Magnitude is one of four geologic factors that relates to intensity. The difference between magnitude and intensity is analogous to a lightbulb. A lightbulb has one wattage (or size) but different intensities. Higher intensity light shines closer to the lightbulb. Light will grow dimmer with distance.
The same principle applies to earthquakes. People will feel more intense shaking closer to the hypocenter. The intensity of shaking decreases with distance. Also, a larger earthquake means more intense shaking compared to a smaller one. For example, two earthquakes occurred one day apart in Ridgecrest, California in July 2019. The difference in magnitude, a M6.4 compared to a M7.1, meant that the shaking was more intense with the larger earthquake and felt at greater distances.
In this module, you can learn about the first of the four geologic factors that contribute to the intensity of earthquake shaking. You will also investigate shaking intensity related to earthquakes of different sizes, with an example from the 2019 Ridgecrest earthquakes.
Keypoints:
Learners will be able to:
Understand that magnitude is one of four factors that cause earthquake shaking intensity
Describe magnitude and intensity of ground shaking, and how they differ
Relate how different magnitude earthquakes in the same location (Ridgecrest, CA) have different shaking intensities
