Final answer:
To locate the epicenter of an earthquake, at least 3 seismic measurements are required. Seismographic stations record the arrival times of S-waves and P-waves to triangulate the epicenter.
Step-by-step explanation:
Seismic measurements are used to locate the epicenter of an earthquake. To accurately determine the location, at least 3 seismic measurements are required. The arrival times of S-waves and P-waves are recorded at three or more seismographic stations, and the differences in arrival times are used to triangulate the epicenter.