Testing a seismic scenario for the damage of the Neolithic wooden well of Erkelenz-Kückhoven, Germany
Klaus-G. Hinzen, Jürgen Weiner, 2009. "Testing a seismic scenario for the damage of the Neolithic wooden well of Erkelenz-Kückhoven, Germany", Palaeoseismology: Historical and Prehistorical Records of Earthquake Ground Effects for Seismic Hazard Assessment, K. Reicherter, A. M. Michetti, P. G. Silva
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A Neolithic wooden well was discovered and excavated between 1989 and 1992 near Erkelenz in the Lower Rhine Embayment. The construction, 3×3 m in size and 13 m deep, was exceptionally large for its time. The larger outer box-frame contained two smaller frames whose construction could be interpreted as an attempt to repair the damaged original well. The outer box was made from 160 oak elements of about 3 m length built in the blockhouse method. The large box is dated to 5090 bc and the two smaller ones to 5057±5 bc by dendrochronological analysis. At c. 8 m depth several elements of the large box are vertically sheared off and the broken parts moved inward and downward. The cause of this damage has not yet been determined. As the well is located only 3 km from one of the active tectonic faults in the Lower Rhine Embayment, a seismogenic origin of the damage is considered and tested in this paper. This question has relevance for determination of seismic hazard in an area with present-day moderate seismicity but documented occurrence of strong surface-rupturing earthquakes from the palaeoseismic record. First, a geotechnical model for the construction pit with a total volume of c. 540–550 m3 is used to prove the stability of the open pit during well construction and to help explain how the well was built. The seismogenic hypothesis is tested in a deterministic approach using theoretically derived ground motion at the site of the well for two simulated earthquakes with magnitudes 6.2 and 6.8. Ground deformation and relative displacement calculated with a finite element model of the casing are found to be too small to account for the documented damage. Among other potential sources of damage, swelling, shrinking or rotting of the wood elements are possible explanations; however, a conclusive answer to this question remains to be found.
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Palaeoseismology: Historical and Prehistorical Records of Earthquake Ground Effects for Seismic Hazard Assessment
Given the tremendous toll in human lives and attendant economic losses, it is appropriate that scientists are working hard to understand better earthquakes, with the aim of forecasting and, ultimately, predicting them.
In the last decades increasing attention has been paid to the coseismic effects on the natural environment, creating a solid base of empirical data for the estimation of source parameters of strong earthquakes based on geological observations. The recently introduced INQUA scale (Environmental Seismic Intensity–ESI 2007 Scale) of macroseismic intensity clearly shows how the systematic study of earthquake surface faulting, coseismic liquefaction, tsunami deposits and other primary and secondary ground effects can be integrated with “traditional” seismological and tectonic information to provide a better understanding of the seismicity level of an area and the associated hazards. At the moment this is the only scientific means of equating the seismic records to the seismic cycle time-spans extending the seismic catalogues even to tens of thousands of years, improving future seismic hazard analyses.
This Special Publication covers some of the latest multidisciplinary work undertaken to achieve that aim. Eighteen papers from research groups from all continents address a wide range of topics related both to palaeoseismological studies and assessment of macroseismic intensity based only on the natural phenomena associated with an earthquake.