A NOTE ON THE RELATIONSHIP BETWEEN DIP-SLIP FAULT PARAMETERS AND PLATE PARAMETERS IN THE 2-DIMENSIONAL MODELING OF PRESEISMIC DEFORMATION

Preseismic lithospheric deformation at a subduction zone can be modell ed as dip-slip dislocation on an inclined fault or as flexure of a thi n plate. Both these models predict a region of positive topography kno wn as forebulge or outer rise. By matching the location and the magnit ude of the forebulge, we derive useful relations between the dip-slip fault parameters and the plate parameters. In particular, we determine the width of a long dip-slip fault of given dip corresponding to a se mi-infinite plate of given thickness. The displacement profiles of the two models are also compared.