Variations of gravity anomaly roughness in Chugoku district, Japan: Relationship with distributions of topographic lineaments

Abstract

Tectonic movement may disturb lateral continuities of crustal structures at weak zones. These lateral discontinuities of density structure cause undulations of the gravity anomaly field whose complexity can be an indicator of past crustal instability. On the other hand, topographic lineaments are formed along weak crustal zones. We would expect therefore that gravity anomaly roughness bears some relation to the distribution of surface lineaments. We develop a statistical method by employing the Bouguer anomaly standard deviation as an index of gravity anomaly roughness in terms of which we interpret the spatial distribution of topographic lineaments in Chugoku district, Japan. Locations of the lineaments, which could be diagnostic of the heterogeneity of the previously damaged crust, tend to coincide with those of high roughness areas of gravity anomaly fields.