An epicentre is the area where the earthquake originated. But how do scientists pinpoint an area? It’s actually quite simple. After an earthquake occurs, scientists look at three or more seismographs. These graphs tell the scientists how long it took for the earthquake to reach each seismograph. With this information, one can find out how far away the epicentre has to be. By drawing circles around the locations of the seismographs, you can find out where the epicentre was by finding where all the circles intersect. This can be seen by the picture below.