Why doesn't the Richter scale work well for shallow earthquakes?
May 07, 2010
in
Earthquake Questions
We’ve been told that there are a number of flaws to the Richter scale (ML), the limitations of the original instrumentation, that it was only designed for use in California and that shallow earthquakes are a practical problem. Can you explain why this should be?
Reading it back, maybe the point is it only works for shallow earthquakes?!
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One comment
Elizabeth H on May 7, 2010 at 1:44 am
Charles Richter developed the scale in the 1930s to measure shallow earthquakes in California. These early measurements of magnitude simply relied on using two factors (the difference in P- and S-wave arrival times and Swave amplitude). The measured earthquakes were less than 600 km (375 miles) from the seismograph stations and occurred at similar depths in the crust. More complex formulae to determine magnitude from seismic body waves or surface waves were developed as the number of
seismograph stations increased and it was recognized that earthquakes occurred at a range of depths.