Deep embrittlement and complete rupture of the lithosphere during the Mw 8.2 Tehuantepec earthquake

Melgar, Diego; Ruiz‐Angulo, Angel; Garcia, E. S. M.; Manea, Marina; Manea, Vlad Constantin; Xu, Xiaohua; Ramírez‐Herrera, María Teresa; Zavala‐Hidalgo, Jorge; Geng, Jianghui; Corona, Néstor; Pérez‐Campos, Xyoli; Cabral‐Cano, E.; Ramirez-Guzmán, L.

doi:10.1038/s41561-018-0229-y

Cited by 51 publications

(33 citation statements)

References 33 publications

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“…Additionally, the choice of hypocenter can have a minor effect on the slip model inversion, but it does not change the main rupture features in the resulting slip models including the depth where the majority of slip occurs. This is supported by the comparison of our preferred model and another one at the hypocenter used by Melgar et al () as shown in Figure S9. Both slip models have a large asperity over depths of 10–70 km.…”

Section: Ffmsupporting

confidence: 83%

Evidence for Rupture Through a Double Benioff Zone During the 2017M_w8.2 Chiapas, Mexico Earthquake

Zhang

Brudzinski

2019

Geophysical Research Letters

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We combine multi‐array relative back‐projection of high‐frequency P waves and finite‐fault modeling of low‐frequency P waves from the 8 September 2017 Mw 8.2 Chiapas, Mexico earthquake to image unilateral rupture on a southeast‐northwest striking subvertical fault plane over depths of 10–70 km. Improved multi‐array relative back‐projection estimates of rupture speed and fault geometry provide key refinements to the slip model from finite‐fault modeling. Compilation of prior seismicity and aftershocks reveals the earthquake initiated in the lower plane of a double Benioff zone (DBZ) and ruptured with large slip across the entire DBZ. The previously aseismic interior does not appear to be due to lack of stress as both planes show downdip extension stresses. Instead, tomographic imaging of DBZs find high Poisson's ratio with fast velocities in the DBZ interior, so we propose that highly hydrated harzburgite generates velocity‐strengthening behavior that inhibits earthquake nucleation, yet it can slip seismically during dynamic weakening from a large throughgoing rupture.

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Section: Ffmsupporting

confidence: 83%

Evidence for Rupture Through a Double Benioff Zone During the 2017M_w8.2 Chiapas, Mexico Earthquake

Zhang

Brudzinski

2019

Geophysical Research Letters

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“…However, the aftershocks are mostly shallower than the slip zone, which precludes using the patterns to constrain the slip distribution, as apparent in Figure c. Aftershock patterns for intraplate ruptures are often complex and indicate activation of activity on faults other than the main rupture plane (e.g., Melgar et al, ; Ye et al, , ). The aftershock distribution coincides with the strong curvature of the upper slab interface in Slab2, along the intraplate transition from Pacific to Yakutat slab (Figure a; Kim et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…While it appears that relatively little structural damage occurred in the 2018 event (other than due to sediment slumping) in comparison to other near‐urban earthquakes like the 1989 Loma Prieta, 1994 Northridge, and 1995 Kobe events, likely as a result of improved building codes adopted after the 1964 earthquake, this type of event is very difficult to plan for, as deformation rates within subducting slabs are much harder to constrain or monitor than deformation on plate boundaries. Other major intraplate earthquakes of this type have occurred in Chile (e.g., Delouis & Legrand, ), Taiwan (e.g., Kanamori et al, ), Sumatra (e.g., Wiseman et al, ), the Philippines (e.g., Ye et al, ), the western Aleutians (e.g., Ye et al, ), Mexico (e.g., Melgar et al, ; Ye et al, ), and in 1949, 1965, and 2001 under Washington State (e.g., Bustin et al, ). When located below populated areas, such events can be very damaging.…”

Section: Introductionmentioning

confidence: 99%

Intraslab Deformation in the 30 November 2018 Anchorage, Alaska, M_W 7.1 Earthquake

Liu

Lay

Xie

et al. 2019

Geophysical Research Letters

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Anchorage, Alaska, was strongly shaken on 30 November 2018 by an MW 7.1 earthquake that ruptured within the underthrust Pacific plate at depths of from 45 to 65 km. Ground failures occurred in saturated lowlands filled with sediments, producing notable road damage, but there was limited structural damage in Anchorage, only ~12 km south of the epicenter. The earthquake has a normal faulting geometry with a shallowly dipping east‐west tension axis indicating intraslab deformation, likely between the underthrust Yakutat terrane and adjacent Pacific seafloor. Separate and joint inversions of teleseismic P and SH waves, regional strong ground motions, and GPS static displacements provide a weak preference for a westward steeply dipping rupture plane with up to 2 m of slip distributed over a single slip patch with dimensions of 20 × 20 km. The ~12 s long rupture expanded northward. Aftershocks occur at shallower depths than the mainshock slip zone.

