C. They unwinds the two strand of DNA.
The seismic traces recorded at station A and station B indicate that station A is further from the earthquake epicenter than station B because the ground movement detected at B was greater than that detected at A, with seismic waves more frequent and less frequent respectively.
<h3>Seismograph</h3>
A seismograph is a device that detects ground movements, including those generated by seismic waves. It consists of the basic sensor of the seismographic instruments of which the seismograph and the seismoscope are part. These movements are then recorded in seismographs, which have been plotted graphs called seismographs.
<h3> Propagation speed</h3>
Seismic station A is located 5,400 kilometers from the earthquake's epicenter. How long would it take for the first S wave produced by this earthquake to reach seismic station A? The propagation speed of this type of waves varies with the medium in which they propagate, with typical values of
- 330 m/s in air
- 1 450 m/s in water
- and 5 000 m/s in granite.
They are not as destructive as S waves or the surface waves that follow them. The propagation speed of these waves is, in general, slightly less than twice that of S waves.
With this information, we can conclude the velocity of propagation of seismic waves and how a seismograph enumerates the distance from the epicenter of an earthquake.
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