P-Waves: The First Recorded Earthquake Waves
When an earthquake occurs, it generates different types of seismic waves that travel through the Earth. The first type of wave to be detected by a seismograph is known as the P-wave, or primary wave.

What are P-Waves?
- P-waves are longitudinal waves that compress and expand the material they travel through.
- They can move through solids, liquids, and gases, making them the fastest seismic waves.

Why are P-Waves First?
- **Speed**: P-waves travel at speeds of 5 to 8 kilometers per second, depending on the geological material they pass through. This speed is greater than that of other seismic waves.
- **Detection**: As P-waves are the first to reach a seismograph, they create the initial recorded signal, allowing scientists to determine the location and magnitude of the earthquake with greater accuracy.

Comparison with Other Waves
- **S-Waves (Secondary Waves)**: These waves arrive after P-waves and can only travel through solids. They are slower and cause more destructive shaking.
- **Rayleigh Waves**: These surface waves follow both P-waves and S-waves, moving in an elliptical motion and causing significant surface damage.
- **Love Waves**: Similar to Rayleigh waves, Love waves also arrive after P-waves and are responsible for much of the destruction in an earthquake but do not move vertically.

Conclusion
In summary, the correct answer to which earthquake wave is first recorded on the seismograph is option 'A', P-waves. Their speed and ability to travel through various materials make them the initial sign of seismic activity, crucial for earthquake analysis and response.