By Nick Gilbert
Researchers from the Ruhr-Universität Bochum(RUB) and their associates from Bristol have described how the growth of crystals is connected to volcano seismicity. They studied the crystal growth in the magma chamber and utilized the results that are attained from the observation of seismic signals. The study can help estimate future volcanic eruptions with greater accuracy.
Magma crystals: False colour image of zoned orthopyroxene crystal used in forensic-style analysis of Mount St Helens 1980 eruption. Different colours reflect different chemical compositions. Yellow, for example, denotes particularly high amounts of iron
The magma chamber is found a few kilometers beneath the volcano and zoned crystals are grown like tree rings inside the chamber. Each zone has slightly different chemical compositions, which alter the physical properties in the magma chamber, for instance the temperature. Thus, the crystals provide a sign of volcanic eruptions and the periods of occurrence.
RUB team evaluated the crystals’ chemical composition from Mount St. Helens and connected these information to seismic signals of the fatal 1980 Mount St. Helens volcanic eruption. The scientists discovered that peaks in the growth correlated with higher seismicity in the months earlier to the eruption.A large number of people live nearby volcanoes, which may explode with little or no warning. This causes extensive damage, disturbance to aviation and affects climate globally. Hence, correlating seismic observations at the surface to the underground processes is a major on-going issue for volcanologists. The method applied by the RUB team can also be used to other active volcanoes.