Between a Rock and a Hard Place

Supervisor profile #3: Dr Matt Watson

Elspeth Robertson November 4, 2013

Dr Matt Watson

Senior Lecturer in Natural Hazards

PhD (2000) “Remote Sensing of Tropospheric Volcanic Plumes”

1) The Twitter challenge: Describe your PhD in 140 characters (if you can remember it)

I used ground- and satellite-based data to quantify volcanic emissions in order to look at volcanic plumbing systems and plume chemistry.

2) What was the best part of your PhD?

Fieldwork with Clive Oppenheimer and Peter Francis. Their schoolboy excitement and English eccentrism coupled with a significant mischievous streak (mostly Clive) set against the backdrop of Etna, Masaya and Soufriere Hills made for some memorable experiences. [Read More]

Science Snap (10): The impact of eruptions

Elspeth Robertson October 31, 2013

Mel Auker brings us our Science Snap this week…

Many people are aware of the May 1980 eruption of Mount St. Helens in Washington State, USA. Common photographs of the huge VEI 5 eruption show the large, billowing eruptive column rising into the stratosphere.

Less iconic are images of the destruction left behind, demonstrating the after-effects of the eruption. The US president at the time, Jimmy Carter, flew over St. Helens soon after and said the area looked “more desolate than a moonscape.” Now, more than 30 years on, the landscape still displays reminders of the awesome power of nature. Below are a selection of photographs taken in August 2011.

From top left, clockwise: 1. “Miner’s Car”, the remains of a car situated approximately 15 km from the volcano at the time of the eruption; 2. Trees flattened by the debris flow; 3. Tree trunks in Spirit Lake, approximately 8 km north of the volcano; 4. Hummocky avalance deposits. Credit: Melanie Auker

The top left photograph is of “Miner’s Car“, which has been left in place as a monument approximately 15 km NE of St. Helens. The heat of the eruption burnt all the exposed paint off the car, though the bumper (at the right of the image) is still largely undamaged. The top right photograph shows large trees flattened by the eruption, mantling the topography and identifying the direction of flow.

The bottom left photograph shows the huge number of tree trunks present in Spirit Lake, approximately 8 km north of St. Helens. As well as flattening trees, the eruption tore thousands from the ground which were deposited in the lake. The volume of material emplaced in the lake has reduced its surface elevation by over 60 m. The bottom right photograph depicts the rounded mounds (hummocks) that form part of the debris avalanche deposit to the north of the volcano. They are formed of relatively intact rocks that once formed the volcano’s summit.

Power within the rift

Elspeth Robertson October 28, 2013

Lying just under the Earth’s surface, the East African Rift is a region rich in geothermal resources. Exploitation of this clean and green energy source is steadily been gaining momentum. What is the geological mix that makes the Rift Valley ripe for geothermal power and how is it being tapped?

The East African Rift, stretching from Djibouti to Mozambique, marks the trace of a continent slowly tearing apart. At rates of about 1-2 cm per year, the African continent will one day split into two separated by a new ocean.

When continental rifting occurs, volcanism shortly follows. As the continent steadily stretches apart, the Earth’s crust thins allowing an easier path for buoyant magma to rise up. Where the magma cracks the surface, volcanoes build up. Dotting the Rift Valley are many active, dormant and extinct volcanoes. Famously active ones include Nyiragongo in the Democratic Republic of Congo, Ol Doinyo Lengai in Tanzania and the bubbling lava lake at Erta Ale volcano in Ethiopia. [Read More]

Science Snap (8): White Island erupts!

Elspeth Robertson October 17, 2013

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