Volcanologists use many different kinds of tools including instruments that detect and record earthquakes (seismometers and seismographs) instruments that measure ground deformation (EDM, Leveling, GPS, tilt),instruments that detect and measure volcanic gases (COSPEC),instruments that determine how much lava is moving underground (VLF, EM-31), video and still cameras, infrared cameras and cameras that work remotely. This is by no means a complete list, volcanologists will use whatever tool they can to help them understand volcanoes.
sensors and thermal images
correlation spectrometer
show the pic of measuring balance of mass
No, nothing is used to measure the Richter scale. The Richter scale is used to measure the intensity of earthquakes.The Volcanic Explosivity Index (VEI) is used to provide a relative measure of the explosiveness of volcanic eruptions.
You would use a correlation spectrometer.
with tools
You measure the amount of baking soda put in he volcano
Volcanic Explosivity Index
Volcanoes are measured on the volcano explosivity index. See the link below for more information.
sensors and thermal images
correlation spectrometer
show the pic of measuring balance of mass
No, nothing is used to measure the Richter scale. The Richter scale is used to measure the intensity of earthquakes.The Volcanic Explosivity Index (VEI) is used to provide a relative measure of the explosiveness of volcanic eruptions.
You would use a correlation spectrometer.
Not by a long way.The caldera of Ngorongoro (the largest volcano near the serengeti) is huge, at 250km2, but that is nothing compared to Yellowstone, with a caldera of about 4000km2.however calderas don't look much like volcanos.Hawaii is perhaps the largest mountainous volcano, if you measure its height from the sea bed.
The arenal volcano is a cindercone volcano not a composite.
A Strato volcano or a composite volcano.