by Staff Writers
Bochum, Germany (SPX) May 31, 2012
How processes below a volcano are linked to seismic signals at the surface is described by scientists from the petrology group of the Ruhr-Universitat Bochum and their colleagues from Bristol in a paper published in Science. They analyzed the growth of crystals in the magma chamber and used results obtained from the monitoring of seismic signals. The research could ultimately help to predict future volcanic eruptions with greater accuracy.
A few kilometers below the volcano a liquid reservoir exists, the magma chamber, which feeds volcanic eruptions. Zoned crystals grow concentrically like tree rings within the magma body and contain critical information.
Individual zones have subtly different chemical compositions, reflecting the changes in physical conditions (for example the temperature) within the magma chamber and thus give an indication of volcanic processes and the timescales over which they occur. During a volcanic eruption, crystals are thrown to the surface in conjunction with the liquid parts of the magma, which quickly petrifies and thus can be sampled.
Mount St. Helens
An increase in crystal growth is also evidence of pulses of magma entering a growing chamber within the volcano, which finally triggers the eruption. In this way, the researchers confirmed what has long been anticipated: a clear evidence of the correlation between crystal growth (fresh magma input) and volcanic seismicity.
Time scales: An expertise of Bochum
For these kinds of studies the researchers use information on how fast certain elements move through minerals (diffusion). The determination of diffusion rates in minerals is another research focus of the petrologists in Bochum.
A relevant study for millions of people
This forensic approach applied by the English-German team can be also applied to other active volcanoes to shed new light upon the nature and timescale of pre-eruptive activity. This will help scientists to evaluate monitoring signals at restless volcanoes and enable better forecasting of future eruptions.
K. Saunders, J. Blundy, R. Dohmen, K. Cashman (2012): Linking petrology and seismology at an active volcano, Science, doi: 10.1126/science.1220066
University of Bristol
Petrology at RUB
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Forest Recovering from Mt. St. Helens Explosion
Greenbelt MD (SPX) May 31, 2012
Mt. St. Helens exploded 32 years ago on May 18. It began with a small series of earthquakes and culminated with the volcano erupting, a cataclysmic collapse of the flank of the mountain and the largest landslide in recorded history. This time series of data shows the explosion and subsequent recovery of life on the volcano. Landsat, a satellite program operated by NASA and the U.S. Geologi ... read more
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