Seismic refraction prospecting

摘要: The seismic method is divided into reflection and refraction techniques, based on whether or not a wave undergoes at the extent of its travel. Thus, while most refracted events have been reflected, reflected refracted, because occurs across any velocity interface in accordance with simple basic Snell’s law. This law states that sine angle incidence to as first side second interface. Where large, near zero it case work, there are many considerations concerning geometry raypath be made interpretation. Basically, papers this volume describe various techniques for separating out special solutions making approximations give us structural geologic picture from study these specializations. The following factors extreme importance surveying’ 1) Distance’ Surveying must accurate order make correct depth determinations refractor by use method. 2) Velocity’ horizons, through which passes, known if an determined. Many velocities can determined data, and, fact, good means establishing needed calculations. 3) Time’ Accurate time information prerequisite, although no more than work. In instances, recorded nearest 1/1,000 sec exploration purposes. The distance parameter will discussed first. surveys between shot receiver may extremely long (25 50 miles), requirement accuracy just vital were very short (a few hundred feet). Because differential involved, errors cause greater themselves. For somecases, experience editor, error three times error. critical information. Of particular important velocity, often used determine subtracted total path amount verticalor converted vertical time.