Dynamic Wedge Failure and Along‐Arc Variations of Tsunamigenesis in the Japan Trench Margin

Ma, Shuo; Nie, Shiying

doi:10.1029/2019gl083148

Cited by 42 publications

(61 citation statements)

References 61 publications

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“…However, this does not mean that erosional margins are completely devoid of sediment cover (Clift and Vannucchi, 2004). It has been suggested that the presence of sediments could enhance tsunamigenesis, by promoting larger uplift (Ma and Nie, 2019). This could explain the large range of N t for subduction zone segments with moderate sediment cover (i.e., T sed ≤ 2 km; Fig.…”

Section: Which Tectonic Setting Is More Prone To Host Tsunamigenic Eamentioning

confidence: 98%

Investigating global correlations between tsunami, earthquake, and subduction zone characteristics

Zelst¹,

Brizzi²,

Rijsingen³

et al. 2022

Preprint

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Tsunamigenic earthquakes pose a large hazard in subduction zones, but it is currently unclear in which - if any - tectonic setting they preferentially occur. We compile the Subduction Nature & Interconnected Tsunamigenic earthquake Characteristics (SNITCH) database with parameters on the geodynamics, megathrust seismicity, and tsunami characteristics for tsunamis caused by earthquakes in all subduction zones. We use a bivariate regression analysis to detect possible relationships between the tsunamigenic earthquake characteristics of a subduction zone and its interplate seismicity, as well as its geometric, structural, and kinematic parameters. We focus our analysis on the normalised number of tsunamigenic earthquakes Nt. The bivariate analysis does not reveal any significant correlations between Nt and the seismogenic zone geometry of the megathrust. However, we do find correlations between Nt and the megathrust seismicity and tectonic parameters characterising a subduction zone. We employ a multivariate Fisher analysis on the tectonic parameters to see which combinations best distinguish the subduction zone segments in which relatively many and few tsunamis occurred. We find that the type of margin (i.e., erosional or accretionary), the trench-normal component of the subduction and convergence velocity, the amount of sediments at the trench and the roughness of the incoming plate are the most important parameters to achieve this. Therefore, tsunamigenic earthquakes may be more prone to occur in tectonic settings where plates subduct relatively fast beneath a sediment-starved, erosional margin. A complex, shallow subduction interface, characterised by multiple faults and fractures that arise at a margin with little trench sediments to smooth subducting plate topography, could account for the larger number of tsunamigenic earthquakes. These results could have implications for hazard assessment.

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Section: Which Tectonic Setting Is More Prone To Host Tsunamigenic Eamentioning

confidence: 98%

Investigating global correlations between tsunami, earthquake, and subduction zone characteristics

Zelst¹,

Brizzi²,

Rijsingen³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Computational earthquake models that are able to account for the curved thrust interface and splay fault networks intersecting with bathymetry, the narrow accretionary wedge, and the complex lithology of subduction zones are challenging. Off-fault yielding processes, which can significantly modulate fault slip near the trench (e.g., (45,81)), pose additional computational demands. These challenges are addressed using the SeisSol software package (e.g., (82)(83)(84)), which solves the nonlinear coupled problem of spontaneous frictional failure across prescribed fault surfaces, seismic wave propagation, and (visco-)plastic Drucker-Prager off-fault damage (e.g., (42)).…”

Section: Earthquake Computational Modelmentioning

confidence: 99%

“…We then analyze a major conundrum (45) of earthquake-tsunami interaction that is ill-constrained by observational data: the interplay of near-trench earthquake dynamics and sedimentary yielding controlling tsunami generation and propagation. We present two additional scenarios with alternative near-trench sedimentary rock strength.…”

