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Satellite
view of volcanoes finds the link between ground deformation and eruption
Satellite
view of volcanoes finds the link between ground deformation and eruption
Date:
April 3,
2014
Source:
University of Bristol
Summary:
Using satellite imagery to monitor which volcanoes are
deforming provides statistical evidence of their eruption potential, according
to a new study. Volcano deformation and, in particular, uplift are often
considered to be caused by magma moving or pressurizing underground. Magma
rising towards the surface could be a sign of an imminent eruption. On the
other hand, many other factors influence volcano deformation and, even if magma
is rising, it may stop short, rather than erupting.
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ESA's
Sentinel satellite, due for launch on April 3rd, should allow scientists to
test this link in greater detail and eventually develop a forecast system for
all volcanoes, including those that are remote and inaccessible.
Volcano
deformation and, in particular, uplift are often considered to be caused by
magma moving or pressurizing underground. Magma rising towards the surface
could be a sign of an imminent eruption. On the other hand, many other factors
influence volcano deformation and, even if magma is rising, it may stop short,
rather than erupting.
Dr Juliet
Biggs and colleagues in the School of Earth Sciences, with collaborators from
Cornell, Oxford and Southern Methodist University, looked at the archive of
satellite data covering over 500 volcanoes worldwide, many of which have been
systematically observed for over 18 years. Satellite radar (InSAR) can provide
high-resolution maps of deformation, allowing the detection of unrest at many
volcanoes that might otherwise go unrecognised. Such satellite data is often
the only source of information for remote or inaccessible volcanoes.
The
researchers applied statistical methods more traditionally used for medical
diagnostic testing and found that many deforming volcanoes also erupted (46 per
cent). Together with the very high proportion of non-deforming volcanoes that
did not erupt (94 per cent), these jointly represent a strong indicator of a
volcano's long-term eruptive potential.
Dr Biggs
said: "The findings suggest that satellite radar is the perfect tool to
identify volcanic unrest on a regional or global scale and target ground-based
monitoring."
The work was
co-funded by the UK Centre for Observation and Modelling of Earthquakes,
Volcanoes and Tectonics (COMET) and STREVA, a research consortium aimed at
finding ways to reduce the negative consequences of volcanic activity on people
and their assets.
"Improving
how we anticipate activity using new technology such as this is an important
first step in doing better at forecasting and preparing for volcanic
eruptions," said STREVA Principal Investigator, Dr Jenni Barclay.
Co-author
Professor Willy Aspinall added: "Global studies of volcano deformation
using satellite data will increasingly play a part in assessing eruption
potential at more and more volcanoes, especially in regions with short
historical records or limited conventional monitoring."
However,
many factors and processes, some observable, but others not, influence
deformation to a greater or lesser extent. These include the type of rock that
forms the volcano, its tectonic characteristics and the supply rate and storage
depth of magma beneath it. Thus, deformation can have different implications
for different types of volcanoes. For volcanoes with short eruption cycles, the
satellite record typically spans episodes that include both deformation and
eruption, resulting in a high correlation between the two. For volcanoes with
long eruption cycles, the satellite record tends to capture either deformation
or eruption but rarely both.
In the past,
radar images of the majority of the world's volcanoes were only acquired a few
times a year, but seismological data indicate that the duration of unrest
before an eruption might be as short as only a few days.
Dr Biggs
said: "This study demonstrates what can be achieved with global satellite
coverage even with limited acquisitions, so we are looking forward to the step-change
in data quantity planned for the next generation of satellites."
The European
Space Agency is planning to launch its next radar mission, Sentinel-1 in early
April. This mission is designed for global monitoring and will collect images
every six to twelve days. Using this, scientists should be able to test the
causal and temporal relationship with deformation on much shorter timescales.
Professor
Tim Wright, Director of COMET, added: "This study is particularly exciting
because Sentinel-1 will soon give us systematic observations of the ups and
downs of every volcano on the planet. For many places, particularly in
developing countries, these data could provide the only warning of an impending
eruption."
Story
Source:
The above
story is based on materials provided by University of Bristol. Note: Materials may be
edited for content and length.
Journal Reference:
- J. Biggs, S.K. Ebmeier, W.P, Aspinall, Z. Lu, M.E. Pritchard, R.S.J. Sparks, T.A. Mather. Global link between deformation and volcanic eruption quantified by satellite imagery. Nature Communications, 2014
Cite This
Page:
University of Bristol.
"Satellite view of volcanoes finds the link between ground deformation and
eruption." ScienceDaily. ScienceDaily, 3 April 2014.
<www.sciencedaily.com/releases/2014/04/140403084458.htm>.