HR: 1330h
AN: S52E-0168    [PDF]
TI: Groundwater Carbon Decrease During a Slow Earthquake Swarm in Central Italy
AU: * Crescentini, L
EM: luca.crescentini@unicam.it
AF: Dipartimento di Scienze della Terra - Universita' di Camerino, Via Gentile III da Varano, Camerino (MC), 62032 Italy
AU: Amoruso, A
EM: antonella.amoruso@aquila.infn.it
AF: Dipartimento di Fisica - Universita' dell'Aquila, Via Vetoio, 10, Coppito (AQ), 67010 Italy
AU: Cardellini, C
EM: geochem@unipg.it
AF: Dipartimento di Scienze della Terra - Universita' di Perugia, Piazza dell'Universita', Perugia, 06100 Italy
AB: Several pre-earthquake and earthquake-induced groundwater anomalies have been reported in the past. During the slow-earthquake swarm recorded by an underground geodetic interferometer (Gran Sasso Massif - Central Italy) in 1997 (Crescentini et al., 1999; Amoruso et al., 2002) a strong positive pH anomaly was observed in the groundwater collected at 1400-m depth nearby the interferometer and close to the source region (Bella and Plastino, 2000; Amoruso et al., 2000). Here we use the PHREEQC code to infer change in the groundwater carbon content during the anomaly. The pH anomaly suggests a decrease in initial CO$_2$ content comparable with the concentration of deeply derived CO$_2$ present in the groundwater from the springs close to the study area (0.2 to 0.5 meq l$^{-1}$, Chiodini et al., 2000) thus indicating a strong temporary diminution of the upward flux of CO$_2$. Comparison with chemical data of groundwater collected at different sites tens to hundreds of meters from the interferometer supports simulation results.
DE: 1829 Groundwater hydrology
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2003 Fall Meeting