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confidence: 99%

“…While outer-rise aftershock sequences help to constrain the extent of slip to the trench during megathrust ruptures (52), the balance between shallow slip and off-fault yielding remains elusive from geodetic and seismic observations. However, both effects have been shown to impact vertical uplift (45,53) and therefore may influence tsunami behavior. To address this, we model tsunami genesis and propagation sourced by dynamic earthquake rupture as detailed in Methods Sec.…”

mentioning

confidence: 99%

“…However, the nature and amount of sediments certainly vary along the megathrust. We expect that taking along-arc variations of rigidity and sediment yield strength into account will lead to along-arc variations in shallow rupture dynamics and tsunami genesis (45).…”

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confidence: 99%

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Stress, rigidity and sediment strength control megathrust earthquake and tsunami dynamics

Ulrich¹,

Gabriel²,

Madden³

2020

Preprint

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Megathrust faults host the largest earthquakes on Earth which can trigger cascading hazards such as devastating tsunamis. Determining characteristics that control subduction zone earthquake and tsunami dynamics is critical to mitigate megathrust hazards, but is impeded by structural complexity, large spatio-temporal scales, and scarce or asymmetric instrumental coverage. Here we show that tsunamigenesis and earthquake dynamics are controlled by along-arc variability in regional tectonic stresses together with depth-dependent variations in rigidity and yield strength of near-fault sediments. We aim to identify dominant regional factors controlling megathrust hazards. To this end, we demonstrate how to unify and verify the required initial conditions for geometrically complex, multi-physics earthquake-tsunami modeling from interdisciplinary geophysical observations. We present large-scale computational models of the 2004 Sumatra-Andaman earthquake and Indian Ocean tsunami that reconcile near- and far-field seismic, geodetic, geological, and tsunami observations and reveal tsunamigenic trade-offs between slip to the trench, splay faulting, and bulk yielding of the accretionary wedge. Our computational capabilities render possible the incorporation of present and emerging high-resolution observations into dynamic-rupture-tsunami models. Our findings highlight the importance of regional-scale structural heterogeneity to decipher megathrust hazards.

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The enhancement of coseismic slip and ground motion due to the accretionary wedge and sedimentary layer in the 2011 Tohoku-Oki earthquake

Li¹,

Huang²

2021

Preprint

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Low-velocity accretionary wedges and sedimentary layers overlying continental plates widely exist in subduction zones. However, the two structures are commonly neglected in velocity models used in slip inversion, ground motion estimation, and dynamic rupture simulation, which may cause a biased estimation of coseismic slip and near-fault ground motions during subduction zone earthquakes. We use the 2011 Mw 9.0 Tohoku-Oki earthquake as an example and reproduce the observed seafloor deformation using 2-D dynamic rupture models with or without an accretionary wedge and a sedimentary layer. We find that the co-existence of the accretionary wedge and sedimentary layer significantly enhances the shallow coseismic slip and amplifies ground accelerations near the accretionary wedge. Hence, stress drop on the shallow fault estimated from the coseismic slip or surface deformation is overestimated when the two structures are neglected. We further simulate a suite of earthquakes where the up-dip rupture terminates at different depths. Results show that a sedimentary layer enhances coseismic slip in all cases, while an accretionary wedge can lead to a sharper decline in slip when negative dynamic stress drop exists on the shallow fault. However, a combination of the two structures tends to enhance fault slip, especially when rupture breaks through a trench. Thus, their combined effects are nonlinear and can be larger than the respective contribution of each structure. Our results emphasize that subduction zones featuring a co-existence of an accretionary wedge and a sedimentary layer may have inherently higher earthquake and tsunami hazards.

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Dynamic Wedge Failure and Along‐Arc Variations of Tsunamigenesis in the Japan Trench Margin

Cited by 42 publications

References 61 publications

Investigating global correlations between tsunami, earthquake, and subduction zone characteristics

Investigating global correlations between tsunami, earthquake, and subduction zone characteristics

Stress, rigidity and sediment strength control megathrust earthquake and tsunami dynamics

The enhancement of coseismic slip and ground motion due to the accretionary wedge and sedimentary layer in the 2011 Tohoku-Oki earthquake

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