GNGTS 2013 - Atti del 32° Convegno Nazionale

continuity to the observations and to fully appreciate possible space-time persistence of TIR anomalies and the amount of usable satellite records within the historical data-set drastically reduces, weakening (particularly in specific zones) the significance of the computed reference fields. Despite this evident limiting factor due to the intrinsic absence of continuity of TIR observations 2 a sensitivity analysis was performed considering all earthquakes with Ml>4 occurred within the investigated areas in the considered period. The sensitivity has been here assumed as the fraction of earthquakes occurred in the investigated area preceded or followed by significant TIR anomalies in the space-time windows previously described In this case 3 the score was of 67% 4 (100% on the Southern Apennine, 33% over the Po Plain) which means 33% of missed events (0% on the Southern Apennine, 67% over the Po Plain: Tab.2). Tab. 1 – Significant sequences of TIR anomalies for both test area. Southern Apennine (yyyymmddPollino.tif) TIR anomaly code (TAC) Po plain (yyyymmddPoPlain.tif) TIR anomaly code (TAC) 20120927 ML 4,1 (Benevento) 20120929Pollino.tif ANS 20120929PoPlain.tif ND 20120930Pollino.tif AS (post) 20120930PoPlain.tif NA 20121001Pollino.tif AVS (post) 20121001PoPlain.tif NA 20121011Pollino.tif NA 20121011PoPlain.tif NA 20121012Pollino.tif ANS 20121012PoPlain.tif ND 20121013Pollino.tif AS (pre) 20121013PoPlain.tif NA 20121014Pollino.tif NA 20121014PoPlain.tif NA 20121025 ML 5,0 (Pollino) 20121112Pollino.tif ANS 20121112PoPlain.tif ND 20121113Pollino.tif NA 20121113PoPlain.tif NA 20121114Pollino.tif AS (false) 20121114PoPlain.tif NA 20130103Pollino.tif NA 20130103PoPlain.tif ANS 20130104Pollino.tif NA 20130104PoPlain.tif NA 20130105Pollino.tif NA 20130105PoPlain.tif NA 20130106Pollino.tif NA 20130106PoPlain.tif NA 20130107Pollino.tif NA 20130107PoPlain.tif AS (pre) 20130125 ML 4,8 (Garfagnana) SCORES AS=2(1 false) AVS=1 (0 false) SCORES AS=1(0 false) Tab. 2 – Results of the sensitivity (left) and reliability (right) analysis performed on the considered testing areas in 2 it should be also noted that still we have no theoretical or experimental elements to justify the systematic occurrence of whatever signal (including, for instance, foreshocks) before whatever earthquakes occurring in whatever place/time. 3 1 additional event in the Southern Italy (Tyrrhenian Sea EQ, 16 Oct 2012, Ml 4.6) and 2 additional in the Po Plain (Lunigiana seismic sequence, 21 Jun 2013, Ml 5.2 and Piacenza EQ, 3 Oct 2012, Ml 4.5) occurred in the considered period and for selected testing areas. 4 note that the persistence of clouds for one missed event (the Lunigiana sequence) makes this score possibly underestimated. 150 GNGTS 2013 S essione 2.1