How do volcanoes change the Earth’s surface? Volcanic Landforms How do volcanoes change the Earth’s surface?

What you will learn What landforms lava and ash create. How the magma that hardens beneath Earth’s surface creates landforms. Other distinct features that occur in volcanic areas.

Landforms from lava and ash Shield volcanoes Cindercone volcanoes Composite volcanoes Lava plateaus

Shield Volcano *Lava* Thin layers of lava cool on top of one another A wide, gently sloping mountain forms gradually over time Example: Hawaiian volcanoes

Cinder Cone Volcano *Lava* Steep, cone-shaped hill or mountain Thick lava (high viscosity) builds up in cone producing ash, cinders, and bombs which pile up around vent after it explodes Example: Sunset Crater in Arizona

Cinders and Bombs

Composite Volcano *Lava* Tall, cone-shaped mountains in which layers of lava alternate with layer of ash Lava flows alternate with explosions i.e. Stratavolcano Example: Mount Fuji in Japan and Mount St. Helens in Washington state

Quick Check What are the 3 types of volcanoes? What are the shapes of each? Which are explosive and which are not? Which ones have lava?

Krakatau Explosion 1883 http://dsc.discovery.com/tv-shows/other-shows/videos/krakatoa-volcano-of-destruction-loudest-explosion-ever.htm

Lava Plateau *Lava* Thin, runny lava flows out of several long cracks in an area The lava travels far before cooling and solidifying Lava flood layers upon lava flood until a raised plateau is formed over millions of years Example: Columbia Plateau in Washington, Oregon, Idaho

Caldera *Lava* Huge hole caused by the volcano collapsing after explosive eruption empties magma chamber Crater Lake in Oregon, Mount Mazama Over time, ash breaks down and releases potassium and phosphorus that plants need. It results in fertile soil.

Volcanic Neck *Magma* Magma hardens in volcano’s pipe, soft rock wears away exposing solid magma Looks like giant tooth

Dike *Magma* Magma that forces itself across rock layers and hardens Underground, horizontal channels or tubes Broadens coasts of Hawaiian islands

Sill *Magma* Magma squeezes between horizontal layers and hardens Magma hardens ACROSS the layers.

Quick Check What is a caldera? What way does a dike go, horizontally or vertically? Which way does a sill go?

Batholith *Magma* Mass of rock formed when magma chamber cools inside crust Rough, jagged texture after weathering and erosion of land above batholith Ex: Half Dome in Yosemite National Park

Dome Mountain *Magma* Formed by small bodies of hardened magma which are forced upwards into dome shape

Geothermal Activity Magma a few km beneath earth’s surface heats underground water. Hot Springs- When groundwater is heated by a nearby body of magma or by a hot rock deep underground. The hot water rises to the surface and collects in a natural pool.

Geysers When rising hot water and steam become trapped underground in a narrow crack. Pressure builds until the mixture suddenly sprays above the surface. A fountain of water and steam that erupts from the ground is a geyser.

Geothermal Energy Water heated by magma can be used as a source of electricity. Steam from underground is piped into turbines and spins a wheel. The moving wheel in the turbine turns a generator that changes the energy of motion into electrical energy. California, New Zealand use it as electricity and Reykjavik, Iceland use this to heat their homes.

Quick Check What’s the difference between a hot spring and a geyser?

Can you guess the type of landform?

Indian Head Mountain, Montana

Laccolith at Fresno Canyon, north of Lajitas Laccolith at Fresno Canyon, north of Lajitas. Big Bend National Park, Texas. Photo credit: USGS Digital Data Series DDS-21 CD-ROM

Photograph by J.D. Griggs on 16 July 1990

Before the eruption After the eruption

photo by Tibi Marin “Magma Boulders”

John Day region in Oregon

Devil's Tower, WY Shiprock, New Mexico http://www.nps.gov/deto/faqs.htm Shiprock, New Mexico

United States India

Mount Aso vents a large cloud of steam at Japan's Aso National Park.

Belknap Volcano, Oregon USGS Photograph taken on October 1, 1984, by Lyn Topinka

Sill can be seen as the dark layer of rock to the left of the snow field. Glacier National Park. Photo credit: USGS Digital Data Series DDS-21 CD-ROM

Dike on south side (left) of Shiprock, a volcanic neck, in the distance. Photo credit: USGS Digital Data Series DDS-21 CD-ROM

Pu`u `O`o Eruption on Flanks of Kilauea, Hawaii Photograph by C. Heliker on 2 June 1986

Olympus Mons: One hundred times larger than Mauna Loa

The Moon Many craters on Earth’s moon were believed to be filled by lava flows.

Venus This picture (mapped via radar in 1994) show the immense extent of Venus's volcanism. She has more in the way of lava flows than the Earth has rivers. Copyright © Dr B.M.Gunn 1998-2003

Volcanoes on Io This image shows what it might look like standing on the surface of Jupiter's moon, Io. A smoldering volcano can be seen against the large image of Jupiter. Smoke added with Photoshop. Background image of Jupiter is a Cassini spacecraft image taken in 2001 while flying by Jupiter on its way to Saturn (Credit: NASA/JPL/University of Arizona).

Neptune's Largest Moon Credit: Voyager 2, NASA Triton: Neptune's Largest Moon Credit: Voyager 2, NASA The above picture of Triton was taken in 1989 by the only spacecraft ever to pass Triton: Voyager 2. Voyager 2 found fascinating terrain, a thin atmosphere, and even evidence for ice volcanoes on this world of peculiar orbit and spin.

Geysers on Triton Credit: NASA, Voyager Project, Copyright Calvin J. Hamilton Frozen, Solid Nitrogen!!! Explanation: In August of 1989 NASA's Voyager 2 spacecraft passed by Neptune, the most distant of the solar system's gas giant planets. Its encounter with Neptune climaxed with its closest approach to Neptune's largest moon Triton. From a distance of about 24,000 miles the robot space probe surveyed Triton's surface, whose temperature averages nearly -400 degrees Fahrenheit (-240 degrees C), and discovered surprising evidence of a complex and active world. For example, the prominent dark streaks in this image seem to come from small volcanoes and may consist of nitrogen frost mixed with organic compounds ejected during geyser-like eruptions.

Image Credits Belknap84_belknap_shield_volcano_10-01-84.jpg Belknap Shield Volcano, Oregon. View from McKenzie Pass. USGS Photograph taken on October 1, 1984, by Lyn Topinka. http://images.google.com/imgres?imgurl=http://vulcan.wr.usgs.gov/Imgs/Jpg/Belknap/Images/Belknap84_belknap_shield_volcano_10-01-84_med.jpg&imgrefurl=http://vulcan.wr.usgs.gov/Volcanoes/Belknap/Locale/framework.html&h=412&w=600&sz=86&hl=en&start=1&um=1&tbnid=QL62pJIDkHz1ZM:&tbnh=93&tbnw=135&prev=/images%3Fq%3Dshield%2Bvolcano%26svnum%3D10%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN http://images.google.com/imgres?imgurl=http://volcanoes.usgs.gov/Imgs/Jpg/Kilauea/32512553-023_large.jpg&imgrefurl=http://volcanoes.usgs.gov/Products/Pglossary/SpatCinCone.html&h=500&w=800&sz=65&tbnid=yh2fxh2p2gCTcM:&tbnh=89&tbnw=143&prev=/images%3Fq%3Dcinder%2Bcone%26um%3D1&start=2&sa=X&oi=images&ct=image&cd=2 http://volcanoes.usgs.gov/Products/Pglossary/aa.html http://volcanoes.usgs.gov/Products/Pglossary/pahoehoe.html 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