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TitreEffects of frictional behavior and geometry of subduction fault on coseismic seafloor deformation
AuteurWang, K; He, J
SourceBulletin of the Seismological Society of America vol. 98, no. 2, 2008 p. 571-579, https://doi.org/10.1785/0120070097
Année2008
Séries alt.Secteur des sciences de la Terre, Contribution externe 20070124
ÉditeurSeismological Society of America (SSA)
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1785/0120070097
Mediapapier; en ligne; numérique
Formatspdf
Sujetscadre tectonique; interprétations tectoniques; subduction; zones de subduction; caractéristiques structurales; failles; failles, effrondrement; déformation; topographie du fond océanique; sismicité; vitesse des ondes sismiques; soulèvement différentiel; croûte océanique; lithosphère océanique; méthode d'analyses par elements finis; établissement de modèles; géologie marine; tectonique
Illustrationsgraphs; plots
Résumé(disponible en anglais seulement)
The seismogenic zone of subduction faults appears to have an updip limit, seaward of which the fault exhibits velocity-strengthening behavior. We use a two-dimensional finite element model including a frictional subduction fault to ex-plore how coseismic strengthening of the updip segment affects seafloor deformation. For a stress drop of a few MPa along the seismogenic zone, strengthening of the updip segment by a comparable amount can prevent the rupture from breaking the trench. The resultant seafloor uplift is much larger than that predicted by a model of equal seismic moment or maximum fault slip in which the seismogenic zone extends to the trench. With a curved-fault geometry, although a lower degree of coseismic strength-ening of the updip segment leads to greater slip in the shallowest part of the fault, it produces smaller seafloor uplift, contrary to a popular belief. Given the paucity of direct observations of the coseismic behavior of the updip segment, the models yield important information for understanding rupture mechanics of subduction faults and tsunami generation. We also illustrate how the results may be used to guide fault slip parameterization in analytical dislocation models.
GEOSCAN ID224001