What does the moment magnitude scale measure and what does it tell us?
Moment magnitude measures the size of events in terms of how much energy is released. Since magnitude scales are logarithmic, an increase of one unit of magnitude on a magnitude scale is equivalent to an increase of 10 times the amplitude recorded by a seismograph and approximately 30 times the energy.
Why is the moment magnitude scale exciting to scientists?
The moment magnitude scale takes a much long time period to determine the size of the earthquake. After the 1960 Chile earthquake the Richter scale registered the earthquake size at magnitude 8.5. Scientists using the moment magnitude scale revised the earthquakes size up to magnitude 9.5.
Why is it important to know the magnitude of an earthquake?
The magnitude of an earthquake is a number that allows earthquakes to be compared with each other in terms of their relative power.
Why is the Richter scale important?
The Richter magnitude scale (often shortened to Richter scale) is the most common standard of measurement for earthquakes. The Richter scale is used to rate the magnitude of an earthquake, that is the amount of energy released during an earthquake.
What is the purpose of the moment magnitude?
The result is called the moment magnitude. The moment magnitude provides an estimate of earthquake size that is valid over the complete range of magnitudes, a characteristic that was lacking in other magnitude scales. What is a Geoid? Why do we use it and where does its shape come from?
How are earthquakes measured on the moment magnitude scale?
The Moment Magnitude Scale measures the amount of energy released by an earthquake event. It is calculated using a formula that includes the rigidity of the rock affected, the distance moved and the size of the area where movement takes place. The video on the left below explains this more fully.
How is the moment magnitude related to the Richter scale?
The moment is then converted into a number similar to other earthquake magnitudes by a standard formula. The result is called the moment magnitude. The moment magnitude provides an estimate of earthquake size that is valid over the complete range of magnitudes, a characteristic that was lacking in other magnitude scales. What is a Geoid?
Why does the local magnitude scale underestimate the magnitude?
At greater depths, distances, or magnitudes the surface waves are greatly reduced, and the local magnitude scale underestimates the magnitude, a problem called saturation.