93 4. Near-surface reflection surveying studies. For each field example we have described the survey design (acquisition parameters) and the applied processing sequence. The reader will find more information about acquisition and survey design in Galbraith (2000), Lansley (2000), Mayne (1962), Meunier and Gillot (2000), Meunier (2011), Monk and Yates (2000), Musser (2000), Vermeer and Hornman (2000), and Chaouch and Mari (2006); more about signal processing in Mari et al. (1999, 2015); and more on seismic processing in Yilmaz (1987), and Robein (2003). 4.1 General notes about acquisition and survey design 2D seismic acquisition is achieved with either end-on (also called off-end) or split dip spreads (Figure 4.2-a). a b Figure 4.2 2D land seismic acquisition: (a) seismic spreads, (b) stacking fold. The individual shot element is defined by the distance between the source and the first receiver, the number of receivers and the distance between two adjacent receivers. A receiver can be a single sensor (geophone for land acquisition) or an array of sensors. If the receiver is a single sensor, the interval between two receivers is of several meters, if it is an array, the interval is of several tens of meters. The maximum source-receiver offset to the far receiver is about the same as the maximum depth of the geological objective. The near receiver offset is chosen to minimize interference between ground roll (surface waves) and reflection arrivals. The distance between reflection points, assumed to be midpoints, is equal to half the receiver interval. For a receiver spread of length L, the length of the reflector illuminated is equal to half
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