The number of Groningen residents whose homes have been damaged by earthquakes has risen to 100,000, new research has revealed.

Around 25,000 homeowners have suffered damage more than once, according to a study carried out by the Rijksuniversiteit Groningen, the local community health service and the municipality. An earlier phase of the study found that thousands of residents felt their health had suffered because of the effect of the quakes.

Only 60% of people whose houses have been hit by quakes once feel safe at home and the figure falls to 38% for those who have suffered damage more than once. The average for the rest of the country is 85%.

The economic affairs ministry cut back the rate of gas extraction in Groningen at the start of this year after an increase in the frequency and magnitude of earthquakes in the area over the last decade. In the first six months of 2016 there were six quakes measuring 1.5 or more on the Richter scale, compared to 12 in the same period the previous year.