http://earthquakequestions.com/how-could-scientists-use-seismograph-station-data-to-locate-the-epicenter-of-an-earthquake.htm Everything You Want To Know About Earthquakes Sat, 28 Jan 2012 23:45:02 +0000 hourly 1 http://wordpress.org/?v=3.3 http://earthquakequestions.com/how-could-scientists-use-seismograph-station-data-to-locate-the-epicenter-of-an-earthquake.htm/comment-page-1#comment-4016 joesixpack Sat, 05 Sep 2009 02:03:57 +0000 http://earthquakequestions.com/how-could-scientists-use-seismograph-station-data-to-locate-the-epicenter-of-an-earthquake.htm#comment-4016 An earthquake generates two types of waves. a surface wave (the so-called "S-wave") and the compression, or sub-surface wave (the P-wave" ). These waves propagate at different speeds, so that the farther away from the epicenter of the quake a seismograph is, the longer between the arrival of each wave. So with one seismograph, we can determine how far away the epicenter is. If we draw a circle on a map of that radius, we now know that it was somewhere on that circumference. If we have a second seismograph, we can draw a second circle which will intersect at two points with the first circle. Now we know that it was at one of those two points. If there is a third seismograph, we can draw a third circle which will intersect at one of those two intersections, and we will have our location. An earthquake generates two types of waves. a surface wave (the so-called "S-wave") and the compression, or sub-surface wave (the P-wave" ). These waves propagate at different speeds, so that the farther away from the epicenter of the quake a seismograph is, the longer between the arrival of each wave. So with one seismograph, we can determine how far away the epicenter is. If we draw a circle on a map of that radius, we now know that it was somewhere on that circumference. If we have a second seismograph, we can draw a second circle which will intersect at two points with the first circle. Now we know that it was at one of those two points. If there is a third seismograph, we can draw a third circle which will intersect at one of those two intersections, and we will have our location.

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