Card Set Information
Geo final exam practice
What type of volcano is Augustine?
Augustine Volcano can produce this type of hazard when it collapses during large eruptions?
how long would it take for a tsunami coming from Augustine volcano to reach Homer, Alaska?
Magma is made at subduction zones by?
Wet partial melting
Decompression melting occurs at which two tectonic areas?
Hot spots, Mid ocean ridges
Shield volcanoes are common in which of the following plate tectonic setting?
What type of partial melting happens at subduction zones?
Wet Partial melting
Name the three plate tectonic regions on earth that produce volcanoes?
Hot Spots, Spreading centers, Subduction zones
Briefly describe decompression melting?
rising mantle rocks expand and as they move to lower pressures they can melt.
Briefly describe wet partial melting?
adding water to hot mantle rocks at subduction zones.
Volcanic earthquakes that show p and s waves are called?
How are VT earthquakes beneath a volcano located?
What is one way we monitor volcanoes?
This type of seismic signal happens when magma rise to the surface causing the volcano to resonate with a continuous vibration:
_______Volcano is exhibiting signs of unrest above its known background level?
________A hazardous eruption is imminent, underway, or suspected.
Volcano shows signs of unrest above known baseline levels.
Heightened unrest, with increased likelihood of eruption.
forecast to be imminent with significant ejection of ash, or eruption is underway and producing significant ash.
Typical background activity. No real threat to those in vicinity.
Elevated unrest. Closely monitored volcano.
Either limited hazards posed by an ongoing but small eruption, or escalating activity signifies increased potential for an eruption to occur.
Highly hazardous eruption imminent or underway.
Volcanoes that have erupted within the past 10,000 years, and usually erupt frequently are considered?
Volcanoes that have been active within the past 10,000 years, but not recently. They may erupt again, but have not erupted in a long while.
Volcanoes that have not erupted within the past 10,000 years and are not expected to ever erupt again. It is approximately 10 million years old.
volcanoes that have not erupted in a long time, and then suddenly surprise everyone by coming back to life.
Volcanoes that explode forcefully. They eject rock fragments out of the vent at high speeds. What type of hazard is this?
Ash fall/Ash clouds
Deadly, hot (200-700 celsius) avalanches of gas, rock fragments, fine powdery ash rushing down the slopes of volcanoes. What type of hazard is this?
Fast moving torrents of muddy, sandy, debris-laden water originating on the flanks of a volcano. What type of hazard is this?
Volcanic eruptions that dump large volumes of pyroclastic flows or landslides into water can cause?
What type of hazard has a typical speed of 1 to 10 km/hour, Usually slow enough that people can leave?
Basalt lava flow
All areas downwind from the volcano are at risk from what type of hazard?
Ash clouds and Ash fall
______ are natural (or human caused) processes that have the potential to wreak havoc, whether humans are threatened or not.
______describes the effects that those hazards may pose for people, property, crops, livestock or other infrastructure in a threatened area?
How many people fly above Alaskan volcanoes each day?
Tacoma, Washington is at risk from which of the following hazards producted by Mt. Rainier?
Mt. Redoubt caused damage to a KLM 747 jet aircraft. how much did this near-disaster cost?
Lahars impacted which of the following alaskan locations during the 2009 eruption of Mt Redoubt, Alaska?
Drift River oil terminal
How many people are at risk from pyroclastic flows from Vesuvious volcano, in Italy?
What % SiO2 is in Basalt?
What % SiO2 is in Andesite?
What % SiO2 is in Dacite?
What % SiO2 is in Rhyolite?
What is the size range for Ash?
What is the size range for Lapilli?
What is the size range for blocks and bombs?
Forms during collapse of the volcano into itself?
Smallest volcano. Made of all granular pyroclasts?
Volcanoes that form underneath glaciers?
Largest volcano by volume. Made of stacks of runny lava flows?
Steepest slope angle. Forms a perfect, tall, conical volcano shape?
Lava erups from a long crack in the ground. Common along mid ocean ridges?
Shield volcanoes have a very low slope angle because they are made of?
Runny lava flows
Volcanic rocks that are full of holes that represent trapped gas bubbles from foamy magna have which type of texture?
Inneous rocks that form as magma completely cools inside the earths crust and never erupts are called?
What does the VEI Scale represent?
Volcano Explosivity Index
How often do large, VEI 8 eruptions typically happen on earth?
1-2 million years
What gas can signify that a volcano might erupt soon?
Hawaiin style eruptions are _____ fountains, have ____Viscosity, ____SiO2 basalt magma and _____ exlosiveness?
Lava, Low, Low, Low
Strombolian eruptions are _____/Lapilli clouds, _____explosiveness, ______SiO2, _______Viscosity?
Ash, Moderate, Low, Low
Vulcanian eruptions are _____clouds, _____-_____ viscosity magma, _______-_______ SiO2, ______-_____ explosiveness?
Ash, medium to high, medium to high, moderate to high
Plinian style eruptions are _____Viscosity, _____gas content, _____ SiO2, ________ explosiveness
high, high, high, highly
Hawaiin erupts what type of magma?
Strombolian erupts what type of magma?
Vulcanian erupts what type of magma?
Plinian erupts what type of magma?
What is the difference between A'a and Pahoe'hoe lava flows?
A'a is slightly higher in viscosity, and flows slightly faster than pahoe'hoe, A'a is breaks itself up and rolls along the ground like a tank tread
Glassy rocks erupt ______causing no time for crystals to form?
Crystalline rocks ______ erupted and is composed of all _______?
Vesiculare rocks contains lots of trapped ____ bubbles?
Porphyritic contains large _______ floating among much smaller ______ and _______?
Glassy rocks are intrusive or extrusive?
Crystalline rocks are intrusive or extrusive?
Vesicular rocks are intrusive or extrusive?
porphyritic rocks are intrusive or extrusive?
Glass and trapped bubbles contained in volcanic rocks signifies that they are?
_______rocks are those that form from magma completely solidifying underneath the ground, that never erupted?
Glassy rocks have few if any _____?
Crystalline contains no ______?
Vesicular rocks are full of ______?
Porphyritic rocks have large _______, surrounded by ______?
Which volcanic rock textures represents magma that has cooled very slowly in the crust of the earth, and never erupted?
Magma that does not fragment, that flows out of the volcano in large masses are _______ eruptions?
Fragmentation of magma results in pulverization to tiny bits of ash are _________ eruptions?
Effusive eruptions happen because the conduit is ______ and _______, allowing gas overpressures to be relieved?
Fractured and leaky
________ eruptions create huge gas over-pressures and allow the magma to fragment itself violently, creating lots of ash?
A block or bomb is a _______?
What controls or causes the shape of a stratovolcano?
Layers of lava and ash/tephra grains
What is the most common type of volcano that occurs at mid ocean ridges?
Alaska's subductions zone most commonly creates which of the following types of volcanoes?
Dry, degassed lava flows result from which type of eruption?
what is a common mineral found in most magmas?
How are VT earthquakes beneath a volcano located?
what are the two volcanic gases that are most important to monitor because they indicate magma is rising up and the volcano is likely to erupt soon?
Which is the largest type of volcano on Earth, by volume?
a. Cinder cone b. Stratovolcano c. Shield volcano d. None of these
The maximum angle to the horizontal at which rocks, soil, etc (granular materials) can form a conical pile is called the:
a. Collapse angle b. Friction c. Angle of repose d. Horizontal angle
Which of the following is the most hazardous type of volcano in terms of impacts to people? 60% of all volcanoes on Earth are this type:
a. Cinder cones b. Fissures c. Stratovolcanoes d. None of these