PROJECT NAME: SIM-CRUST: seismic imaging and monitoring of the upper crust: exploring the potential low-enthalpy geothermal resources of Ireland”

The SIM-CRUST project is focused on the development and application of passive seismic techniques to geothermal research. Controlled-source seismology has been widely used as a standard tool for geothermal exploration in the past decades. However, attenuation and scattering from complex, shallow crustal structures can blur the reconstructed image of the subsurface due to the low-energy content of the sources. Passive seismics make use of natural seismicity to explore the subsurface elastic properties. Both local and distant earthquakes can be used to evaluate seismic velocity at depth, and to constrain the presence of seismic anisotropy, which relates to both fluids and cracks in the rock matrix.

The main activities of the project are focused on two widely used techniques: the Local Earthquake Tomography and the teleseismic Receiver Function. The former technique is based on the analysis of microseismicity (Mw<3.0) within small (D<40km) regions and can be used both to build 3D model and to monitor the time-evolution of the seismic properties of the investigate volumes. The latter technique makes use of teleseismic converted waves to map sharp velocity contrasts at depth (e.g. the sediment-basement interface) with a resolving power of some hundreds of meters.

The SIM-CRUST project comprises the development of two high-density (inter-station distance < 10km) seismic networks to explore the Donegal granite region and the Dublin basin, and it will benefit from and integrate results of the IRETHERM project (www.iretherm.ie).

The SIM-CRUST project is supported by Science Foundation Ireland & the Marie-Curie Action COFUND under Grant Number 11/SIRG/E2174.

Figure 1. Heat flow map of Ireland, with the location of the two seismic networks deployed during the SIM-CRUST project. Modified from Goodman et al. (2004). The SIM-CRUST project promotes: (a) seismic exploration of one of the the most promising regions for geothermal resources in Ireland, and (b) a complementary seismological study of the area of the first planned geothermal plant in the south of the Dublin basin.

Goodman et al., Geothermal Energy Resource Map of Ireland, Sustainable Energy Ireland report, 2004 (http://www.seai.ie/uploadedfiles/FundedProgrammes/FinalReport.pdf)