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 two centuries. Recent eruptions (1967, 1969, and 1970) and the volcanic unrest episodes that happened in 1992, 1999, and 2014–2015 demonstrate that the occurrence of future volcanic activity is a valid and pressing concern for scientists, technical and logistic personnel, and tourists, that are visiting or working on or near the island. We present a unifying evolutionary model of the magmatic system beneath Deception Island by integrating new petrologic and geochemical results with an exhaustive database of previous studies in the region. Our results reveal the existence of a complex plumbing system composed of several shallow magma chambers (≤10 km depth) fed by magmas raised directly from the mantle, or from a magma accumulation zone located at the crust-mantle boundary (15–20 km depth). Understanding the current state of the island’s magmatic system, and its potential evolution in the future, is fundamental to increase the effectiveness of interpreting monitoring data during volcanic unrest periods and hence, for future eruption forecasting.

Previous published data, combined with our results of 13 new radiocarbon ages and extensive geological fieldwork, indicate that during the past 11 ka 24 monogenetic basaltic eruptions occurred in the north sector of Gran Canaria. These eruptions can be grouped into three periods of eruptive activity: 1900-3200 14 C a BP; 5700-6000 14 C a BP; and an older period represented by only one eruption, El Draguillo, dated at 10 610 AE 190 14 C a BP. Archaeological studies have shown that the more recent eruptions affected prehistoric human settlements on the island. Field studies demonstrate that the eruptions typically built strombolian cones (30-250 m in height) and associated relatively long lava flows (100-10 350 m in length); a few eruptions also produced tephra fall deposits. The total erupted volume of these eruptions is about 0.388 km 3 (46.1% as tephra fall, 41.8% as cinder cone deposits and 12.1% as lava flows). The relatively low eruption rate ($0.04 km 3 ka À1 ) during the past 11 ka is consistent with Gran Canaria's stage of evolution in the regional volcano-tectonic setting of the Canary Archipelago. The results of our study were used to construct a volcanic hazards map that clearly delimits two sectors in the NE sector of Gran Canaria, where potential future eruptions would pose a substantial risk for densely populated areas.

Almost exactly half a century after the eruption of the Teneguía Volcano on La Palma (26 October to 28 November 1971), a new eruption occurred on the island and lasted for 85 days from 19 September until 13 December 2021. This new eruption opened a volcanic vent complex on the western flank of the Cumbre Vieja rift zone, the N‐S elongated polygenetic volcanic ridge that has developed on La Palma over the last c. 125 ka. The Cumbre Vieja ridge is the volcanically active region of the island and the most active one of the Canary Islands, hosting half of all the historically recorded eruptive events in the archipelago. The 2021 La Palma eruption has seen no direct loss of human life, thanks to efficient early detection and sensible management of the volcanic crisis by the authorities, but more than 2800 buildings and almost 1000 hectares of plantations and farmland were affected by lava flows and pyroclastic deposits. Satellite surveillance enabled accurate mapping of the progressive buildup of the extensive and complex basaltic lava field, which together with monitoring of gas emissions informed the timely evacuation of local populations from affected areas. Lava flows that reached the sea constructed an extensive system of lava deltas and platforms, similar to events during earlier historical eruptions such as in 1712, 1949 and 1971. Long‐term challenges in the aftermath of the eruption include protection of drainage systems from potential redistribution of tephra during high rainfall events, the use of the large surplus quantities of ash in reconstruction of buildings and in agriculture, and the crucial concerns of where and how rebuilding should and could occur in the aftermath of the eruption. Finally, there remain strong financial concerns over insurance for properties consumed or damaged by the eruption in the light of future volcanic hazards from the Cumbre Vieja volcanic ridge.

A complete framework of chronostratigraphic, petrographic, geochemical and thermobarometric data allows a reinterpretation of the evolution of the Plio-Quaternary volcanism in Gran Canaria. Bulk-rock and mineral chemistry has been used to define P – T crystallization paths, based on clinopyroxene–melt thermobarometry. Mafic magmas mainly crystallized at mantle depths (17–22 km) with secondary fractionation at crustal levels (1.5–8.0 km), suggesting multistage magma ascent. Crystallization of evolved magmas took place at crustal depths (3–15 km). The complexity of the magmatic plumbing system increased in the last 1 Ma, as shown by the presence of reverse zoned clinopyroxenes in the lavas, with green diopside–hedenbergite cores surrounded by brown diopsidic rims. Petrographic and chemical features of such clinopyroxenes support a xenocrystic origin of the green cores, related to magma mixing or mingling processes between pre-existing colder evolved magmas and new batches of hot basic magmas. The evolution of the magmatic feeding system beneath Gran Canaria was affected by the long-term uplift of the island as a result of lithospheric flexure caused by loading of the neighbouring island of Tenerife. This uplift favoured the generation of giant landslides and nesting of the recent volcanic activity (the last 1 Ma) within landslide basins. The association of rifts, giant landslides and nested volcanism with a higher degree of magmatic differentiation is proposed to constrain the plumbing system model.

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