TThe 2012 August 27 Mw7.3 El Salvador earthquake: Expression of weak coupling on the Middle America subduction zone

Halldor Geirsson, Peter C. Lafemina, Charles Demets, Douglas Antonio Hernandez, Glen S. Mattioli, Robert Rogers, Manuel Rodriguez, Griselda Marroquin, Virginia Tenorio

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Subduction zones exhibit variable degrees of interseismic coupling as resolved by inversions of geodetic data and analyses of seismic energy release. The degree to which a plate boundary fault is coupled can have profound effects on its seismogenic behaviour. Here we use GPS measurements to estimate co- and post-seismic deformation from the 2012 August 27, Mw7.3 megathrust earthquake offshore El Salvador, which was a tsunami earthquake. Inversions of estimated coseismic displacements are in agreement with published seismically derived source models, which indicate shallow (<20 km depth) rupture of the plate interface. Measured post-seismic deformation in the first year following the earthquake exceeds the coseismic deformation. Our analysis indicates that the post-seismic deformation is dominated by afterslip, as opposed to viscous relaxation, and we estimate a post-seismic moment release one to eight times greater than the coseismic moment during the first 500 d, depending on the relative location of coseismic versus post-seismic slip on the plate interface. We suggest that the excessive post-seismic motion is characteristic for the El Salvador-Nicaragua segment of the Central American margin and may be a characteristic of margins hosting tsunami earthquakes.

Original languageEnglish (US)
Pages (from-to)1677-1689
Number of pages13
JournalGeophysical Journal International
Volume202
Issue number3
DOIs
StatePublished - Jul 2 2015

Fingerprint

El Salvador
subduction zone
Earthquakes
earthquakes
earthquake
Tsunamis
tsunami
margins
Nicaragua
inversions
moments
seismic energy
datum (elevation)
geodetic datum
seismic moment
estimates
plate boundary
Global positioning system
rupture
slip

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

Cite this

Geirsson, Halldor ; Lafemina, Peter C. ; Demets, Charles ; Hernandez, Douglas Antonio ; Mattioli, Glen S. ; Rogers, Robert ; Rodriguez, Manuel ; Marroquin, Griselda ; Tenorio, Virginia. / TThe 2012 August 27 Mw7.3 El Salvador earthquake : Expression of weak coupling on the Middle America subduction zone. In: Geophysical Journal International. 2015 ; Vol. 202, No. 3. pp. 1677-1689.
@article{d0e4040006b547fbb7dcb5518bf6ca79,
title = "TThe 2012 August 27 Mw7.3 El Salvador earthquake: Expression of weak coupling on the Middle America subduction zone",
abstract = "Subduction zones exhibit variable degrees of interseismic coupling as resolved by inversions of geodetic data and analyses of seismic energy release. The degree to which a plate boundary fault is coupled can have profound effects on its seismogenic behaviour. Here we use GPS measurements to estimate co- and post-seismic deformation from the 2012 August 27, Mw7.3 megathrust earthquake offshore El Salvador, which was a tsunami earthquake. Inversions of estimated coseismic displacements are in agreement with published seismically derived source models, which indicate shallow (<20 km depth) rupture of the plate interface. Measured post-seismic deformation in the first year following the earthquake exceeds the coseismic deformation. Our analysis indicates that the post-seismic deformation is dominated by afterslip, as opposed to viscous relaxation, and we estimate a post-seismic moment release one to eight times greater than the coseismic moment during the first 500 d, depending on the relative location of coseismic versus post-seismic slip on the plate interface. We suggest that the excessive post-seismic motion is characteristic for the El Salvador-Nicaragua segment of the Central American margin and may be a characteristic of margins hosting tsunami earthquakes.",
author = "Halldor Geirsson and Lafemina, {Peter C.} and Charles Demets and Hernandez, {Douglas Antonio} and Mattioli, {Glen S.} and Robert Rogers and Manuel Rodriguez and Griselda Marroquin and Virginia Tenorio",
year = "2015",
month = "7",
day = "2",
doi = "10.1093/gji/ggv244",
language = "English (US)",
volume = "202",
pages = "1677--1689",
journal = "Geophysical Journal International",
issn = "0956-540X",
publisher = "Wiley-Blackwell",
number = "3",

