[S13-5] Earthquake source mechanics V

[S13-5-01] Asperity imaging of the ML6.0 2016 Amatrice, Italy, earthquake from dynamic rupture simulation

^○Hideo Aochi^{1, 2} (1.Ecole Normale Superieure, Paris, France, 2.BRGM, Orleans, France)

Several damaging earthquakes of magnitude 5.5 – 6.4 have occurred in the Central Italy since August 24th 2016. The earthquakes show normal faulting mechanisms, coherent with the formation of regional tectonics surrounding the Apennine Mountain. We aim to characterize dynamic source parameters (asperity distribution) from the dynamic rupture and wave propagation simulations, firstly for the ML6.0 August 24th 2016 earthquake. We hypothesis that fault heterogeneity is represented by a combination of circular patches of asperity and determine their physical parameters. We apply the boundary domain method combining boundary integral equation and finite difference schemes. The calculation is still too expensive to run systematic inversion process, but the simulations indicate a better combination of the dynamic rupture parameters, in terms of patch dimension, location and frictional parameters. When focusing on one of the nearest ground motion record of Amatrice (epicentral distance of about 10 km), a single patch toward up-dip and strike directions between the hypocenter and this station is suggested. Its dimension is not larger than a radius of 4 km and static/dynamic stress drops of 4 and 6 MPa or more, respectively.