The exhibit says that the most reliable sign of a volcanic eruption is probably earthquakes in the area of the volcano. Other signs can be gas emissions and surface deformation which is kind of like when lots of pressure builds up in the magma chamber in the volcano before the volcano erupts, and it causes cracks on the surface of the volcano.

Photo courtesy of USGS

 

 Now that you've completed this part of your training session, here's a fun experiment that you can do to make your own volcano explode.