Seismic Sensors Probe Lipari’s Underground Plumbing

Abstract

Just north of the island of Sicily, near the toe of Italy’s “boot,” a chain of volcanic islands traces a delicate arc in the Mediterranean Sea. This chain, the Aeolian Islands, popular tourist resorts in proximity to some of Earth’s most active and well-known volcanoes, including Etna and Stromboli. Lipari, the largest of these islands, lies of the island of Vulcano, for which these eruptive features are named. Lipari is less well characterized than some of the other nearby volcanoes, but one research group setting out to change this. This is the first time that a dense seismic array has been deployed to investigate a hydrothermal system in the volcanically active Aeolian Islands. Lipari is located ~80 kilometers north of the well-monitored Etna volcano. The island’s hydrothermal system, in which magma heats the water underground, is not to eruptive centers, but, rather, is connected to the regional fault system that delimits the western boundary of the active Ionian subduction zone. Lipari holds a unique place in our understanding of the tectonic evolution and hydrothermal activity of volcanoes emplaced in subduction zones (https://eos.org/projectupdates/ understanding-volcanic-eruptions-where-plates-meet). Within the framework of the ring-shaped Aeolian arc, the unexpected NNW–SSE alignment of Lipari andbeen related to a major regional discontinuity, the Tindari-Letojanni (https://www.researchgate.net/publication/311738886_Structural_architecture_and_active_deformation_pattern_in_the_northern_sector_of_the_Aeolian-Tindari- Letojanni_fault_system_SE_Tyrrhenian_Sea-NE_Sicily_from_integrated_analysis_of_field_marine_geophys) subduction transform edge propagator (STEP (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JB012202)) fault, a tear in a tectonic plate that allows one part of the plate to plunge downward while an adjacent remains on the surface.