Which statement accurately describes a pyroclastic flow?
Which statement accurately describes a pyroclastic flow? Pyroclastic flows, which consist of hot gases infused with incandescent ash and lava fragments, can reach many miles away from their sources because they are nearly frictionless and are driven by gravity.
Which of the following describes the movement of the North American and Caribbean plates?
Which of the following describes the movement of the North American and Caribbean Plates? The Caribbean Plate is moving to the east and the North American Plate is moving to the west.
What is the action of lava flows out of the interior is called?
A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.)
What type of volcanic cone is illustrated in the gigapan image?
This pan shows the basaltic-andesitic cinder cone known as SP Crater and the greater San Francisco Volcanic Field. The pan was taken at an elevation of roughly 1,900 meters AMSL (above mean sea level) from the crater's southeastern side; the crater's maximum elevation is nearly 2,125 meters AMSL at the crater rim.
Which of the following describes a pyroclastic flow quizlet?
Which of the following describe a pyroclastic flow? It is a very dangerous volcanic hazard. It is also known as a nuée ardente. Choose all of the hazards associated with volcanic ash.
What is pyroclastic flow quizlet?
Pyroclastic Flow. Pyroclastic flows are high-density mixtures of hot, dry rock fragments and hot gases that move away from the vent that erupted them at high speeds. They may result from the explosive eruption of molten or solid rock fragments, or both.
What is the movement of the Caribbean plate?
The Caribbean Plate is moving eastward about 22 millimeters per year in relation to the South American plate. In Venezuela, much of the movement between the Caribbean Plate and the South American Plate occurs along the faults of Boconó, El Pilar and San Sebastián.
What kind of plate motion formed the eastern Caribbean islands?
Motion along its northern boundary (in the plate boundary zone region) is dominantly strike-slip (sideways motion between the plates), with a small component of subduction (one plate sinks under the other plate).
How does lava flow happen?
Lava forms when magma erupts from a volcano. As pressure is released gases, dissolved in the magma, bubble out so the composition of lava changes. Most lava flows are formed by the eruption of hot (around 1200oC) basalt magma, (see video clip above).
What is lava flow in volcano?
Lava flows are streams of molten rock that pour or ooze from an erupting vent. Lava is erupted during either nonexplosive activity or explosive lava fountains.
What type of volcano is SP Crater?
cinder cone SP Crater, 40 km (25 mi) north of Flagstaff, is an excellent example of a cinder cone, and its associated lava flow extends for 7 km (4.3 mi) to the north of the cone.
Which types of volcanoes are composed of alternating layers of pyroclastics and lava?
stratovolcanoes Composite volcanoes (stratovolcanoes) have been the sources of some of the more famous and destructive eruptions, such as those of Mount St. Helens, Vesuvius, and Krakatoa. Built up over millions of years, they consist of alternating layers of lava and pyroclastic debris that can approach slopes as steep as 45 degrees.
How is a volcanic crater connected to a magma chamber?
During volcanic eruptions, molten magma and volcanic gases rise from an underground magma chamber, through a tube-shaped conduit, until they reach the crater's vent, from where the gases escape into the atmosphere and the magma is erupted as lava.
How did Crater Lake Oregon form quizlet?
The lake was formed after the collapse of an ancient volcano, posthumously named Mount Mazama. This volcano violently erupted approximately 7,700 years ago. That eruption was 42 times as powerful as the 1980 eruption of Mt.
How does pyroclastic flow form?
Pyroclastic flows can also form when a lava dome or lava flow becomes too steep and collapses. Pyroclastic flows often occur in two parts. Along the ground, lava and pieces of rock flow downhill. Above this, a thick cloud of ash forms over the fast-moving flow.
What does pyroclastic flow mean?
A pyroclastic flow is a hot (typically >800 °C, or >1,500 °F ), chaotic mixture of rock fragments, gas, and ash that travels rapidly (tens of meters per second) away from a volcanic vent or collapsing flow front. Pyroclastic flows can be extremely destructive and deadly because of their high temperature and mobility.
Is the Caribbean plate convergent divergent or transform?
transform plate In the Caribbean Sea, the U. S. Virgin Islands lie along a transform plate boundary where the small Caribbean Plate moves eastward past the oceanic part of the North American Plate.
How does the Caribbean plate interact with other plates?
On the western edge of the plate is a continuous subduction zone where the Cocos, Panama, and North Andean Plates are all converging with the Caribbean Plate. The Cocos Plate is subducting beneath the Caribbean Plate, while the Caribbean Plate is subducting below both the Panama Plate and the North Andean Plate.
What type of tectonic plate is the Caribbean plate?
oceanic tectonic plate The Caribbean Plate is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off the north coast of South America.
How did the Caribbean volcanoes form?
The largest group of the Caribbean Islands were formed by volcanoes erupting from the ocean floor while many other islands broke off the North American continent millions of years ago. Several of the smaller islands are a result of coral buildup peeking through the ocean's surface.
What is lava flow in a volcano?
Lava flows are streams of molten rock that pour or ooze from an erupting vent. Lava is erupted during either nonexplosive activity or explosive lava fountains.
Where do lava flows occur?
They are very common on fast-spreading mid-ocean ridges such as the East PacificRise. Sheet flows form at much higher eruption rates than pillow flows. The high eruptionrates allow rivers of lavas to form that can flow across the seafloor.
How did lava form?
Since it is lighter than the solid rock around it, magma rises and collects in magma chambers. Eventually, some of the magma pushes through vents and fissures to the Earth's surface. Magma that has erupted is called lava. Some volcanic eruptions are explosive and others are not.
How does Sunset Crater get its lava?
Sunset Crater appeared in the winter of 1064-65 when molten rock sprayed out of a crack in the ground high into the air, solidified, then fell to earth as large bombs or smaller cinders. As periodic eruptions continued over the next 200 years, the heavier debris accumulated around the vent creating a 1,000 foot cone.
What type of lava does Sunset Crater have?
Sunset Crater Volcano rises over part of the Bonito Lava Flow created during its eruption.
Which is formed from alternate solidification of both lava and pyroclastics deposits?
Composite or Stratovolcanoes (Fig. 5.14) erupt both lava and pyroclastic deposits. The slopes of stratovolcanoes are therefore composed of lava flows alternating with layers of pyroclastic deposits.
What type of volcano has steep slopes made of alternating layers of ash and silica lava?
stratovolcanoes Some of the Earth's grandest mountains are composite volcanoes–sometimes called stratovolcanoes. They are typically steep-sided, symmetrical cones of large dimension built of alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs and may rise as much as 8,000 feet above their bases.
Which of the following describes a volcanic crater?
A crater is a bowl-shaped depression, or hollowed-out area, produced by the impact of a meteorite, volcanic activity, or an explosion.
How is a volcanic crater formed?
They are formed by blasts or other explosive eruptive phenomena, including phreatic and phreatomagmatic processes. Some craters persist long after eruptions have ceased, but they will eventually be degraded and removed by erosion. Other craters are buried by later eruptions or filled by lava domes growing in them.
How did Crater Lake Oregon form?
Crater Lake was formed by the fall of a volcano. Mount Mazama, a 12,000-foot-tall volcano, erupted and collapsed approximately 7,700 years ago, forming Crater Lake.