How to Monitor Volcanic Activity

Measure the seismic activity of the volcano's surrounding area. Earthquakes and tremors occur near a volcano as it prepares to erupt. If the surrounding area experiences increased seismic activity, the likelihood of an eruption occurring increases as well. Additionally, the type of earthquake that occurs can indicate the current activity level of the volcano. A volcano tectonic earthquake is caused by the movement of magma, while a harmonic tremor earthquake occurs when magma pushes against rocks below the Earth's surface. Long-period earthquakes happen when increased gas pressure vibrates against the sides of the volcano.

Monitor the gas emissions from the volcano. Gases begin to escape from the volcano as magma nears the surface. Note the amount of volcanic gas that is emitted over an extended period of time. As the magma begins to elevate, the amount of gas released from a volcano increases.

Remotely monitor volcanic activity by using a satellite's sensor. Professionals can use satellites to detect any electromagnetic energy that's absorbed, reflected, radiated, or scattered by a volcano. Satellites can employ several different methods to monitor volcanic activity. Cold eruption clouds can be monitored from volcanoes by using data from two different thermal wavelengths. Sulfur dioxide from the volcano's gas can be monitored too. Satellites can also view thermal signatures to indicate heating on the ground prior, during or after a volcanic eruption.

Note changes in the ground that's surrounding the volcano. If the volcano appears to swell around its base, then it's likely that magma has accumulated near the surface. Measure the changes in a volcano's physical size over time, as well as the tip of the slope, to determine the timing of an impending eruption. If the volcano swelling is accompanied by earthquakes or gas emissions, then the volcano is likely very close to erupting.