Between a Rock and a Hard Place

Volcanoes

Science Snap (8): White Island erupts!

James Hickey is a PhD student in the School of Earth Sciences at the University of Bristol. A geophysicist and volcanologist by trade, his PhD project is focussed on attempting to place constraints on volcanic unrest using integrated geodetic modelling.

White Island is a small volcano roughly 30 miles off the coast of the Bay of Plenty in New Zealand. It is part of the Taupo Volcanic Zone, which is also home to the impressive Lake Taupo, a flooded caldera that formed in an eruption (a ‘super-eruption’ if you must) approximately 27,000 years ago. White Island, or Whakaãri in Maori, has been one of the most active volcanoes in New Zealand for the past 150,000 years, and its close accessibility makes it a haven for volcanologists and tourists alike. It was even once mined for sulphur. However, its danger shouldn’t be underestimated.

On the evening of the 11th October 2013 (local time) a small explosive eruption occurred, throwing up a column of ash and depositing mud over the crater floor – as can be seen in the image below (and check the video here, including volcanic lightning at 15 seconds). Alert levels were immediately raised and the Aviation Colour Code upped to Orange. This activity was preceded by 15 months of unrest, that is deviation from the background behaviour of a volcano towards a level that might be cause for concern in the short-term. The aviation warning was soon reduced back down, but the volcanic alert level remains at 2, as a similar event can be expected without prior warning.

Before (left) and after (right) images of the small eruption taken from a web camera positioned on the north crater rim. You can clearly see the mud layer deposited by the explosion. Image credit: GNS Science

 

Fortunately no one was injured in this recent eruption. But as this island offers such a unique opportunity for tourists, with up to 10,000 visitors a year, there is a real need to maintain the monitoring and improve our understanding of the processes that preclude volcanic eruptions.

Above: a photo I took as a bumbling 18 year-old tourist in 2006 whilst on a visit to White Island. It’s likely the stream of people in the picture would have been seriously injured by the eruption that took place. In the background you can see steam from fumaroles that give the island its ‘White’ name. Credit: James Hickey

 

Science Snap (5): Volcan de Colima’s lava dome

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Credit: Elspeth Robertson

This photograph, taken from a helicopter, is of the lava dome at Volcan de Colima volcano, Mexico in November 2009. Volcan de Colima has been active throughout history with over 40 eruptions since the sixteenth century. The last explosive Plinian eruption was in 1913 blasting out the summit crater. Nowadays, eruptions tend to be effusive with eruptions of lava flows and the gradual build up of the volcanic dome. The dome is formed through extrusion of viscous lava that builds up into the flat-topped dome seen in the photo. Over time, the dome increases in volume and will eventually start to spill over the volcanic edifice creating spectacular incandescent rock falls.

The wispy looking fog you can see surrounding the dome is steam emanating from the dome, which despite its cool exterior, reaches temperatures of 380 degrees Celsius.

Science Snap (3): Earth’s biggest volcano?

Screen Shot 2013-09-10 at 10.09.48James Hickey is a PhD student in the School of Earth Sciences at the University of Bristol. A geophysicist and volcanologist by trade, his PhD project is focussed on attempting to place constraints on volcanic unrest using integrated geodetic modelling.

 

 

 

The newly discovered submarine Tamu Massif (pictured below), approximately 1500 km east of Japan, has been proposed as the world’s largest volcano. At ~450 km x 650 km it dwarfs Mauna Loa of Hawaii by a factor of 50 in its spatial extent, and is comparable in size to Olympus Mons on Mars (as well as the United Kingdom!).

The seismically-imaged Tamu Massif. Image credit: BBC News.

The seismically-imaged Tamu Massif. Image credit: BBC News.

What marks this volcano out as being so special is that rather than consisting of a group of individual volcanoes, it is believed to be one single system. Seismic studies have shown the layers of lava that build up the giant volcano all originate from one single vent. They then slope outwards from the centre to form a very broad shield-like massif.

Samples taken on the volcano by the Integrated Ocean Drilling Program show very little chemical variability and indicate an age of ~145 million years. At this time, Tamu Massif is believed to have formed at a triple junction between three tectonic plates. But quite how so much lava managed to make its way through the crust in potentially one prolonged event remains unclear. Equally intriguing is the prospect of more of these structures existing – now we have unearthed one from its hiding place, maybe many more will follow…

The Cascades: A carbonate geochemist’s point of view

UntitledKT Cooper is a PhD student in the School of Earth Sciences at the University of Bristol. A carbonate geochemist by training, she is currently on a three-month secondment to Houston, Texas, USA working with Exxon Mobil.

Recently, I was lucky enough to visit a fellow Bristol Earth Sciences PhD student in Vancouver, Washington for a weekend of volcano-spotting (and hiking) in the Cascades. As a non-volcanologist, I was just excited to get some fresh air, good weather and great company for a few days and didn’t really give a thought to the prospect of seeing volcanoes. All I can say, in hindsight, is that I was foolish to think of them as merely a backdrop for our weekend. They were totally breath-taking, awe-inspiring and now I can really understand why so many of my peers are fascinated with them.

Mt Hood in the Cascades, Portland, USA. Credit: Katherine Cooper

Mount Hood in the Cascades, Portland, USA. Credit: Katherine Cooper

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