Such noise phenomena are nothing unusual in earthquakes and are reported very frequently. The cause of the noise is the coupling of the vibrating ground to the atmosphere, where these vibrations are then 'transformed' into sound waves. Depending on the nature of the ground and the characteristics of the seismic waves, this can be a single noise or a prolonged rumble (often compared to a truck driving by). The US Geological Survey has compiled a small overview here (with focus on the USA).