Data is gathered from seismic waves read from strategically placed listening devices to form a map of subsurface rock formations. The "source" of energy applied at the surface is commonly via a "thumper" truck, which uses a large, heavy iron plate which is raised by a hoist and dropped from a height of several feet to impact (or "thump") the ground. Other units employ vibrating plates to create a series of vibrations. Seismic waves, as they reflect and bounce off rock layers of differing density and types, give geologists critical information necessary to identify rock layers, faults or natural fractures, and areas of uplifts, karsts and sink-holes. Identification of these subsurface geologic details allows considered placement of lateral lines and drill sites to maximize productivity of planned wells.



The mechanics of thumper trucks generally require that they not be used on paved surfaces because of the force of the impact which can break or disintegrate concrete or asphalt road surfaces. Crews laying out cables can also crush landscape beds, break bushes or trees, or leave fences and gates open allowing pets or livestock to get out. Shock waves emitted by the trucks can also panic or stress livestock and ribbon flags and trash left behind by seismic crews can harm livestock and native species through ingestion. Whie most seismic crews operating in urban areas operate carefully to minimize negative impact, owners will be wise to incorporate specific provisions addressing damages and requiring notice prior to entry into private areas of their property.



After a lease has been finalized and bonus money credited to the mineral owner, allowing seismic analysis of the subsurface will improve the ability of the operator to plan and stage the drilling and fraccing process. Agreeing to limited seismic testing at this stage, therefore, can enhance production on which a mineral owner's royalties will be based. Before that point, however, allowing seismic operations can have the same effect as laying down your card hand for your opponent to evaluate prior to bidding against you. If seismic testing reveals fauting and karsts, operators who may otherwise have leased property and paid significant bonus rentals may withdraw offers completely. This is referred to within the industry as "seismic condemnation" and can eliminate lease offers.



Understanding how and when seismic testing is effectively used is the best step in determining whether and when to agree to allow seismic crews access to your property. Regardless of when the decision is made to allow seismic testing, protective clauses for reasonable setbacks and requiring evidence of insurance should be part of the negotiation process prior to allowing seismic access.



This article has been prepared by Virginia A. Moore, an attorney practicing in Flower Mound, TX. It is intended to be general and informative in nature and does not constitute legal advice. (C) LAW OFFICES OF VIRGINIA A. MOORE