A forward test of the Decelerating-Accelerating Seismic Strain model in the Mediterranean

In the last two decades several studies have shown that strong earthquakes are preceded by a sequence of smaller shocks that occur near the focal region of the mainshock with a decelerating time behaviour and by another sequence of shocks that occur in a broader region, exhibiting an accelerating mode with time. Both sequences have predictive properties expressed by empirical relations which are supported by theory. These relations form the Decelerating-Accelerating Seismic Strain (D-AS) model that allows the estimation (prediction) of the mainshock. In the present work eleven couples of such sequences are identified, which in turn probably correspond to eleven strong (M≥6.3) mainshocks ensuing in the Mediterranean area (34oN-45oN, 6oW-42oE). The time of origin, tc, the magnitude, M, and the epicenter coordinates, E(ϕ, λ), for each of these expected mainshocks are estimated (predicted) by the D-AS model. Model uncertainties are also provided and several statistical tests are performed in order to allow an objective forward testing and evaluation of the efficiency of the model for intermediate-term earthquake prediction, at the end of the prediction window (end of 2013).