Is there an equation for finding how far away an earthquake's epicenter is?
Sep 07, 2010
in
Earthquake Questions
It’s what we’re doing in science, except we were given textbooks with a graph telling you the answer. My friend and I just wanted to know if there was another way to find the distance.
oh, and we ARE doing the whole p and s wave thing and drawing circles with compasses to find the location…
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2 comments
A.Ganapathy India on September 7, 2010 at 12:56 am
The graph gives you the arrival time of P wave and S wave. The difference in the arrival time multiplied with the speed difference is the distance of epicenter. The ratio of speed is 1.7 : 1. The average difference in speed is about 8 k/m for each second difference in arrival time of S wave minus P wave. The sensing time will increase depending upon the distance and magnitude. The longer the sensing time at very low magnitude also from strong earthquakes only.This what helped me to issue the warning 2 hours before Tsunami struck our coast.My earthquake alarm sensed the wave for an unusual time of 12 minutes .Therefore I said that I have sensed a very big earthquake which I never heard in the history.But local T.V.Stations refused to accept my findings. You need three seismograph to find the location of epicenter but to find only the disatance one seismograph will do.
t3hbook4ddict on September 7, 2010 at 12:56 am
No, you have to use the difference in the time of arrival of the P and S waves (at the place where they were recorded) to determine the distance from where they were recorded (for example, 50 miles). You need to do this with three different places and then you use a compass (centered on where the waves were recorded) and draw a circle 50 miles around the location (proportional to the map). Once you do that with each of the three locations, the intersection of the circles will be the epicenter.