Volcanism seminar
for the excursion to Sicily 2004
Michael Wack
8.6.2004

Geophysical Surveillance Methods of Active Volcanoes

Abstract:

Nowadays more and more people live in the direct neighbourhood of active volcanoes. So it is very important to monitor these volcanoes to be able to predict eruptions and to protect lives and infrastructure. This is mainly achieved with geophysical methods. The still important classical methods like seismic and tilt measurements are today endorsed with the so called 'remote sensing' by satellites since it allows to survey large areas without having to install a lot of equipment in the site.

References:

Hans-Ulrich Schmincke: Vulkanismus, Wissenschaftliche Buchgesellschaft, Darmstadt 2000

Jacques-Marie Bardintzeff: Vulkanologie, Ferdinand Enke Verlag, Stuttgart 1999

Ollier Cliff: Volcanoes—An Introduction to Systematic Geomorphology, MIT Press, Cambridge MA (USA) and London (UK) 1975

http://vulcan.wr.usgs.gov/Monitoring

http://www.educeth.ch/stromboli/beso/pdf/monitoraggio-stromboli-en.pdf

http://volcanoes.usgs.gov/About/What/Monitor

http://www.esa.int

http://www.geo.uni-leipzig.de/~geosf/merapi/

http://flir.images.alaska.edu/

You can get the presentation and the handout at: http://www.skriptweb.de/geo

Geophysical Parameter	What are the reasons?	How to measure it?	What does it tell us?
seismic activity	Several typical signals Tremors Cracking of rocks due to the pressure of magma Landslides Normal tectonic earthquakes	Seismometers Acoustic flow monitors (AFM)	Tremors are one of the most important indicators for an eruption in the near future With multiple seismometers it's possible to locate the source position of the signals and probably to track its way Since no S-waves propagate through magma, you can locate magma chambers
deformations of the surface	Ascending magma expands the volcano. The slopes get steeper. After an eruption, the volcano deflates.	Tilt meters Electronic distance measuring (EDM) with laser light Satellite radar interferometry GPS	An increasing tilt of the volcano slopes is a strong hint for a lot of magma flowing into the volcano, which will probably conduct to an eruption
thermal variations	Ascending magma near the surface Hot gases	Thermometers at the ground Infra-red pictures from satellites from aircrafts from ground	An increase in temperature normally is a hint of magma approaching the surface. So it is common that an eruption will occur at a hot point
electrical, magnetic, gravitational variations	Movement of the magma in depth	Voltmeters, magnetometers, gravimeters	With numerical models one can try to reconstruct the internal structure and processes of the volcano

(c) Michael Wack 2004	http://www.skriptweb.de

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2004-05-26T15:39:21

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