFC3082500); and the Shandong Provincial Natural Science Foundation of China (No. ZR2022QD002); and the Shandong Provincial Taishan Scholar Construction Project (No. tsqn202507091); and the Shandong Provincial Young Innovators Team (No. 2024KJH183). We gratefully acknowledge Dr. Qingjun Jiang of the Affiliated Hospital of Qingdao University for providing technical assistance with three-dimensional computed tomogra-phy scanning of the core samples.

Supplementary material

Supplementary data to this article can be found online at https://doi.org/10.1016/j.ijmst.2025.09.009.

References

[1] Guo XS, Fan N, Zheng DF, Fu CW, Wu H, Zhang YJ, Song XL, Nian TK. Predicting impact forces on pipelines from deep-sea fluidized slides: A comprehensive review of key factors. Int J Min Sci Technol 2024; 34(2):211-25.

[2] Zhu CQ, Peng JB, Jia YG. Marine geohazards: Past, present, and future. Eng Geol 2023;323:107230.

[3] Guo XS, Sun JK, Liu YH, Chen XJ, Liang DF, Liu XL. Rheological characterization and modeling of ultra-high-velocity fluidized submarine landslides. Phys Fluids 2024;36:121705.

[4] Wang ZH, Jia YG, Liu XL, Wang D, Shan HX, Guo L, Wei W. In situ observation of storm-wave-induced seabed deformation with a submarine landslide monitoring system. Bulletin of Engineering Geology and the Environment 2018;77:1091-102.

[5] Nisbet EG, Piper DJW. Giant submarine landslides. Nature 1998; 392 (6674):329-30.

[6] Tanyas¸ HK, van Westen CJ, Allstadt KE, Jessee MN, Görüm T, Jibson RW, Godt JW, Sato HP, Schmitt RG, Marc O, Hovius N.Presentation and analysis of a worldwide database of earthquake-induced landslide inventories. J Geophys Res Earth Surf 2017; 122(10):1991-2015.

[7] Du P, Li LL, Kopf A, Wang DW, Chen KJ, Shi HB, Wang WT, Pan XY, Hu G, Zhang PZ. Earthquake-induced submarine landslides (EQISLs) and a comparison with their terrestrial counterparts: Insights from a new database. Earth Sci Rev 2025;261:105021.

[8] Hühnerbach V, Masson DG. Landslides in the north Atlantic and its adjacent seas: An analysis of their morphology, setting and behaviour. Mar Geol 2004; 213(1-4):343-62.

[9] Bryn P, Berg K, Forsberg CF, Solheim A, Kvalstad TJ. Explaining the storegga slide. Mar Petrol Geol 2005; 22(1-2):11-9.

[10] Karstens J, Haflidason H, Berndt C, Crutchley GJ.Revised Storegga Slide reconstruction reveals two major submarine landslides 12, 000 years apart. Commun Earth Environ 2023;4:55.

[11] Locat J, Lee HJ. Submarine landslides: Advances and challenges. Can Geotech J 2002; 39(1):193-212.

[12] Stoecklin A, Friedli B, Puzrin AM. Sedimentation as a control for large submarine landslides: Mechanical modeling and analysis of the santa barbara basin. JGR Solid Earth 2017; 122(11):8645-63.

[13] Zhu CQ, Jiao XR, Cheng S, Li QP, Liu KH, Shan HX, Li CX, Jia YG. Visualizing fluid migration due to hydrate dissociation: Implications for submarine slides. Environ Geotech 2023; 10(3):218-26.

[14] Zhu CQ, Cheng S, Li QP, Shan HX, Lu JA, Shen ZC, Liu XL, Jia YG. Giant submarine landslide in the South China Sea: Evidence, causes, and implications. J Mar Sci Eng 2019; 7(5):152.

[15] Georgiopoulou A, Masson DG, Wynn RB, Krastel S. Sahara Slide: Age, initiation, and processes of a giant submarine slide. Geochem Geophys Geosyst 2010; 11 (7):Q07014.

[16] Tian ZC, Huang JJ, Song L, Zhang MW, Jia YG, Yue JH. The interaction between internal solitary waves and submarine canyons. J Mar Environ Eng 2024;11:129-39.

[17] Lüdmann T, Betzler C, Lindhorst S, Lahajnar N, Hübscher C. Submarine landsliding in carbonate ooze along low-angle slopes ( Inner Sea, Maldives). Mar Petrol Geol 2022;136:105403.

[18] Flemings PB, Long H, Dugan B, Germaine J, John CM, Behrmann JH, Sawyer D. Pore pressure penetrometers document high overpressure near the seafloor where multiple submarine landslides have occurred on the continental slope, offshore Louisiana, Gulf of Mexico. Earth Planet Sci Lett 2008; 269(3-4):309-25.

