About Volcanic Domes

Volcanic domes, also known as lava domes, can be found within the craters or overflows of much larger more volatile composite volcanoes, such as the volcanoes of the Lesser Antilles.

Growth

• A volcanic dome is created when lava that does not have the power to travel great distances piles out of the vent of a volcano and collects around the vent. The U.S. Geological Survey explains that the collected lava quickly cools and hardens before shattering, with pieces collecting around the sides of the volcano.

Types

• San Diego State University reports volcanic domes to be of varying sizes with a variety of slope angles. It is common for volcanic domes to form with thick steep slopes, but lower profile slopes can be created as a dome forms.

Composition

• Volcanic domes can be created from a variety of substances found within volcanos, such as basaltic andesite and rhyolite. Crystal-rich dacite is found in many volcanic domes, while others can be formed from obsidian, which is volcanic glass.

Time

• The Santiaguito Dome in Guatemala is the site of the longest known dome building event ever recorded. The Santiaguito Dome began growing in 1922 and as of 2009 was still expelling lava and still growing.

Examples

• Volcanic domes are found throughout the world in association with much larger composite volcanoes such as Mont Pelee in Martinique. Lassen Peak and the Mono Domes in California are examples of volcanic domes.