Donegal Seismic Network

The Co. Donegal represents a perfect target for deep (0-5km depth) geothermal investigation for several reasons. First, radiogenic granites are exposed at the surface in the eastern half of the county, but they are likely to be buried in the westernmost portion, where they outcrops in some place in Fanad. The Donegal Granite is also the Ireland's highest surface heat-flow area, with an anomaly as large as 80 mW/m2 . Finally, Lough Swilly is the most seismic active on-shore area in all Ireland. The presence of a relatively high-level of seismicity suggests potential for secondary, fluid-filled porosity along faults.

The SIM-CRUST project installed and maintains a seismic network of 12 temporary seismic stations equipped with broadband seismometers (Guralp CMG-40T). The inter-station distance ranges between 5 and 20 km, smaller in the area of the last Mw=2.2 seismic event occurred in Jan 26th 2012. The network will operate for 2-3 years to collect data on both local seismicity and teleseismic waves. Such data will be used to map the main anomalies in the seismic velocities at depth, and the presence of seismic anisotropy within the shallow (0-5km depth) crust.

Figure 1. Donegal seismic network. Colored triangles represent broadband seismic stations deployed in Co. Donegal during the SIM-CRUST project. The seismic network covers the area across the main geological structures in the region and (possibly) overlies buried granites. Modified from Hutton and Alsop (Journal of the Geological Society, 2004)


ACKNOWLEDGMENTS

We thanks all the kind persons who helped to install and maintain the seismic network in Donegal. In particular, we are deeply in-debt with John O'Raw and Danny Mc Fadden for their fundamental help to introduce us to a number of land-owners in Donegal. David Mc Gloin, Michelle Johnstone, Henry and Martin Callaghan, Henry McKinney, Gerard Mc Daid, Michael Tinney gave us the opportunity of installing the seismic stations. We also thank the Donegal County council for permission to access Fort Dunree site. We are grateful to Derek Flanagan for his help in the maintenance of the seismic station near Milford. NPA acknowledged long discussions on geothermal research with Dr. Alessandro Amato during fieldwork in Donegal.


PUBLICATIONS and MEETING ABSTRACTS

Piana Agostinetti N. (2016) Elastic structure and seismicity of Donegal (Ireland): insights from passive seismic analysis, Geophysical Research Abstracts, 18, EGU2016-11496, EGU general assembly, Vienna

Piana Agostinetti N. and Licciardi, A. (2015) SIM-CRUST: seismic imaging and monitoring of the upper crust: exploring the potential low-enthalpy geothermal resources of Ireland, Proceeding of the 2015 World Geothermal Congress, Melbourne, Australia

Piana Agostinetti N. (2013) Geothermal exploration via passive seismic analysis, 56th Ireland Geological Research Meeting, Derry

Piana Agostinetti N. (2013) SIM-CRUST:Seismic imaging and monitoring of the upper crust: exploring the potential low-enthalpy geothermal resources of Ireland, Geothermal Association Ireland meeting, Dublin