Groundwater-level Anomalies Associated with a Hypothetical Preslip Prior to the Anticipated Tokai Earthquake: Detectability Using the Groundwater Observation Network of the Geological Survey of Japan, AIST.- Earthquake-related Changes in Groundwater Levels at the Dogo Hot Spring, Japan.- Flow Changes and Geochemical Anomalies in Warm and Cold Springs Associated with the 1992–1994 Seismic Sequence at Pollina, Central Sicily, Italy.- Precursory Subsurface 222Rn and 220Rn Degassing Signatures of the 2004 Seismic Crisis at Tenerife, Canary Islands.- Soil H2 and CO2 Surveys at Several Active Faults in Japan.- Diffuse Emission of Hydrogen from Poás Volcano, Costa Rica, America Central.- Anomalous Emissions of SO2 During the Recent Eruption of Santa Ana Volcano, El Salvador, Central America.- Crater Lake Temperature Changes of the 2005 Eruption of Santa Ana Volcano, El Salvador, Central America.- Temporal Variability of Major and Trace Element Concentrations in the Groundwaters of Mt. Etna (Italy): Effects of Transient Input of Magmatic Fluids Highlighted by Means of Cluster Analysis.- Continuous, Direct Gas-Geochemical Monitoring in Hydrothermal Vents: Installation and Long-Term Operation on Nisyros Island (Greece).