sound waves?

Question

Someone was walking and they felt a vibration. A few seconds later they hear a loud explosion. What is the reason for this?

does it have something to do with frequency?

Answer 1

Good question.

The reason for this has to do with the speed of sound being different in different materials.

The speed of sound in air is about 340 meters per second. That means if something explodes 1700 meters away, the sound takes five seconds to reach them by air.

However, the speed of sound in the ground is significantly faster. It might only take 2 seconds for sound to travel 1700 meters through the ground.

So, the explosion sends out vibrational waves through both the air and ground, but the wave in the ground travels much faster, reaching the person before the wave in the air.