Seismic reflection and topography insights into Ries crater diameter and megablock zone

Abstract Most of the extensive crater‐wide geophysical studies at the Ries impact structure were made decades ago when the origin of the structure was still being debated. Although it is one of the most studied impact structures, its internal structure was not imaged in high resolution until recently. In 2017, we acquired four reflection seismic profiles with a total length of 22.1 km that cover the central basin with the goal of imaging a potential buried collapsed central uplift, crystalline ring, megablock zone, and the southern Vorries region outside the crater rim. These reflection seismic profiles inside the crater generally agree with the previous interpretations. However, the size of the crater needs reconsideration. The crater is evident as a topographically low and flat crater area (basin floor) with a diameter of 22 km whose outline becomes obvious when using the Terrain Ruggedness Index. The seismic profiles provide insight that the current expression of the crater basin is related to the extent of the large‐offset normal faults in the subsurface that created space for the Bunte Breccia and postimpact sediments that are more uniformly erodible resulting in flat terrain. Our results suggest that the topographic and subsurface crater morphology is formed based on target strength structure.