Final answer:
The lag time between P-waves and S-waves is found by subtracting the arrival time of the P-wave from the arrival time of the S-wave, and this is a true statement. P-waves arrive first at seismograph stations and are used along with S-waves to calculate the distance to an earthquake's epicenter. The precision of these measurements is essential for accurate detection of seismic events.
Step-by-step explanation:
The process to calculate the lag time between the arrival of P-waves (Primary waves) and S-waves (Secondary waves) at a seismograph station is an important concept in seismology. The lag time is calculated by subtracting the arrival time of the P-wave from the arrival time of the S-wave (P - S). This value gives us the time difference which is critical in estimating the distance to an earthquake's epicenter. Seismologists utilize the differences in travel times and speeds of these seismic waves to locate the source of earthquakes. P-waves typically reach the stations first since they travel faster through the Earth's crust, whereas S-waves follow and cause more significant shaking due to their transverse wave motion. Therefore, the statement given in the question is true.
As for the question regarding standing waves, this statement is false. A standing wave is formed by the superposition of two waves that are identical, traveling in opposite directions, and are in phase.
In seismology, high precision in measuring the arrival times of P and S-waves is crucial for accurately determining the epicenter. The precision of the measurement can affect the ability to detect and locate seismic events, such as underground nuclear tests, which is an important aspect in monitoring compliance with international test bans.