GNGTS 2015 - Atti del 34° Convegno Nazionale

32 GNGTS 2015 S essione 2.1 spring; iii) the occurrence of hydrogeological co-seismic effects associated with the strongest earthquakes recorded in the region (increase in turbidity and flow rate of the water, disappearance and formation of new springs), as documented through local chronicles; iv) the occurrence of recent, intense superficial fracturing with different orientation, which testifies about the active stress field and/or tectonics of the area (Bencini et al., 1990); v) the ease of access to the site, which simplifies maintenance operations of the automatic station. A significant positive anomaly of CO 2 dissolved concentration, not correlated to temperature, electrical conductivity and rainfall amounts, was observed about 20 days before a seismic event, on May 30, 2013. This feature has been interpreted as a clear evidence of sudden gas release at depth within the system (see also Pierotti et al. , 2015). The Gallicano monitoring station has been installed on April 15, 2003. During the period 01/12/2008 - 30/06/2010 the station has been off, due to the failure of the embedded personal computer. The personal computer was replaced with a commercial data logger on June 30, 2010. On October 21, 2013 the station was completely flooded by the overflowing of the Turrite Gallicano river. During the period April 15, 2003 - October 21, 2013, more than 900 thousand data were acquired. Data processing have been carried out by adjusting the ALICE index (Absolutely Local Index of Change of the Environment) (Tramutoli, 1998) to dissolved CO 2 data, acquired every day, midnight, and previously filtered with moving median smoothing (Box and Jenkins, 1976; Velleman and Hoaglin, 1981). The index for the 2012 months was calculated using the formula: where is the average of the CO 2 value for each month of the year in the period 2004-2011, while the standard deviation is calculated for each month in the period 2004 - 2011. The index for the 2013 months was calculated using the formula: where is the average value of CO 2 for each month of the year in the period 2004-2012, while the standard deviation is calculated for each month in the period 2004 - 2012. The following figures represent the index values calculated since March 2012. The INGV group reconsidered literature available Helium isotopic data and compared them with fault occurrence in Italy. In particular the DISS database was considered. In principle ¾ Helium ratio could contribute to understand if mantle derived fluids are detectable at ground surface. The analysis reached no definitive results since heat flow anomalies could affect data evaluation. Anyway obtained findings helped in data reanalysis. Geological and man-induced constraints to satellite TIR signals. In recent years TIR signals have been utilized by many research groups in researches oriented to earthquake prediction researches. In particular during S3 Project the Research Unit 3 based in Potenza University devoted proper activities to RETIRA index and to eventual precursory signal detected in concomitance with some seismic events occurred in Italy. To better understand physical constraints due to gas emission processes some further researches were carried out by Research Unit 2, in particular: 1. a data base of natural gas emissions (CO 2 and CH 4 ) was set up. Available data bases set up by DPC-INGV were utilized and updated by recent technical reports (e.g. Martinelli et al. , 2012; Etiope, 2015; Ferrari and Severi, 2015); 2. a data base compiled by ISPRA about man induced CO 2 , N 2 O and CH 4 emissions was considered following the ISPRA inventory (it/sia-ispra/inventaria/disaggregazione- dellinventario-nazionale-2010);