Question

1. what type(s) of wave is known as s - wave?

options: primary wave, secondary wave, surface wave, primary and secondary wave, primary, secondary, and surface wave

1. what type(s) of wave is known as l - wave?

options: primary wave, secondary wave, surface wave, primary and secondary wave, primary, secondary, and surface wave

Explanation:

For question 17: Seismic secondary waves are defined as S-waves; they are transverse body waves that travel through Earth's interior.
For question 18: Seismic surface waves are also known as L-waves (long waves), which travel along Earth's surface and cause most damage during earthquakes.

Answer:

1. Secondary Wave
2. Surface Wave