A new approach to sensing volcanic rumblings
A model of Mount St Helens, Washington, USA. Image: Gross, Soueid Ahmed and Revil
If you go down beneath the surface, under the rugged exterior, and into the inner workings of volcanoes things get interesting. In a recent study, researchers from Australia and France have combined NCRIS enabled esys-eScript modelling software with inversion code in a new approach to capture first rumbles earlier, deeper, and in greater detail than ever before.
Surprise!
Volcanoes are inherently unpredictable and prone to surprise eruptions, rumbles and fiery ejecta. Despite having an array of tools to keep an eye on many restless and active volcanoes — often from the safe distance of a volcano observatory — a key challenge for volcanologists is to know exactly where and
when they might explode.
In the most recent example in Iceland, scientists were able to use seismic data to predict the eruption and get on the ground at a safe distance before the eruption. They did this using seismic data which started to increase in frequency and amplitude in a crate near Fagradalsfjall in the nation’s southeast.
Scientists descended on the area near an erupting volcano in Iceland's southwest on Sunday, as lava continued to pour from the crater near Fagradalsfjall, a mountain on the Reykjanes Peninsula since Friday.
They were able to predict the volcanic eruption using seismic data of the region. Video: Global News
Sensing the subsurface
Now, researchers have discovered a new way to reveal structure and movements below the rugged volcanic topography in brilliant and detailed 3D. In this new study, Professor Lutz Gross from The University of Queensland and AuScope’s SAM Program and his collaborators explain their innovative new approach to sensing topographically complex landscapes that sit atop active hydrothermal systems.
The approach involves the induced polarisation (IP) geophysical surveying technique and new sensors that can be placed across a rugged surface without being restricted by long cables. In essence, scientists can cast a wide ‘net’ over a volcano in any configuration and with any spacing that they like — the further apart the sensors are, the deeper one can look. This new technique offers supreme capability over cabled techniques that result in reduced data quality.
Induced polarization (IP) surveys involve injecting electrical current into the ground via time-series sensors (red-coloured) and then measuring current from receiving sensors (grey-coloured) after the charge has travelled through the rock mass. This data allows scientists to imagine the internal structure of volcanoes, which in turn could improve our understanding of hydrothermal systems and allow the monitoring of active volcanoes and the potential risk of collapse. Image: Gross, Soueid Ahmed and Revil
Press play
Once the researchers completed data collection in this study, they were then able to load it onto the computer into an AuScope enabled inversion code and combine it with surface topography data to generate a detailed 3D model. This model allowed the team to assess sensitivity over a particular volcanic environment, and also inform a more refined survey design — an iterative process that can be employed in future investigations.
A 3D generated model based on Mount St Helens, USA, Lutz Gross
This breakthrough in geo imaging will allow geoscientists to model large volcanic regions, create time-lapse geoelectrical models and discover new geothermal resources — an important finding for communities living in active volcanic settings like the Pacific ‘Rim of Fire’.
STORY IN A NUTSHELL
Researchers from The University of Queensland and France have combined NCRIS enabled esys-eScript geological modelling software an inversion code in a new way to help volcanologists capture first volcanic rumbles earlier, deeper, and in greater detail than ever before.
AUTHORS
Philomena Manifold,
Dr Andrea Codd and
Jo Condon