Did You Know?
On any given day, as many as 10 volcanoes may be spewing ash or lava somewhere on Earth.
One of the most violent but beautiful reminders that we live on a geologically restless planet are volcanic eruptions. Around 550 volcanoes have erupted at least once in historic times, and around 50 or 60 are active each year. On any given day, as many as 10 volcanoes may be spewing ash or lava somewhere on Earth.
Some volcanoes, such as Mount Etna in Italy, erupt almost constantly for years on end. Others, like Mount St. Helens, erupt rarely and sometimes extremely destructively. Like Etna and Mount St. Helens, many of the most dangerous and explosive erupters are stratovolcanoes, which are made of layers of ash and lava from previous eruptions. They tend to be steep-sided cone-shaped volcanoes and often rise strikingly above the surrounding landscape.