Aspects of the geological landscape that Southern Utah is famous for – Pine Mountain, Veyo volcano and lava flows – come from volcanic activity in the area, all stemming from the supervolcano "Wah Wah Springs."
While Utah does not have any active volcanoes, several basalt flows in the West Desert area are only several hundred years old. In addition, eruptions of volcanoes in the western United States, including the Yellowstone caldera, could result in volcanic ash clouds and significant deposition in Utah.
Black Rock Spring in Utah's West Desert is home to a large deposit of Obsidian. Born from the volcanic activity in the area millennia ago, Obsidian is a smooth volcanic glass.
Yellowstone is one of the largest known volcanoes in the world and the largest volcanic system in North America. The volcano is found above an intra-plate hot spot that has been feeding the magma chamber underneath Yellowstone for at least 2 million years.
The St. George area cinder cones erupted as long ago as 1.4 million years and as recently as 27,000 years ago, reshaping the land by filling waterways with basalt and carving new canyons with their lava flows.
USGS scientists are currently working on this question. Mount Shasta doesn't erupt on a regular timescale. Research indicates that the volcano erupts episodically with ten or more eruptions occurring in short (500-2,000 year) time periods separated by long intervals (3,000-5,000 years) with few or no eruptions.
Scientists have discovered 240 cubic miles of semi-molten magma below the Long Valley Caldera, a supervolcano in eastern California near Mammoth Mountain. The long-dormant supervolcano is currently a 20-mile-long caldera, or a crater that forms after an eruption forces the mouth of a volcano to collapse.
Mt. Shasta is a stratovolcano made of alternating layers of lava and ash from previous eruptions. Mt. Shasta is an active volcano that has erupted at least once per 800 years for the past 10,000 years, with an increased eruption frequency of about once per 250 years over the past 750 years.
Mount Shasta is a potentially active volcano located within the southern part of the Cascade Range in Siskiyou County. It is the highest volcano in California, with an elevation of 14,179 ft. The stratovolcano last erupted in 1786, is believed to have been observed by French explorer Lapérouse.
Mount Whitney is not a volcano like most of its neighbors in California. Most of the mountain is made up of mostly granite, a type of igneous rock
Door Point Volcano was discovered in 1963 by Shell Oil Company in an exploratory oil well drilling. It is the only known volcanic structure in the northern and western Gulf of Mexico. It is thought to be Louisiana's only volcanic structure.
Although it is commonly believed that Lake Tahoe is volcanic in origin, the Lake Tahoe Basin was actually formed by geologic block faulting 25 million years ago. Several active volcanoes poured lava into the basin, eventually damming the outlet near the present town of Truckee.
The closest volcanic area to Los Angeles is the Coso Volcanic Field that lies just north of Ridgecrest, California, about 181 miles north of Los Angeles.
If Shasta erupted, it could put people in harm's way in the towns of Mount Shasta, Weed Yreka and Dunsmuir. The eruption would be capable of producing pyroclastic flows or surges when they do erupt — fast-moving flows of hot ash, rock and gas sweeping down the sides of mountains.
In volcanology, a lava dome is
a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano.
Examples of lava domes.
| Name of lava dome | Sollipulli lava dome |
|---|
| Country | Chile |
|---|
| Volcanic area | Southern Volcanic Zone |
|---|
| Composition | Andesite to Dacite |
|---|
A caldera-causing eruption is the most devastating type of volcanic eruption. It permanently alters the environment of the surrounding area. A caldera is not the same thing as a crater. Craters are formed by the outward explosion of rocks and other materials from a volcano.
Supervolcanoes occur when magma in the mantle rises into the crust but is unable to break through it and pressure builds in a large and growing magma pool until the crust is unable to contain the pressure. This can occur at hotspots (for example, Yellowstone Caldera) or at subduction zones (for example, Toba).
Lava Butte is part of the Newberry National Volcanic Monument.
| Lava Butte |
|---|
| Geology |
| Age of rock | About 7,000 years |
| Mountain type | Cinder cone |
| Last eruption | About 7,000 years ago |
A volcano which has not erupted in the past 10,000 years is often listed as extinct. The extinct volcano no longer has a lava supply. An extinct volcano is no longer near an active geologic hot spot, if it ever was. Dormant volcanos may still erupt, whereas extinct ones cannot or still may have one percent chance.
Composite volcano magma is felsic, which means it contains silicate-rich minerals rhyolite, andesite, and dacite. Low-viscosity lava from a shield volcano, such as might be found in Hawaii, flows from fissures and spreads.
Composite cones. Composite cones are some of the most easily recognizable and imposing volcanic mountains, with sloping peaks rising several thousand meters above the landscape. Also known as stratocones, composite cones are made up of layers of lava, volcanic ash, and fragmented rocks.
Cinder Cone and the Fantastic Lava Beds
| Cinder Cone |
|---|
| Mountain type | Extinct Cinder cone |
| Volcanic arc | Cascade Volcanic Arc |
| Last eruption | 1666 |
| Climbing |
Active volcanoes have a recent history of eruptions; they are likely to erupt again. Dormant volcanoes have not erupted for a very long time but may erupt at a future time. Extinct volcanoes are not expected to erupt in the future.
These fiery peaks have belched up molten rock, hot ash, and gas since Earth formed billions of years ago. Volcanoes are Earth's geologic architects. Some 1,500 volcanoes are still considered potentially active around the world today; 161 of those—over 10 percent—sit within the boundaries of the United States.
During the mid-Holocene, a maar was formed in central Colorado near the junction of the Colorado and Eagle Rivers west of the Gore Range. Today, this is known as Dotsero.
- Mount Saint Helens, Washington.
- Mount Rainier, Washington.
- Mount Shasta, California.
- Mount Hood, Oregon.
- Three Sisters, Oregon.
- Yellowstone Super Volcano (Special Mention)
Fumaroles are openings in the earth's surface that emit steam and volcanic gases, such as sulfur dioxide and carbon dioxide. A fumarole can vent for centuries or quickly go extinct, depending on the longevity of its heat source.
Instead, volcanoes are built by the accumulation of their own eruptive products -- lava, bombs (crusted over ash flows, and tephra (airborne ash and dust). A volcano is most commonly a conical hill or mountain built around a vent that connects with reservoirs of molten rock below the surface of the Earth.
