抄録
The mechanical behavior of a plate entering a trench has been investigated through comparison between the amount of faulting present in the outer trench wall and the maximum bending stress, as inferred from fitting bathymetry data seaward of the trench axis to the theoretical deflection curve for the bending of an elastic plate. Out of 20 circum-Pacific trench profiles examined, 16 satisfy a quantitative test for elastic behavior seaward of the trench axis and exhibit a consistent relationship between maximum inferred bending stress and the roughness of topography on the outer trench wall. This result, in conjunction with the distribution of earthquake focal mechanisms within the subducting plate, is consistent with a model of an 80km thick lithospheric plate having an elastic core approximately 30km thick, outside of which brittle failure occurs.
