1. What are the contributions in "Co2 inflow and elements desorption prior to a seismic sequence, amatrice‐norcia 2016, italy" ?
To evaluate these signals as reliable seismic precursors and effective predictive tools, the authors studied the geochemical processes that caused these anomalies.. Using chemical and isotope models, the authors show that increased concentrations of arsenic and vanadium, a slight increase in boron concentrations, and a concomitant lowering of the boron isotope ratio may be due to mineral desorption ( e. g., from iron oxides and/or clays ).. Their observations confirm the pivotal role of CO2 in the release of trace elements by alteration of solid phases and provide a new understanding of earthquake‐related water chemical anomalies.
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2. What is the common weathering product of volcanic ashes?
It is worth noting that cristobalite, kaolinite, and zeolites are the typical weathering products of volcanic ashes and tephra (Bishop et al., 1998).
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3. What is the main reason for the aquifer's stability?
the stability of groundwater flow, showing minimal seasonal oscillations, allows for an optimal evaluation of groundwater changes due to reasons other than hydrogeological causes (i.e., seasonal recharge/discharge cycles, surface water/groundwater interaction, and lateral flow or leakage).
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4. What is the role of carbonates in the aquifers?
The fractured carbonates correspond to primary aquifers hosting regional groundwater flows (>10 m3/s from main springs) that converge from different hydrogeological units toward the study area.
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![Figure 4. pH (−log[H+]) versus Cext (molality) calculated from total inorganic carbon. In (a), the linear best fits of water samples S1 to S4 are shown. In (b), all sampled waters, S1 to S4 and S5 to S7, are compared with water‐CO2 equilibria at Taverage = 13 °C, P = 10 −1 MPa, and different logfCO2 values (+numbered and dotted best‐fit curve). The black small dots show the composition of the Sulmona basin groundwater, as found in the literature (Conese et al., 2001; Iride, 2008). In both diagrams, the values detected in the S4 spring following the L'Aquila 2009 earthquake are also shown (black small dot withmean ± standard deviation bars; Chiodini et al., 2011). Cinf (gray field) and cutoff‐warning Cext thresholds (arrows) are shown for comparison (see main text for details; Chiodini et al., 2000; Frondini et al., 2018; Martini, 2016) along with the inferred desorption triggering value (Cext = 0.007 mol; Figure 3). In (b), the dashed curve represents the pH‐Cext exponential best fit of a high CO2 water issuing from a deep borehole in the Northern Apennine watershed (Bicocchi et al., 2013). The deep borehole draws fluid from a reservoir in the Upper Triassic rocks (Bicocchi et al., 2013). In this case, the equilibria between dissolved constituents and gases are first calculated at the temperature and pressure values at depth (T= 120 °C and P= 69MPa). Second, shallow degassing is simulated, recalculating the water‐gas equilibria by decreasing the logfCO2 (X numbered and dashed best fit curve) at the same average conditions of the water sampled in this study (S.I.calcite = 0, Taverage = 13 °C and P = 10−1 MPa). As a comparison, the same calculation at P = 20 MPa is also shown (X numbered and dashed best fit line). The solid curve shows that the exponential best fit for the S4 samples extends to higher and lower pH values.](/figures/figure-4-ph-log-h-versus-cext-molality-calculated-from-total-33qo6iyf.webp)
