The first week of September was spent on yet another excursion, this time to the EUROVOLC Summer School on Mt Etna, focussed on “Understanding sub-surface volcanic processes”. EUROVOLC (The European Network of Observatories and Research Infrastructures for Volcanology) aims to promote interaction between volcano researchers and observatories across Europe, and part of its role is to provide training workshops for PhD and postdoctorate level researchers to learn about volcano monitoring.
Things kicked off with an icebreaker meal at our hotel in the sleepy town of Linguaglossa on the NE slopes of Etna, where I was introduced to the 30 or so fellow attendees. Almost all were PhD students and postdocs from across the world, with a huge range of interests from volcano ground deformation to landslides on the flanks of volcanic edifices. The first morning of the workshop focused on understanding seismicity related to volcanoes, including how to interpret different types of seismic signals produced by moving magma (see below).
For anyone interested, real time seismic data from Etna and Stromboli volcanoes can be accessed online here: http://www.ct.ingv.it/en/real-time-seismic-signal.html
After feasting on a three-course lunch (which we soon learned was to become the norm) we headed outside for a demonstration of seismic and infrasonic (sound wave) monitoring equipment, which ended up being filmed by a local news network for TV!
The second day involved an introduction to more monitoring techniques, such as measuring tilt of the ground, strain (change in volume due to stress) and changes in gravity. Shortly before lava fountaining episodes at Etna, tilt and strain start to decrease due to deflation, as the magma leaves a deeper reservoir and erupts. A negative gravity anomaly also accompanies these changes, due to the accumulation of gases/foam in the conduit feeding the eruption – the negative anomaly occurs because gases have a lower density than the rising magma and surrounding solid rock.
In the afternoon we got to have a go at setting up the gravimeter and making some measurements, before rounding off the day with lessons about what the crystals and chemistry of Etna’s lavas can tell us about its eruptive behaviour.
More updates on the EUROVOLC Summer School coming soon, including the Etna fieldtrip!