Role of poroelasticity during the early postseismic deformation of the 2010 Maule megathrust earthquake

Peña, Carlos; Metzger, Sabrina; Heidbach, Oliver; Bedford, Jonathan; Bookhagen, Bodo; Moreno, Marcos; Oncken, Onno; Cotton, Fabrice

doi:10.1002/essoar.10510987.1

Cited by 2 publications

(1 citation statement)

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“…The effects of fault relocking are not included in our models considering its minor role in early postseismic deformation. Poroelastic effects may be important at the time scale of several days to months in the main rupture area (e.g., Mcormack et al., 2020; Peña et al., 2022), but in general are overshadowed by the effect of VER and afterslip for the focus time scale of this study (a few years). We first use two‐dimensional (2‐D) synthetic models to illustrate the general physical mechanism with an emphasis on clarifying and thus simplifying conceptualization.…”

Section: Introductionmentioning

confidence: 74%

Finding Simplicity in the Complexity of Postseismic Coastal Uplift and Subsidence Following Great Subduction Earthquakes

Luo

Wang

2022

JGR Solid Earth

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Following great subduction earthquakes, postseismic deformation of coastal areas shows consistent seaward motion but complex vertical deformation. Understanding both the horizontal and vertical components in the same geodynamic framework presents challenges. Here, by modeling short‐term (a few years) postseismic viscoelastic relaxation (VER) and afterslip following synthetic and real subduction earthquakes, we demonstrate that the complexity of the vertical deformation can be explained in simple terms. Along a margin‐normal profile, VER results in an up‐down‐up trisegment, long‐wavelength pattern common to most megathrust earthquakes, including near‐trench uplift, midway subsidence, and near‐arc uplift, with locations controlled by coseismic fault slip. The magnitude of the first two segments is controlled mainly by oceanic mantle viscosity, and the third by mantle wedge viscosity. In contrast with VER, afterslip results in an up‐down bimodal pattern of variable wavelengths specific to individual earthquakes. Its site‐specific and heterogeneous nature is primarily responsible for the complexity in vertical deformation, but its effect can be adequately modeled using a simple elastic model. If the coast is near the megathrust rupture zone, variable combinations of the VER and afterslip effects lead to either uplift or subsidence. If the coast is in the near‐arc segment of VER deformation, uplift usually occurs. Modeling the common VER process enables the identification of site‐specific afterslip, which helps to understand the mechanism of afterslip in the context of the broad spectrum of fault slip behavior. Our results also have important implications to deciphering coastal paleoseismic records to constrain coseismic versus postseismic deformation of ancient earthquakes.

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Section: Introductionmentioning

confidence: 74%