What is the instrument to measure volcano?

Question

What is the instrument to measure volcano?

Answer 1

There isn't any one instrument to 'measure' a volcano, infact, you can't 'measure' a volcano. If you're referring to its height, they use an instrument that measures distance, and angle. They select a place at sea level, or a previously known height, then they point the instrument at the peak, measure the distance, and angle it is at. Then they use the equation:

cos x=o/h

o=hcos x.

Where o is the height, h is the distance and x is the angle.

If you're referring to the strength of the eruption then sesimometers, (shaking) and they measure the height of the plume and the amount of ash.

Answer 2

seismometers and seimographs