Making Leveling Measurements
Making Leveling Measurements
Here a number of geologists are making leveling measurements over an
active lava shield (the profile of Pu'u 'O'o cinder cone is in the
background). One geologist is using a level to sight on a barely-visible
leveling rod (arrow) that is being held vertical by an assistant. Another
assistant is holding another rod behind where this photo was taken, and
the fourth person takes notes. The back level rod person will then
leapfrog ahead and the level will also move forward to set up between
them. This time-consuming process is still the best way to get an idea of
the volume of a newly-erupted feature, and repeated measurements can show
volume changes through time.
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