WHEN THE earthquake hit Dublin, no one expected it. There hadn't been any significant seismic activity in Ireland since 1951, and even that event had been comparatively mild, writes KARL WHITNEY
Then, at about 7.57am on July 19th, 1984, with no advance warning, the earth shook with a previously unknown ferocity in Dublin and all the way along the east coast of Ireland. The epicentre of the quake was at a point south-west of Caernarvon on the Lleyn peninsula in Wales.
The focus of the earthquake was a fault line 20km below ground level: two plates of the Earth’s crust slipped against each other, causing friction, which built up into the tremendous energy that was abruptly, violently, released as an earthquake. The resulting tremor took mere moments to reach the Irish coast and, once it hit, the effects lasted between five and 10 seconds.
The possibility that an earthquake would affect Ireland had previously seemed remote; an earthquake, or temblor, was something exotic – something that happened on the other side of the world – rather than something that shook you out of bed and made your house creak and sway on a Thursday morning. It was either that or you knew it as a metaphor: dramatic, seemingly life-changing news events were routinely referred to as being like an “earthquake”.
But when the earth moved, the earth really did move.
People rolled out of shaking beds all over the east coast; some checked to see if the noise had been made by men on the roof, or if there had been an explosion. One woman wondered why the pans in her kitchen were shaking. Another woman on a bus into the city centre, on her way to work, felt the vehicle lurch oddly. A man convinced himself that his washing machine had switched itself on, and that it was now jumping around the room. Another man, living at the top of the Thomas Clarke tower in Ballymun, felt the whole building sway. Some didn’t notice it at all.
By the end of July, cricketers reported that the wickets at Pembroke’s ground in Sydney Parade were playing better since the earthquake.
IN 1908, a Jesuit priest, Fr William J O’Leary, SJ, installed the first seismograph in Ireland, placing it in Mungret College in Limerick. The Jesuit order had traditionally been interested in scientific knowledge, and the order had become intrigued by seismography, installing its first seismograph in Manila in 1868. The Mungret College machine, of local design, consisted of an inverted pendulum suspended by steel wires which recorded data on two drums. This machine was moved to Rathfarnham Castle in 1916, where it remained until around 1961.
In 1963, Ireland joined the international network of seismic listening posts, having installed a standard seismometer in Valentia Observatory in Co Kerry. Nevertheless, on a local level, the seismographs had very little of importance to record. During a period which spanned almost the entire 20th century, there had been a minimal amount of seismic activity experienced in Ireland.
The 1984 quake, therefore, was by a long way the most significant earthquake to have hit Ireland. The front page of the next day’s Irish Times declared that the tremor “demolished the myth that dangerous earthquakes cannot happen here”. In fact, at around 5.5 on the Richter scale, the temblor remains, in the words of the British Geological Service, “one of, if not the largest, of those for which magnitude can be determined or estimated” in Britain. It was also recorded by the United States Geological Service as one of the year’s most significant earthquakes worldwide.
On the morning of the earthquake, at the offices of the Dublin Institute for Advanced Studies in Merrion Square, the geophysical staff of the school of cosmic physics, studied the readings coming from eight different seismic monitoring stations around Leinster. These stations were set on bedrock at points arranged in a triangular pattern. The geophysical section had begun to record seismological activity in 1977.
In the first hour after the initial event, 13 aftershocks were detected on the section’s equipment; this number soon grew to 20. Staff checked the seismological record to find out if there had been any warning signs prior to the quake; there had been none.
On Saturday July 21st, the geophysics section printed a questionnaire in newspapers asking for the public’s responses to a number of different questions about their experiences of the earthquake. One of the questions asked respondents if they were “Sitting, Standing, Lying Down, Sleeping, Active, Listening to the Radio”, at the time of the tremor.
Over the next number of weeks the aftershocks dropped in frequency, but reached levels of intensity comparable to the quake itself: on the evening of Sunday, July 29th, two aftershocks, of 4 and 3.5 on the Richter scale, occurred within 25 minutes of each other. On Saturday August 19th, another aftershock, of 4.5 was felt in the afternoon – the worst seismic occurrence since the initial event.
But the earthquake was swiftly returned to metaphor. Dr Desmond Connell wrote to this newspaper warning that a proposed introduction of divorce “shows all the signs of an impending Constitutional earthquake”. Another letter-writer, focusing his ire on government instability, blamed the recent earthquake on the “Curse of coalitions, and the catastrophes that inevitably follow in their train”. A later correspondent to the Letters page believed Ireland’s problems did not arise from an earthquake or hurricane; they were instead “entirely self-inflicted by venal politicians”.
In November, papers were referring to revolutionary stirrings in Poland as “an earthquake of which the tremors will soon be felt”. Earthquakes, like revolutions, once again seemed exotic and distant.