Question

An earthquake produces which kind of sound before the mainshock wave begins

• A. ultrasound
• B. infrasound
• C. audible sound
• D. None of these

Answer 1

The correct option is B

infrasound

Explanation :

1. Earthquakes produce low frequency (i.e., 5 Hz) infrasound before the mainshock waves begin which possibly alerts the animals and they get disturbed.
2. People use this frequency range for monitoring earthquakes and volcanoes, and charting rock and petroleum formations below the earth.

So, the correct option is an option (B).