A seismometer is commonly used to measure volcanic activity, detecting seismic waves produced by movements within the Earth's crust. Other instruments include tiltmeters to measure ground deformation and gas sensors to monitor emissions of gases like sulfur dioxide. Additionally, satellite technology can provide valuable data on volcanic activity by capturing thermal and gas emissions from above.
Volcanic Explosivity Index
There is no single instrument used to "measure a volcano" as was asked. Chemical analysis of gases and lava samples is conducted in the laboratory. Lasers are used in conjunction with GPS and other information networks to log change in the size and shape of the volcano. Certainly we keep track of seismic activity. And these are just primary evaluations we do to study a volcano.
scientists use seismometers to measure the earthquake below the volcano.
-JLO
A seismograph is used to measure seismic activity that might preclude a volcanic eruption, but it is not used to measure the magnitude of a volcano like it is used to measure the magnitude of an earthquake or nuclear explosion. Volcanologist use the Volcanic Explosive Index to measure a volcanic eruption's magnitude.
Strain gauges, tilt meters and creep meters as well as high precision GPS may be used to measure surface deformations.
Use may also be made of synthetic aperture radar and a process known as InSAR where the radar is used to create a series of very accurate (mm scale) topographic maps of an area either from a satellite or aircraft. These are then compared to each other and any difference is highlighted. This process is known as interferometry. If any deformation is occurring, this will be recorded other time and the interferometry process will highlight exactly where.
An anemometer is the instrument that measures wind direction using a wind vane.
lectometer
a scale
A ruler or tape measure.
an 'ammeter'
This instrument is a balance.
An instrument that measures heat and cold is called a thermometer.
A calorimeter measures heat. In contrast, a thermometer measures temperature.A thermometer bolometer - an instrument that measures heat radiation; extremely sensitive calorimeter - a measuring instrument that determines quantities of heatHeat is measured with a ThermometerThermometerThermometer or calorimeterThermometerthermometerHeat is measured with a thermometer.
An anemometer is the instrument that measures wind direction using a wind vane.
A thermometer measures molecular energy.
a calender
ruler
An aeroplane
spirometer
grams
A ruler
a creep meter