Consider the following statements: I. The Richter Scale is a logarithmic scale and so an increase of one magnitude unit represents a factor of 10 times in amplitude. II. Each integer reading of the Richter scale has an energy 100 times that of the previous integer reading. Which of the statements given above is/are correct?

Statement I is correct: the Richter (local) magnitude is a logarithmic scale, and each whole-number increase corresponds to a tenfold increase in the measured seismic-wave amplitude on a seismogram [2]. Statement II is incorrect: energy release does not increase by 100× per whole magnitude; instead, an increment of one magnitude corresponds to roughly a 32× increase in radiated seismic energy (approximately 10^1.5 ≈ 31.6) [2]. Thus the common misconception that energy rises by 100× per unit is false; amplitude scales by 10× while energy scales by about 32× per integer magnitude step [2].

Sources

1. [2] https://www.usgs.gov/programs/earthquake-hazards/earthquake-magnitude-energy-release-and-shaking-intensity
2. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 14: Earthquakes > 14.5. Richter Magnitude Scale > p. 182