Volcanoes
volcanic neck
A deposit of hardened magma in a volcano's pipe.
dike
A slab of volcanic rock formed when magma forces itself across rock layers.
sill
A slab of volcanic rock formed when magma squeezes between rock layers.
cinder cone
A steep, cone-shaped hill or small mountain made of volcanic ash, cinders, and bombs piled up around a volcano's opening.
island arc
A string of islands formed by the volcanoes along a deep-ocean trench.
composite volcano
A tall, cone-shaped mountain in which layers of lava alternate with layers of ash and other volcanic materials.
dormant:
A volcano that is not currently active, but that may become active in the future.
volcano
A weak spot in the crust where magma has come to the surface.
shield volcano
A wide, gently sloping mountain made of layers of lava and formed by quiet eruptions.
Which continents contain volcanoes
All of them
What sequence of events could lead to magma becoming soil?
Crystallization followed by exposure and weathering.
The Hawaiian volcanoes are examples of what type of volcano
Shield
Where can classic examples of shield volcanoes be found?
The Hawaiian volcanoes are classic examples of shield volcanoes. The eruption is not always in one large vent, but in can occur in fissures. The lava that is emitted from Hawaii begins to cool as it reaches the surface of the Earth. The cooling lava causes many wonderful appearances
A hot spot is an area where material from deep within the mantle rises and then melts, forming magma
True
Volcanoes that form along a mid-ocean ridge occur at a diverging plate boundary
True
What are the two main transport mechanisms of lava
Tubes and channels
Which of the following is not one of the main volcano shapes
Vented volcano
Dissolved minerals trapped in magma under tremendous pressure provide the force for a volcanic eruption.
false
The viscosity of magma depends upon its silica content and its
temperature.
Which of the following helps to determine how easily magma flows
the amount of silica in the magma
Volcanic belts form along
the boundaries of Earth's plates.
geothermal activity:
Energy produced from the Earth's intense interior heat.
A quiet eruption may produce this type of slow moving, cooler lava that hardens to form rough chunks
aa
element
substance that cannot be separated or broken down into simpler substances by chemical means
visocsity
A liquid's resistance to flowing.
pipe
A long tube through which magma moves from the magma chamber to Earth's surface.
Ring of Fire
A major belt of volcanoes that rims the Pacific Ocean.
batholith
A mass of rock formed when a large body of magma cools inside the crust.
silica
A material found in magma that is formed from the elements oxygen and silicon
If geologists detect many small earthquakes in the area near a volcano, what can they infer about the volcano? b. It is probably about to erupt. c. It is extinct. d. It is a good source of geothermal energy.
...
Which of the following is NOT found at converging oceanic plate boundaries
...
Which of the following is not a method or instrument used to predict volcanic eruptions? a. seismographic monitoring c. tiltmeters b. underground microphones d. surveillance by satellite
...
What is the name for the region of volcanic activity in the Atlantic Ocean
The Mid-Atlantic Rift
Which is more likely to be dangerous-a volcano that erupts frequently or a volcano that has been inactive for a hundred years? Why?
a volcano that hasn't been active for a hundred years because of viscosity which is the resistance to flow and one that has been inactive for a hundred years would have a low viscosity and would stick more for a better but more dangerous explosion.
hot spot
An area where magma from deep within the mantle melts through the crust above it.
A mass of rock formed when a large body of magma cools inside the crust is called a
batholith.
Granite is an example of:
both : Igneous Rock and Magma that has cooled below the earth's surface
Granite is an example of
both Igneous rock and Magma that has cooled below the earth's surface
Geologic processes that assist in the formation of metamorphic rock include
both: tectonic folding and faulting
When ash, cinders, and bombs build up in a steep pile around a volcano's vent, the result is a
cinder cone volcano ** not sure**
Magma that hardens vertically underneath the surface will form a sill.
false
The opening through which magma flows through a volcano to the Earth's surface is a caldera.
false
string of volcanic landforms along a convergent boundary
island arc
Magma flows easily when it is low in ______, a material made of oxygen and silicon
silica
compound
substance in which two or more elements are chemically joined.
