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Deception Island is one of the most active volcanoes in Antarctica with more than twenty explosive eruptions in the past two centuries. Any future volcanic eruption(s) is a serious concern for scientists and tourists, will be detrimental to marine ecosystems and could have an impact to global oceanographic processes. Currently, it is not possible to carry-out low and high frequency volcanic gas monitoring at Deception Island because of the arduous climatic conditions and its remote location. Helium, neon and argon isotopes measured in olivine samples of the main eruptive events (pre-, syn- and post caldera) offer insights into the processes governing its volcanic history. Our results show that: (i) ascending primitive magmas outgassed volatiles with a MORB-like helium isotopic signature (3He/4He ratio); and (ii) variations in the He isotope ratio, as well as intensive degassing evidenced by fractionated 4He/40Ar* values, occurred before the beginning of the main eruptive episodes. Our results show how the pre-eruptive noble gas signals of volcanic activity is an important step toward a better understanding of the magmatic dynamics and has the potential to improve eruption forecasting. [ABSTRACT FROM AUTHOR]

Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica, with more than 20 explosive eruptive events registered over the past few centuries. Recent eruptions (1967, 1969, and 1970) and volcanic unrest episodes (1992, 1999, and 2014–2015) demonstrate that volcanic activity will likely occur in the future. Despite this, there has been a considerable increase in the number of scientific bases, tourist activities and air and vessel traffic in the region during the last several decades. The escalation in interest has increased the amount of infrastructure and population numbers exposed to a future eruption. Thus, there is an urgent need to develop an accurate long-term assessment of the volcanic hazard of the island. However, past attempts have always been limited by the incompleteness of the eruptive record. Volcanic ash layers found in marine and lacustrine sediment cores and glaciers outside Deception Island are a fundamental source of information for reconstructing the explosive eruptive record of the volcano. The spatial distribution of the tephra layers, as well as their physicochemical analysis are invaluable for determining the size and explosiveness of past eruptive events, as well as for assessing the extent and impact of their related hazards (e.g., ash fall out). In order to overcome the dispersion of existing data among numerous publications and to facilitate the analysis of available information on tephra layers sourced in Deception Island, we present the DecTephra (Deception Island Tephra Record) database. The current database version contains 362 tephra layers (including cryptotephras) located at sites up to 3115 km distant from the island. For each tephra layer, the database includes: (i) the location and simple description of the sampling site; and (ii) the key petrologic and geochemical features of each tephra layer. A preliminary analysis of the information contained in the DecTephra database (e.g., magma composition, explosiveness, eruptive recurrence, etc.), validates it as a key tool for evaluating past explosive activity of the volcano. In addition, it can function as a valuable resource for paleoenvironmental and paleoclimatic studies requiring tephrostratigraphical and tephrochronological control at local and regional scales. DecTephra also has the potential to help to assess the contribution of volcanic forcing to Holocene climate variability in the Southern Hemisphere. • Deception Island is one of the most active volcanoes in Antarctica. • The eruptive record is incomplete hindering a complete volcanic hazard assessment. • Volcanic ash layers are fundamental for reconstructing the explosive eruptive record. • DecTephra compiles existing data on tephra layers sourced in Deception Island. • DecTephra is a valuable resource for paleoenvironmental and paleoclimatic studies. [ABSTRACT FROM AUTHOR]