"'I have never seen an event of this magnitude on our system before. It was quite a startling thing to see."
Dr Tom Blake oversees the State's only seismographic network, a recording system run by the Dublin Institute for Advanced Studies that can pick up signals from earthquakes occurring right around the world. He was stunned to see the readouts from the quake off Sumatra that triggered the devastating tsunami in the Indian Ocean on December 26th.
"It registered nine on the Richter scale and is quite a rare event," he says. The "intense squiggly trace" left on the recorder testified to the enormous energy released by the quake, he adds. "We were able to pick up the event 14 minutes after it occurred."
Blake is an experimental officer in the geophysics section of the Institute's School of Cosmic Physics. "The network was started up in 1978 by Prof Brian Jacob. The idea was to set up a national recording centre for seismic events."
The institute's system joined with an existing recording station opened in the 1960s in the meteorological station at Valentia, Co Kerry.
Today there are two separate networks; one within the State with stations in Dublin, Offaly, Cavan and Kerry, and another connected into a wider European seismological network. This recording node is based in the Dublin Mountains, says Blake.
The system is very sensitive and can detect the shock-waves sent out by explosions detonated in quarries right across the State. It can also pick up waves sent through the earth after an earthquake, allowing the institute to make a valuable contribution to earthquake research. "We sit on the edge of the Atlantic, so the data we supply is unique," he says.
No early indication of the event was given by the system given its age, says Blake, who argues for an investment by Government in more modern equipment. He would like to see more money put into a system to enable it to alert us automatically in the event of a major quake.
While the Sumatran quake was the largest yet recorded by the system, our strongest regional quake occurred in July 1984 off the coast of Anglesey, Wales. This registered 5.4 on the Richter scale, and caused some minor structural damage along the east coast.
The two to three local earthquakes recorded here in a typical year here aren't noticed at all, measuring only one to two on the Richter scale.