The bill for dealing with the consequences of earthquakes linked to gas production in Groningen has passed the €1 billion mark, latest figures show.

The Nederlandse Aardolie Maatschappij (NAM), which is responsible for gas extraction in the northern province, has spent €1.089 billion on repairs, strengthening buildings, prevention and research, according to a quarterly report by the national co-ordinator for Groningen.

Just over half the total – €520 million – was taken up by handling nearly 75,000 claims for damage caused by earth tremors. The figure is more than double the estimate of €250m that formed the basis of a deal with the provincial government to compensate those affected.

A further €316 million has been allocated to safety and preventive measures, including supporting buildings at risk of damage, while €160 million has gone on mitigating plans such as subsidising solar panels or buying out homeowners who are unable to sell their properties.

Tens of thousands of homes in Groningen have had to be shored up as a result of increased earthquake activity caused by decades of gas extraction. The government has agreed to limit production to 27 billion cubic metres this year following a court ruling.

The NAM has bought out 61 homes in the province, 12 of which have been demolished. So far only one has been sold on.