Final answer:
The greater the time difference between the arrival of P-waves and S-waves, the farther away the epicenter is from the seismograph station. This is used to determine the epicenter's distance and can also affect the detection range of seismic events such as earthquakes or underground nuclear tests.
Step-by-step explanation:
The time difference between the arrival of P-waves and S-waves at a seismographic station provides important information about the distance of the epicenter from that station. P-waves, being faster, arrive first, followed by S-waves. The greater the time lag between these two types of waves, the farther away the epicenter is from the station. Therefore, the correct answer to the quiz question is A. the farther away is the epicenter. This method relies on understanding that P-waves (primary waves) and S-waves (secondary waves) travel at different speeds through the Earth's crust, with P-waves typically traveling faster than S-waves.
For instance, if the speed of an S-wave is 2 km/s and that of a P-wave is 6 km/s, and the respective arrival time difference recorded is 10 seconds, the epicenter would be calculated to be at a distance using the formula derived from their speeds and the time difference. Similarly, the precision of the measurements taken by seismographs to calculate the epicenter's distance can also indicate potential limitations in detecting underground nuclear tests based on seismic waves.
When considering earthquake damage at varying distances from the epicenter, interference patterns may cause constructive interference leading to higher damage even farther away from the epicenter, despite the usual drop in the intensity of waves as they move away from the source.