Anomalies in geophysical and geochemical parameters revealed on the occasion of the Spitak (M=6.9) earthquake

On the ocasion of the Spitak earthquake (December 7, 1988) irregularities in several geophysical and geochemical parameters were revealed. In this paper data on anomalies in the water level in deep wells and in the helium content in thermal waters are presented. Data were collected from sites located in Georgia. The presented anomalies can be attributed to the processes that preceded and accompanied the earthquake; the presence of a time delay in the onset of the helium content anomalies at different sites could be an indication of the stress propagation.(AU)

Radon and helium soil - gas tracers of active and seismic tectonic structures in Italy

Soil-gas surveys in seismic areas in Italy highlighted a close relationship between terrestrial gas leakage and seismically active faults. The helium leakage in the Irpinia region, just after the 1980 earthquake, and radon and helium leakage in the Phlegraean Fields represent two explicative examples of how active fault systems can be traced by the soil-gas technique. The transport of He and Rn by pressure-driven upflows, linked to tectonic stresses, along more permeable pathways, provides the basis for an unconventional research perspective in the field of seismic hazard and zonation.(AU)