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This programme aims to give a broad look at some of the major techniques used in geophysical exploration. three methods, gravity, magnetic and seismic are examined.
Metadata describing this Open University video programme
Module code and title: S333, Earth science topics and methods
Item code: S333; 02
First transmission date: 02-05-1976
Published: 1976
Rights Statement:
Restrictions on use:
Duration: 00:25:00
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Producer: Peter Clark
Contributors: Geoff Bennett; Nicholas Gant; Peter Howell; David Jackson
Publisher: BBC Open University
Keyword(s): Aeromagnetic surveys; Geophysical exploration; Gravity; I.G.S. gravimetric survey; Land, sea and air; Magnetic; Maps; Seismic; Seismic profiles; Seismic reflection method
Footage description: Film shots of a team from the Institute of Geological Sciences carrying out a gravity survey in Morecambe Bay. Dennis Jackson (V/O) explains what is happening. Dennis Jackson, in the studio, introduces the programme. Peter Howell with a Worden Gravity Meter. He explains first how the instrument works and then how readings are recorded. Howell at a drawing board explains how a gravity contour map for the Wensleydale area around Askrigg was constructed. He then explains how models were used to compute and predict a concealed granite under the country rocks in this area. Shots of model. Howell shows a core sample of the granite. Film shots of a ship-board gravity survey being carried out. Commentary by Jackson explains what is happening. Shots of all the equipment being used. Shots of a magnetic survey being carried out at the same time. Commentary by Jackson continues. Film shots of an aerial magnetic and gravitational survey being carried out by helicopter. Nicholas Gant with part of an airborne magnetometer record trace. He points out the components of the trace. Gant goes on to explain how contour maps are prepared from this data. A magnetic contour map of southern England is shown. Gant points out various features. Gant explains how these contours are then interpreted in terms of geological structure. He uses several graphic aids to compare actual with theoretical profiles. Film shots of a shipboard North Sea seismic reflection survey in progress. Commentary by Jackson explains in detail what is happening, particularly how the various pieces of equipment work. The survey is looking for evidence of hydrocarbons (oil and natural gas). Jackson, in the studio with a sparker, explains how this piece of seismic equipment works. Geoff Bennett (Amoco Processing Centre, London) explains how the North Sea geophysical data is processed by computer. Bennett goes on to explain how the geophysicist constructs his geological structure map from the computer print-out data. He points out particularly significant interfaces on the printout and produces a completed structure map showing the structure of an actual gas field (The Indefatigable Field).
Master spool number: 6HT/71788
Production number: 00525_1208
Videofinder number: 1888
Available to public: no