Is sometimes triggered by water rainfall in a displaced mass?
Changes in Hydrologic Characteristics – heavy rains can saturate regolith reducing grain to grain contact and reducing the angle of repose, thus triggering a mass movement. Heavy rains can also saturate rock and increase its weight.
What feature of water is an internal cause of slope failure?
Since water is heavier than air, this increases the weight of the soil. Weight is force, and force is stress divided by area, so the stress increases and this can lead to slope instability. Water has the ability to change the angle of repose (the slope angle which is the stable angle for the slope).
Why would landslides be less likely to occur in areas that receive only moderate amounts of rainfall?
The principal difference between a debris flow and a mudflow is ________. Why would landslides be LESS likely to occur in areas that receive only moderate amounts of rainfall? Large amounts of rain increase cohesion. Small amounts of rain increase cohesion.
What type of mass movement moves the most material averaged over the earth’s land and over long times quizlet?
What type of mass movement moves the most material, averaged over the Earth’s land and over long times? The many, small events move the most material. As rocks move to streams in many places, such as Pennsylvania, the slow and steady motions are more important than the few dramatic events.
What is accurate about the planet’s climate system group of answer choices?
What is accurate about the planet’s climate system? The wind blows because heating near the equator drives convection cells in the atmosphere, and the winds appears to curve to the left or right over the surface of the planet because of friction produced by the spherical planet’s rotation beneath the atmosphere.
What tectonic setting is primarily responsible for producing Crater Lake?
subduction
What causes tectonic plates to move?
The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift.
What tectonic setting is primarily responsible for producing?
Push-together, pull-apart and slide-past. What tectonic setting is primarily responsible for producing Olympic National Park as well as the hills on which San Francisco is built? A. Hot-spot.
What is the plate tectonic setting for Crater Lake quizlet?
What tectonic setting is primarily responsible for producing Crater Lake? Feedback: Crater Lake, the hole left by the cataclysmic eruption of Mt. Mazama, sits above a subduction zone, where one tectonic plate goes below another as they come together. The cartoon above illustrates a specific geologic process.
What is the approximate diameter of the rim of the Okmok Caldera quizlet?
What is the approximate diameter of the rim of the Okmok Caldera? 6miles 2.
What is the origin of Crater Lake volcano quizlet?
Formed from when Mt. Manzama (Strata-Volcano with felsic magma) erupted 6600 years ago, which is also the most recent explosion. In the explosion the magma chamber emptied completely and the top collapsed, creating the crater. The crater is now a lake with extremely clear water, 5 miles long.
What is the origin of Crater Lake 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. The basin or caldera was formed after the top 5,000 feet of the volcano collapsed.
What makes up most of volcanic gas?
Magma contains dissolved gases, which provide the driving force that causes most volcanic eruptions. By far the most abundant volcanic gas is water vapor, which is harmless. However, significant amounts of carbon dioxide, sulfur dioxide, hydrogen sulfide and hydrogen halides can also be emitted from volcanoes.
What record does Crater Lake hold?
608 m
Where is the course of most rhyolitic magma?
Where is the course of most rhyolitic magma? Magma is below the ground and has more trapped gasses; lava is the same except for gasses and on the surface.
Which component of magma is the highest and lowest in value?
Felsic magma has the highest silica content of all magma types, between 65-70%. As a result, felsic magma also has the highest gas content and viscosity, and lowest mean temperatures, between 650o and 800o Celsius (1202o and 1472o Fahrenheit).
What elements has the highest amount in the magma?
Oxygen, the most abundant element in magma, comprises a little less than half the total, followed by silicon at just over one-quarter. The remaining elements make up the other one-quarter. Magmas derived from crustal material are dominated by oxygen, silicon, aluminum, sodium, and potassium.
What type of magma has the lowest silica content?
MAGMA COMPOSITION AND ROCK TYPES
| SiO2 CONTENT | MAGMA TYPE | VOLCANIC ROCK |
|---|---|---|
| ~50% | Mafic | Basalt |
| ~60% | Intermediate | Andesite |
| ~65% | Felsic (low Si) | Dacite |
| ~70% | Felsic (high Si) | Rhyolite |
What causes magma in the lower mantle of earth to rise up toward the crust?
Magma has the tendency to rise because it weighs less than surrounding hard rock (liquids are less dense than solids) and because of the pressure caused by extreme temperature. The pressure is reduced as magma rises toward the surface. Dissolved gases come out of solution and form bubbles.
How deep in the earth is magma?
“What we are now saying is that with just a trace of carbon dioxide in the mantle, melting can begin as deep as around 200 kilometers. “When we incorporate the effect of trace water, the magma generation depth becomes at least 250 kilometers.”
What three things determine how thick or thin magma is?
The three things that determine how thick or thin magma is temperature, silica content, and gas content.
What is the force of magma beneath to move?
A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upwards.
Where is the largest volcano?
Hawaii’s Mauna Loa
Can a volcano cause an earthquake?
Volcanically-caused long period earthquakes are produced by vibrations generated by the movement of magma or other fluids within the volcano. Pressure within the system increases and the surrounding rock fails, creating small earthquakes.
What is the difference between magma and lava?
Scientists use the term magma for molten rock that is underground and lava for molten rock that breaks through the Earth’s surface.
What is the most powerful type of volcano?
A supervolcano must erupt more than 1,000 cubic km (240 cubic miles) of material, compared with 1.2 km3 for Mount St. Helens or 25 km3 for Mount Pinatubo, a large eruption in the Philippines in 1991. Not surprisingly, supervolcanoes are the most dangerous type of volcano.
Which is hotter magma or lava?
When geologists refer to magma, they’re talking about molten rock that’s still trapped underground. If this molten rock makes it to the surface and keeps flowing like a liquid, it’s called lava. They’re also the hottest variety of magma, reaching temperatures between 1,800 degrees to 2,200 degrees Fahrenheit.
Whats hotter fire or lava?
While lava can be as hot as 2200 F, some flames can be much hotter, such as 3600 F or more, while a candle flame can be as low as 1800 F. Lava is hotter than a typical wood or coal-buring fire, but some flames, such as that of an acetylene torch, is hotter than lava.