Epicentre
The program simulates the survey of the epicentre of an earthquake.
The method is based on the fact that the primary waves P have a propagation
speed about twice as great as that of the secondary waves S.
Three stations of survey measure the delay
with which the S waves arrive in respect to the P waves. For this, by knowing the propagation speed
of the two types of waves, it is possible to calculate the distance of the epicentre. It should
be on a circumference that has its centre in the station and its radius equal to the calculated
distance . With two other stations it is possible to
calculate two other circumferences that intersect the first one on the point corresponding to the
epicentre.
At the end of the simulation, in the tool bar, it is possible to see the data regarding
the delays .
Click button to have sound.
With button it is possible to go to
the page of the space-time graph at the end of the simulation.
By clicking on button a segment parallel
to the axis of time is drawn, that indicates the delay, that uniting the two curves. It starts from
the position T = 0 and moves towards greater values of T. In coincidence with the measured values of
, the corresponding distances are marked,
so that we obtain the three radii.
With button it is possible to see in
succession the page of the simulation and that of the graphics.
By clicking on button
it is possible to start a new simulation with new features.
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