The object of the project was to map the resistivity structure of the Grímsvötn geothermal system in detail using (far-) off-central TEM soundings (a variation of the LOTEM method). To locate and estimate the extent of magma bodies in the uppermost 3-5 km of the crust, using the resistivity data along with other existing geophysical data from the area (such as gravity, magnetic and seismic data), and to build a conceptual model of the whole geothermal system. The unique situation in Grímsvötn, i.e. a glacier covered geothermal system, means that the natural thermal output can be estimated quite accurately. The geo-scientific and geothermal value of the project is to compare the size of the geothermal system and thermal output to estimate the thermal output of other systems, based on their structure and volume. The project also has a technical value as this variation of (LO)TEM measurements has not been used in Iceland before.

Due to unforeseen incidents caused by the volcanic eruptions in Eyjafjallajökull in 2010 and in Grímsvötn in 2011 the project was stopped and redefined. Deep resistivity surveys have greatly improved the understanding of the inner and deep nature of volcanic high-temperature geothermal systems. In this study the Long Offset Transient Electro-Magnetic (LOTEM) method will be used to map the spatial extent and depth span of resistivity anomalies within the Grímsvötn geothermal system, located in the Vatnajökull Glacier.