Sounds like a big boom to me.

Quake: Listening to Earthquakes: "When a loudspeaker produces sound it shakes. During an earthquake the ground shakes. To convert the earthquake shaking to sound we make the loudspeaker shake the same way the ground did. But, if we really did that the sound would be too low for people to hear. So, we speed things up so that the loudspeaker moves back and forth much faster than the ground did and then we can hear it."