The IRIS (Incorporated Research Institute of Seismology) Seismic Monitor will allow your class to visualize the most recent quakes and their magnitudes in this region.
Desmos | Graph of Richter Magnitudes
YummyMath | Earthquakes and Richter Magnitude
The Richter magnitude scale was developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs.
Although it may seem like science fiction, man-made earthquakes have been a reality for decades. It has long been understood that earthquakes can be induced by impoundment of water in reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids into underground formations.