Geoscience Reference
In-Depth Information
Part of this chapter is devoted to an analysis of the impact of damaging earthquakes
on architectural heritage buildings in Belgium. In this regard, we conducted two different
investigations to better evaluate the importance of the damage caused by two past earth-
quakes that demonstrate the real benefit of such an approach. We first investigated the
repairs and pathologies of the churches in the epicentral area of the 23 February 1828
chapter. Second, we studied the houses in the centre of the village of Soiron, located in the
epicentral area of the M
, 1692 Verviers earthquake, to estimate their age and identify
This information is used in Section 8.5.7 to formulate hypotheses on the intensity of the
earthquake in the village, which are discussed in the light of the information collected in
historical sources.
=
6
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8.4 Damage quantification
Most of the buildings damaged during the destructive twentieth- and nineteenth-century
earthquakes that occurred in the study area can be classified as low-rise unreinforced brick-
masonry buildings. That is because, even if the building types have evolved to either steel
or reinforced concrete construction, low-rise brick masonry (or mixed concrete-brick)
continues to be the type of construction typically chosen by the population. Thus, the
building inventory continues to include masonry structures that are sometimes very old.
Hence, the main information at our disposal concerns this kind of building. Nevertheless,
knowing the range of vulnerabilities of such unreinforced masonry buildings and other
types of buildings, it should always be possible to evaluate the potential damage for the
other types of buildings by comparison with the damage observed to masonry buildings.
Because comparison of the impact of historical earthquakes and more recent ones can
only be done using seismic intensity values, it seems advisable to define the seriousness of
damage to the buildings by a damage scale associated with the intensity scale used. For this
reason, we quantified the degree of damage according to the European Macroseismic Scale
where degree 1 (D1) corresponds to negligible to slight damage, degree 2 (D2) to moderate
damage (cracks in numerous walls, partial falling of chimneys, etc.), degree 3 (D3) to heavy
damage (significant cracks in most of the walls, chimneys rupture at the junction with the
roof, etc.), degree 4 (D4) to very heavy damage (serious weakness of the walls, partial
structural failure of roofs and floors), and degree 5 (D5) to complete or nearly complete
building collapse.
losses for this earthquake with the damage scale associated with HAZUS, providing a way
to evaluate seismic risks
(
Figure 8.2
)
. Therefore, it is also logical to use the damage scale
defined by HAZUS for the present study. Fortunately, there is a good correlation between
