Richter Magnitude - Frequency of Occurrence Distribution

Many independent researchers worked to develop reliable methods for estimating recurrence intervals for earthquakes (e.g., 

Characteristic effects of shallow shocks in populated areas Approximate Richter magnitude Number of earthquakes per year Energy (megawatt- 

Adapted from Earth, 4th edition by Frank Press and Raymond Siever. Copyright t974, 1978, 1982, 1986 W.H. Freeman and Company. Reprinted with permission. 

The second stage was a statistical analysis of the data available from the NGSDC database and several other smaller databases to extract the frequency-magnitude (f-M) relations for earthquakes originating in widely different regions of the earth. 

Previous studies indicated that each region was different. However, the f-M distribution after correction for magnitude and time bias is applicable worldwide. 

---