The seismic waves are those that travel through the earth's layers. They are classified as P, S, and L waves. These waves are primary, secondary, and longitudinal waves.
- The Primary waves are the first to record at the epicenter. They are also called body waves. The P waves move through the solids and liquids while the S waves move through the solids only.
- As per the graph, If the P waves reach the seismogram 6 minutes after the earthquake. The secondary waves reach in three and half a minute then the seismogram will be located 3000 km from the epicenter.
Hence the option B is correct.
Learn more about the graph to answer the questions.
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