The Richter magnitude of an earthquake - given that one has
occurred - has been hypothesized to be exponentially distributed.
In Southern California the value of the parameter of this
distribution has been estimated to be 2.35. What is the probability
that any given earthquake will be larger than 6.3, the magnitude of
the disastrous 1933 Long Beach earthquake? In the Southern
California region there is on the average one earthquake per year
with magnitude equal to or greater than 6.1. What is the
probability of an earthquake in this area of magnitude greater than
7.7, "a truly great earthquake," in any given year?