Which seismic wave arrived first at a seismograph station Which arrived last?

The first seismic wave to arrive at a seismograph station is the Primary wave (P-wave), which is a compressional wave that travels fastest through the Earth. The last to arrive is the Secondary wave (S-wave), which is slower and involves shear motion. Generally, surface waves, which are generated by the interactions at the Earth's surface, arrive after both P-waves and S-waves.