Monitoring the Combined Effects of Induced Earthquakes and Climate Change on a Heritage Building in Groningen

Heritage buildings are often subjected to loading conditions that they were not exposed to in their earlier life span. Induced earthquakes in non-seismic regions caused by energy exploitation activities, or strains in the ground that are caused by the climate changes, are new phenomena that alter the usual loading situations for historical buildings. In this paper, monitoring results of a historical building in Groningen (Nether-lands) in case of induced seismicity as well as climate change effects has been presented. Long-term monitoring results, detected cracks and relevance of the monitoring data are discussed. In the special case of Groningen, weak and agri-cultural soil properties dominate the structural response in the region. The gas extraction activities caused a soil subsidence in the giant Groningen Gas Field, resulting decameters of settlement in the entire area, thus an increase of the ground water level in respect to the ground surface. This is the reason why the heritage structures in the region are more vulnerable to soil-water-foundation interactions caused by climate change as compared to the time these heritage structures were constructed. The ground water monitoring as well as the interaction of soil move-ments with the structural response become important. The study presented here suggests ways on how to effectively monitor historical structures subjected to induced seismicity as well as harsh climate effects at the same time. It was shown here that the newly developed cracks on the structure were detected in a very narrow time window, coinciding with extreme drought and a small induced earthquake at the same time. One explanation provided here is that the soil parameters, such as shrinking of water-sensitive soil layers, in combination with small earthquakes, may cause settlements. The soil effects may superimpose with the earthquake effects eventually causing small cracks and damage. The effects of the climate change on historical buildings is rather serious, and structures on similar soil conditions around the world would need detailed monitoring of not only the structure itself but also the soil-foundation and ground water conditions.