Identify, among the known or still unknown faults, the one that probably generated the earthquake and understand the distribution of the movement (slip) along the plane of the fault itself. This is the objective of the INGV/IREA-CNR Working Group, (National Institute of Geophysics and Volcanology - INGV and the National Research Council - Institute for Electromagnetic Sensing of the Environment, CNR-IREA of Naples) which analyzed the satellite data for the study of seismic sources. Once the fault that generated the earthquake has been identified, geologists and seismologists compare the data of this modeling with the data obtained from field surveys and the faults already known in the literature in order to characterize the current movements and possibly also the seismic history of the fault itself. In addition to the geometry of the fault plane, it is important to simulate (and therefore hypothesize as realistically as possible) the movement of the fault itself by determining which portions of it were activated during the earthquake and by how much they moved. Starting from the displacement maps of the earth's surface, it is possible to model the seismic source of the earthquake, i.e. reproduce the displacement field measured by the satellite with a theoretical displacement field, by varying, from time to time, the parameters that characterize the seismic source (genetic seismic fault) until obtaining a theoretical seismic source whose displacement field on the surface is very similar to that observed from the satellite. This approach to modeling is called "data inversion", precisely because starting from the observed to identify and characterize the source of the strain. Geology teaches us that faults are not regular planes that cut the earth's crust, but rather articulated surfaces that also show great variations in their orientation in space and in their angle of inclination with respect to the vertical. However, in order to be able to solve a numerical problem in a short time (those of a seismic emergency), ie that of reproducing, with computer simulations, the displacement field produced by the movement of a fault, some simplifications must be introduced. In the models the faults are simplified as planes and the earth's crust as a perfectly elastic medium, leaving out geometric complications and inelastic behavior of the crust.
Earthquake in central Italy: seismic source modeling and stress transfer on neighboring faults
- Details