The city of Pylos was chosen as a pilot case for the risk assessment exercise due to its location within
the study zone, its manageable size that allows detailed building stock vulnerability assessment and
due to the fact that it is characterized by a relatively older but also rich and mixed building stock. A
GIS-based Buildings Database of Pylos containing almost all the existing buildings in the town was
created following building-by-building street level surveys.
The geotechnical hazard map for the town
of Pylos is proposed based on the findings of previous geotechnical investigations. The different soil
units were interpreted according to their ground motion amplification potential which was found to be
limited within the boundaries of Pylos town. Vulnerability functions for the construction classes of the
area differentiated by period of construction and height were developed making use of Greece’s
extensive experience of recent damaging earthquakes. The ground motion parameter in these functions
is the European Macroseismic Scale (EMS) of intensity. We collected damage data from the 1986
Kalamata, 1993 Pyrgos, 1995 Aegion and 2003 Lefkada Island earthquakes. The damage data from
each event were homogenized so that they could lend themselves to vulnerability assessment. In total
28,680 buildings are contained in this database affected by intensities in the EMS range of V to X. It
is for the first time that such a database was developed in Greece.
The damage potential to Pylos town for scenarios for EMS intensity VI, VII, VIII and IX was
estimated. The occurrence probability of these scenarios was derived and loss ratio maps at the town
block level were produced for each scenario. A benefit-cost analysis of various mitigation scenarios
was finally performed. At first we assessed the level of loss mitigation that can take place without any
targeted mitigation program. This was done by projecting today’s building stock of Pylos town to 20
years in the future on the basis of the trends seen in the 1990-2008 period. Then we presented benefitcost
analysis for three different mitigation options related to building strengthening programs (one for
the pre-1985 reinforced concrete buildings and two for the unreinforced stone masonry buildings). We
found that the mitigation programs for strengthening the unreinforced stone masonry buildings are
economically beneficial, while the programme for the reinforced concrete buildings is not
economically beneficial.
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Figure 8. Predicted damage distribution in the city of Pylos for intensity VIII
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