Silverpit: the Morphology of a Terrestrial Multi-ringed Impact Structure

Introduction: The Silverpit impact structure was discovered during 2001 on three-dimensional (3D) seismic data obtained during routine hydrocarbon exploration in the southern North Sea [1]. It is now known that five commercially-acquired 3D seismic datasets partially cover the structure and approximately 80% of Silverpit is imaged by high-resolution 3D data (Figure 1). Two boreholes had been drilled through the structure during the 1990’s. The results of detailed analysis of cutting samples are not yet available to confirm the impact origin of Silverpit. However, the morphology of the central crater-form strongly suggests a complex impact crater [2]. Unusually for terrestrial craters, Silverpit is surrounded by up to ten concentric deformation rings, extending to 10 Km from the crater centre. These rings are closely spaced in relation to the total diameter of the structure, resembling Valhalla-type craters seen on icy satellites such as Callisto and Europa [3].