Determination of near surface geophyscial properties by impulsive displacement events

摘要

The invention is an improved technique for measuring near surface attributes of the ground while conducting a seismic survey. The improved technique is enabled by an electric vibe using a number of linear electric motors that direct a rod or piston to contact the ground in a recurring fashion. By applying constant force on the rods of the linear electric motors against the ground, the penetration into the ground may be measured for both rate and overall deformation. This information provides an accurate indication of viscosity and stiffness. In addition shear velocity and compression velocity may be measured and in some conditions, even the type of prominent shear wave may be identified for the area.

主权项

1. A process for measuring near surface properties of the ground for use in seismic prospecting, the process comprising:
a) providing a grid of linear motors arranged in a frame and oriented generally vertically such that each linear electric motor includes a rod that in operation extends down to contact the ground with a lower end of the rod; b) extending the rods with a constant force against the ground for a period of time and measuring electrical feedback at one of more linear electric motor to create a feedback circuit; c) measuring the rate of penetration for each rod into the ground; d) measuring the overall deformation of the ground made by each rod; and e) computing a viscosity and stiffness of the ground based on the rate of penetration and overall deformation measured.