The intended seismic risk from gas production is negligible for gas fields N05-A and N05-A-North, which thus fall in the lowest seismic risk category (SRA Cat. I). TNO and SSM endorse this assessment. The Tanzanite-Oost gas field has a probability of trembling of 19%, but on the basis of a more detailed analysis data is also classified in the lowest seismic risk category. Because of the low negligible seismic risk and the large distance to the Wadden (islands) and the mainland, no detrimental effects and damage as a result of soil vibration are expected from this gas production.
The geological composition of the GEMS area and the gas reservoir consists of good permeable sandstone. It probably will not be necessary to use fracking. The technology used in such cases, including the possible application of hydraulic stimulation, is described in the extraction plan.
The intended soil subsidence caused by gas production is estimated to be less than 5 centimetres at the deepest point of the subsidence basin after completion of the production phase. TNO and SodM endorse this calculation and indicate that the soil subsidence basin lies entirely in the North Sea and that the soil subsidence will not affect the Wadden Islands and the mainland.