Understanding Earthquake Measurement

Earthquake strength is measured by magnitude and intensity. Magnitude quantifies the energy released at the source, calculated using seismometers. Each unit increase in magnitude results in a tenfold increase in ground motion. Intensity measures the shaking felt, influenced by factors like distance from the epicenter, location, and underlying geology. Soft soils can amplify shaking compared to bedrock.

What are the two primary ways to measure the strength of an earthquake?

• Magnitude and Frequency

• Magnitude and Intensity

• Intensity and Duration

• Frequency and Duration

What tool do scientists use to record earthquakes?

• Barometers

• Thermometers

• Seismometers

• Anemometers

How is earthquake magnitude calculated?

• Based on the duration of the earthquake

• Based on the ground motion and distance from the earthquake

• Based on the number of aftershocks

• Based on the depth of the earthquake

What happens to ground motion with each unit increase in magnitude?

• It doubles

• It triples

• It remains the same

• It increases by a factor of 10

How much greater is the ground motion of a magnitude 6 earthquake compared to a magnitude 4 earthquake?

• 10 times greater

• 100 times greater

• 50 times greater

• 20 times greater

What factors affect the intensity of shaking felt during an earthquake?

• Magnitude and time of day

• Weather conditions and time of year

• Magnitude and number of aftershocks

• Distance from the epicenter and underlying geology

Why do people on soft soils experience more shaking than those on bedrock?

• Soft soils are more stable

• Soft soils reduce shaking

• Soft soils absorb more energy

• Soft soils amplify shaking