Seismic Surveillance of Cologne Cathedral

The strong-motion net work (SeFoNiB) with 19 stations set up in 2006 by Cologne University in the Lower Rhine Embayment (LRE) (Hinzen and Fleischer 2007) includes the first modern seismic stations within the Cologne city limits, the only German megacity with a significant seismic hazard. In a cooperative venture with the Dombauverwaltung Koln and Cologne University, the network was recently supplemented by five stations within Cologne Cathedral, one of the largest Gothic cathedrals and a World Heritage monument since 1996. Large clerical and other historic buildings have been the focus of several seismological studies, often aiming to reveal the vulnerability of the structures. Petrini and Casolo (2002) described techniques to study the vulnerability of historical and monumental buildings. For example: Meskouris and Hinzen (2003) studied the dynamic behavior of the towers of Cologne Cathedral for the 750th anniversary of the building. They calculated the eigenmodes of the towers and simulated effects of a magnitude 6 earthquake on a nearby fault. Kuhlmann et al. (2003) made a detailed finite element model of the Dom (cathedral) in Aachen, Germany, to study its dynamic earthquake behavior. Facke et al. (2006) investigated the eigenmodes of the Cologne Cathedral’s nave with temporary measurements at 10 locations. Casolo and Sanjust (2007) studied the cathedral of Syracuse, Italy, using a finite element model and a specific rigid body spring model. Proano et al. (2007) determined the seismic vulnerability of Lima Cathedral, Peru, and showed that the most vulnerable components of the structure are the two towers and other masonry elements in the front wall. Rivera et al. (2008) studied earthquake effects on the Mexico City Cathedral by analyzing free-field records and measurements taken within the building during moderate local earthquakes. Due to large differences between dominant frequencies of earthquake ground motions at the site and modal frequencies …