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mechanism is pure normal faulting at a depth of 17 km on the Peel fault, which is the eastern
border fault of the Roer Valley graben (Camelbeeck and van Eck, 1994 ; Ahorner, 1994 ) .
This earthquake was felt over a large area of western and central Europe with a mean
radius of perceptibility of about 440 km (Meidow and Ahorner, 1994 ) . Bouwkamp ( 1994 )
noticed that the main damage was restricted to failure and cracking of brick masonry
chimneys and parapets. There were very few cases in which the upper portion of chimneys
had toppled over and damaged the tiles on the roof. A partial collapse of gable ends,
inadequately tied to the wooden roof structures, was also noticed in a few cases, as well as
diagonal shear cracking of exterior masonry walls. This damage was mainly observed in
old masonry structures, some of them dating back to the eighteenth century. More modern
steel and reinforced concrete constructions were far less affected by the earthquake.
Meidow and Ahorner ( 1994 ) also mentioned damage on 150 churches in Germany,
predominantly in the epicentral area, but also at larger distances in Cologne, Bonn, and
Koblenz ( Figure 8.4 a ). Damage was also observed on different churches located in the
Netherlands, with the most affected one being situated in Herkenbosch (Bouwkamp, 1994 ) .
The official macroseismic inquiry (Haak et al ., 1994 ) reported a maximum intensity
of VII (on the MSK scale), but there is no description of the way this intensity value
was calculated. Another analysis of the seismic intensities caused by this earthquake was
performed by Meidow and Ahorner ( 1994 ) , who established a macroseismic map for the
German territory. They also assessed the maximum intensity as VII (in the MSK scale)
and justified this value based on the number of buildings that were significantly damaged
in the localities to which this intensity has been attributed. They also mentioned that eight
buildings were uninhabitable in Germany and had to be evacuated.
The only study that evaluated the amount of damage experienced by buildings in the
localities affected by the Roermond earthquake is that of Pappin et al .( 1994 ) . The analysis
of their observations is available at the Cambridge Earthquake Impact Database: www.
ceqid.org/ . These authors provided a statistical analysis of the damage caused to residential
masonry buildings located in the Netherlands and western Germany. In the most affected
localities, the percentage of moderate damage (EMS-98 degree 2) did not exceed 17% of
the buildings and there are only two localities where a little (2 and 3%) extensive damage
(EMS-98 degree 3) was observed ( Figure 8.3 b ). From these numbers, they assigned a
maximum intensity value of VI (on the MSK scale) to the most affected localities. We
agree with this interpretation because in order to reach intensity VII (on the EMS-98 scale)
many buildings (more than 10%) of vulnerability class A should have experienced extensive
damage (EMS-98 grade 3), and this is clearly not the case. Note that Pappin et al . ( 1994 )
did not visit the locality of Herkenbosch where significant damage was notified.
The Roermond earthquake presents two particularities that are important to take into
consideration for regional seismic risk studies. The first one, underlined by Meidow and
Ahorner ( 1994 ) , is that the observed maximal intensity is low for its magnitude by com-
parison with other earthquakes in the Lower Rhine Embayment. Its focal depth, which is
deeper than usual in the Lower Rhine Embayment, is the first factor that explains the low
epicentral intensity. A second factor is the strong seismic energy absorption by the 1500 m
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