Question

Check all of the following statements that are true regarding seismic waves.

Seismic waves are caused by the vibration of rock.
	P-waves travel fastest and are the first to arrive at a seismometer station.
	P-waves typically have the largest amplitude (height) when viewed on a seismogram.
	P-waves and S-waves are both travel through the interior of Earth rather than along the surface.
	A recording from a single seismogram will tell you the direction the seismic waves came from

Answer 1

1. True-Seismic waves are caused by the energy emanating from rock body/surface. This energy release is often related to sudden energy release at times due to elastic unloading of rocks, the release of super-incumbent load etc. These waves make their journey through rock bodies and reach the surface of Earth where they are analysed for various purposes.

2. True- Primary waves are amongst the fastest wave and hence the first to arrive at the seismic station. P waves can travel through solids as well as liquid. However, their speed is reduced in liquids. They are similar to sound waves and move through compression and rarefaction of the medium.

3. False-Surface Waves have the largest amplitude when viewed on the seismogram

4. False-Surface waves travel through the Earth’s surface. They are analogous to water ripples. They are found to be the destructive of all waves.

5. False- Modern Seismograph station utilise 3 seismograms to measure the direction of the waves.