Abstract In the last two centuries, demographic expansion and extensive urbanization of volcanic areas have increased the exposure of our society to volcanic hazards. Antarctica is no exception. During the last decades, the permanent settlement and seasonal presence of scientists, technicians, tourists and logistical personnel close to active volcanoes in the south polar region have increased notably. This has led to an escalation in the number of people and the amount of infrastructure exposed to potential eruptions. This requires advancement of our knowledge of the volcanic and magmatic history of Antarctic active volcanoes, significant improvement of the monitoring networks, and development of long-term hazard assessments and vulnerability analyses to carry out the required mitigation actions, and to elaborate on the most appropriate response plans to reduce loss of life and infrastructure during a future volcanic crisis. This chapter provides a brief summary of the active volcanic systems in Antarctica, highlighting their main volcanological features, which monitoring systems are deployed (if any), and recent (i.e. Holocene and/or historical) eruptive activity or unrest episodes. To conclude, some notes about the volcanic hazard assessments carried out so far on south polar volcanoes are also included, along with recommendations for specific actions and ongoing research on active Antarctic volcanism.

Abstract Following more than 25 years of exploration and research since the last regional appraisal, the number of known subaerially exposed volcanoes in the northern Antarctic Peninsula region has more than trebled, from less than 15 to more than 50, and that total must be increased at least three-fold if seamounts in Bransfield Strait are included. Several volcanoes remain unvisited and there are relatively few detailed studies. The region includes Deception Island, the most prolific active volcano in Antarctica, and Mount Haddington, the largest volcano in Antarctica. The tectonic environment of the volcanism is more variable than elsewhere in Antarctica. Most of the volcanism is related to subduction. It includes very young ensialic marginal basin volcanism (Bransfield Strait), back-arc alkaline volcanism (James Ross Island Volcanic Group) and slab-window-related volcanism (seamount offshore of Anvers Island), as well as volcanism of uncertain origin (Anvers and Brabant islands; small volcanic centres on Livingston and Greenwich islands). Only ‘normal’ arc volcanism is not clearly represented, possibly because active subduction virtually ceased at c. 4 Ma. The eruptive environment for the volcanism varied between subglacial, marine and subaerial but a subglacial setting is prominent, particularly in the James Ross Island Volcanic Group.

Abstract Young volcanic centres of the Bransfield Strait and James Ross Island occur along back-arc extensional structures parallel to the South Shetland island arc. Back-arc extension was caused by slab rollback at the South Shetland Trench during the past 4 myr. The variability of lava compositions along the Bransfield Strait results from varying degrees of mantle depletion and input of a slab component. The mantle underneath the Bransfield Strait is heterogeneous on a scale of approximately tens of kilometres with portions in the mantle wedge not affected by slab fluids. Lavas from James Ross Island east of the Antarctic Peninsula differ in composition from those of the Bransfield Strait in that they are alkaline without evidence for a component from a subducted slab. Alkaline lavas from the volcanic centres east of the Antarctic Peninsula imply variably low degrees of partial melting in the presence of residual garnet, suggesting variable thinning of the lithosphere by extension. Magmas in the Bransfield Strait form by relatively high degrees of melting in the shallow mantle, whereas the magmas some 150 km further east form by low degrees of melting deeper in the mantle, reflecting the diversity of mantle geodynamic processes related to subduction along the South Shetland Trench.

Abstract We review here data and information on Antarctic volcanism resulting from recent tephrostratigraphic investigations on marine cores. Records include deep drill cores recovered during oceanographic expeditions: DSDP, ODP and IODP drill cores recovered during ice-based and land-based international cooperative drilling programmes DVDP 15, MSSTS-1, CIROS-1 and CIROS-2, DVDP 15, CRP-1, CRP-2/2A and CRP-3, ANDRILL-MIS and ANDRILL-SMS, and shallow gravity and piston cores recovered in the Antarctic and sub-Antarctic oceans. We report on the identification of visible volcaniclastic horizons and, in particular, of primary tephra within the marine sequences. Where available, the results of analyses carried out on these products are presented. The volcanic material identified differs in its nature, composition and emplacement mechanisms. It was derived from different sources on the Antarctic continent and was emplaced over a wide time span. Marine sediments contain a more complete record of the explosive activity from Antarctic volcanoes and are complementary to those obtained by land-based studies. This record provides important information for volcanological reconstructions including approximate intensities and magnitudes of eruptions, and their duration, age and recurrence, as well as their eruptive dynamics. In addition, characterized tephra layers represent an invaluable chronological tool essential in establishing correlations between different archives and in synchronizing climate records.

Abstract Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica, with more than 15 explosive eruptive events registered over the past two centuries. Recent eruptions (1967, 1969 and 1970) and volcanic unrest episodes in 1992, 1999 and 2014–15 demonstrate that the occurrence of future volcanic activity is a valid and pressing concern for scientists, logistic personnel and tourists that are visiting or are working on or near the island. Over the last few decades, intense research activity has been carried out on Deception Island to decipher the origin and evolution of this very complex volcano. To that end, a solid integration of related scientific disciplines, such as tectonics, petrology, geochemistry, geophysics, geomorphology, remote sensing, glaciology, is required. A proper understanding of the island's evolution in the past, and its present state, is essential for improving the efficiency in interpreting monitoring data recorded during volcanic unrest periods and, hence, for future eruption forecasting. In this chapter, we briefly present Deception Island's most relevant tectonic, geomorphological, volcanological and magmatic features, as well as the results obtained from decades of monitoring the island's seismic activity and ground deformation.