Do your seismic sensors stay on the bottom
thcrozier,
No, our hydrophone sensors are in a towed-cable array, up to 8000 m long by 800 m wide, moving at 4.5 kts. That's the reason we need fishing boats to keep out of the way, for our mutual benefit. We don't want to tangle with their drift nets and they don't want to lose their gear.
The hydrophones have a bandwidth of less than 10 Hz to 200-300 Hz. They would certainly register the low-frequency noise from an ocean impact in the vicinity - we pick up ship's propellor noise from quite long distances.
However, as a practical matter, there are no seismic vessels operating at the moment, since we are still in the NE Monsoon. Although this is the dry season in southern Vietnam, the winds and waves are too high for us to operate - too much wave-induced noise in the sensors.