Which of the following statements is FALSE about the magnitude of earthquakes?
A.
Magnitudes of earthquakes are based on powers of ten
B.
An earthquake of magnitude 3 on the scale is 1.5 times more intense than a magnitude 2
C.
Great earthquakes can have a magnitude of 8 or higher
D.
Over a million earthquakes of magnitude 2–2.9 are felt per year
E.
The Richter and Moment Magnitude scales are used to describe the magnitude of an earthquake
If A is true, what about B? One of those two have to be false.
The FALSE statement about the magnitude of earthquakes is:
B. An earthquake of magnitude 3 on the scale is 1.5 times more intense than a magnitude 2.
This statement is incorrect. The magnitude scale for earthquakes is logarithmic, not linear. It means that an earthquake of magnitude 3 is actually 10 times more intense than an earthquake of magnitude 2, not 1.5 times.
To determine which of the statements is false about the magnitude of earthquakes, we can evaluate each statement.
A. Magnitudes of earthquakes are based on powers of ten.
This statement is true. The magnitude of earthquakes is measured using logarithmic scales, such as the Richter or Moment Magnitude scale. These scales are based on powers of ten, where each whole number increase in magnitude represents a tenfold increase in the amplitude of seismic waves.
B. An earthquake of magnitude 3 on the scale is 1.5 times more intense than a magnitude 2.
This statement is also true. The magnitude scale is logarithmic, meaning that each unit increase represents a tenfold increase in wave amplitude and approximately 32 times more energy release. Therefore, a magnitude 3 earthquake is indeed 1.5 times more intense than a magnitude 2 earthquake.
C. Great earthquakes can have a magnitude of 8 or higher.
This statement is true. Great earthquakes, also known as major earthquakes, can indeed have magnitudes of 8 or higher. These events are typically more destructive and have a higher impact on affected regions.
D. Over a million earthquakes of magnitude 2–2.9 are felt per year.
This statement is also true. Earthquakes of magnitude 2–2.9 are considered minor or small earthquakes. These relatively lower magnitude earthquakes occur frequently, and it is estimated that over a million such earthquakes are felt worldwide per year.
E. The Richter and Moment Magnitude scales are used to describe the magnitude of an earthquake.
This statement is true. Both the Richter scale and the Moment Magnitude scale are commonly used measures of earthquake magnitude. The Richter scale was the first widely used magnitude scale, while the Moment Magnitude scale is a more accurate and modern scale that takes into account various factors related to the earthquake, such as the area of the fault rupture and the amount of slip.
Based on the evaluations, all of the statements are true. Therefore, none of the statements are false about the magnitude of earthquakes.