Question

which is one step that geologists use to find the epicenter of an earthquake?
they measure the difference between arrival of p waves and s waves.
they look at data from at least one seismograph.
they obtain information about the intensity of earthquakes.
they draw circles around the epicenter from three locations.

Explanation:

To find the epicenter of an earthquake, geologists measure the time difference between the arrival of P - waves (primary waves, faster) and S - waves (secondary waves, slower). This time difference helps calculate the distance from the seismic station to the epicenter. Using data from at least three seismographs (not one), they can triangulate the epicenter. Information about earthquake intensity is related to the Mercalli scale (which measures effects on people, buildings etc., not directly for finding the epicenter). And they draw circles around the seismic stations (not around the epicenter) with radii equal to the calculated distances from each station to the epicenter, and the intersection of these circles is the epicenter.

Answer:

They measure the difference between arrival of P waves and S waves.