[19] Baeten NJ, Laberg JS, Vanneste M, Forsberg CF, Kvalstad TJ, Forwick M, Vorren TO, Haflidason H. Origin of shallow submarine mass movements and their glide planes: Sedimentological and geotechnical analyses from the continental slope off northern Norway. J Geophys Res Earth Surf 2014; 119(11):2335-60.

[20] Wang WW, Wang DW, Wu SG, Völker D, Zeng HL, Cai GQ, Li QP. Submarine landslides on the north continental slope of the South China Sea. J Ocean Univ China 2018; 17(1):83-100.

[21] Masson DG, Harbitz CB, Wynn RB, Pedersen G, Løvholt F. Submarine landslides: Processes, triggers and hazard prediction. Philos Trans A Math Phys Eng Sci 1845; 2006(364):2009-39.

[22] Shepherd JW, Paumard V, Lang S, George AD. Investigating relationships between shoreline process regime, shelf-margin architecture, and deep-water sand delivery: Insights from the early post-rift Hammerhead shelf margin (Bight Basin, southern Australia). Gondwana Res 2024;135:208-33.

[23] Qi K, Gong CL, Zhang JY, Andresen KJ, Jin ZK. Relative sea-level control on the building of two distinct shelf-margin clinothems on the late-Quaternary Pearl River margin: Insights from numerical stratigraphic forward modelling. Basin Res 2023; 35(2):842-64.

[24] Tsai CH, Huang CL, Hsu SK, Doo WB, Lin SS, Wang SY, Lin JY, Liang CW. Active normal faults and submarine landslides in the Keelung Shelf off NE Taiwan. Terr Atmos Ocean Sci 2018; 29(1):31-8.

[25] Rydningen TA, Laberg JS, Kolstad V. Seabed morphology and sedimentary processes on high-gradient trough mouth fans offshore Troms, northern Norway. Geomorphology 2015;246:205-19.

[26] Jintasaeranee P, Snidvongs A. Morphometric analysis of the Andaman outer shelf and upper slope: Implications for the recent slope failure events. Acta Oceanol Sin 2023; 42(9):44-52.

[27] Sultan N, Savoye B, Jouet G, Leynaud D, Cochonat P, Henry P,Stegmann S, Kopf

[28] A. Investigation of a possible submarine landslide at the Var delta front (Nice continental slope, southeast France). Can Geotech J 2010; 47(4):486-96.

[29] Chen DX, Wang XJ, Völker D, Wu SG, Wang L, Li W, Li QP, Zhu ZY, Li CL, Qin ZL, Sun QL. Three dimensional seismic studies of deep-water hazard-related features on the northern slope of South China Sea. Mar Petrol Geol 2016;77:1125-39.

[30] Zhou QJ, Li XS, Zhou H, Liu LJ, Xu YQ, Gao S, Ma L. Characteristics and genetic analysis of submarine landslides in the northern slope of the South China Sea. Mar Geophys Res 2019; 40(3):303-14.

[31] Han JH, Xu GQ, Li YY, Zhuo HT. Evolutionary history and controlling factors of the shelf breaks in the Pearl River Mouth Basin, northern South China Sea. Mar Petrol Geol 2016;77:179-89.

[32] Zhu CQ. Study on the genesis and evolution process of submarine landslides in the Pearl River Canyon Group in the northern South China Sea. Qingdao: Ocean University of China; 2020. Doctoral dissertation.

[33] Li W, Alves TM, Wu SG, Rebesco M, Zhao F, Mi LJ, Ma BJ. A giant, submarine creep zone as a precursor of large-scale slope instability offshore the Dongsha Islands (South China Sea). Earth Planet Sci Lett 2016;451:272-84.

[34] Jia YG, Tian ZC, Shi XF, Paul Liu J, Chen JX, Liu XL, Ye RJ, Ren ZY, Tian JW. Deep-sea sediment resuspension by internal solitary waves in the northern South China Sea. Sci Rep 2019; 9(1):12137.

[35] Zhou H, Liu LJ, Xu YQ, Zhou QJ, Gao S. Sediment characteristics and paleoenvironmental significance of Core DLW3101 from northern slope of the South China Sea. Haiyang Xuebao 2018; 40(7):103-15. In Chinese.

[36] Wang L, Wu SG, Li QP, Wang DW. Submarine slides and influencing factors in the continental shelf break area of the Pearl River Mouth Basin. Mar Sci 2016; 40(5):131-41. In Chinese.

[37] Li ZH, Yang Y, Zhu CQ, Jia YG, Kou HL. Contribution of rapid sedimentation to submarine landslides and its influencing factors. Chin J Rock Mech Geotech Eng 2023; 42(05):1225-36. In Chinese.

