How are volcanoes predicted?
There are several things volcanoes do before they erupt: They exhibit anomalous 1) seismic activity, 2) ground deformation, 3) gas emissions, and 4) thermal emissions. So scientists monitor changes in these characteristics and try to forecast the likelihood of an eruption. There are usually hours to day to weeks of warning for a volcano. The accuracy varies with volcano – sometimes a volcano shows all the signs of waking up, but then nothing happens. But for volcanoes that are closely monitored, the forecasts are very good and we are getting better at it all the time. Unfortunately, earthquakes exhibit no known warning signs more than seconds before the quake hits.
