LAST night’s tremor in Co Donegal and today’s 6.8 magnitude earthquake in Japan was felt as far away as the West of Ireland and recorded on a newly installed seismometer at the Cliffs of Moher.
Funded by the Geological Survey of Ireland (GSI) and part of the Outreach Programme for Seismology in Schools, run by the Irish National Seismic Network (INSN), the state-of-the-art device is the first of its kind to be installed in County Clare. The Burren and Cliffs of Moher Geopark also has become the latest Geopark to operate a seismometer.
Tom Blake, INSN Director and Experimental Officer with the School of Cosmic Physics at the Dublin Institute for Advanced Studies (DIAS), said that the seismometer is so sensitive that it can easily pick up strong seismic activity on the other side of the world.
He explained: “This morning’s earthquake near the east coast of Honshu (Japan) was clearly picked up by the Cliffs of Moher seismometer approximately 10 minutes after it struck at 9:08 AM local time. High atmospheric pressure over Western Europe, which resulted in a reduction background seismic noise, helped to provide a very clear reading.”
Mr. Blake continued: “Our Earth is more elastic that one might think. An earthquake has the same effect on the Earth as a pebble does when dropped into a pool. The ripple effect of other recent earthquakes in Negros (The Philippines) and Siberia (Russia) was felt in north Clare when the energy or shockwave from the quakes travelled under the Cliffs of Moher and were subsequently registered by the seismometer.”
Mr. Blake said that the Cliffs of Moher seismometer is sensitive enough to record small earth tremors that occasionally occur around Ireland, the most recent of which was felt in north Donegal on Tuesday night (13 March 2012). The 1.1 magnitude tremor struck at a depth of 3 kilometres at 9:23 PM in the Buncrana and Milford regions.
A 2.7-magnitude trembler two years ago in Lisdoonvarna, located just 6 miles from the Cliffs of Moher, remains the strongest onshore earthquake recorded in Ireland since records began in 1978.
“Although Ireland does not sit on any major plate margin, it is still susceptible to earthquakes as we saw in Donegal this year and in Clare in May 2010. The new seismometer would certainly have been well placed to register and record the north Clare earthquake. This was a very important seismic event as it was the first time that a tremor had occurred in the west of Ireland since records began” commented Mr. Blake.
Meanwhile, Mr. Blake noted that the success to date of the seismometer in the Burren and Cliffs of Moher Geopark since its installation during February could become the catalyst for the formation of a Geopark seismic network.
“Already, we have seen seismometers installed at the Marble Arch Caves Geopark in County Fermanagh, the Copper Coast Geopark in Waterford, and now the Burren and Cliffs of Moher Geopark. I would like to see a similar type instrument fitted out at every Geopark in Europe. Our understanding of earthquakes would be greatly improved by the development of such an expansive network”, stated Mr. Blake.
The new seismometer is on public display at the Cliffs Exhibition at the Cliffs of Moher Visitor Experience.
According to Cliffs Director and Clare Tourism Forum member, Katherine Webster: “Visitors to the exhibition at the Cliffs can see the seismometer in action. It is so sensitive it can pick up actions such as a person jumping up and down, although these readings do show up differently from an earthquake. We are delighted that the Burren and Cliffs of Moher Geopark is now part of a potential European Geopark seismic network, something which is being promoted by Tom Blake.”
The DIAS began modern seismic recordings in 1978. The Irish National Seismic Network (INSN) now features five permanent stations in Dublin, Kerry, Galway, Donegal and Wexford, along with 55 other seismometers around the country. For more see www.dias.ie.