Gravity measurements have been made over many years by DIAS (e.g. Thirlaway 1951, Murphy 1952, 1974; , O’Reilly et al., 1996, Readman et al., 1997). There is more than 23,000 stations in total. The data coverage shown averages at about 4.2 stations per 10 km square, equivalent to an average spacing of about 1.55 km. The measurements have usually been made at or near to Ordnance Survey of Ireland bench marks or spot heights, and terrain corrections (rarely greater than 0.5 mGal) have been made where necessary. To view gravity station locations click here.
The overall accuracy is estimated to be about 0.2 mGal. The variation in the thickness of the overburden cover leads to uncertainty in calculating the Bouguer anomaly that in extreme cases can be up to 1.5 mGal for peat bog. The magnitude of the effect is rarely known so for simplicity the data reduction procedure in calculating the Bouguer anomaly has assumed a constant density of 2670 kg m -3 above sea-level datum.
Commercial data licence fee
€0.30 per point (for one year licence) + €250 licensing fee and €250 data preparation fee.
Multi-year licences are possible up to a maximum of 5-years, with approximately 50% reduction for each successive year so a 2 year licence is €0.45 per point, 3 year licence is €0.525 per point, 4 year licence is €0.5625 per point, and a 5 year licence is €0.60 per point.
The gravity data can be made freely available to academic users upon request.
Murphy, T. 1974. – Gravity Anomaly Map of Ireland. Communications of the Dublin Institute for Advanced Studies, Series D, Geophysical Bulletin No. 32.
O’Reilly, B.M., Readman, P.W. & Murphy, T. 1996. The gravity signature of Caledonian and Variscan tectonics in Ireland. Physics and Chemistry of the Earth 21, 299-304.
Readman, P.W., O’Reilly, B.M. & Murphy, T. 1997. Gravity gradients and upper crustal tectonic fabrics, Ireland. Journal of the Geological Society, London 154, 817-828.
Thirlaway, H.I.S. 1951. – Measurements of gravity in Ireland: Gravimeter observations between Dublin, Sligo, Galway and Cork. Geophysical Memoirs, Dublin Institute for Advanced Studies Ireland, No. 2, part 3.