GNGTS 2014 - Atti del 33° Convegno Nazionale

GNGTS 2014 S essione 1.1 15 been collected in July 2014 in a period of stable meteorological conditions (i.e., an average day temperature of 25°C and no precipitation). Field analyses have been conducted for CO 2 , CH 4 , O 2 , H 2 S and H 2 by directly attaching the probe to a Multiwarn portable gas analyser (Draeger Instruments) which has a measuring range up to 100% for CO 2 , 0-100% LEL for CH 4 , up to 1000 ppm for H 2 S, and up to 100 ppm for H 2 . Field analyses have been also conducted for Rn by pumping gas directly from the probe into the Lucas cell of an RDA200 detector (EDA-Scintrex Instruments). Further, samples have been collected for laboratory analysis by injecting 60 mL of soil gas into a previously-evacuated, 25 mL stainless-steel canister sealed with a rubber septum. ��� ������� ���� ���� �������� ��� The samples have been analysed for He on a mass spectrometer (Varian Leak Detector), and then for other gases on Fisons 8000- series bench Gas Chromatographs (GC) equipped with a Flame Ionisation Detector (FID) for the analysis of CH 4 ,C 2 H 2 ,C 2 H 4 , and C 3 H 8 , and with a Thermal Conductivity Detector (TCD) for the analysis of CO 2 , O+ Ar, and N 2 . ��� ����� ���������� ��� ���� ���������� ����� �� �������� The eld instrument has been calibrated prior to shipping to the eld site. CO 2 ux measurements have been accomplished by using an in-house developed ux chamber system that consists of an accumulation chamber of known volume (V) and surface area (A) connected to an infrared detector within a control unit (Beaubien et al. , 2014). Results and discussion. Preliminary results of the structural analysis indicate the occurrence of a complex 3D framework, characterised by multiple sets of extensional and strike-slip Fig. 2 – Images of the Colle Sponeta area. Frontal view (a, taken from the E) and profile view (b, taken from the N) of the Colle Sponeta fault scarp. c: Sinkhole, with bubbling due to a free gas phase upwelling (see Fig. 3 for location).