THE EFFECT OF INPLANE FORCE VARIATIONS ON A FAULTED ELASTIC THIN-PLATE, IMPLICATIONS FOR RIFTED SEDIMENTARY BASINS

Studies of flexural motions of lithosphere commonly apply a differenti al equation based on the thin-plate approach. In this approximation, t he flexural response to a changing horizontal inplane force depends on ly on the curvature of the midplane of the thin-plate representing the mechanical behaviour of the lithosphere. However, in cases where an a brupt change of the geometry of the lithosphere occurs the midplane of the thin-plate is offset. We demonstrate that the combination of the offset with an inplane horizontal force produces an additional, rheolo gy independent moment at the position of the geometry change. This eff ect has been overlooked by,previous studies of lithosphere deflections , and thin-plate problems in general. In the presented analysis, the t hin-plate with an abrupt change in plate geometry represents lithopshe re with a mechanically healed, inactive fault. However, the derived an alytical solutions are,general and can be used to study problems with similar abrupt geometry changes.