Charles Francis Richter
Charles Francis Richter
Charles Francis Richterwas an American seismologist and physicist...
NationalityAmerican
ProfessionScientist
Date of Birth26 April 1900
CountryUnited States of America
earthquakes drs plot
[In plotting earthquake measurements] the range between the largest and smallest magnitudes seemed unmanageably large. Dr. Beno Gutenberg then made the natural suggestion to plot the amplitudes logarithmically.
devil plot lucky
I was lucky because logarithmic plots are a device of the devil.
above curves parallel quite rank roughly saw
I saw that I could now rank the earthquakes one above the other. Also, quite unexpectedly the attenuation curves were roughly parallel on the plot.
affect given result site structures
We have a given site, and we have to ascertain what disturbances will affect the structures on that site as a result of an earthquake.
correct ground increase involves magnitude repeatedly represents
I repeatedly have to correct this belief. In a sense, magnitude involves steps of 10 because every increase of one magnitude represents a tenfold amplification of the ground motion. But there is no 'scale of 10' in the sense of an upper limit.
large magnitude middle produce rating relative using
For example, some stars put out large amounts of energy in the infrared part of the spectrum, so that this can produce a different relative magnitude rating than using light energy from the middle of the spectrum.
becomes considers engineer foundation ground light local motion occur proposed structure
From here, it becomes an engineering problem; the engineer considers the ground motion that will occur and evaluates the requirements of the proposed structure in the light of the local foundation conditions.
closer constant except magnitude proved scale scaling truth
What emerged, of course, was that the magnitude scale presupposed that all earthquakes were alike except for a constant scaling factor. And this proved to be closer to the truth than we expected.
apply extending great gutenberg less magnitude parts played scale usual
Incidentally, the usual designation of the magnitude scale to my name does less than justice to the great part that Dr. Gutenberg played in extending the scale to apply to earthquakes in all parts of the world.
antiquated collapse due life mostly point property unsafe
I usually point out that most loss of life and property has been due to the collapse of antiquated and unsafe structures, mostly of brick and other masonry.
assigned avoid finely point quite three turned
We would have been happy if we could have assigned just three categories, large, medium, and small; the point is, we wanted to avoid personal judgments. It actually turned out to be quite a finely tuned scale.
frequently instrument itself magnitude scale visitors
There is another common misapprehension that the magnitude scale is itself some kind of instrument or apparatus. Visitors will frequently ask to 'see the scale.'
curve individual standard
By moving them vertically, a representative mean curve could be formed, and individual events were then characterized by individual logarithmic differences from the standard curve.
correction might recorded suggested terms
I suggested that we might compare earthquakes in terms of the measured amplitudes recorded at these stations, with an appropriate correction for distance.