Richter Scale
Introduction
The Richter scale, developed in the 1930s by Charles F. Richter, is a logarithmic scale used to quantify the energy released by an earthquake. It is one of the most well-known scales for measuring the magnitude of earthquakes, although it has been largely replaced by the moment magnitude scale (Mw) for more precise measurements.
History
Charles F. Richter, a seismologist at the California Institute of Technology (Caltech), developed the Richter scale in 1935 in collaboration with Beno Gutenberg. The scale was initially intended for use only in a particular study area in California, and was later extended for global use.
Scale Description
The Richter scale is a base-10 logarithmic scale. This means that each whole number increase on the scale represents a tenfold increase in measured amplitude and approximately 31.6 times more energy release. For instance, an earthquake of magnitude 5 on the Richter scale releases 31.6 times more energy than an earthquake of magnitude 4.
Measurement
The Richter scale measures the amplitude of seismic waves recorded by seismographs. Adjustments are made for the variation in the distance between the various seismographs and the epicenter of the earthquakes. The scale was originally calibrated to be roughly proportional to the energy release of earthquakes in Southern California.
Limitations
The Richter scale saturates and underestimates the strength of very large earthquakes. This is because the high frequency seismic waves recorded locally to the earthquake diminish in amplitude with increasing distance from the epicenter. This limitation led to the development of other scales, such as the moment magnitude scale (Mw), which is now the most widely used scale to measure the size of earthquakes.
Moment Magnitude Scale
The moment magnitude scale (Mw) is a logarithmic scale used to measure the size or magnitude of earthquakes. It was developed to succeed the Richter scale in the 1970s when it became clear that the Richter scale was inadequate for measuring very large earthquakes. The Mw scale measures the total energy released by an earthquake and does not saturate as the Richter scale does.
Conclusion
While the Richter scale has been largely replaced by the moment magnitude scale, it remains a significant development in the field of seismology. It was the first scale to allow for the comparison of the size of earthquakes occurring in different locations, and it remains in use for small to medium-sized seismic events.