What types of instruments do vulcanologist's use and what do they do?

Question

What types of instruments do vulcanologist's use and what do they do?

Answer 1

One of the earliest signs of an impending eruption is often a subtle change in seismic activity beneath a volcano. In cooperation with universities and state agencies, the USGS monitors seismic activity near volcanoes using networks of seismometers. When unusual activity is detected, more seismometers and other instruments may be installed by a response team to better determine if an eruption is likely.

earthquakes are monitored by installing seismometers that send information continuously via radio to a central recording site (observatory), scientists can determine the sizes and locations of earthquakes near a volcano. They look for specific types of earthquakes that are often associated with volcanic activity, including long- period volcanic earthquakes and volcanic tremor. An increase in the number or size of earthquakes beneath a volcano usually means that an eruption is more likely.

ground movements are measured: Ground deformation (swelling, subsidence, or cracking) is measured with a variety of techniques, including Electronic Distance Meters (EDM), the Global Positioning System (GPS), precise leveling surveys, strainmeters, and tiltmeters. EDMs use lasers to accurately measure changes in distance between benchmarks (fixed points) with repeated measurements. GPS makes use of satellites orbiting the Earth to determine and track the locations of points. Strainmeters and tiltmeters are used to monitor subtle changes in shape of the ground surface.



Volcanic gases are measured by instruments to measure sulfur dioxide and carbon dioxide can be mounted in aircraft to determine the quantity of gas being emitted on a daily basis. Such instruments can also be used in a ground-based mode. An instrument that detects carbon dioxide can be installed on a volcano and configured to send data continuously via radio to an observatory. Sulfur dioxide in volcanic clouds can also be measured from space with instruments aboard satellites.

Field observations by experienced volcanologists go hand in hand with more sophisticated equipment and techniques to form a complete system for monitoring volcanoes. Field observations may include water temperature and pH (acidity) measurements, or observations of ground cracking and new areas of avalanching rocks. An experienced observer can integrate many different types of data on the spot and design simple measurements to further assess the significance of volcanic unrest. There is no substitute for well-trained, experienced observers when trying to figure out how a volcano will behave.