Geology Reference
In-Depth Information
Seismometers are so sensitive they can detect energy waves from earthquakes that oc-
cur on the other side of the planet!
Using the quantitative information collected from seismographs, a scientist named
Charles Richter at CalTech in 1935 began to measure the magnitude of earthquakes. The
Richter scale he developed is a
logarithmic scale,
which means that each unit on the
scale is 10 times the magnitude of the previous value. For example, an earthquake of
magnitude 4 on the Richter scale has 10 times the energy of a magnitude 3 earthquake
and 100 times the energy of a magnitude 2 earthquake. That is a huge difference!
Figure 10-6:
A seis-
mogram of S and P
waves.
