Question

Consider the following statements regarding the earthquakes:Which of these statements are correct?

1. The intensity of earthquake is measured on Mercalli scale
2. The magnitude of an earthquake is a measure of energy released.
3. Earthquake magnitudes are based on direct measurements of the amplitude of seismic waves.
4. In the Richter scale, each whole number demonstrates a hundredfold increase in the amount of energy released.

• A. i, ii, iii
• B. ii only
• C. All
• D. ii, iii

Answer 1

Answer:

A. i, ii, iii

Mercalli scale

• The Mercalli Intensity Scale, also known as the Modified Mercalli Intensity (MMI) scale, is used to measure the intensity or the effects of an earthquake at specific locations.
• It assesses the earthquake's impact on people, buildings, and the natural environment.

Magnitude of an earthquake

• The magnitude of an earthquake is indeed a measure of the total energy released during the seismic event.
• It quantifies the earthquake's size and is typically measured using scales like the Richter scale or the moment magnitude scale (Mw).
• Earthquake magnitudes are determined based on measurements of seismic waves, specifically the amplitude and period of these waves.
• The Richter scale, for example, calculates magnitude using the amplitude of the seismic waves recorded on seismographs.
• In the Richter scale , each whole number increase actually represents a tenfold increase in the amplitude of seismic waves and approximately 31.6 times more energy released, not a hundredfold increase.