EQ Magnitude, Energy Release, and Shaking Intensity

This shows the shaking amplitude recorded on 3 different seismometers from the M6.9 Loma Prieta, CA earthquake in 1989. All 3 stations are about the same distance from the earthquake to the south, but the type of local geology beneath the instrument influences the amount of shaking at that location. Bedrock shakes the least, and soft mud the most.