Lateral change of in-plate stress and outer-rise seismicity along the
southern Mariana trench
Abstract
We modeled the bending deformation of the subducting plate at the
southern Mariana using a 3-D elastic plate flexural model. Intraplate
stresses were investigated, with the along-strike variable boundary
loadings. In order to match the observed plate geometry, boundary
vertical loading near the Challenger Deep had to be set twice of that in
the region further east within our study area. By comparing results
between 2-D and 3-D models, we found that the difference on estimating
plate stress can exceed 20% when there is an along-strike variation in
plate bending. Finally, we found that the sharp lateral variation in the
σ and the σ corresponded to an outer-rise earthquake cluster at the
southern Mariana subduction zone, indicating that along-strike variation
in σ and σ may be a significant mechanism to cause non-uniform
distribution of outer-rise earthquakes.