Methana Magmatic Observational Experiment (MeMaX) – seismological monitoring of magmatic and tectonic activity in the western Saronic Gulf region, Greece

Large-scale historical volcanic eruptions caused significant destruction in the Mediterranean region (e.g., Thera/Santorini explosion circa 1600 BCE). The South Aegean Volcanic Arc remains active, and in addition to primary volcanic hazards such as ashfall and lava flows, active submarine and coastal volcanoes have the potential to trigger tsunamis as secondary volcanic hazard. These tsunamis pose a threat even to far-distant coastlines. With increasing population density, infrastructure development, and seasonal tourism, both primary and secondary volcanic risks along the Aegean coasts are increasing, even with respect to smaller, more frequent eruptions. Our focus is on the western Saronic Gulf region within the Aegean Sea, as possible impacts may even extend into the greater Athens metropolitan area. There, the dormant volcanoes of the Methana volcanic system, which last erupted in 230 BCE, and the submarine Pausanias Volcanic Field pose an underappreciated hazard. We search for evidence of yet undetected magmatic activity through the identification of related microseismic events and describe the design of the related MeMaX experiment. ... mehrSince 2019, the National Observatory of Athens and the University of Patras operate six seismic stations on Methana and the nearby Peloponnese mainland. In March 2024, an additional 15 seismic recording stations were deployed for a two-years period across Methana, Aegina, Agistri, Kyra, and Poros islands and the mainland Peloponnese. This network configuration provides a dense and good azimuthal coverage of seismic ray paths for earthquake location and structural analysis. The continuous recordings enhance the observational capacities for earthquake detection, e.g. the first results indicate that the noise at the recording sites is quite low and that low magnitude events to ML ca. 0 can be recorded with a very good signal-to-noise ratio. This geophysical experiment is part of the MULTI-MAREX initiative.