Long-lived shallow slow-slip events on the Sunda megathrust

Mallick, Rishav; Meltzner, A. J.; Tsang, L. L.; Lindsey, E. O.; Feng, Lujia; Hill, Emma M.

doi:10.1038/s41561-021-00727-y

Cited by 23 publications

(25 citation statements)

References 73 publications

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“…The deformation, rupture behaviour and slip potential of plate boundary megathrusts at convergent margins are complex and vary greatly from one subduction zone to another (Nanayama et al 2003;Mallick et al 2021). Some megathrusts are poised to produce occasional great earthquakes separated by patchy moderate seismicity (e.g., Chile subduction zone) or frequent moderate to large earthquakes (e.g., Mexican subduction zone) and releases the stresses that builds up during the interseismic period due to continued plate convergence (Rajendran, et al 2007).…”

Section: Rationale For the Present Studymentioning

confidence: 99%

“…Recurring/similar earthquakes are generally caused by repeated slip in small patches bounded by creeping aseismic regions and releases elastic energy accumulated on a locking fault during interseismic period (Peng et al 2010;Obra et al 2016). The interseismic slip rate de cit which is presumed to be based on the frictionally locked asperities that increases the kinematic coupling/locking between plates and promotes seismic subduction (Mallick et al 2021). Contrary interseismic creep indicates absence of frictional locking, lower stored strain and less chances for coseismic slip to trigger a great earthquake, but their interactions with adjacent faults/segments can make them dangerous (Mallick et al 2021;Igarashi and Kato, 2021;Lindsey, et al 2021).…”

Section: Rationale For the Present Studymentioning

confidence: 99%

“…The interseismic slip rate de cit which is presumed to be based on the frictionally locked asperities that increases the kinematic coupling/locking between plates and promotes seismic subduction (Mallick et al 2021). Contrary interseismic creep indicates absence of frictional locking, lower stored strain and less chances for coseismic slip to trigger a great earthquake, but their interactions with adjacent faults/segments can make them dangerous (Mallick et al 2021;Igarashi and Kato, 2021;Lindsey, et al 2021). As far as Sumatra-Andaman subduction zone is concerned, Sumatran parts of megathrusts features a 600 km long locked patch, where stored strain is released during great earthquakes as witnessed by 2004 event (Sieh, 2005;Meltzner, et al 2007Meltzner, et al , 2010.…”

Section: Rationale For the Present Studymentioning

confidence: 99%

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Tectonic Geomorphology and Seismic Hazard of the East Boundry Thrust in northern segment of the Sunda-Andaman subduction zone

Bhat

Balaji

Ganai

2022

Preprint

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The East Boundary Thrust (EBT), is a ~ 500 km long linear to curvilinear deformation zone along the Sunda-Andaman plate edge convergent margin. EBT is the main active tectonic structure responsible for accretionary prism formation and accommodates the bulk of present crustal deformation in the outer arc ridge of the Andaman and Nicobar subduction zone. The EBT marks the up dip expression of subduction mega thrust progressing towards the Andaman trench in the form of actively accreting the frontal prism and deforming the trench sediment sequences above the detachment. We conducted paleoseismic trench investigations of the Jarawa Thrust (JT) (northern 300km segment of EBT) at two specific sites between Ferrargunj in the south and the Radhanagar in the north Andaman. Structural and stratigraphic relationships exposed in a trench excavated across the 6 m high scarp at Ferrargunj show the scarp to be the result of single earthquake. Dating of sediment offset by the fault with optical luminescence indicates the displacement occurred between 2160 ± 300 BP and 400 ± 50 BP. Complex structural deformation is observed in the trench excavated across 10 m high scarp at Radhanagar that similarly indicates the scarp is due to single earthquake. The present findings are helpful for seismic hazard evaluation of the Andaman and Nicobar region, where greater slip deficit and no great earthquake (M ≥ 8) have been accounted so far and suggests potential for earthquakes larger than observed historically.

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Section: Rationale For the Present Studymentioning

confidence: 99%

Section: Rationale For the Present Studymentioning

confidence: 99%

Section: Rationale For the Present Studymentioning

confidence: 99%

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Tectonic Geomorphology and Seismic Hazard of the East Boundry Thrust in northern segment of the Sunda-Andaman subduction zone

Bhat

Balaji

Ganai

2022

Preprint

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“…A 15-year-long (1966-1981) SSE was proposed to explain the observations in the Banyak Islands, located above the rupture zone of the 2005 M w 8.6 earthquake (see also Tsang et al, 2015), although the 25 years gap between the two events challenges the existence of a causal link. Some of the long-term variations could however be more directly related to subsequent megathrust earthquakes: a 32-year long surface deformation anomaly was interpreted as an SSE in the shallow part of the plate interface, before the 1861 E M 8.5 megathrust earthquake (Mallick et al, 2021); the authors propose that this long duration SSE could have been triggered and sustained by elevated pore fluid pressure, and then stopped by subsequent drainage caused by the mainshock. In Japan, Hasegawa and Yoshida (2015), Heki and Mitsui (2013), Loveless and Meade (2016), Mavrommatis et al (2014), Mavrommatis et al (2015), and Yokota and Koketsu (2015) infer slip rate variations over 15 years along the Japan Trench before the 2011 Tohoku earthquake.…”

