Patent ID: 8371416

Claim:
An improved process for delivering a vibratory sweep signal into the ground for acquiring seismic data where the process comprises: (a) providing a seismic vibrator vehicle carrying a vibrator system with a lift mechanism to raise and lower the vibrator system where the vibrator system includes a baseplate and a baseplate drive system connected to the baseplate to move the baseplate up and down; (b) providing at least one holddown weight sensing device for sensing the weight of the vehicle on the baseplate when the baseplate is lowered to the ground; (c) lowering the baseplate to the ground using the lift mechanism to transfer a substantial portion of the weight of the vehicle to the baseplate; (d) operating the vibrator system to create a sweep of vibrations into the ground; (e) sensing the holddown weight on the baseplate during the sweep of vibrations; and (f) adjusting the lift mechanism to substantially maintain the holddown weight on the baseplate to be substantially constant during the sweep.