VolcaPot: Madison Myers et Philipson Bani

Le prochain VolcaPot se fera lundi prochain: le Lundi 4 Décembre à 14h en salle de séminaire. Le format sera un peu spécial car nous aurons deux présentations en une:

– La première sera aminée par Madison Myers qui a commencé son Post-Doc au sein de notre laboratoire. Ce sera l’occasion pour elle de se présenter à l’équipe pendant 10 à 15 min.

– La seconde sera quand à elle aminée par Philipson Bani. Le résumé se trouve en dessous:

Titre: Aoba (Ambae) 2017 eruption

After more than 300 years being dormant, Ambae resumed volcanic activity in the early 1990s. It commenced with volcanic gases released into Lake Voui that progressively transformed a once neutral lake water that hosted multiple islets covered by green vegetation into a 50 millions cubic meters of acidic water. Voui is thus considered as one of the largest acid crater lakes worldwide. This first manifestation culminated in 1995 with a phreactic eruption that alerted the whole 7000 inhabitants of the Island, but no evacuation was ordered. Ten years later in 2005, lake Voui went through another eruption but this time it exhibited a spectacular surtseyan type manifestation that progressively built a new islet of 500 m in diameter and 50 m height. Parts of the population were evacuated, particularly those from the central parts of Ambae, to the tips of the island at greatest distance from the lake. Some of the villagers, however, choose to rely on their tradition beliefs and refused to be evacuated. In 2006, Voui went through a remarkable and exceptional color change from blue to red affecting the whole volume of the lake – a rare phenomenon that has puzzled many scientists. It was later explained as resulting from iron oxidation. Eleven years later, on September 6, 2017, a new eruption began, more powerful with explosions that can be heard on neighboring islands and the glow at night can be seen up to 50 km from the summit. Currently the activity continues with lava pouring out from a new islet within the lake Voui and notable amount of ash continues to be released by the eruptive activity. This 2017 manifestation has triggered a state of emergency imposed by the national government, leading to the evacuation of the whole island – a total of 11000 inhabitants were evacuated to the neighboring islands, including Santo, Maewo and Pentecost. This eruption escalation on Ambae over the last 22 years is a threat to a rapid growing population (from 7000 inhabitants in 1995 to 11000 in 2017).

This presentation will provide information on the ongoing eruption of Ambae.