Earth Planets Space, Vol. 56 (No. 5), pp. e5-e8, 2004E-LETTER
Takeshi Kudo1, Akihiko Yamamoto2, Tsuyoshi Nohara1, Hirohisa Kinoshita1, and Ryuichi Shichi3
1Tono Geoscience Center, Japan Nuclear Cycle Development Institute, Japan
2Graduate School of Science, Hokkaido University, Japan
3College of Engineering, Chubu University, Japan
(Received February 17, 2004; Revised May 8, 2004; Accepted May 14, 2004)
Tectonic movement may disturb lateral continuities of crustal structures at weak zones. These lateral disconti-nuities 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.
Key words: Gravity anomaly, roughness, standard deviation, lineament, Chugoku District, active fault.