Methodology:

Shot-point location was determined using RTK GPS methods. Receivers used were Leica 530. One receiver operated as a base station, located in the middle of each survey area. The other receiver was operated as a real-time rover.

Seismic source for each shot was 450 g of Pentolite explosive buried at 30 m depth in holes made by a hot-water drill.

Data acquisition used a spread of 48 geophones (40 Hz natural frequency) spaced at 10 m intervals with an offset from shot to first geophone of 30 m. Shot-spacing and move-up per shot was 240 m, giving single fold coverage.

Line length varied between 33 and 12 shots.

The data provided comprise sorted raw shot gathers. Raw field data for each line were sorted into sequential traces and written to a single SEG-Y file.

The metadata provided contain the GPS-derived position of each shot point (latitude (decimal degrees), longitude (decimal degrees), elevation (m relative to WGS-84 ellipsoid).

Seismic data were processed with Halliburton-Landmark ProMAX software under academic license to BAS.

Horizontal and vertical position of each shot point is given. These were determined using dual-frequency GPS surveying with a precision of approximately 10 cm.

Vertical precision is given by the sample interval of 0.2 ms. Note this is given in time, not depth; no depth conversion has been applied.

Data collection:

Seismic data were acquired using OYO 40 Hz single geophones and Geometrics GEODE 48-channel seismic data logger recording in SEG-2 format.

Data were logged at 4 kHz; record length was 4 s.

Data processing (sorting and writing to SEG-Y format) done using ProMax seismic processing software.

Data quality:

SEG-Y data include relative geometry in the headers with a shot point interval of 240 m and a receiver interval of 10 m. Only shot locations were surveyed to provide accurate location and elevation. Receiver locations must be determined by interpolation and extrapolation using the shot point profiles.