This image shows the remains of a lahar on the slopes of Mt. Akutan in Alaska.
Click on image for full size Image from: U.S. Geological Survey, photo by Robert McGimsey
Lahars are mudslides caused by the mixing of volcanic ash and debris with water. They can occur when the heat from a volcano melts snow and ice on the volcano's summit, or if an eruption disturbs a crater lake.
Lahars can cause great environmental and economic damage. They can cover fertile fields and topple buildings.
Lahars are very dangerous, and anyone caught in the path of one is in great danger of death from severe crushing injuries.
How did life evolve on Earth? The answer to this question can help us understand our past and prepare for our future. Although evolution provides credible and reliable answers, polls show that many people turn away from science, seeking other explanations with which they are more comfortable....more
Lassen Peak is an example of what is called a "volcanic dome". The most recent eruptive activity occurred at Lassen Peak in 1914-1917. The eruption began on May 30, 1914, with a small vent near the summit...more
On 16 December 1631 between 6:00 and 7:00 am an unexpected eruption began. Darkness fell over the entire area around the volcano, and there were continuous earthquakes. During the night of 16-17 December,...more
Volcanic eruptions come in many different forms. Shield volcanoes usually only spew lava and hot gases. These lavas flow slowly down the mountain with speeds of 15 miles per hour or slower. Composite volcanoes...more
Mt. Mazama was once among a cluster of stratovolcanoes stretching along the Washington and Oregon coast. This cluster of volcanoes includes Mt. Hood, Mt. Rainier, and Mt. St. Helens. The magma chamber...more
One of the most powerful volcanic explosions in the history of the world occured at Krakatoa in the last century. Krakatoa was formerly a volcanic island located between Java and Sumatra. It was located...more
Mt. Etna is Europe's largest active volcano. It is located in a region where the African plate meets the Eurasian plate. The last major eruption of Mt. Etna occurred in 1992. ...more
Mt. Pelee is not a very tall volcano, in fact it is an example of what is called a "lava dome". An extremely destructive eruption of Mount Pelee occurred in 1902. A coastal town, about 4 miles downslope...more