Why is the minimum three seismic stations needed to fid the epicenter of earthquake?

 Locating the epicenter. At least three seismic stations are needed to find the earthquake epicenter.

If there is information from only one station, the epicenter of the earthquake could at any point on that circle. If there is information from two stations, the circles intersect at two points, so there are two possible epicenters. With three stations, the circles intercept at only one point, which must be the epicenter

answer: electrons