Seismic deformation in the Mediterranean area estimated by moment tensor summation

Abstract

Theoretical relationships allow the distributed deformation due to seismic activity to be quantified on the basis of the analysis of moment tensors. We apply this method to a data set consisting of seismic events that have occurred in the past 85 yr (1908–1992) along the most important seismogenic zones of the Mediterranean region. We use the Centroid Moment Tensor (CMT) Catalog prepared at Harvard University, covering the last 16 yr, and older data from Jackson & McKenzie (1988). We determine the seismic deformation and compare it to estimates of the overall deformation as obtained from global plate motion and geological studies. We generally find that the geometry of seismic deformation is similar to tectonic predictions. Even though spanning a shorter time interval, the CMT Catalog often gives a better estimate of deformation geometry than the whole data set (85 yr). Seismic deformation generally ranges from less than 10 per cent to more than 90 per cent of the total deformation. Uncertainties arise because data sets may not be representative of the long‐term seismic behaviour of each zone. More reliable estimates for comparison with geodynamic processes should result from analysis of a longer time period, for which no instrumental data are available. The similarity of the deformation geometry using CMT data with tectonic expectations suggests, for several zones, the possibility of using historical data to infer longer term deformation rates based on current deformation geometry. Copyright © 1995, Wiley Blackwell. All rights reserved