Earthquakes Equidistance from Seismograph Station

This animation in our travel time series uses the gridded sphere to help see equal distances, the expanding circles of the wavefronts are shown only for the first earthquake, the subsequent show the exaggerated cartoon bouncing to represent the arrival of the compressive pea, the shearing S in the rolling surface wave seen on the seismograms. The PS and surface waves arrive at similar intervals for all 5. The exact replication of these seismograms indicates that the inside of this earth is of uniform composition, thus the travel times and amplitudes are equal. In a real world, the amplitude and speed of the seismic waves are altered by the materials that they pass through giving similar but unique seismograms.