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“…The last SSE of the region, which began in May 2017 and ended in June 2018, occurred during the period of intense seismic activity in the region. In September 2017, two large intraslab earthquakes take place, in Chiapas area (Mw 8.1, 07 September 2017) and in Puebla state (Mw 7.2, 19 September 2017) (Figure a) (Melgar, Pérez‐Campos, et al, ; Melgar, Ruiz‐Angulo, et al, ; Mirwald et al, ; Segou & Parsons, ; Suárez et al, ). In February 2018, an interface thrust earthquake occurred in Oaxaca state (Pinotepa earthquake, Mw 7.1, 16 February 2018).…”

Section: Context Of the Study Of Sses In The Mexican Subduction Zone mentioning

confidence: 99%

Independent Component Analysis and Parametric Approach for Source Separation in InSAR Time Series at Regional Scale: Application to the 2017–2018 Slow Slip Event in Guerrero (Mexico)

et al. 2020

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Separating different sources of signal in Interferometric Synthetic Aperture Radar (InSAR) studies over large areas is challenging, especially between the long‐wavelength changes of atmospheric conditions and tectonic deformations, both correlated to elevation. In this study, we focus on the 2017–2018 slow slip event (SSE) in the Guerrero state (Mexico) where (1) the permanent GPS network has a low spatial density (less than 30 stations in an area of 300 × 300 km) with uneven distribution; (2) the tropospheric phase delays can be as high as 20 cm of apparent ground displacements, with a complex temporal evolution; (3) the tested global weather models fail to correct interferograms with enough accuracy (with residual tropospheric signal higher than the tectonic signal); and (4) the surface displacement caused by the seismic cycle shows complex interactions between seismic sequences and aseismic events. To extract the SSE signal from Sentinel‐1 InSAR time series, we test two different approaches. The first (parametric method) consists of a least squares linear inversion, imposing a functional form for each deformation or atmospheric component. The second uses independent component analysis of the InSAR time series. We obtain time series maps of surface displacements along the radar line of sight associated with the SSE and validate these results with a comparison to GPS. Combining those two approaches, we propose a method to separate atmospheric delays and tectonic deformation on time series data not corrected from atmospheric delays. From the extracted ground deformation maps, we propose a first‐order slip inversion model at the subduction interface during this SSE.

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Deep embrittlement and complete rupture of the lithosphere during the Mw 8.2 Tehuantepec earthquake

Cited by 51 publications

References 33 publications

Evidence for Rupture Through a Double Benioff Zone During the 2017M_w8.2 Chiapas, Mexico Earthquake

Evidence for Rupture Through a Double Benioff Zone During the 2017M_w8.2 Chiapas, Mexico Earthquake

Intraslab Deformation in the 30 November 2018 Anchorage, Alaska, M_W 7.1 Earthquake

Independent Component Analysis and Parametric Approach for Source Separation in InSAR Time Series at Regional Scale: Application to the 2017–2018 Slow Slip Event in Guerrero (Mexico)

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Deep embrittlement and complete rupture of the lithosphere during the Mw 8.2 Tehuantepec earthquake

Cited by 51 publications

References 33 publications

Evidence for Rupture Through a Double Benioff Zone During the 2017Mw8.2 Chiapas, Mexico Earthquake

Evidence for Rupture Through a Double Benioff Zone During the 2017Mw8.2 Chiapas, Mexico Earthquake

Intraslab Deformation in the 30 November 2018 Anchorage, Alaska, MW 7.1 Earthquake

Independent Component Analysis and Parametric Approach for Source Separation in InSAR Time Series at Regional Scale: Application to the 2017–2018 Slow Slip Event in Guerrero (Mexico)

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Evidence for Rupture Through a Double Benioff Zone During the 2017M_w8.2 Chiapas, Mexico Earthquake

Evidence for Rupture Through a Double Benioff Zone During the 2017M_w8.2 Chiapas, Mexico Earthquake

Intraslab Deformation in the 30 November 2018 Anchorage, Alaska, M_W 7.1 Earthquake