P
P-waves are the first seismic waves to arrive at a seismograph station.
p-waves
The fastest seismic waves, P-waves, will arrive first at a seismograph station after an earthquake. P-waves are compressional waves that can travel through both solids and liquids, allowing them to arrive at a station before the slower S-waves and surface waves.
The seismograph station closest to the earthquake epicenter would have recorded P-waves first, followed by stations farther away. Since P-waves are the fastest seismic waves, they are the first to arrive at a seismograph station after an earthquake.
The first waves to arrive at a seismograph station are primary waves, or P waves.
The primary waves (P-waves) are the first to reach a seismograph after an earthquake. These waves are faster than other seismic waves and can travel through both solid and liquid materials.
In a seismic event, the waves that reach a seismograph station last are called surface waves. These waves travel along the Earth's exterior and typically have lower speeds compared to the faster primary (P) waves and secondary (S) waves. Surface waves can cause significant ground shaking and damage but arrive after the initial P and S waves.
Longitudinal waves are called primary waves because they are the fastest seismic waves and are the first to be detected by seismographs in an earthquake. They are also known as P-waves because they are the first wave type to arrive at a seismograph station.
It would take about 5-7 minutes for the primary or P-waves to reach a seismograph station in Miami, Florida from Seattle, Washington. These waves travel faster than secondary or S-waves, which would arrive a few minutes later.
S-waves cannot travel through the earth's outer core as it is liquid. Surface (Love and Rayleigh) waves cause the most damage to buildings. P-waves are the first to arrive at seismograph stations.
The time difference between the arrival of P waves and S waves at a seismograph station is used to determine the distance of an earthquake's epicenter. By measuring this time lag and knowing the speed at which each wave travels through the Earth's interior, scientists can calculate the distance the waves traveled to reach the station. The farther apart the arrival times of P and S waves, the greater the distance of the epicenter from the station.
The P waves vibrate very quickly out from the epicenter first in all directions, in a circular way passing the station.The S waves then vibrate out from the epicenter a few seconds later and cause the sideways shaking of the land as they pass the station.The P wave then reflects off the core of the Earth and bounces back past the station, followed by the S wave a few seconds later because both waves reflect off the earths core back to the epicenter.