engleski

Statistical selection of the 'best' seismic source mechanisms from inversions of synthetic volcanic long-period events

Inversions for the source mechanism of long-period (LP) seismicity recorded on volcanoes have become increasingly common and are used to interpret fluid driven processes. The source mechanism considered for LP inversions usually consists of a symmetric moment tenor with and without single forces. Also, constrained inversions have been performed where one presumes a specific source geometry which reduces the degrees of freedom in the inversion. To select the correct solution from the different possible mechanisms, the Akaike information criterion (AIC) has been used. However, since AIC performs well only if the inverted model is close to the true model, we tested its ability to select the correct model in LP inversions. Using synthetic datasets generated on Mt Etna, Italy with a tomography velocity model and the Green's functions calculated for a simplified, homogeneous velocity model, we have investigated (i) if any of the inversion source models can recover the true mechanism and (ii) the ability of the Akaike and Bayesian information criteria (BIC) to select the correct model. Results show that in some cases it is possible to recover the mechanism but never the source magnitude and that the BIC is a better measure than the AIC in selecting the true source model though in numerous cases both criteria fail to select the correct solution. Therefore, the BIC should be used as opposed to the AIC if it is necessary to select an appropriate source. Caution should be used when using the statistical measure in any seismic inversion application.

source mechanism ; LP inversions ; Mt Etna

nije evidentirano