[38] Andersen KH, Lunne T, Kvalstadn TJ, Forsberg CF. Deep water geotechnical engineering. In: 24th National Conference of the Mexican Social Work of Soil Mechanics. Mexico: Mexican Social Work of Soil Mechanics, 2008.

[39] Li ZH, Chen T, Liu HL, Ji CS, Zhu CQ, Hu C, Jia YG. Earthquake response and post-earthquake stability assessment of submarine clay slopes. Appl Ocean Res 2022;127:103322.

[40] Biscontin G, Pestana JM, Nadim F. Seismic triggering of submarine slides in soft cohesive soil deposits. Mar Geol 2004; 203(3-4):341-54.

[41] Biscontin G, Pestana JM. Factors affecting seismic response of submarine slopes. Nat Hazards Earth Syst Sci 2006; 6(1):97-107.

[42] Liu HY, Lin CS, Zhang ST, Zhang B, Jiang J, Tian HX, Liu H. Quaternary sequence stratigraphic evolution of the Pearl River Mouth Basin and controlling factors over depositional systems. Mar Geol Quaternary Geol 2019; 39(1):25-37. In Chinese.

[43] Gatter R, Clare MA, Kuhlmann J, Huhn K. Characterisation of weak layers, physical controls on their global distribution and their role in submarine landslide formation. Earth Sci Rev 2021;223:103845.

[44] Al-Mufti ON, Arnott RWC, Hinton MJ, Alpay S, Russell HAJ. Using computed tomography (CT) to reconstruct depositional processes and products in the subaqueous glaciogenic Champlain Sea basin, Ottawa, Canada. Geomorphology 2022;403:108165.

[45] Bellwald B, Urlaub M, Hjelstuen BO, Sejrup HP, Sørensen MB, Forsberg CF, Vanneste M. NE Atlantic continental slope stability from a numerical modeling perspective. Quat Sci Rev 2019;203:248-65.

[46] Xie YB, Wu TY, Sun J, Zhang HY, Wang JL, Gao JW, Chen CX. Sediment compaction and pore pressure prediction in deepwater basin of the South China Sea: Estimation from ODP and IODP drilling well data. J Ocean Univ China 2018; 17(1):25-34.

[47] Xie BY. Geophysical identification characteristics and genetic mechanism of shallow water flow in deepwater basin of northern South China Sea. Beijing: University of Chinese Academy of Sciences; 2018. Doctoral dissertation.

[48] Hussein A, Zhao LX, Chen YY, Wang JL. Rock physics characteristics of marine sediments in the South China Sea: The link between the geological factors and elastic properties. Front Earth Sci 2023;10:931611.

[49] Sun QL, Wang Q, Shi FY, Alves T, Gao S, Xie XN, Wu SG, Li JB. Runup of landslide-generated tsunamis controlled by paleogeography and sea-level change. Commun Earth Environ 2022;3:244.

[50] Wang YX, Wang R, Zhang JM. Large-scale seismic seafloor stability analysis in the South China Sea. Ocean Eng 2021;235:109334.

[51] Guo XQ, Zhu B, Liu JC. Experimental study of undrained shear strength and cyclic degradation behaviors of marine clay in Pearl River Estuary. Rock Soil Mech 2016; 37(5):1005-12. In Chinese.

[52] Fan N, Nian TK, Zhao W, Lu S, Song L, Yin P. Rheological test and strength model of submarine mud flow. Rock Soil Mech 2018; 39(9):3195-202. In Chinese.

[53] Zhang W, Li Y, Zhou SW, Jiang ZB, Wu F, Liang WZ. Experimental research on cyclic behaviors of clay in the northern region of South China Sea. Rock Soil Mech 2018; 39(7):2413-23. In Chinese.

[54] Nian TK, Guo XS, Zheng DF, Xiu ZX, Jiang ZB. Susceptibility assessment of regional submarine landslides triggered by seismic actions. Appl Ocean Res 2019;93:101964.

[55] Kvalstad TJ, Andresen L, Forsberg CF, Berg K, Bryn P, Wangen M. The Storegga slide: Evaluation of triggering sources and slide mechanics. Mar Petrol Geol 2005; 22(1-2):245-56.

[56] L’Heureux JS, Vanneste M, Rise L, Brendryen J, Forsberg CF, Nadim F, Longva O, Chand S, Kvalstad YJ, Haflidason H. Stability, mobility and failure mechanism for landslides at the upper continental slope off Vesterålen. Norway. Mar Geol 2013;346:192-207.

[57] Wan ZF, Zhang W, Ma C, Liang JQ, Li A, Meng DJ, Huang W, Yang CZ, Zhang JF, Sun YF. Dissociation of gas hydrates by hydrocarbon migration and accumulation-derived slope failures: An example from the South China Sea. Geosci Front 2022; 13(2):101345.