Tambora Caldera

CALDERA – EffeCts of lArge voLcanic eruptions on climate and societies: UnDerstand the impacts of past Events and related subsidence cRises to evAluate potential risks in the future

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We have exciting news!!!  Our Synergia project will be funded by the Swiss National Science Foundation! This project will help scientists to better understand the impacts of large volcanic eruptions on the Climate System and their effects on human societies.

Indian Himalaya

Warming increases risk of snow avalanches in the western Himalayas

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Often called the Third Pole, the Hindukush-Karakoram-Himalaya region, comprising the Tibetan plateau and the surrounding mountains, is the most glaciated place on Earth outside the North and South Poles. Its cryosphere is extremely susceptible—and the surrounding communities and ecosystems vulnerable—to the effects of climate change. Juan Ballesteros-Cánovas and colleagues at the University of Geneva have used tree-ring data to reconstruct more than 150 years of snow avalanches on a typical western Himalayan mountainside in northern India.

Multi-proxy dating the ‘Millennium Eruption’ of Changbaishan to late 946 CE

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Ranking among the largest volcanic eruptions of the Common Era (CE), the ‘Millennium Eruption’ of Changbaishan produced a widely-dispersed tephra layer (known as the B-Tm ash), which represents an important tie point for palaeoenvironmental studies in East Asia. Hitherto, there has been no consensus on its age, with estimates spanning at least the tenth century CE. Here, we identify the cosmogenic radiocarbon signal of 775 CE in a subfossil larch engulfed and killed by pyroclastic currents emplaced during the initial rhyolitic phase of the explosive eruption. Combined with glaciochemical evidence from Greenland, this enables us to date the eruption to late 946 CE.

Annales_Spirenses

Volcanology : Chronicling a medieval eruption

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The eruption of Samalas in Indonesia in 1257 ranks among the largest sulfur-rich eruptions of the Common Era with sulfur deposition in ice cores reaching twice the volume of the Tambora eruption in 1815. Sedimentological analyses of deposits confirm the exceptional size of the event, which had both an eruption magnitude and a volcanic explosivity index of 7. During the Samalas eruption, more than 40 km3 of dense magma was expelled and the eruption column is estimated to have reached altitudes of 43 km. However, the climatic response to the Samalas event is debated since climate model simulations generally predict a stronger and more prolonged surface air cooling of Northern Hemisphere summers than inferred from tree-ring-based temperature reconstructions. Here, we draw on historical archives, ice-core data and tree-ring records to reconstruct the spatial and temporal climate response to the Samalas eruption.