How to Predict a Volcano Eruption

Until recently, volcanic eruptions were feared, but accepted as unavoidable and unpredictable natural phenomena. With improvements in monitoring technology, however, scientists are now usually able warn the public of an eruption before it takes place. If you don't happen to have a seismograph or correlation spectrometer on hand, don't worry. Here are some basic indications that a volcano might be about to blow.

Instructions

Difficulty: Moderate

1. Look for plumes of smoke or clouds of gas on or around the volcano that aren't typically there. As magma flows into the chambers beneath a volcano and rises to the surface, it can cause different gases to be released, which geologists keep a close eye on for changes in quantity or composition.
2. Look out for any changes in seismic activity near the volcano. Many volcanoes continuously give off rumbles or tremors, but a sudden increase in the number or strength of these quakes can indicate impending eruption.
3. Take note of strange activity that you may not immediately recognize as a tremor. While tremors may be obvious, rumbling and causing objects to rattle, they may also have seemingly no effect on a sturdy building and may just sound like a passing airplane or truck.
4. Observe any alterations in the shape or elevation of the ground in the surrounding area. Bulges, cracks or increased slope in the ground are all indicators of activity beneath.
5. Check with local rangers or members of the U.S. Geological Survey to see if the volcano has erupted in recent history. If it has, then geologists will have labeled it as an "active" volcano, which increase the likelihood of an eruption in the future.

Tips & Warnings

• Though it's tempting to check out lava flows and actively erupting volcanoes up-close, never get closer to them than your local authorities will allow.