Oceanic plate subduction and continental extrusion in Sumatra: Insight from S-wave anisotropic tomography

Wang, Xiao; Liu, Xin; Zhao, Dapeng; Liu, Bo; Qiao, Qingyu; Zhao, Long

doi:10.1016/j.epsl.2022.117388

Cited by 8 publications

(11 citation statements)

References 45 publications

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“…The difference in the direction and size of horizontal and vertical deformation during the preseismic phase was observed from DoY 002 to DoY 032 for Mentawai earthquake and from DoY 002 to DoY 058 for South Solok earthquake (Figure 4). In the preseismic phase of Mentawai earthquake, most observation station moved towards the northeast, consistent with the direction of the subduction of the Indo-Australian Plate against the Eurasian Plate ( Wang et al, 2022), with the greatest concentration of energy accumulation is seen on the island of North Pagai. The SLBU and SMGY stations located in North Pagai have the largest velocity of 4.97 mm/month with a movement direction of N29.40E for SLBU stations and 4.69 mm/month with a movement direction of N22.85E for SMGY stations.…”

Section: Comparative Analysis Of the Deformation Of The Mentawai Eart...supporting

confidence: 58%

Comparison of Deformation Vectors Due to Earthquake in Subduction Zone and Sumatran Fault for Each Phase of Earthquake Cycle

Monica

Friska²,

Arisa³

et al. 2022

JIF

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This study compares the deformation in West Sumatra due to the earthquakes in the subduction zone and the Sumatran Fault. The Mw6.0 Mentawai earthquake 2019 with a thrust fault mechanism and the Mw5.4 South Solok earthquake 2019 with a strike-slip fault mechanism were used as case studies for the subduction zone and Sumatran Fault, respectively. The deformation was observed using 12 SuGAr (Sumatra GPS Array) and 8 InaCORS (Indonesian Continuously Operating Reference Station) stations, which were processed using GAMIT/GLOBK software. There are differences in the deformation vectors of the two earthquakes. The Mentawai earthquake experienced larger energy accumulation than the South Solok earthquake. The coseismic phase of the Mentawai earthquake experienced the largest horizontal shift at the SLBU station, which was 15.48 mm in the direction of S29.96W, while the South Solok earthquake is found to horizontally shift the CSDH station at the size of 5.75 mm towards S11.45E. The postseismic phase of the Mentawai earthquake lasted 60 days, longer than the South Solok earthquake (20 days). The difference in deformation characteristic between these two earthquakes found in this study will be valuable information in modeling earthquakes in Sumatra.

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Section: Comparative Analysis Of the Deformation Of The Mentawai Eart...supporting

confidence: 58%

Comparison of Deformation Vectors Due to Earthquake in Subduction Zone and Sumatran Fault for Each Phase of Earthquake Cycle

Monica

Friska²,

Arisa³

et al. 2022

JIF

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“…Hence, the minimum size of the structures we focused on is ∼33 km horizontally and vertically. As compared with the lateral resolution of the previous Vp models in this region (1.2° in Liu et al., 2021 and 0.5° for anisotropic results in Wang, Liu, et al., 2022), our model has a higher spatial resolution reaching 0.3°.…”

Section: Methodssupporting

confidence: 47%

“…However, their results have poor depth resolution in the mantle. Surface‐wave anisotropic tomography shows that the fast‐velocity direction beneath the Toba caldera is trench‐normal, and subslab hot material may penetrate through the subducted slab in a narrow channel beneath the vicinity of Toba (Wang, Liu, et al., 2022). Because the fast‐velocity direction is approximately parallel to the mantle flow in the upper mantle (Zhang & Karato, 1995), the fast orientations suggest that the subslab mantle material ascends to the mantle wedge through the slab window ( L4 anomaly in Figures 10a, 10b, and 11).…”

Section: Resultsmentioning

confidence: 99%

“…Previous tomographic studies in this region have unveiled the main features of the crust and upper mantle (e.g., Hall & Spakman, 2015;Liu et al, 2021;Toyokuni et al, 2022;Wang, Liu, et al, 2022). However, their low resolution prevented adequate imaging of the detailed structures.…”

Section: Tomographic Images and Tectonic Implicationsmentioning

confidence: 99%

“…However, their station coverage was still too sparse to capture the fine details of slab tearing beneath the Toba caldera. A recent surface‐wave tomographic study revealed trench‐normal seismic anisotropy beneath Sumatra (Wang, Liu, et al., 2022). Note that surface waves have a relatively high vertical resolution but lower lateral resolution compared to body‐wave tomography (e.g., Zhao, 2015).…”

Section: Introductionmentioning

confidence: 99%

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A Slab Window Beneath North Sumatra Revealed by P‐Wave Mantle Tomography

Zhao

Lin

et al. 2023

JGR Solid Earth

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Passive seismic studies have suggested that slab tearing occurs beneath North Sumatra, albeit the slab morphology is somewhat poorly constrained. The lack of resolution on the slab means that the presence of a tear has not been validated, and that the main factors responsible for slab tearing are hard to discern. We use a large seismic data set to determine a new 3‐D high‐resolution tomographic model of the crust and upper mantle beneath North Sumatra, which reveals a well‐defined low‐velocity channel that cuts across the subducting slab through a cavity. This feature cannot be reconciled with a tear in the slab, as previously suggested. Our relocated earthquakes exhibit a protruding cluster of seismicity along the subducted Investigator Fracture Zone, indicating that the high reliefs of the Investigator Fracture Zone possibly enhance the coupling between the subducted slab and the overriding plate. Shear stress resulting from the differential coupling in the slab may have created an area of mechanical weakness in correspondence of the fossil‐spreading ridges, which eventually led to the formation of a slab window. This window allows the exchange of mantle material from the subslab region up to the Toba volcano. We propose that the previously damaged parts (e.g., fracture zones and spreading centers) of the oceanic plate could help promote the growth of a slab window.

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GPS velocities and uniform slip rates across Siulak and Dikit segments: implication to segmentation and seismic moment deficits along Sumatran fault system

Lubis,

Natasya,

Handayani

et al. 2024

Acta Geophys.

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Oceanic plate subduction and continental extrusion in Sumatra: Insight from S-wave anisotropic tomography

Cited by 8 publications

References 45 publications

Comparison of Deformation Vectors Due to Earthquake in Subduction Zone and Sumatran Fault for Each Phase of Earthquake Cycle

Comparison of Deformation Vectors Due to Earthquake in Subduction Zone and Sumatran Fault for Each Phase of Earthquake Cycle

A Slab Window Beneath North Sumatra Revealed by P‐Wave Mantle Tomography

GPS velocities and uniform slip rates across Siulak and Dikit segments: implication to segmentation and seismic moment deficits along Sumatran fault system

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