Volcanoes
What causes volcanoes to erupt?
A volcano can look like it would do little harm. They can stay silent, or dormant, for a long time. You never know when they may wake up. Knowing when they will erupt is very important. Do you know why?
Many people live near a volcano. Volcanoes can cause a lot of damage. That is why we need to learn about them. Scientists study them to keep us safe.
Some volcanoes are very active. They erupt a lot. A volcano in Hawaii is like that. It has erupted for three decades. It never explodes like some others. It just belches out lava. The lava comes out slow and thick. The lava moves very slowly. You can walk faster than the lava. Why is it helpful to know its speed?
Some volcanoes may sit quiet for a long time. One day they just suddenly erupt. Quick events like these can cause many problems. If people are not aware, they cannot prepare. They must be ready to move to safety.
These fast eruptions can drop a lot of ash onto an area. Ash is very fine. It is about the size of sand. It can bury homes and cars. The hot lava can start fires. The blast can even knock down trees.
The pressure builds inside the volcano. This happens over many years. This is what happened at Mt. St. Helens. It sat quiet for 150 years. All the while, the pressure built up. In 1980, changes could be seen and felt. There were small earthquakes. A bulge was seen on the mountain. Why do you think these changes were important to notice?
Some scientists want to learn more about volcanoes. They study how often a volcano may erupt. They want to know what to expect. People depend on what they learn. Why is it important to learn about volcanoes?
