This is an image of Crater Lake in Oregon, USA.
Click on image for full size
Image from: U.S. Geological Survey
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 under Mt. Mazama took 15,000-40,000 yrs to form.
During the few centuries preceding the last, climactic eruption, at least two other large eruptions occurred. Ash and pumice from one of these eruptions extended into eastern Washington and western Nevada.
The last climactic eruption of Mt. Mazama occured 6850 years ago, over a number of months, and produced major outbursts of ash, lava, and hot vapors. Deposits from this series of eruptions have been found in 8 western states and 3 Canadian provinces.
Following the final series of eruptions, the cone of the volcano collapsed into the magma chamber, and Mt Mazama became dormant except for activity which formed a small cinder cone in the center (shown in this picture). The collapsed volcano filled with water and became what we now know as Crater Lake.
The Yakima Indians who lived near Mt. Mazama when it collapsed have a different story of what caused the mountain to fall.
Shop Windows to the Universe Science Store!
Our online store
includes issues of NESTA's quarterly journal, The Earth Scientist
, full of classroom activities on different topics in Earth and space science, as well as books
on science education!
You might also be interested in:
Volcanoes form when hot material from below risesand leaks into the crust. This hot material, called magma, comes either from a melt of subducted crustal material, and which is light and buoyant after...more
Cinder cones are simple volcanoes which have a bowl-shaped crater at the summit and only grow to about a thousand feet, the size of a hill. They usually are created of eruptions from a single opening,...more
Ash is made of millions of tiny fragments of rock and glass formed during a volcanic eruption. Volcanic ash particles are less than 2 mm in size and can be much smaller. Volcanic ash forms in several ways...more
Lava can move in broad flat lava flows, or it can move through tight channels or tubes. Lava flows tend to cool quickly and flow slowly. The fastest lava outside of channels moves at about 6 mi/hr an easy...more
Plates at our planet’s surface move because of the intense heat in the Earth’s core that causes molten rock in the mantle layer to move. It moves in a pattern called a convection cell that forms when...more
Many kinds of surface features are clues that our lithosphere is sliding. Two types of features can form when plates move apart. At mid ocean ridges, the bottom of the sea splits apart and new crust is...more
Magma consists of remelted material from Earth's crust and fresh material from other regions near the Earth's surface. When magma is erupted onto the surface in the form of lava, it becomes silicate rock....more