Predicting volcanoes
Volcanologists use several instruments to monitor volcanoes and predict their eruptions.
Seismometer
One of the tools used to monitor volcanoes is a seismometer. Seismometers detect the movement of rocks in the earth's crust, which could sometimes be associated with the rising of magma beneath awakening volcanoes. Since eruptions are usually preceded by tremors in the ground, or earthquakes, these devices help predict possible eruptions by measuring the intensity and direction of the tremors. The modern seismometer design used by scientists today was created by John Milne, an English seismologist and geologist.
Gravimeter
Gravimeters are used to detect rising magma levels underneath the surface of the earth by measuring the electric currents given off by the magma. Flowing magma can also be detected by these instruments.
Landsat
Scientists measure the temperatures and gases created by volcanoes using a Landsat satellite. The satellite uses infrared sensors to monitor changes in the temperature or gas levels of the volcano. If there is an increase in sulfur dioxide or other gases, an eruption is possible to occur.
Tiltmeter
A tiltmeter measures changes in ground elevation near volcanoes. If these changes occur, it means that the magma levels are changing. The ground will bulge out if magma rises closer to the surface.
These devices are only a few of the many machines used by volcanologists. There are still several more instruments scientists use, and they are still looking for new ways to predict volcanic eruptions.