Question

which statement describes the mercalli scale?
○ this scale measures seismic waves based on their size
○ this scale rates an earthquake according to how much damage it causes.
○ this scale produces a single rating for earthquakes that reach the surface.
○ this scale measures the magnitude of an earthquake based on the size of seismic waves.

Explanation:

The Mercalli scale is a measure of earthquake intensity, which is determined by the damage and effects an earthquake causes. The first option is incorrect as measuring seismic wave size is for the Richter or moment - magnitude scales. The third option is wrong because the Mercalli scale has different ratings (intensities) at different locations based on damage, not a single rating for the earthquake. The fourth option describes the Richter/moment - magnitude scales (measuring magnitude via seismic waves), not the Mercalli scale. Only the second option correctly states that the Mercalli scale rates an earthquake according to the damage it causes.

Answer:

B. This scale rates an earthquake according to how much damage it causes.