I remember a similar incident happening to a Canadian Airlines jet, in Vancouver. I think it was atrributed to poor building methods and material on the appron. Partly because some of the airport is built on marsh and what once was water.
As to sound, the lower velocity the less noice. Older engines use mixing lobes to mix the hot core flow with fan air to slow the speed of the jet blast, and lower the noise output. More modern engines have larger fans, and smaller cores with more shafts to make the engines smaller, and to control speeds of the rotating cores.