Similarity of Gravity Anomaly Patterns in Asymmetric Active Regions

Abstract

THE currently favoured explanation for the asymmetric active regions¹ involves the downthrusting of the lithosphere into the mantle at the edges of continental margins as the result of the differential movement of lithospheric blocks². The parameter used to describe this differential movement is the slip rate². This is, of course, an inferred quantity, but it has been shown empirically¹ that the inferred slip rate is proportional to another parameter of the asymmetric active regions, the length of the Benioff zone. Fig. 1 examines the relationship of the gravity anomalies to other parameters of the asymmetric active regions, particularly slip rate as indicated by the length of the Benioff zone. It shows gravity anomalies over seven regions of varying length of Benioff zone and the profiles are stacked above a common zero anomaly point.