Which seismic wave is the first to arrive at a seismograph station following an earthquake, characterized by compressional and dilatational particle motion?

💡 Solution & Explanation

Primary waves are body waves that compress and expand the ground in the direction they are traveling, making them the fastest moving seismic waves recorded by seismographs. Secondary waves arrive subsequent to P-waves and propagate through shear motion which restricts them to solid media. Analyzing the time interval between the arrival of P-waves and S-waves enables seismologists to locate the epicenter of an earthquake.