GNGTS 2022 - Atti del 40° Convegno Nazionale

220 GNGTS 2022 Sessione 2.1 correlation coefficient, the conditional probability of an EQ event given the observation of an EC event can be written P(EQ|EC+Δt) = P(EQ) + corr(EQ,EC+Δt) {[1 – P(EQ)] P(EQ) [1/P(EC) − 1]}^½, (2) where P(EQ) = N EQ /N d , P(EC) = N EC /N d , and Δt is the time delay in days between the two events. Thus, P(EQ) = 0.033 and P(EC) = 0.034. Calculating (2), P(EQ|EC+Δt) = 0.033 + 0.952 R(Δt) If we start considering an average probability to observe an earthquake every 30 days, the observation of a CO 2 anomaly at Gallicano Station increase the earthquake probability to 0.131, with a probability gain near to 4, for earthquakes that at least satisfy the relation (1). Fig. 2 - Time variation of the irregular component of CO 2 at Gallicano (values corrected by detrending the seasonal component). On the right, the histogram distribution is shown along with its best fit and residual curves. Fig. 3 - Matthew’s correlation coefficients in the range Δt from -15 to +15 days, note that a pronounced peak occurs at -2 days, which means that CO 2 anomalies prevalently anticipate seismic activity of 2 days. References Cioni, R., Guidi, M., Pierotti, L., Scozzari, A.; 2007: An automatic monitoring network installed in Tuscany (Italy) for studying possible geochemical precursory phenomena . Nat. Hazards Earth Syst. Sci. 7 , 405–416. Fidani, C.; 2018: Improving Earthquake Forecasting by Correlations Between Strong Earthquakes and NOAA Electron Bursts , TAO, 29 (2), 117-130. Fidani, C.; 2020: Probability, Causality and False Alarms using Correlations Between Strong Earthquakes and NOAA High Energy Electron Bursts . Ann. Geophys., 63 (5), PA543. Fidani, C.; 2021: West Pacific earthquake forecasting by NOAA electron bursts with independent L-shells and ground based magnetic correlations. Frontiers in Earth Science, 9 , 673105. Makridakis, S., Wheelwright, S.C., Hyndman, R.J.; 1998: Forecasting Methods and Applications , third ed. John Wiley and Sons, New York, p. 642. Matthews, B. W.; 1975: Comparison of the predicted and observed secondary structure of T4 phage lysozyme . Biochimica et Biophysica Acta (BBA) - Protein Structure. 405 (2), 442–451. Pierotti, L., Botti, F., D’Intinosante, V., Facca, G., & Gherardi, F.; 2015: Anomalous CO 2 content in the Gallicano thermo- mineral spring (Serchio Valley, Italy) before the 21 June 2013, Alpi Apuane earthquake (M= 5.2) . Physics and Chemistry of the Earth, Parts A/B/C, 85 , 131-140. Sugisaki, R.; 1981: Deep-seated gas emission induced by the earth tide: a basic observation for geochemical earthquake prediction . Science 212 , 1264–1266. Wyss, M., 1991. Evaluation of Proposed Earthquake Precursors. In: Wyss M. (Ed.), Published by AGU in Cooperation with IASPEI. Special Publication, 94pp. Wyss, M., Booth, D.C., 1997. The IASPEI procedure for the evaluation of earthquake precursors . Geophys. J. Int. 131 , 423–428.