Download Study questions for Exam #2

Study questions for Exam #2 – Thursday March 9th
Review of Exam #1
Exam #2 will include questions from Exam #1 related to the chronology of some of the
important events in earth history, energy sources that drive plate tectonic and climate, and
plate tectonics, faults and earthquakes – so review the answers to the questions on test #1
Lecture #8 – 1980 eruption of Mt St Helens
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What type of tectonic activity caused volcanism to occur at Mt St Helens?
What causes the generation of magmas in this type of tectonic environment?
What compositional type of magmas are erupted from Mt St Helens?
What shape or type of volcanic landform is Mt St Helens?
What type of faulting is related to this tectonic environment?
What are the names of two other volcanoes in the cascade range?
Does these volcanoes erupt passively or explosively?
What was the frequency of eruptions from Mt St Helens in the last 500 years prior
to the 1980 eruption?
9) What were 3 types of precursor activity observed at the Volcano prior to the
explosive eruption of May 18th 1980
10) About how long a time period did this precursor activity occur for prior to the
May 18th eruption?
11) Whys did the volcano erupt with a lateral blast directed to the north?
12) How much magma was erupted by Mt St Helens on May 18th, 1980.
13) Over how long a time period did the eruption last?
14) What process caused the Mt St Helens magma to explode, or in general what
causes explosive eruptions rather than passive eruption of lava flows.
15) What kind of volcanic deposits were formed from the collapse of the eruptive
column on the flanks of the volcano?
16) Besides the blast itself, and the collapse of the eruptive column on the flanks of
the volcano, what other process related to the eruption caused damage and death
as far west as the Columbia river?
17) Approximately how many people were killed in the eruption?
18) Has the volcano been active again since the May 18th eruption?
19) Are any other of the Cascade volcanoes possibly explosive?
20) What type of volcanic activity occurs along the San Andreas fault near San
Francisco?
21) What type of volcanoes are generated by the thrust faults below Los Angeles?
Lecture #9 – Magma types, genesis and eruption styles
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In what part of the earth are magmas generated?
What type of magmas form at oceanic spreading ridge/rift systems?
How are these magmas generated in this tectonic environment?
What type of magmas form in continental rift systems like the basin and range
extensional area in the western US?
5) What type of magmas are generated above subduction zones?
6) How are magmas generated in this tectonic environment?
7) What type of magmas are generated at hot-spots?
8) How does volcanism at hot-spots coming through continental crust differ from
that in oceanic regions?
9) What type of magmas are erupted along strike-slip plate boundaries such as the
San Andreas fault?
10) What causes a volcanic eruption to be explosive?
11) What types of magmas tend to erupt explosive and what type passively?
12) What are 2 different factors that influence the viscosity of a magma?
13) Which type of magmas have low viscosity? Which have high viscosity?
14) Which magmas tend to erupt explosively –those with low or high viscosity?
15) What compositional types of magmas are erupted in Iceland?
16) What type of magmas are erupted in the Cascade range in the western US?
17) What types of magmas are erupted above the Yellowstone hot-spot?
18) What tectonic processes causes volcanism in Mt Vesuvius in Italy and Santorini
Island In Greece?
19) What type of tectonic process causes volcanism in Mt Kilamenjaro and other
volcanoes in the African rift Valley?
Lecture #10 – Volcanic landforms I
1) What factor controls the shape of the volcanic landforms created in different
volcanically active regions?
2) What type of volcanic shapes or landforms do the Hawaiian islands have?
3) What type of volcanic shapes or landforms do the Colombia plateau basalts have?
4) When did the Columbia plateau basalts form?
5) What type of tectonic activity generated these basalts?
6) Where are plateau basalts forming in the western US in recent times?
7) What type of volcanic shapes or landforms do the volcanoes in the Cascade
volcanic arc have?
8) How much basalt was erupted in the 1783 Laki eruption?
9) What type of tectonic activity generates volcanic activity in the area of the
Colorado plateau?
10) Is there any volcanic activity in Colorado? Why?
11) What causes the formation of a caldera?
12) Why did the formation of the calderas at Krakatoa and Santorini cause
exceptional death and damage? When did Santorini erupt?
13) Where is Mt Mazama?
Lecture #11 – Volcanic Landforms II
1) What type of tectonic activity generates the giant resurgent calderas in
Yellowstone park?
2) How long has this tectonic activity been active?
3) How many calderas are nested together in Yellowstone Park?
4) Approximately how long a time period occurred between the formation of each?
5) When did the last one form?
6) When might the next one form?
7) How large a volume of magma was erupted from Yellowstone in the last giant
caldera forming event?
8) What are three indication at Yellowstone of continued activity and the possibility
of a new giant event?
9) What type of tectonic activity causes the formation of the giant calderas at Long
Valley and Valles New Mexico?
10) For how long has this tectonic activity been active in the western US?
11) Are these system active or extinct?
12) How many active systems that generated giant calderas in the last 1 million years
are known world-wide?
13) Based on this number, what is the average time period between formation
somewhere on the earth of a giant caldera?
14) What is the name, location and age of the youngest such giant caldera know?
15) So when might the next form?
16) Where is the largest caldera ever formed located?
17) How much magma was erupted from this giant caldera?
18) When did it form?
19) What was the tectonic causes or environment of its formation?
20) What type of tectonic activity produced the Table Mountain basalts in Golden?
Lecture #12 – global effects of volcanism
1) What could be the negative effects of sector collapse of a Cascade volcano such
as Mt Rainer?
2) Is there any evidence that such sector collapses of Casacade volcanoes have
occurred in the past?
3) What could be the negative effects of the sector collapse of an oceanic island
volcano?
4) The sector collapse of what volcanoes threatened the western Pacific coast of
North and South America?
5) The sector collapse of what volcanoes threaten the eastern Atlantic coast of North
and Southern America?
6) Is there any evidence that oceanic island volcanoes have undergone sector
collapse in the past?
7) What toxic gases are emitted during volcanic eruptions?
8) What gas causes suffocation?
9) What volcanic gas has the most potential to effects global climate?
10) Would a lot of this gas cause warming or cooling of the climate? Why?
11) What gas causes the formation of acid rain?
12) Is SO2 most abundant in basaltic or rhyolitic magmas?
13) Is water most abundant in basaltic or rhyolitic magmas?
14) In what tectonic environment does the largest basalt flows form?
15) When did the dinosaurs become extinct?
16) When and where did the Deccan trap basalts erupt?
17) In what tectonic environment did these basalts form?
18) Which has amore significant effect on global climate; the amount of ash or the
amount of SO2 emitted in an explosive eruption? Why?
19) How much magma was erupted by the Laki eruption in Iceland in 1783? What
type of magma was this. Was it a passive or explosive eruption. In what type of
tectonic environment is magma generated below Iceland?
20) How much magmas was erupted by the Tambora eruption in Indonesia in 1815?
What type of magma was this? Was this an explosive or passive eruption? In what
type of tectonic environment do magmas and volcanoes form in Indonesia?
Lecture #13 – magnetic reversals
1) When did the last reversal of the earth’s magnetic field occur?
2) About how often has the field reversed in the last few million years?
3) What happens to the strength of the magnetic field as it undergoes a reversal of
directions?
4) How much has the field decreased in strength in the last 2000 years?
5) How long does it take a magnetic reversal to occur, from the time the intensity
starts to increase until the field builds itself back in the opposite direction?
6) What role does the magnetic field play in making the earth a nice place to live?
7) What are some of the negative effects if the magnetic field strength goes to zero?