Small‐scale gravity modeling of upper crustal structures in the Araba Valley along the Dead Sea Transform

Abstract

A detailed three‐dimensional (3‐D) gravity model of upper crustal structures was created for the Dead Sea Transform in the Araba/Arava Valley, located some 80 km south of the Dead Sea Basin. The density model covers an area of ∼30 × 30 km and incorporates results from several recent geophysical experiments performed in this region. The model presented is a local density model that focuses on the uppermost crustal layers to a depth of ∼5 km. Therefore, in order to separate the effect of regional structures (such as the crust‐mantle boundary) from that of local structures within the crust, a residual anomaly was computed from a newly compiled Bouguer gravity anomaly database. In contrast to the Bouguer anomaly, which is negative across the entire study area, the residual gravity field contains both positive and negative values. The 3‐D structural image of the upper crust reveals that the basement east and west of the Dead Sea Transform is vertically offset by 1.5 to 2.8 km. Considering the 105 km of sinistral displacement of the Dead Sea Transform, this result confirms the findings of other geophysical measurements that show an abrupt change in the physical parameters and geometry of the two lithological blocks that are juxtaposed along the Dead Sea Transform. Additionally, analysis of the calculated gravity gradients suggests that the Dead Sea Transform and the neighboring Zofar fault could be offset at depth with respect to the present‐day traces at the surface.