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confidence: 99%

Fourteen‐Year Acceleration Along the Japan Trench

et al. 2021

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A common assumption regarding the seismic cycle is to consider the inter-seismic strain rate as being constant over time (Savage & Thatcher, 1992). Recently, long-term changes in slip rate, or interface locking, have been inferred or suggested in the context of subduction zones. Long-term slow slip events (L-SSEs) with a duration of a few years have been documented in Alaska (duration of 2-9 years) (

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“…On the basis of findings from elsewhere (e.g. Mallick et al, 2021), it is also plausible that longer-lasting SSEs may also have been occurring on a multi-decadal timescale along the Kapiti Coast, which could have further reduced the rate of twentieth century relative sea-level rise. An alternate explanation for the shift in may relate to variability in the depth or distribution of plate coupling over time under Pāuatahanui, which may have resulted in changes in the sense of vertical land movement.…”

Section: Discussion Of Trend Estimationsmentioning

confidence: 97%

Foraminiferal Sea-Level Reconstructions From Major New Zealand Cities: Implications for Long-Term Vertical Land Movement Trends from Centennial Baselines

King¹

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<p>Vertical land movement variability around the coasts of New Zealand has introduced a great deal of uncertainty to projections of future sea-level rise around major coastal cities. To gain an understanding of how this movement has occurred and changed over time, as well as the other factors driving sea-level change around major cities, four new sea-level reconstructions are presented. These records are from salt marshes in Greater Wellington (Pāuatahanui), Dunedin (Aramoana) and Auckland (Catalina Bay and Rangiototo Island. At Pāuatahanui, relative sea-level rise has risen by 1.50 ± 0.59 mm/yr since 1855, with either a gradual or abrupt deceleration during the twentieth century, followed by a rapid acceleration from ~2000-present to >3 mm/yr, which is not observed at the Wellington tide gauge. This change indicated that modern ~1.7 mm/yr land subsidence rates recorded by global positioning systems from adjacent to Pāuatahanui salt marsh over the last 20 years is a recent feature, the onset of which is recorded in the salt marsh record. Had this not been the case, the rate of relative sea-level rise reconstructed at Pāuatahanui would have been much greater. At Aramoana, which lies at the mouth of Otago Harbour, relative sea level has risen by 2.18 ± 0.83 mm/yr since 1881, showing excellent agreement with the Dunedin tide gauge, with a specific ~60-year recurring trend of accelerations and decelerations replicated at both the salt marsh and the tide gauge. This trend is not observed at other southern South Island foraminiferal sea-level reconstructions, and appears to be due to the influence of Southern Annular Mode (SAM) variability, on the basis of comparisons between the rate of relative sea-level rise and SAM trends. The close agreement between the tide gauge (subsiding by only ~0.69 mm/yr) and the salt marsh (whose sea-level record indicates only very marginally more subsidence) suggests that the high degree of subsidence measured in the city centre is localised to the city, and the result of the compression of soft underlying sediments by large man-made structures. The Pāuatahanui and Aramoana sea-level reconstructions yield valuable insights into the processes that have driven relative sea-level change around Greater Wellington and Dunedin, which will assist in understanding how sea-level rise will affect these sites in the future. One key finding has been the revelation of spatial variability in land movement even on what was considered to be the local scale, to the extent that neither Aramoana truly reflects the scale of sea-level rise at the coast of Dunedin city, nor does Pāuatahanui at the coast of Wellington city. The two sea-level reconstructions from Auckland appear to be less reliable than those from elsewhere, but yield valuable insights into the influence of local processes including freshwater runoff triggered by catchment disturbance, species infaunality, and dissolution on foraminiferal sea-level reconstructions.</p>

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Long-lived shallow slow-slip events on the Sunda megathrust

Abstract: Long-lived shallow slow-slip events on the Sunda megathrust

Cited by 23 publications

References 73 publications

Tectonic Geomorphology and Seismic Hazard of the East Boundry Thrust in northern segment of the Sunda-Andaman subduction zone

Tectonic Geomorphology and Seismic Hazard of the East Boundry Thrust in northern segment of the Sunda-Andaman subduction zone

Fourteen‐Year Acceleration Along the Japan Trench

Foraminiferal Sea-Level Reconstructions From Major New Zealand Cities: Implications for Long-Term Vertical Land Movement Trends from Centennial Baselines

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