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The following photos are meant to give you a flavor of what it is like to work on a Hawaiian volcano. They illustrate some of the techniques that are used to study active volcanoes, most of which are also used to study the rest of the world's volcanoes. Keep in mind also, that there are lots of indoor techniques that are equally important for understanding what a volcano is doing. Important examples of these are the analysis of seismic signals and geochemical studies of erupted lavas and gases.
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Electronic Distance Measurement![]() EDM stands for Electronic Distance Measurement. This is the view from behind a cluster of EDM reflectors looking back towards the EDM "gun". It isn't really a gun, but rather a sophisticated laser that can measure very precisely the time it takes for a laser beam to make the round-trip from the "gun" to the reflectors, and back. Using this time, the known speed that the laser travels (the speed of light), and correcting for air temperature and pressure, the distance can be determined to a precision of 1 part per million (i.e. 1 mm over a distance of 1 km). |