An active volcano is any volcano that:
Has not been worn away by erosion
Is currently erupting or has erupted in geologically recent times
Is located on a tectonic plate boundary
Has not erupted recently but is likely to erupt in the future
2. Question 2
Which of the following is a type of volcano formed predominantly from hardened basalt lava flows?
3. Question 3
Stratovolcanoes are typically composed of alternating layers of:
Volcanic ash and lava
Rhyolite volcanic ash and basalt volcanic ash
Rhyolite lava and basalt lava
Two separate volcanoes that merge to form one
4. Question 4
A measurable change in the heat flow of a locality on the earth is taken to be an indication of:
The impending occurrence of an earthquake along a fault in the next 24 hours
A sudden increase in the rate of radioactive decay in rocks of the subsurface at the locality
The validity of the hydrologic cycle
The probability that a volcano at the locality will erupt
5. Question 5
All of the following are somewhat effective means of dealing with volcanic hazards EXCEPT:
Steering the direction of a lava flow
Plugging a volcano’s vent
Accurately predicting a volcanic eruption
Cooling a lava front with water
6. Question 6
Which of the following statements about lava is TRUE?
Lava is more explosive than magma.
Lava with a high gas content tends to be more explosive than lava with a low gas content.
Lava with a mafic composition is more explosive than lava with a felsic composition.
All of the other choices are true.
7. Question 7
A volcanic ash flow (a nuée ardente or glowing avalanche):
Has the potential to incinerate nearby towns
Consists of a muddy mixture of meltwater and lava
Is produced from ash that blows high up into the air before settling back to Earth
Poses little threat to life because the ash is light and cool
8. Question 8
A caldera forms:
From a thick layer of cool ash that settles near the volcano
When the magma chamber beneath a volcano drains suddenly during a massive eruption/explosion, and the volcano collapses to form a circular depression
When a river cuts off a meander and leaves a semi-circular lake filled with water
Where a mountain stream deposits an apron of fine sediment at the base of the mountain
9. Question 9
The explosion of Mount Saint Helens in 1980:
Is the largest volcanic explosion that is known to have occurred in the geologic record
Is a tiny explosion when compared to the explosion that resulted in the Yellowstone caldera.
Is typical of eruptions of shield volcanoes
Was unrelated to the occurrence of lahars in nearby river valleys
10. Question 10
True or false? The burial and destruction of Pompeii by Mount Vesuvius in 79 AD was due to rapidly flowing basalt lava.
11. Question 11
Which volcano tends to have mainly non-explosive eruptions?
Mount Vesuvius, Italy
Mount Pelee, Martinique
Mount Saint Helens, Washington
12. Question 12
Which of the following mountain chains is composed primarily of volcanoes formed at an ocean-continent collision zone?
13. Question 13
True or false? The products of volcanic eruptions include lava flows and explosively erupted volcanic ashfalls.