Strain rate analysis over the Central Apennines from GPS velocities: the development of a new free software

Abstract

Displacements or velocities obtained by GPS data processing over repeated surveys can provide useful information on tensional states of terrestrial crust, in those areas in which many stations well spatially distributed are present. In particular, the strain (or strain rate) can be computed over the nodes of a regular grid with suitable size to define a high density deformation field. A new method was deployed to generate easily and quickly the deformation pattern from GPS velocities and to evaluate the significance: values, related to an assigned grid point, can be truly considered only if the GPS stations are well distributed around it. The approach validation was performed by means of synthetic data derived from the theoretical displacement field generated by a Mogi model source. A complete analysis on the velocity pattern of the CaGeoNet network (Central Apennine chain, Italy) was performed providing strain rates and showing both extensional and compressive behaviour at the same values, along the Apennine chain axis.