How many traces will be present in a zero-offset section that is generated from the following marine seismic survey? Near offset = 100 m Shot interval = 20 m Receiver interval = 10 m Number of shots = 100 Number of receivers = 1000 (Figure not to scale)
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Total CMP-covered length = spread length + sail-line distance; divide by the CMP bin size (half the receiver interval, since shot interval = 2 x receiver interval here).
Work entirely in units of the receiver interval (10 m), so every count becomes a simple whole number.
Spread length in receiver-interval units: \(\dfrac{100+999\times10}{10}=\dfrac{10090}{10}=1009\)
Sail-line length in receiver-interval units: \(\dfrac{99\times20}{10}=\dfrac{1980}{10}=198\)
Add the two contributions (spread illuminated by a stationary streamer + the extra ground covered as the boat advances): \(1009+198=1207\) receiver-interval units of subsurface coverage.
Now switch to CMP bins. Since the standard bin size for this design (shot interval = 2 x receiver interval) is half a receiver interval, every receiver-interval unit of ground corresponds to exactly 2 CMP bins: \(N_{traces}=1207\times2=2414\)
This confirms, via a purely unit-counting route, that the zero-offset section contains \(\boxed{2414}\) traces, option (B).
