The locations of earthquakes are often associated with topographic features. The locations of earthquakes vary in depth. The rate of earthquakes varies over time. Seismicity rates may be related to properties of the Earth's crust. Energy released by earthquakes can be recorded, measured, and analyzed.
Energy is released by earthquakes in the form of seismic waves.
Different types of seismic waves cause the shaking we feel. Seismic waves are sensed by seismometers. The seismic waves are recorded as seismograms. Earthquakes are located and characterized by studying seismograms. The nature of the fault rupture that produces an earthquake can affect the amount and distribution of the energy released.