The resistance of a liquid to flowing is called ___
viscosity
The crater is the bowl-shaped area around a volcano's central vent.
true
The greater the viscosity of a liquid, the slower it flows.
true
Which temperature is typical of magma?
1000 degrees Celsius
crater
A bowl-shaped area that forms around a volcano's central opening; a large round pit caused by the impact of a meteoroid.
geyser
A fountain of water and steam that builds up pressure underground and erupts at regular intervals.
pahoehoe
A hot fast-moving type of lava that hardens to form smooth ropelike coils.
According to the rock cycle, which of the following transitions are possible? Assume an unlimited number of steps
An intrusive igneous rock becomes a sedimentary rock. A sedimentary rock becomes soil. A metamorphic rock becomes an extrusive igneous rock. All of the above are possible
According to the rock cycle, which of the following transitions are possible? Assume an unlimited number of steps.
An intrusive igneous rock becomes a sedimentary rock. A sedimentary rock becomes soil. A metamorphic rock becomes an extrusive igneous rock. All of the above are possible.
physical property
Any characteristic of a substance that can be observed or measured without changing the composition of the substance.
chemical property
Any property of a substance that produces a change in the composition of matter
A lava flow cools as it moves away from the vent. How would this affect the surface appearance of the lava flow
Each layer of overlapping lava cools down with the other creating a ripple-like appearance after the lava becomes rock
What could cause an igneous rock to become soil?
Exposure and weathering
What combination of processes can transform a metamorphic rock to sediments
Exposure, weathering and erosion.
What combination of processes can transform a metamorphic rock to sediments?
Exposure, weathering and erosion.
When magma undergoes crystallization above ground, what type of rock results?
Extrusive igneous rock
What is pillow lava? How did it get its name
Fluid lava erupted or flowing under water may form a special structure called pillow lava. Such structures form when molten lava breaks through the thin walls of underwater tubes, squeezes out like toothpaste, and quickly solidifies as irregular, tongue-like protrusions. This process is repeated countless times, and the resulting protrusions stack one upon another as the lava flow advances underwater. The term pillow comes from the observation that these stacked protrusions are sack- or pillow-shaped in cross section. Typically ranging from less than a foot to several feet in diameter, each pillow has a glassy outer skin formed by the rapid cooling of the lava by water. Much pillow lava is erupted under relatively high pressure created by the weight of the overlying water; there is little or no explosive interaction between hot lava and cold water. The bulk of the submarine part of a Hawaiian volcano is composed of pillow lavas
In terms of a volcano, what are bombs?
Fragments of fluid or partially fluid lava or rock larger than 64 millimeters in size that are blasted into the air by volcanic explosions. Bombs are ejected during the eruption in a semi-solid, or partial molten, condition, while blocks are ejected during the eruption in a solid state. Volcanic bombs undergo widely varying degrees of aerodynamic and/or impact shaping, depending on their fluidity, during the flight through the atmosphere and subsequent impact with the ground. Based on their shapes after they hit the ground, bombs are variously described, in the following graphic terms:
Where is the world's largest volcano located
Hawaii
Hardened magma in a volcano's pipe remaining after softer rock around it has eroded away is a batholith
false
How is ash different from ordinary household dust
In general, surfaces should be vacuumed to remove as much ash as possible from carpets, furniture, office equipment, appliances, and other items. Portable vacuum systems equipped with high-efficiency particulate filtering systems are recommended whenever possible. The severity of ash intrusion depends on the integrity of windows and entrances, the air intake features, and the care exercised to control the transport of ash into a building or home via shoes and clothing. Care should also be taken to avoid further contamination during the emptying, cleaning, and maintenance of vacuum equipment. In hot climates, where windows are permanently open, or absent, clean up of houses may be needed several times per day. Clean up inside should only be undertaken after the outside areas have been well cleared.
If geologists detect many small earthquakes in the area near a volcano, what can they infer about the volcano?
It is probably about to erupt
aa
Lava that is cooler and slower-moving is called aa
lava
Liquid magma that reaches the surface; also, the rock formed when liquid lava hardens.
Which of the following is an accurate list of some of magma's physical properties?
