Earthquake magnitude research

When C.F. Richter introduced ‘an instrumental earthquake magnitude scale’ in 1935, his purpose was to attempt to put into an order local earthquakes in southern California. Now the ‘Richter Scale,’ a fairly sophisticated and distant offshoot of Richter's original arbitrary amplitude measurements, is a nearly universally accepted reference for earthquake magnitude. What factors earthquake magnitude encompasses, and to what degree of accuracy, are the subjects of intense research efforts today. The earthquake magnitude factor is the ‘most studied one in seismology,’ according to Markus Båth (Earthquake Magnitude—Recent Research and Current Trends, Earth Sci. Rev., 17, 315–398, 1981). Båth points out that magnitude is a far more fundamental concept than ‘size’ or strength, or how devastating to humans an earthquake might be. The magnitude scale is a measure of the total energy released by an earthquake, and thus is the basis of seismology. Applications of magnitude measurements include all aspects of earthquakes, such as epicentral distance, focal depth, wave type and period, and source analysis. Båth's recent study is indeed useful ‘for geologists, tectonophysicists and engineers—[and]—for seismologists…’