Predicting exactly when a volcano will erupt is next to impossible. Today geologists are becoming much more accurate in making the public aware that a volcano is showing signs that it may erupt in the near future.

In the months before Mt. St. Helens erupted geologists knew the mountain was getting restless. A magnitude 4.1 earthquake was recorded on March 20 (about 2 months before the large eruption). Many shallow earthquakes were recorded over the next seven weeks. Magma moving higher and higher inside the mountain was causing these earthquakes. As the magma rose it formed a large bulge on the north flank. This bulge was growing daily and the geologists knew that an eruption was soon to be.

What the authorities did was evacutate most of the people in and near the mountain. Some decided to stay. Almost everyone that was near the eruption was instantly killed. In all, 57 people died. Without the evacuation perhaps as many as 30,000 deaths would have been attributed to Mt. St. Helens fury.

The geologists in the photo are measuring a growing fissure near the lava dome in Mt. St. Helens crater. As magma rises the fissure will grow wider telling the geologists that the magma is rising again.

Scientists can not stop a volcano from erupting but with constant monitoring they can warn and evacuate people and save lives.

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