# How to find out epicentre of earthquake?

You may confuse that many agencies locate different points for the epicentre of same earthquake, it may happens because of recording stations around the possible location.

Here is one example of one method to find out epicentre.

To figure out just where that earthquake happened, you need to look at your seismogram and you need to know what at least two other seismographs recorded for the same earthquake. You will also need a map of the world, a ruler, a pencil, and a compass for drawing circles on the map.

Here is one example of one method to find out epicentre.

To figure out just where that earthquake happened, you need to look at your seismogram and you need to know what at least two other seismographs recorded for the same earthquake. You will also need a map of the world, a ruler, a pencil, and a compass for drawing circles on the map.

FIGURE 1 - OUR TYPICAL SEISMOGRAM FROM BEFORE,

THIS TIME MARKED FOR THIS EXERCISE (FROM BOLT, 1978).

**Finding the Epicenter**

You have just figured out how far your seismograph is from the epicenter and how strong the earthquake was, but you still don't know exactly where the earthquake occurred. This is where the compass, the map, and the other seismograph records come in.

1. Check the scale on your map. It should look something like a piece of a ruler. All maps are different. On your map, one centimeter could be equal to 100 kilometers or something like that.

2. Figure out how long the distance to the epicenter (in centimeters) is on your map. For example, say your map has a scale where one centimeter is equal to 100 kilometers. If the epicenter of the earthquake is 215 kilometers away, that equals 2.15 centimeters on the map.

Using your compass, draw a circle with a radius equal to the number you came up with in Step #2 (the

**radius**is the distance from the center of a circle to its edge). The center of the circle will be the location of your seismograph. The epicenter of the earthquake is somewhere on the edge of that circle.FIGURE 3 - THE POINT WHERE THE THREE CIRCLES INTERSECT IS THE EPICENTER OF THE EARTHQUAKE. THIS TECHNIQUE IS CALLED 'TRIANGULATION.' |

4. Do the same thing for the distance to the epicenter that the other seismograms recorded (with the location of those seismographs at the center of their circles). All of the circles should overlap. The point where all of the circles overlap is the approximate epicenter of the earthquake.

(Source : UPSeis)

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