Virtual Volcano Vacation #109 WINNER! – Ambrym

Ambrym volcano of Vanuatu - image via ambrym.travel - photographer unknown

Ambrym volcano of Vanuatu – image via ambrym.travel – photographer unknown

There are features that I find particularly attractive in volcanoes such as steep calderas, sommas, double-craters, welded tuffs and such, and the presence of those features definitely influences where I choose to hide each week. The problem is that those features, especially if they are rare or unique, lead the Search Party to me quickly. So sometimes I have a hard time sending postcards that are interesting without finding ones that are too interesting to keep the hunt at least somewhat challenging. That strategy was really hard to follow this week while hiding in the South Pacific in the Vanuatu archipelago basking in the warm happy glow of the lava lakes of Ambrym.

Ambrym volcano - 2009 photo of lava lake in Marum crater - public domain image via Wikimedia Commons

Ambrym volcano – 2009 photo of lava lake in Marum crater – public domain image via Wikimedia Commons

Ambrym isn’t just a volcano. The entire triangular island is a basaltic shield volcano and is fueled by subduction of the Australian plate beneath the edge of the Pacific plate at the New Hebrides (also the name of the Vanuatu island nation before it gained independence in 1980) subduction zone.

South Pacific plate boundaries - original map By Eric Gaba (Sting - fr:Sting) [CC BY-SA 2.5] via Wikimedia Commons (modified by me to focus on Vanuatu)

South Pacific plate boundaries – original map By Eric Gaba (Sting – fr:Sting) [CC BY-SA 2.5] via Wikimedia Commons (modified by me to focus on Vanuatu)

Around 50 CE, a VEI 6 plinian eruption formed the large 12 km wide caldera in the center of the otherwise jungle island. Two active cones dominate the landscape within the caldera, and sometimes people even mistake them for two different volcanoes. Marum to the east, and Benbow to the west both often contain active lava lakes, making the volcano of particular interest to scientists as well as the more intrepid thrill-seeking variety of tourist.

Ambrym volcano - Marum - image via tripadvisor.com - photographer unknown

Ambrym volcano – Marum – image via tripadvisor.com – photographer unknown

Ambrym is one of the most active volcanoes of the entire island arc, having been observed in eruption 53 times since 1774, around the time Captain James Cook was exploring the region and England was establishing colonies. Benbow was given its name by Cook to honour Admiral John Benbow.

Ambrym volcano - Benbow - image via tripadvisor.com - photographer unknown

Ambrym volcano – Benbow – image via tripadvisor.com – photographer unknown

The volcano tends to erupt explosively several times a century, but can produce dangerous gas emissions. Also in 1979, Ambrym’s eruptive activity caused destructive acid rain to fall across the island, destroying vegetation, contaminating the water supply and buring some of the island’s human inhabitants. Today it and other volcanoes of the islands are monitored by Vanuatu Geohazards Observatory.

Also, kids, do not try this at home even IF you have a lava lake and your parents’ permission.

Congratulations Jesper for being the first and only one to find me. Somehow I suspected the lava lakes were calling to you. But even an army of penguins cannot stop me from escaping again this coming Monday, to a new adventure at a new volcano.

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