# Task 4 - Seismic source estimates and associated effects

### Objectives

This task involves only research and it is driven toward future improvements of the shakemaps. In particular attention is put toward a more realistic definition of the finite source for earthquakes larger than M5.5, and to the determination of 3D Green's functions on the regional scale and to local 1D Green’s functions locally. To the purpose of providing more realistic shakemaps, we aim at integrating the ground motion parameters of interest retrieved from real data with the results inferred from synthetic seismograms. This approach should allow for the computation of shakemaps that take explicitly into account the finite fault effects (e.g., source geometry, directivity, radiation pattern, etc.) on the ground motion estimation that, in general, are not captured by empirical predictive equations.

The starting points of this task are the rapid determination of the moment tensor, which is of primary importance for getting some initial, robust estimation on the fault mechanism (e.g., see the activities outlined in the Task 2 - size of the earthquake and the orientations of the fault planes; Dreger, 2002), and the selection of the rupturing plane from inversion for the finite fault using a linear approximation, that is, an under-parameterized fault model that still is capable to provide information on some main features like active fault plane and directivity (e.g., Dreger and Kaverina, 2000).

### First Annual Meeting: 19-21 October 2009