Liquid, ~1000 degrees Celsius, cools above or below ground
Which of the following is an accurate list of some of magma's physical properties?
Liquid, ~1000 degrees Celsius, cools above or below ground.
Which of the following processes would result in magma
Melting intrusive igneous rock
Which of the following processes would result in magma?
Melting intrusive igneous rock.
Which of the following rock types form from placing other rocks under heat and pressure
Metamorphic rock
What type of volcanic eruption is the most destructive?
Plinian
Hardened magma in a volcano's pipe remaining after softer rock around it has eroded away is a batholith.
false
What are the most important methods and instruments used to predict volcanic eruptions?
Seismic Monitors Monitoring a mountain's seismic activity was one of the first methods used to predict volcanic eruptions. An increase in earthquakes can be a sign of an impending eruption. Researchers use seismic monitors to track the many small tremors that occur around a volcano. Modern seismometers can record the intensity, escalation, and epicenters of earthquakes. In Hawaii, researchers have more than 60 seismic monitoring stations on the Big Island alone.
lava flow
The area covered by lava as it pours out of a volcano's vent.
Why is rock cycle a more appropriate term than rock pathway in most instances?
The end point is often the same as the starting point.
How long did the eruptive period of Paricutin last?
The eruption began in 1943 and ended in 1952.
pyroclastic flow
The expulsion of ash, cinders, bombs, and gases during an explosive volcanic eruption
caldera
The large hole at the top of a volcano formed when the roof of a volcano's magma chamber collapses.
magma
The molten mixture of rock-forming substances, gases, and water from the mantle.
What is the name of the world's largest volcano? Where is it located? When was its last eruption? What type of volcano is it
The name of the world's largest volcano is Mauna Loa. it can be found in the United States Hawaii and Pacific Ocean. its last eruption was in 1984 CE. it is a shield volcano.
vent:
The opening through which molten rock and gas leave a volcano.
magma chamber
The pocket beneath a volcano where magma collects.
What are the three main volcano shapes? What are the elements that all the different volcano types have in common? Describe each of these elements
The three main shapes of volcanoes are scoria cone which is straight sides with steep slopes and large summit crater. The second shape is a shield volcano which is very gentle slpes and conves upward. The third is a stratovolcano which is gentle lower slopes, but steep upper slopes and concave upward. It is a small summit crater. volcanic vent is an opening exposed on the earth's surface where volcanic material is emitted. All volcanoes contain a central vent underlying the summit crater of the volcano. The volcano's cone-shaped structure, or edifice, is built by the more-or-less symmetrical accumulation of lava and/orpyroclastic material around this central vent system. The central vent is connected at depth to a magma chamber, which is the main storage area for the eruptive material. Because volcano flanks are inherently unstable, they often contain fractures that descend downward toward the central vent, or toward a shallow-level magma chamber. Such fractures may occasionally tap the magma source and act as conduits for flank eruptions along the sides of the volcanic edifice. These eruptions can generate cone-shaped accumulations of volcanic material, called parasitic cones. Fractures can also act as conduits for escaping volcanic gases, which are released at the surface through vent openings called fumaroles.
On which continents can volcanoes be found
Volcanoes are found on every continent.
What is the Mid-Atlantic Rift?
There are also other areas of intense volcanism under the Atlantic Ocean. This is referred to as the Mid-Atlantic Rift, and is an area that is being rifted apart. Two plates are moving in opposite direction, and the Earth "heals" the wound by the lava of the volcanoes.
extinct volcano
Volcanoes that have been dormant for millions of years, and are not expected to erupt again
What determines the viscosity of magma? What else determines whether a volcano will erupt violently or calmly?
Volcanic eruptions could be thought as a continuum between two end members. At one extreme is the gentle effusion of lava. Most Hawaiian eruptions would be a examples of this type of eruption. At the other extreme is the explosive ejection of ash from a vent. The May 18, 1980 Mount St. Helens eruption would be an example of this type of eruption. The two main factors that influence how a volcano will erupt areviscosity and gas content. Both are related to the composition of themagma. Hawaiian volcanoes tend to erupt basalt, which is low in viscosity and low in gas content (about 0.5 weight percent). The gas that is present can readily escape and little pressure builds up in the magma. At the other extreme, rhyolite magmas are very viscous and can contain a lot of gas (up to 7-8 weight present). As the magma moves into the vent and the pressure drops, the gas wants to escape. The magma is very sticky and resists the expansion of the gas bubbles. Ultimately, enough bubbles grow and expand to blow the magma into ash size fragments and eject them violently into the atmosphere.
