Why is economic geology essential to our progress? It has been said that agriculture is the most basic of man's activities, but in this time of overpopulation and indeed in the preceding centuries it would have been impossible to feed the world's teeming millions without recourse to mining and the use of minerals and metals for ploughing, fertilization, harvesting, food preparation and so on. Indeed, of these two basic industries— agriculture and mining—mining is the older. It started some 500000 years ago when man commenced exploring for tool-making materials — flint, obsidian, quartzite were chipped and ground to sharp cutting edges. Early man found that some localities were richer than others and began to search for these richer deposits, to mine them, establish axe factories and to trade in the finished products. He soon developed an appreciation of their geological occurrence. For example, by 3 000 B.C. large underground flint mines were in operation at Grime's Graves in Norfolk, U.K. and it is clear that the miners had noted that particular horizons in the chalk host rock carried the best and most numerous flints.

The onset and rapid spread of canals across the face of Britain in the late eighteenth century, closely followed by the building of the railway network in the early nineteenth century, were largely responsible for making the study of the strata, or stratigraphy, a subject of both practical and economic value. It is not surprising, therefore, that it was a land surveyor and canal engineer, William Smith (1769–1839), working initially in southern and eastern England, who first worked out that rock strata were not randomly disposed around the country but arranged in a definite order.

This book provides a general introduction to the most important methods of geophysical exploration. These methods represent a primary tool for investigation of the subsurface and are applicable to a very wide range of problems. Although their main application is in prospecting for natural resources, the methods are also used, for example, as an aid to geological surveying, as a means of deriving information on the Earth’s internal physical properties, and in engineering or archaeological site investigations. Consequently, geophysical exploration is of importance not only to geophysicists but also to geologists, physicists, engineers and archaeologists. The book covers the physical principles, methodology, interpretational procedures and fields of application of the various survey methods.The main emphasis has been placed on seismic methods because these represent the most extensively used techniques, being routinely and widely employed by the oil industry in prospecting for hydrocarbons. Since this is an introductory text we have not attempted to be completely comprehensive in our coverage of the subject. Readers seeking further information on any of the survey methods described should refer to the more advanced texts listed at the end of each chapter. <...>

Geotechnical engineering is concerned with the application of civil engineering technology to some aspect of the earth, usually the natural materials found on or near the earth's surface. Civil engineers call these materials soil and rock. Soil, in an engineering sense, is the relatively loose agglomerate of mineral and organic materials and sediments found above the bedrock. Soils can be relatively easily broken down into their constituent mineral or organic particles. Rock, on the other hand, has very strong internal cohesive and molecular forces which hold its constituent mineral grains together. This is true for massive bedrock as well as for a piece of gravel found in a clay soil. The dividing line between soil and rock is arbitrary, and many natural materials encountered in engineering practice cannot be easily classified. They may be either a "very soft rock" or a "very hard soil." <...>