Investigation of an elevated sands unit at Tralispean Bay, South-West Ireland – potential high-energy marine event

A sequence of high elevation sands containing both broken and whole marine shells, as well as many mega-sized, raft-shaped boulders (1-3m across) has been discovered at Tralispean Bay, West Cork, Ireland. Ground-Penetrating Radar (GPR), ground surveying and differential GPS (dGPS) show that the sediments cover an area of c.0.75ha, reaching a maximum height of c.+18.5m ODM, with interconnected pockets of sand varying in thickness of up to 1m. Coring, lithostratigraphic study, granulometry, organics loss-on-ignition and carbonate content analyses, together with examination of micro- and macrofossils, indicate that the shelly sands were deposited rapidly, under high energy conditions. Informal interviews with local residents, as well as the extent of the sands, suggest that the deposit is not the result of human actions. Elevations reached by the sediments, the presence of mega-boulders, and other indicators make it unlikely that these sediments arose from storm activity. It is possible that they have been deposited as the result of a tsunami. The radiocarbon (AMS) date obtained places the age of such an event at 1465 AD (Cal BP 485). At present, no clear historical record has been identified of any tsunami impacts affecting the south coast of Ireland other than the Lisbon earthquake of 1755

A newly reconciled dataset for identifying sea level rise and variability in Dublin Bay

We provide an updated sea level dataset for Dublin for the period 1938–2016 at yearly resolution. Using a newly collated sea level record for Dublin Port, as well as two nearby tide gauges at Arklow and Howth Harbour, we perform data quality checks and calibration of the Dublin Port record by adjusting the biased high water level measurements that affect the overall calculation of mean sea level (MSL). To correct these MSL values, we use a novel Bayesian linear regression that includes the mean low water values as a predictor in the model. We validate the re-created MSL dataset and show its consistency with other nearby tide gauge datasets. Using our new corrected dataset, we estimate a rate of sea level rise of 1.1 mm yr−1 during 1953–2016 (95 % credible interval from 0.6 to 1.6 mm yr−1 ), and a rate of 7 mm yr−1 during 1997–2016 (95 % credible interval from 5 to 8.8 mm yr−1). The overall sea level rise is in line with expected trends, but large multidecadal variability has led to higher rates of rise in recent years