Question: Do volcanoes shape the landscape and if they do how and why?

James Verdon answered on 27 Jun 2012:

Hi capp,

Of course volcanoes shape the landscape – have you ever seen images of the tall cone-shaped volcanoes like Mount Fuji:

http://en.wikipedia.org/wiki/Mount_Fuji

Volcanoes spew out lava, which is hot molten rock. As the lava cools, it solidifies. So the volcano is constantly building itself up with piles and piles of solidified lava, as well as layers of ash as well.

One of the largest examples is the Mauna Loa volcano on Hawaii. The sea floor around Hawaii is 5,000m deep, and the volcanic mountain reaches an elevation of about 4000m. So the total height from sea floor to peak is 9000m. That is more than Everest (which is not a volcano), which is about 8000m. The only reason Everest is at a higher elevation is because it starts at a higher level. Mauna Loa is actually a bigger mountain, but it has to start on the sea bed, not on land like Everest.

Sometimes, however, volcanoes can erupt explosively. Then, rather than creating a mountain, they will blow away a crater. These volcanic craters are often called calderas: all that’s left of the volcano is a big hole in the ground. The island of Santorini in Greece is a good example of this:

All that’s left is a ring of islands around the edge of the crater, and a big hole in the middle created by explosions, that has now been filled with water.