It was a bleak morning, this morning, on Killiney Beach for the unveiling of a commemorative plaque to Robert Mallet, the father of seismology.
In October 1849, aged 39, Robert, and his son John, who was a geology student at TCD, decided to carry out a remarkable experiment on Killiney Beach. They wanted to prove that energy moved through sand and rock in waves that could be measured, and they designed a ‘controlled’ experiment to prove this was so.
The two Malletts buried a keg of gunpowder in the ground, and detonated it. They measured the energy wave that traveled through the sand at a distance of half a mile away, with a seismoscope. The experiment worked, and a seismic reading was generated that showed clearly, energy moved through sand in waves.
Robert also worked closely with William Rowan Hamilton, another great Irish scientist and mathematician. William had suggested to Robert that he might apply the laws of physics, as they apply to light, in order to describe how the energy generated by the explosion would pass through sand and rock (for the rock measurements he set up a seismoscope on nearby rocky Dalkey Island, rather than the sandy beach). Robert took William’s advice and Robert’s report on his experiment became the foundation of modern seismology.
Today, Dún Laoghaire-Rathdown County Council unveiled a plaque on Killiney Beach, commemorating this landmark experiment.