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63 Cards in this Set
- Front
- Back
Approx. time of Santorini/Thera event |
~1650 BCE |
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VEI of Santorini/Thera |
6 |
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What (possibly) caused the downfall of the Minoan civilization on Crete? |
The Santorini/Thera eruption |
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How high was the plinian column for Santorini? |
23 miles high |
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What is a plinian style eruption? |
So called for its similarity to Vesuvius' eruption. |
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Name some geologic events surrounding the Santorini/Thera eruption. |
Earthquakes, explosive ejections, magma chamber breach, ash eruption, collapse. |
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Name some geologic consequences of the Santorini/Thera eruption. |
Air flow deposits, surge deposits, ash flow deposits. |
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What is the stratigraphic method of reconstructing volcanic history? |
The sequence of events is preserved in rock layers, the oldest on the bottom, the youngest on top. Composition of the layers provides historical clues. |
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What types of material pollute the air after an eruption? |
Gasses, rock particles, ash. |
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What are the main (non-toxic) gasses released during an eruption? |
H2O, CO2, SO2 (water, carbon dioxide, sulfur dioxide) |
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What are the toxic gasses released during an eruption? |
HCl, HF, H2SO4, H2S (hydrochloric acid, hydrofluoric acid, sulfuric acid, hydrogen sulfide) |
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What is the typical composition of our atmosphere? |
N2, O2, CO2, SO2 (nitrogen, oxygen, carbon dioxide, sulfur dioxide) |
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What element of volcanic emissions can destroy the ozone layer? |
Chlorine |
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Do volcanoes contribute significantly to the greenhouse effect? |
No. They are important on the geologic timescale. |
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What happens when volcanic particles block sunlight? |
Sulfate aerosols form. |
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How long ago did Toba erupt? |
74,000 years ago |
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What was the VEI of the Toba eruption? |
8 (megaeruption) |
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What were the consequences of the Toba megaeruption? |
global temps dropped 3-5 degrees C widespread burning of jungles/forests ozone drops by 60% |
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What year was the Nevado del Ruiz event? |
1985 |
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Describe the pyroclastic flows from Nevado del Ruiz |
8m of debris avalanche and pyroclastic flow on summit and flanks of volcano |
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Describe the lahars associated with Nevado del Ruiz |
60 km/hr 50 m thick increased to 4 times their original volume |
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Describe the lava flows associated with Nevado del Ruiz |
2-5 m deep |
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What was the major obstacle in raising alarm during the Nevado del Ruiz |
The noise of eruption was very loud |
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What were the casualties from the Nevado del Ruiz event? |
23,000 killed 5,000 injured 5,000 homes destroyed |
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What are the advantages of acoustic flow monitors? |
used to detect lahars sent by radio signaling don't require human supervision worked well for the Redoubt volcano in Alaska |
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What year did Pinatubo erupt? |
1991 |
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Progression of events prior to eruption at Pinatubo: |
1. earthquakes in March 2. fissure opened in April 3. steaming began 4. SO2 emission increased from 500-5,000 tons/day 5. creation of lava dome 6. increase in shallow, low frequence quakes (June 14) |
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What day did Pinatubo erupt? |
June 15 (massive eruption) |
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What was the impact on climate from Pinatubo? |
Global temperatures decreased 0.5C |
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What was the role of accumulated volatiles in the Pinatubo eruption? |
In the 500 years prior to the eruption, volcanic gases accumulated, forming bubbles 5-15 km deep |
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Describe the effects of Pinatubo lahars |
the lahars devastated the city from 1991-92 in 1994 another lahar came through and destroyed all recovery progess (put your house on stilts!) |
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What kind of lava is more likely to interact with water? |
Mafic lava |
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What can occur when water and magma interact? |
Eruptions |
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How can we tell how explosive a water/magma eruption will be? |
amounts of water and magma, pressure of overlying material |
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What are the sources of heat in Martian volcanism? |
Primordial, radiogenic, tidal, solar |
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Describe the Noachian period of Martian history |
warm/wet early Mars, valley network |
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Describe the Hesperian period of Martian history |
volcanism, outflow channels, oceans |
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Describe the Amazonian period of Martian history |
low impact rates, tharsis volcanism, cold/dry late Mars |
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Types of Martian volcanoes |
Shield (larger than Hawaiian) Tholi (small, dome shaped, steep flanks) Paterae (low, flat shields) |
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What kind of volcanism is evident on the Moon? |
Basaltic |
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Some unusual features of Lunar volcanism are: |
Flow fronts, wrinkle ridges, sinuous rilles |
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Describe the pyroclastic flows found on the Moon: |
100 found, from very deep sources age of deposits ~3.5 billion yrs or older |
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What types of volcanoes are abundant on Venus? |
small shields with a small central crater |
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Out of Mars, Venus and Earth, which has the most preserved volcanic landforms? |
Venus |
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Which planet has the longest lava channels? |
Venus longest channel in the solar system is 6800 km |
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What is the typical size of Venusian calderas? |
60-80 km in diameter |
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Unique features of Venusian volcanism include: |
Sapas Mons, cone volcanoes, Sacajawea patera (elliptical caldera), 4 overlapping domes |
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What is the only body in our solar system (besides Earth) with confirmed active volcanism? |
Io (Jupiter's moon) |
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Describe Io's volcanism: |
-plumes that rise hundreds of km above surface -eruption temperatures are much high than on Earth |
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What does it mean when a planet or moon's surface has few craters? |
It means the surface of the body is young. |
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Describe the surface of Europa: |
-covered in water ice -cracks and ridges formed due to Jupiter's tides -evidence of liquid ocean beneath ice -active tectonics and icy flows |
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What does Ganymede have in common with Europa? |
early icy tectonics |
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Does Ganymede have an old or young surface? |
The surface shows a range of ages. |
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Describe the surface of Callisto: |
-cratered: old surface -eroded and covered with dark layer |
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What is the effect of Jupiter's tide on Io's interior? |
gravitational kneading keeps the combined metal and silicate interior hot and partially molten |
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Why does Io appear red? |
It's sulfur content. The sulfur will eventually condense into rings. |
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Why do scientists think there is an ocean beneath Europa's ice? |
There is a magnetic field. |
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What is the probable cause of an ice flow over a ridge on Europa? |
The flow erupted as a viscous glacial mass. |
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What evidence is there of tectonic activity on Ganymede? |
-tectonic rifting of impact craters -different colored areas are tectonically deformed |
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What are the chances of dying from a volcanic event? |
1:10 million |
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-formation of islands -fertile volcanic soil -geothermal energy -local climate is cooler at higher elevations -more local rainfall |
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What do tubeworms do? |
absorb hydrogen sulfide from hot water absorb oxygen from cold water |
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What have we found in oceanic volcanic glass? |
Evidence of supporting microbial life, even up to 3.5 billion years ago |