What is the correct order of arrival of seismic waves at a seismograph after an earthquake?

Correct option is D

The correct answer is (d) P-waves, S-waves, surface waves
Explanation:
· Seismic waves travel at different speeds, which determines the order in which they are recorded by a seismograph.
· P-waves (Primary Waves): These are the fastest waves and are the first to arrive at the surface.
· S-waves (Secondary Waves): These travel slower than P-waves and arrive second.
· Surface Waves (L-waves/R-waves): These travel along the Earth's crust and are the slowest, arriving last.
· Therefore, the sequence is always P-waves → S-waves → Surface waves.
The image below is a seismogram showing the characteristic arrival times of the three main types of seismic waves:
Information Booster:
· Body Waves vs. Surface Waves: P and S waves are called "Body Waves" because they travel through the Earth's interior. Surface waves travel only along the surface.
· P-Waves (Primary): They are longitudinal waves (compressional, like sound). They can travel through solids, liquids, and gases.
· S-Waves (Secondary): They are transverse waves (shear). Crucially, they can only travel through solids. This property was essential in determining that the Earth's outer core is liquid.
Additional Information:
· Destructive Power: Although Surface waves arrive last, they are the most destructive because they cause the most horizontal and vertical ground motion.
· Epicenter Location: The time difference between the arrival of the P-wave and the S-wave (the S-P interval) is used to calculate the distance of the seismograph station from the earthquake's epicenter.