What features form as an oceanic plate moves across a hot spot
When an oceanic plate moves along hot spots, they gradually form a series of volcanic mountains
What are the most common types of volcanic eruptions? Which type is the most destructive? Give an example of the most destructive type
Within these two broad eruption categories, there are several typical eruption varieties. The most common eruption types are: Plinian Eruptions: These awesome eruptions can inflict serious damage on nearby areas -- the eruption that buried Pompeii and Herculaneam was a Plinian eruption. They are initiated by magma with very high viscosity and gas content. The powerful upward thrust of the expanding gases propels pyroclastic material as high as 30 miles (48 km) in the air, at hundreds of feet per second. The eruption, which can last hours or even days, produces a towering, sustained eruption plume. This dumps a huge amount of tephra, fallen volcanic material, on surrounding areas (usually more to one side, depending on how the wind blows). Additionally, a Plinian eruption can produce extremely fast moving lava flows that destroy everything in their path. Hawaiian Eruptions: Generally, these eruptions are not very destructive or explosive. They don't thrust much pyroclastic material into the air, producing instead a relatively sluggish flow of low-viscosity, low-gas-content lava. This flow can take a couple of different forms. The most impressive display is the fire fountain, a fountain of bright orange lava pouring hundreds of feet in the air, for a few minutes or sometimes several hours. The more typical eruption style is a steady lava flow from a central vent, which can produce wide lava lakes, ponds of lava forming in craters or other depressions. Lava flows and spatter from fire fountains can certainly destroy surrounding vegetation or trees, but the flow is usually slow enough that people have plenty of time to make it to safety. Hawaiian eruptions are so named because they are common to Hawaii's volcanoes. Strombolian Eruptions: These eruptions are fairly impressive but not particularly dangerous. They thrust small amounts of lava 50 to a few hundred feet (15 to 90 meters) in the air, in very short bursts. The lava has a fairly high viscosity, so gas pressure has to build to a high level before it will thrust the material upward. These regular explosions can produce impressive booming sounds, but the eruptions are relatively small. Strombolian eruptions generally don't produce lava flows, but some lava flow may follow the eruption. These eruptions produce a small amount of ashy tephra.
The huge hole left by the collapse of a volcanic mountain is called a
caldera.
Tall, cone-shaped mountains in which layers of lava alternate with layers of ash are called
composite volcanoes.
A substance made of two or more elements that have been chemically combined is a(n) ____
compound
The Pacific Plate is located under the Pacific Ocean. Its movement has created the Island Arc and the Ring of Fire. This plate demonstrates ____
convergent boundaries
Which two transitions can magma undergo?
crystallization above ground and crystallization below ground
Magma that forces across rock layers hardens into a
dike.
If a volcano's magma is high in silica, the volcano will probably
erupt explosively.
A dormant volcano is erupting or may erupt in the near future.
false
In volcanic areas, groundwater heated by magma is a source of
geothermal energy
molten rock above ground
lava
The main hazard from a quiet volcanic eruption is
lava flows
location of most volcanoes
plate boundaries
What can be used to identify a substance or to predict how it will behave
physical and chemical properties
The long tube in the ground that connects the magma chamber to Earth's surface is called the
pipe
Three quarters of dry land on earth is covered by which type of rock?
sedimentary rock
The viscosity of magma depends on its ___
silica content
What landform is created when magma squeezes between rock layers to form a hardened slab of rock
sill
A batholith is a mass of rock that forms when a large body of magma cools inside the crust
true
Geysers are formed when groundwater is heated by nearby magma
true
Magma sometimes forces its way out of the side of a volcano through a vent.
true
When magma hardens in a volcano's pipe, the result will eventually be a landform called a
volcanic neck
