Modern seismology began not in San Francisco or Naples, but in Dublin,writes Mary Mulvihill.
You'd expect modern research into earthquakes would have started in some place that was prone to these natural disasters. Yet it began in Grafton Street in 1846, when a Dublin engineer, Robert Mallet, presented his proposal for a modern science of seismology to the Royal Irish Academy.
Mallet wanted to bring earthquakes "within the range of exact science. . . and deduc from. . . the enormous mass of disconnected and often ill-observed facts. . . a theory of earthquake motion". He coined numerous new technical terms, including the words "seismology" and "epicentre", invented the first completely automatic seismometer, and then spent the next 30 years pioneering the analysis of earthquakes.
This scientifically-minded engineer was born in Dublin in 1810 and, after studying classics and mathematics at TCD, joined his father's iron business. Robert made their Victoria Foundry into Ireland's leading engineering works. Their projects included steam barrel-washing plants for Guinness's brewery, cast-iron swivel bridges for the Shannon navigation, a metal lighthouse tower for the Fastnet Rock, mortar guns for the Crimean War, and much of the ironwork for Ireland's developing railway network.
Yet he also found time to experiment with electricity, test sea water for pollution, investigate corrosion in iron ships, and study geology - how glaciers move, how slate formed, and what happens when the Earth quakes.
By the time he got to the RIA in 1846, he had invented the first self-registering seismometer. It involved five glass tubes (four held horizontally, and the fifth vertically) filled with mercury and connected in an electrical circuit. Any tremor would break the mercury's contact with the circuit, producing a pencil mark on a paper sheet, the longer the disturbance, the longer the pencil mark.
In 1849, Robert Mallet began some explosive experiments. To investigate how seismic waves travel through the Earth's surface, he detonated gunpowder at Killiney beach, Dalkey quarry and elsewhere, and measured how long the shockwave took to travel through the sand and rock (825 feet/second in sand, he calculated, and a faster 1,165 feet/second in granite). Today, prospectors use the same principle to identify the underlying geology in a region.
After Naples was rocked by a catastrophic quake in 1857, Mallet went there to conduct the first thorough analysis of an earthquake site. By analysing how buildings fell and other patterns, Mallet deduced that the cause was a series of shock waves from a deep focus point or epicentre.
In 1858 he and his son John compiled On the Facts and Theory of Earthquake Prevention, a detailed catalogue of every recorded earthquake, including one in 1,606 BC at Mount Sinai which is mentioned in Exodus.
The two analysed all manner of patterns, including the seasonal occurrence of earthquakes, whether tides had any influence, and reports of animal behaviour and springs disappearing. . . but they could find no factors that would predict when an earthquake might occur. Modern geologists continue that search today.
For all of this work, Robert Mallet is acknowledged as the father of modern seismology. A crater on the Moon is named after him, and a plaque at Ryder's Row off Dublin's Parnell Street, marks his birthplace. You can read Mallet's seismological paper in the Transactions of the Royal Irish Academy (June 1846), and see samples he collected at Naples in TCD's geology museum (tel: 01-6772941, Mon-Fri).
Mary Mulvihill's award-winning book, Ingenious Ireland, is published by TownHouse/Simon & Schuster