What makes volcano erupts

An excellent example of successful forecasting occurred in Volcanologists from the U. Geological Survey accurately predicted the June 15 eruption of the Pinatubo Volcano in the Philippines, allowing for the timely evacuation of the Clark Air Base and saving thousands of lives.

Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Discover World-Changing Science. Read more from this special report: A Guide to Volcanoes.

Get smart. Sign up for our email newsletter. Sign Up. Learn and look out for volcano risks and warning signs. Become familiar with volcano hazard map and danger zones. Be aware of secondary risks such as landslides and flash floods. Support vulnerable people to evacuate or shelter in place safely. Prepare and practice evacuating or sheltering in place. Watch: how to prepare for a volcanic eruption. Featured document. Volcanoes: Key Messages. Related links.

What is a disaster? Prepare your family and home. Partner with us Appeals Evaluations of our work Donor response. Read more: Curious Kids: why doesn't lava melt the side of the volcano? Volcanoes have many different shapes and sizes, some look like steep mountains stratovolcanoes , others look like bumps shield volcanoes and some are flat with a hole a crater or caldera in the centre that is often filled with water.

For example, if you try to blow bubbles in cooking oil though a straw, the bubbles can escape quite easily because the cooking oil is runny. It is the same with volcanoes. When magma rises towards the surface gas bubbles start to form. Whether or not they can escape as the magma is rising affects how explosive the eruption will be. Lava is what we call magma when it reaches the surface. However, where the magma is very sticky, like jam or peanut butter, and if it contains a lot of bubbly gas then the gas can get stuck and eruptions can be very powerful and explosive, like the recent eruptions at Fuego volcano in Guatemala.

In explosive eruptions the frothy, bubbly magma can be ripped apart into tiny bits called volcanic ash. This is not ash like you get after a barbecue or fire, it does not crumble away in your fingers. It is very sharp and is dangerous to breathe in. Some explosive volcanoes can send ash high up into the sky and it can travel around the world over different countries.