## The Magnitude!

Join High Touch High Tech in celebrating
Richter Scale Day
April 26th!

Does the
name Charles F. Richter mean anything to you? Is he your friend on Facebook or Instagram?
Is he a YouTube Star? No! Back in 1935, 86 years ago, this man developed a
mathematical way to determine the strength of earthquakes!

You may have
heard the term “Richter scale”, but the official name is Richter Magnitude
scale. Charles Richter was working at the California Institute of Technology
and developed a mathematical device to compare the size of earthquakes. Trying
to determine the strength of earthquakes is no easy task. In fact, it is extremely
complicated and requires serious math.

The
magnitude of an earthquake is determined from the logarithm of the amplitude of
waves recorded by seismographs. Adjustments are included for the variation in
the distance between the various seismographs and the epicenter of the
earthquakes. The epicenter is where the earthquake first began. On the Richter
Scale, magnitude is expressed in whole numbers and decimal fractions.

For
example, a magnitude 5.3 might be computed for a moderate earthquake, and a
strong earthquake might be rated as magnitude 6.3. Because of the logarithmic
basis of the scale, each whole number increase in magnitude represents a
tenfold increase in measured amplitude; as an estimate of energy, each whole
number step in the magnitude scale corresponds to the release of about 31 times
more energy than the amount associated with the preceding whole number value.
Amazing!!

Richter
was born in Overstock, Ohio.  He grew up with his maternal grandfather,
who moved the family to Los Angeles in 1909. After graduating from LA high
school, he attended Stanford University.
In 1928, he began work on his PhD in theoretical physics from the
California Institute of Technology, but, before he finished it, he was offered
a position at the Carnegie Institute of Washington.

He became
fascinated with seismology (the study of earthquakes and the waves they produce
in the earth). Thereafter, he worked at the new Seismological Laboratory in
Pasadena, California under the direction of Beno Gutenberg.

In 1932, Richter and Gutenberg developed a
standard scale to measure the relative sizes of earthquake sources, called the
Richter scale. In 1937, he returned to the California Institute of Technology,
where he spent the rest of his career, eventually becoming professor of
seismology in 1952.

Richter
chose to use the term “magnitude” to describe an earthquake’s
strength because of his early interest in astronomy; stargazers use the word to
describe the brightness of stars.

Gutenberg
suggested that the scale be logarithmic so an earthquake of magnitude 7 would
be ten times stronger than a 6, a hundred times stronger than a 5, and a
thousand times stronger than a 4. (The 1989 earthquake that shook San
Francisco was magnitude 6.9.)

The
Richter scale was published in 1935 and immediately became the standard measure
of earthquake intensity. Richter did not seem concerned that Gutenberg’s name
was not included at first; but in later years, after Gutenberg was already
dead, Richter began to insist for his colleague to be recognized for expanding
the scale to apply to earthquakes all over the world, not just in southern
California. Since 1935, several other magnitude scales have been developed. But
it is the Richter scale that remains the standard.

Interested in becoming a seismologist for the day? Create your own earthquake with our at-home experiment, Shaker Table. Test the magnitude of your earthquake and give it a rating from the Richter Scale!