Volcanic Activity
Practice Test
1.
What letter in the figure depicts the possible beginning of a pluton like a stock?
a.
B
b.
none of the above
c.
A
d.
C
2.
When magma reaches Earth's surface it is called __________.
a.
rock
b.
intrusive
c.
lava
d.
a batholith
3.
A tabular pluton that cuts across preexisting rock is called a __________.
a.
stock
b.
sill
c.
laccolith
d.
dike
4.
Rhyolitic magma has the __________ viscosity, the __________ gas content and the __________ silica content of any type of magma.
a.
highest, highest, highest
b.
lowest, lowest, lowest
c.
lowest, highest, highest
d.
highest, lowest, lowest
5.
When does magma form?
a.
when volcanoes erupt
b.
when new minerals form due to chemical changes in the rock
c.
when grains have been compacted together
d.
when temperatures are hot enough to melt rock
6.
A __________ is a large intrusive igneous rock body that covers at least 100 square km.
a.
batholith
b.
dike
c.
laccolith
d.
sill
7.
__________ is the internal resistance to flow of a liquid.
a.
Specific gravity
b.
Gravity
c.
Viscosity
d.
Weight
8.
The table shows how many eruptions were experienced by volcanoes in the past 100,000 years. Which volcano is the least likely to experience a huge eruption in present day?
Feature
State
Late Pleistocene
Holocene
Huge
Huge
Large
Medium
Small
Mount Baker
WA
1
3
Glacier Peak
WA
2
7
Mount Rainier
WA
1
1
10
Mount St. Helens
WA
7
Mount Adams
WA
4
Mount Hood
OR
3
Mount Jefferson
OR
1
Three Sisters
OR
2
2
Newberry Caldera
OR
1
3
Crater Lake
OR
1
2
Medicine Lake
CA
8
8
Mount Shasta
CA
1
2
10
Lassen Peak
CA
4
1
2
Total
7
1
10
20
49
a.
Lassen Peak
b.
Mount Shasta
c.
Mount Hood
d.
Mount Rainier
9.
How was the volcano cone shown in the figure formed?
a.
material is ejected into the air and falls back to earth
b.
uplifting of mountains before exploding into a volcano
c.
a mixture of lava and volcanic fragments
d.
layer upon layer of basaltic lava accumulating during nonexplosive eruptions
10.
What type of volcano forms from alternating layers of tephra and nonexplosive lava?
a.
cinder cone
b.
composite volcano
c.
shield volcano
d.
caldera
11.
Where is andesitic magma found?
a.
on islands in the Pacific, such as Hawaii
b.
inside of continental crust
c.
in the middle of oceanic crust
d.
at the margins of continents
12.
What letter in the figure depicts the possible beginning of plutons like dikes and sills?
a.
B
b.
none of the above
c.
A
d.
C
13.
Where do most volcanoes form?
a.
along the Mid-Atlantic Ridge
b.
at plate boundaries
c.
far from plate boundaries
d.
in the southern hemisphere
14.
How is a volcanic crater connected to a magma chamber?
a.
by a vent
b.
by a hot spot
c.
by tephra
d.
by a sill
15.
What is the name for an igneous intrusion that is smaller than a batholith but similar in shape?
a.
laccolith
b.
stock
c.
sill
d.
dike
