Q:

What are active, dormant and extinct volcanoes?

A:

Every volcano has its own eruptive history, and most can be classified into three main types that are based on the volcano's general form and eruptive pattern. Categorizing a volcano as active, dormant or extinct is one way of acknowledging its eruptive history, though these categories are necessarily inexact and subjective.

A volcano is considered active if it has erupted within known history, which, according to the Global Volcanism Program, is usually defined as within the past 10,000 years or since the Ice Age. Volcanoes that are currently erupting or have shown signs of unrest, such as gas discharges or triggering earthquakes, are also classified as active volcanoes.

A dormant volcano is one that has not erupted for the past 10,000 years but could erupt again. Once a dormant volcano erupts, it then falls into the category of active volcano. The Yellowstone Caldera in Yellowstone National Park, for example, has not erupted for 600,000 years as of 2014, but scientists believe it is a sleeping or dormant volcano and could still erupt in the future.

An extinct volcano, on the other hand, is one that experts don't expect to erupt ever again because it has been cut off from its supply of magma. Classic examples of extinct volcanoes include the chain that created the Hawaiian Islands.

Learn More

Related Questions

  • Q:

    What causes a volcano to erupt?

    A:

    A volcano erupts when the pressure of a subterranean pool of magma becomes great enough to crack the earth's crust. Whether the eruption results in a violent explosion or a slow seepage depends on several different factors, according to How Stuff Works.

    Full Answer >
    Filed Under:
  • Q:

    What are the three main types of volcanoes?

    A:

    The three main types of volcanoes are composite, shield and cinder cone volcanoes. Each type of volcano is formed a different way and possesses specific characteristics indicative of its type.

    Full Answer >
    Filed Under:
  • Q:

    What were the dates of Mount Etna's last two eruptions?

    A:

    As of 2014, the two most recent flank eruptions of Italy's Mount Etna were in 2014 and in 2008 to 2009. Etna is one of the world's most active volcanoes, with nearly constant lava flow and related geologic activity.

    Full Answer >
    Filed Under:
  • Q:

    Who are famous volcanologists?

    A:

    Three of the more famous volcanologists in history were David A. Johnston and husband and wife Maurice and Katia Krafft. The married couple dedicated their adult lives to documenting volcanic eruptions on film before being killed by a volcanic eruption in Japan, according to "Volcano World, a Department of Geosciences publication at the Oregon State University (OSU).

    Full Answer >
    Filed Under:

Explore