Picture 1 shows instruments used to collect gas coming from the ground near an active volcano. Picture 2 shows a satellite image where each band of color shows a different amount of ground movement around a volcano. The table gives more information on the two types of volcano observations.
picture 1 shows instruments outside on the ground, and picture 2 shows bands of different colors around a certain area
Image courtesy of USGS
Type of Measurement Explanation
observing gases given
off at Earth's surface
measures how fast different gases of volcanoes are coming to the surface
uses instruments placed near volcanoes to collect the information
instruments measure the amount of certain chemicals in the gases
using satellites to observe
movement of the ground
at Earth's surface
measures how much the ground is moving around a volcano
uses satellites in space orbiting the Earth
the satellites take pictures to show how much the ground is moving around
the volcano
Using the information, which statement best compares the two types of volcano observation for helping predict eruptions?
A.
Satellite pictures can be easily taken from outer space, but gas measuring instruments need more complicated satellites to help them work.
B.
Observing gases from the ground is more expensive than using satellites, but satellites can take samples of gases from the ground.
C.
Observing gases from the ground is less expensive than using satellites, but bad weather and animals may cause damage to the instruments.
D.
Satellite pictures can show how much lava comes out of a volcano, but gas measuring instruments can show how much the surface is shaking.
1 answer
The best statement that compares the two types of volcano observation for helping predict eruptions is:
C. Observing gases from the ground is less expensive than using satellites, but bad weather and animals may cause damage to the instruments.
This statement accurately reflects the comparison in terms of cost and potential issues faced by ground instruments that monitor gas emissions.
