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

Kudo, Takeshi; Yamamoto, Akihiko*; Nohara, Tsuyoshi   ; Kinoshita, Hirohisa; Shichi, Ryuichi*

We investigate whether distributions of topographic lineaments in Chugoku district, Japan, may be related to variations of standard deviation (SD) of gravity anomalies. Tectonic movement may disturb lateral continuities of crustal structures at weak zones. These lateral discontinuities of the density structure cause undulations of gravity anomaly fields whose complexities can be an indicator of the past crustal instability. On the other hand, topographic lineaments are formed along weak crustal zones. We would expect therefore that the gravity anomaly complexities have some relations to distributions of surface lineaments. As an index of gravity anomaly complexities in terms of which we interpret spatial distribution of topographic lineaments, we employ Bouguer anomaly SD inside a circular region with adequate radius. The results show that locations of the lineaments, which could be diagnostic of heterogeneity of the previously damaged crust, tend to coincide with those of high SD area