Kinematic barrier constraints on the magnitudes of additional great earthquakes off the east coast of Japan

• Autores: John P. Loveless, Brendan J. Meade
• Localización: Seismological Research Letters, ISSN 0895-0695, ISSN-e 1938-2057, Vol. 86, Nº. 1, 2015, págs. 202-209
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • In the wake of the 2011 great Tohoku-Oki, Japan, earthquake, questions were asked about the extent to which this earthquake ruptured a part of the subduction zone that had been strongly coupled in the decades prior to the event (Avouac, 2011; Lay and Kanamori, 2011; Loveless and Meade, 2011). The primary means for investigating this question is the analysis of interseismic geodetic data. These data record both tectonic motions and the accumulation of elastic strain the upper crust. Combined with elastic dislocation and block models, Global Navigation Satellite System (GNSS) data from the GNSS Earth Observation Network System (GEONET) array had been used to estimate the spatial variation in interseismic coupling (defined as the fraction of relative motion between tectonic plates that contributes to elastic strain accumulation) along the Japan trench subduction interface prior to the occurrence of the 2011 event (Nishimura et al., 2004; Suwa et al., 2006; Hashimoto et al., 2009; Loveless and Meade, 2010). Each of these estimated interseismic coupling distributions identified a partially to strongly coupled region, extending for ~400??km between 36° and 40° north latitude along the Japan trench, approximately bounding the lateral and down-dip extents of the coseismic rupture (Loveless and Meade, 2011). However, none of these estimates show a perfect spatial correspondence between the coseismic rupture extent and complete preseismic coupling. Rather, the coseismic rupture was laterally bounded by regions of the Japan subduction zone with a coupling fraction c of ~0.3, in which 30% of the relative plate motion contributes to elastic strain accumulation during the interseismic regime (Loveless and Meade, 2011). This spatial relationship could result from insufficient elastic strain accumulation around portions of the interface characterized by...