"Sonic cannon"? Nice bit of hyperbole. Everyone else just calls them airguns.
That ~ 250 dB @ 1m is a bit misleading. It won't be that loud at 1m because airgun arrays are not point sources. Additionally, there shouldn't be anything that close as it's standard practice to start at a lower amplitude and ramp up slowly. The amplitude falls off with distance quite quickly.
This technology has been in widespread use for decades.