Seismic Surveillance of Cologne Cathedral

Hinzen, Klaus‐G.; Fleischer, Claus; Schock-Werner, Barbara; Schweppe, Gregor

doi:10.1785/gssrl.83.1.9

Cited by 12 publications

(5 citation statements)

References 10 publications

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“…These stations provided good records of events with magnitudes down to M L 1 or even lower in case of small hypocentral distances. Four accelerometer stations (Farr et al 2007) and the simplified geologic information is based on the 1:200,000 geologic map of Germany (Zitzmann 2003) (Hinzen et al 2012;Hinzen 2014).…”

Section: The Networkmentioning

confidence: 99%

Seismicity in the Northern Rhine Area (1995–2018)

2020

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Since the mid-1990s, the local seismic network of the University of Cologne has produced digital seismograms. The data all underwent a daily routine processing. For this study, we re-processed data of almost a quarter century of seismicity in the Northern Rhine Area (NRA), including the Lower Rhine Embayment (LRE) and the Eifel Mountain region (EMR). This effort included refined discrimination between tectonic earthquakes, mine-induced events, and quarry blasts. While routine processing comprised the determination of local magnitude ML, in the course of this study, source spectra-based estimates for moment magnitude MW for 1332 earthquakes were calculated. The resulting relation between ML and MW agrees well with the theory of an ML ∝ 1.5 MW dependency at magnitudes below 3. By applying Gutenberg-Richter relation, the b-value for ML was less (0.82) than MW (1.03). Fault plane solutions for 66 earthquakes confirm the previously published N118° E direction of maximum horizontal stress in the NRA. Comparison of the seismicity with recently published Global Positioning System–based deformation data of the crust shows that the largest seismic activity during the observation period in the LRE occurred in the region with the highest dilatation rates. The stress directions agree well with the trend of major faults, and declining seismicity from south to north correlates with decreasing strain rates. In the EMR, earthquakes concentrate at the fringes of the area with corresponding the largest uplift.

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Section: The Networkmentioning

confidence: 99%

Seismicity in the Northern Rhine Area (1995–2018)

2020

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“…St. Peter’s Cathedral is centrally located in downtown Cologne, one of the few major cities in Germany with seismic hazard due to its location in the Lower Rhine Embayment [ 44 , 45 ]. Data was collected at 100 m height in the 157.4 m tall north tower, the cathedral’s bells are located at the south tower, and the central train station, which is adjacent to the cathedral, adds to the city noise [ 45 ]. Three time spans were chosen for comparison of building signal with the sensors self-noise.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Six-Degree-of-Freedom Sensors for Building Health Monitoring

Murray-Bergquist

Bernauer

Igel

2021

Sensors

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Six-degree-of-freedom (6DoF) sensors measure translation along three axes and rotation around three axes. These collocated measurements make it possible to fully describe building motion without the need for an external reference point. This is an advantage for building health monitoring, which uses interstory drift and building eigenfrequencies to monitor stability. In this paper, IMU50 6DoF sensors are characterized to determine their suitability for building health monitoring. The sensors are calibrated using step table methods and by comparison with earth’s rotation and gravity. These methods are found to be comparable. The sensor’s self-noise is examined through the power spectral density and the Allan deviation of data recorded in a quiet environment. The effect of temperature variation is tested between 14 and 50 °C. It appears that the self-noise of the rotation components increases while the self-noise of the acceleration components decreases with temperature. The comparison of the sensor self-noise with ambient building signal and higher amplitude shaking shows that these sensors are in general not sensitive enough for ambient signal building health monitoring in the frequency domain, but could be useful for monitoring interstory drift and building motion during, for example, strong earthquake shaking in buildings similar to those examined here.

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“…In all cases, the energy extends over the entire frequency range, from 0.1 to 50 Hz, the maximum frequency that can be explored with our dataset. Hinzen et al (2012), analyzed the frequency content of the seismic signals recorded during the ringing of a large bell in the Cologne Cathedral, observing the largest response amplitudes at 0.833 Hz, a value falling between the first and second eigenfrequencies of the tower. In our cases, the largest amplitudes are observed at frequencies ranging between 10 Hz (Lunas) and 37 Hz (Sta Maria M.).…”

Section: Discussionmentioning

confidence: 99%

Church bells and ground motions

Díaz

2020

J Seismol

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Although the primary objective of seismic stations is the recording of waves generated by natural seismicity, the sensors can detect vibrations generated by different sources of natural and anthropogenic origin. The interest in identifying these sources has increased in the last years with the use of background seismic vibrations to obtain images of the crustal structure by tomographic methods and to monitor different natural processes. We present here a very particular case of these type of sources, the bell ringing in churches to indicate the passage of time. In some particular cases, the vibrations generated by the ringing of the bells are recorded in seismic stations installed near the bell towers. We review different examples throughout Europe of this particular kind of seismic records to illustrate how the seismic records can provide information on the traditions followed to mark the hours in some European countries, which turn out to be very different. The objective is not only to publicize this curious records, but also to show that bridges can be built between very different scientific disciplines, such as seismology and social sciences, since the seismic data offers a new tool to researchers interested in investigating ethnographic aspects related to how the passage of time is marked in different European cultures.

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Seismic Surveillance of Cologne Cathedral

Cited by 12 publications

References 10 publications

Seismicity in the Northern Rhine Area (1995–2018)

Seismicity in the Northern Rhine Area (1995–2018)

Characterization of Six-Degree-of-Freedom Sensors for Building Health Monitoring

Church bells and ground motions

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