Details
| Original language | English |
|---|---|
| Pages (from-to) | 593-618 |
| Number of pages | 26 |
| Journal | SOLID EARTH |
| Volume | 16 |
| Issue number | 7 |
| Publication status | Published - 2 Jul 2025 |
Abstract
Aftershocks of megathrust earthquakes at subduction zones may be driven by stresses arising from the topography of the forearc. However, the effect of topographic stresses on aftershock triggering is quantitatively not well understood and has been neglected in Coulomb failure stress models that assess whether the stress change caused by an earthquake promotes or inhibits failure on nearby faults. Here we use analytical and numerical models to examine the importance of topographic stresses on Coulomb failure stress changes caused by megathrust earthquakes. We show that topographic stresses are a prerequisite for widespread aftershock seismicity in the forearc and that their superposition with tectonic stresses leads to a dependence of the forearc stability on the stress state before and after the earthquake. The dependence can be taken into account by determining the Coulomb failure stress change between optimal failure planes before and after the earthquake, which requires constraining the total stresses in the forearc. Applying our modelling approach to the 2011 Mw 9.0 Tohoku-Oki and 2010 Mw 8.8 Maule megathrust earthquakes yields coseismic Coulomb failure stress changes of up to ∼ 40 MPa, which promoted the majority of aftershocks in the Japanese and Chilean forearcs. The model results further reveal that the spatial distribution of aftershocks was not only influenced by the megathrust stress drop and the proximity of faults to failure but also by local differences in forearc topography and pre-earthquake stress state. Our analysis highlights the significance of total stresses in Coulomb failure stress calculations, enabling a better estimation of seismic hazard at subduction zones.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geophysics
- Agricultural and Biological Sciences(all)
- Soil Science
- Earth and Planetary Sciences(all)
- Geology
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
- Earth and Planetary Sciences(all)
- Earth-Surface Processes
- Earth and Planetary Sciences(all)
- Stratigraphy
- Earth and Planetary Sciences(all)
- Palaeontology
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: SOLID EARTH, Vol. 16, No. 7, 02.07.2025, p. 593-618.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Importance of forearc topography for the triggering of aftershocks of megathrust earthquakes
T2 - insights from mechanical models and the Tohoku-Oki and Maule earthquakes
AU - Dielforder, Armin
AU - Bocchini, Gian Maria
AU - Hampel, Andrea
N1 - Publisher Copyright: © Author(s) 2025. This work is distributed under the Creative Commons Attribution 4.0 License.
PY - 2025/7/2
Y1 - 2025/7/2
N2 - Aftershocks of megathrust earthquakes at subduction zones may be driven by stresses arising from the topography of the forearc. However, the effect of topographic stresses on aftershock triggering is quantitatively not well understood and has been neglected in Coulomb failure stress models that assess whether the stress change caused by an earthquake promotes or inhibits failure on nearby faults. Here we use analytical and numerical models to examine the importance of topographic stresses on Coulomb failure stress changes caused by megathrust earthquakes. We show that topographic stresses are a prerequisite for widespread aftershock seismicity in the forearc and that their superposition with tectonic stresses leads to a dependence of the forearc stability on the stress state before and after the earthquake. The dependence can be taken into account by determining the Coulomb failure stress change between optimal failure planes before and after the earthquake, which requires constraining the total stresses in the forearc. Applying our modelling approach to the 2011 Mw 9.0 Tohoku-Oki and 2010 Mw 8.8 Maule megathrust earthquakes yields coseismic Coulomb failure stress changes of up to ∼ 40 MPa, which promoted the majority of aftershocks in the Japanese and Chilean forearcs. The model results further reveal that the spatial distribution of aftershocks was not only influenced by the megathrust stress drop and the proximity of faults to failure but also by local differences in forearc topography and pre-earthquake stress state. Our analysis highlights the significance of total stresses in Coulomb failure stress calculations, enabling a better estimation of seismic hazard at subduction zones.
AB - Aftershocks of megathrust earthquakes at subduction zones may be driven by stresses arising from the topography of the forearc. However, the effect of topographic stresses on aftershock triggering is quantitatively not well understood and has been neglected in Coulomb failure stress models that assess whether the stress change caused by an earthquake promotes or inhibits failure on nearby faults. Here we use analytical and numerical models to examine the importance of topographic stresses on Coulomb failure stress changes caused by megathrust earthquakes. We show that topographic stresses are a prerequisite for widespread aftershock seismicity in the forearc and that their superposition with tectonic stresses leads to a dependence of the forearc stability on the stress state before and after the earthquake. The dependence can be taken into account by determining the Coulomb failure stress change between optimal failure planes before and after the earthquake, which requires constraining the total stresses in the forearc. Applying our modelling approach to the 2011 Mw 9.0 Tohoku-Oki and 2010 Mw 8.8 Maule megathrust earthquakes yields coseismic Coulomb failure stress changes of up to ∼ 40 MPa, which promoted the majority of aftershocks in the Japanese and Chilean forearcs. The model results further reveal that the spatial distribution of aftershocks was not only influenced by the megathrust stress drop and the proximity of faults to failure but also by local differences in forearc topography and pre-earthquake stress state. Our analysis highlights the significance of total stresses in Coulomb failure stress calculations, enabling a better estimation of seismic hazard at subduction zones.
UR - http://www.scopus.com/inward/record.url?scp=105022478332&partnerID=8YFLogxK
U2 - 10.5194/se-16-593-2025
DO - 10.5194/se-16-593-2025
M3 - Article
AN - SCOPUS:105022478332
VL - 16
SP - 593
EP - 618
JO - SOLID EARTH
JF - SOLID EARTH
SN - 1869-9510
IS - 7
ER -