}

Geirsson, H, Lafemina, PC, Demets, C, Hernandez, DA, Mattioli, GS, Rogers, R, Rodriguez, M, Marroquin, G & Tenorio, V 2015, 'TThe 2012 August 27 Mw7.3 El Salvador earthquake: Expression of weak coupling on the Middle America subduction zone', Geophysical Journal International, vol. 202, no. 3, pp. 1677-1689. https://doi.org/10.1093/gji/ggv244

TThe 2012 August 27 Mw7.3 El Salvador earthquake : Expression of weak coupling on the Middle America subduction zone. / Geirsson, Halldor; Lafemina, Peter C.; Demets, Charles; Hernandez, Douglas Antonio; Mattioli, Glen S.; Rogers, Robert; Rodriguez, Manuel; Marroquin, Griselda; Tenorio, Virginia.

In: Geophysical Journal International, Vol. 202, No. 3, 02.07.2015, p. 1677-1689.

Research output: Contribution to journalArticle

TY - JOUR

T1 - TThe 2012 August 27 Mw7.3 El Salvador earthquake

T2 - Expression of weak coupling on the Middle America subduction zone

AU - Geirsson, Halldor

AU - Lafemina, Peter C.

AU - Demets, Charles

AU - Hernandez, Douglas Antonio

AU - Mattioli, Glen S.

AU - Rogers, Robert

AU - Rodriguez, Manuel

AU - Marroquin, Griselda

AU - Tenorio, Virginia

PY - 2015/7/2

Y1 - 2015/7/2

N2 - Subduction zones exhibit variable degrees of interseismic coupling as resolved by inversions of geodetic data and analyses of seismic energy release. The degree to which a plate boundary fault is coupled can have profound effects on its seismogenic behaviour. Here we use GPS measurements to estimate co- and post-seismic deformation from the 2012 August 27, Mw7.3 megathrust earthquake offshore El Salvador, which was a tsunami earthquake. Inversions of estimated coseismic displacements are in agreement with published seismically derived source models, which indicate shallow (<20 km depth) rupture of the plate interface. Measured post-seismic deformation in the first year following the earthquake exceeds the coseismic deformation. Our analysis indicates that the post-seismic deformation is dominated by afterslip, as opposed to viscous relaxation, and we estimate a post-seismic moment release one to eight times greater than the coseismic moment during the first 500 d, depending on the relative location of coseismic versus post-seismic slip on the plate interface. We suggest that the excessive post-seismic motion is characteristic for the El Salvador-Nicaragua segment of the Central American margin and may be a characteristic of margins hosting tsunami earthquakes.

AB - Subduction zones exhibit variable degrees of interseismic coupling as resolved by inversions of geodetic data and analyses of seismic energy release. The degree to which a plate boundary fault is coupled can have profound effects on its seismogenic behaviour. Here we use GPS measurements to estimate co- and post-seismic deformation from the 2012 August 27, Mw7.3 megathrust earthquake offshore El Salvador, which was a tsunami earthquake. Inversions of estimated coseismic displacements are in agreement with published seismically derived source models, which indicate shallow (<20 km depth) rupture of the plate interface. Measured post-seismic deformation in the first year following the earthquake exceeds the coseismic deformation. Our analysis indicates that the post-seismic deformation is dominated by afterslip, as opposed to viscous relaxation, and we estimate a post-seismic moment release one to eight times greater than the coseismic moment during the first 500 d, depending on the relative location of coseismic versus post-seismic slip on the plate interface. We suggest that the excessive post-seismic motion is characteristic for the El Salvador-Nicaragua segment of the Central American margin and may be a characteristic of margins hosting tsunami earthquakes.

UR - http://www.scopus.com/inward/record.url?scp=84940092786&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84940092786&partnerID=8YFLogxK

U2 - 10.1093/gji/ggv244

DO - 10.1093/gji/ggv244

M3 - Article

AN - SCOPUS:84940092786

VL - 202

SP - 1677

EP - 1689

JO - Geophysical Journal International

JF - Geophysical Journal International

SN - 0956-540X

IS - 3

ER -