This is an image of a pyroclastic flow going down the slopes of a volcano to the sea.
Click on image for full size
Image from: U.S. Geological Survey, photo by B. Yount
Mt. Pelee is not a very tall volcano, in fact it is an example of what is called a "lava dome". It had a big eruption in 1902 which wiped out most people in a town downslope.
During the eruption, a burning cloud of hot ash and gases swept into the town. A similar eruption is illustrated in this picture of an Alaskan volcano.
Survivors of this eruption included one man who was in an underground jail cell, as well as sailors who were off-shore and witnessed the destruction of the city from a distance. Comments by these eyewitnesses included the following:
- "The mountain was blown to pieces, there was no warning."
- "It was like a giant oil refinery."
- "There was hurled straight toward us a solid wall of flame. It sounded like a thousand cannon."
- "The wave of fire was on us and over us like a flash of lightning. It was like a hurricane of fire."
- "The town vanished before our eyes."
Shop Windows to the Universe Science Store!
Learn about Earth and space science, and have fun while doing it! The games
section of our online store
includes a climate change card game
and the Traveling Nitrogen game
You might also be interested in:
Ash is formed as a volcano erupts when rocks made by the volcano blow apart into millions of tiny pieces. The rocks are still very hot, because they just formed from lava. If the hot rocks come into contact...more
Cinder cones are simple volcanoes which have a cone shape and are not very big. Compare the size of this volcano to the strato-volcano in this image. They are usually made of piles of lava, not ash. During...more
Lava can move in two ways, wide flat lava flows, or through channels which squeeze the lava into a small area. The fastest lava flows move at about 6 mi/hr, an easy jog, but they average between 2/3 and...more
Plates at our planetís surface move because heat in the Earthís core causes molten rock in the mantle layer to flow. We used to think the Earthís plates just surfed on top of the moving mantle, but now...more
Many kinds of surface features are clues to a sliding lithosphere. Two types of features can form when plates move apart. At ocean ridges, the crust splits apart to make room for molten mantle rock. Continental...more
When magma is erupted onto the surface in the form of lava, it becomes silicate rock. With each different eruption of the volcano, lava which comes to the surface is made of slightly different chemicals,...more
As the Earth cools, hot material from the deep interior rises to the surface. Hot material is red in this drawing, under an ocean shown in blue green. The hotter material raises the nearby layers, and...more