Περίληψη:
Messinia is located in SW Peloponnese (Greece), in the vicinity of the
Hellenic Arc which is one of the most seismically active areas of
Europe. The arc is dominated by reverse faulting, whereas normal faults
are mapped onshore, mainly striking N-S. Large earthquakes have occurred
in the study area, both in the historical and instrumental periods. In
the present study, a Probabilistic Seismic Hazard Assessment (PSHA) is
applied to estimate the Peak Ground Acceleration (PGA), Peak Ground
Velocity (PGV), Peak Ground Rotational Acceleration (PGRA) and Peak
Ground Rotational Velocity (PGRV) for the broader Messinia region. PGRA
and PGRV are not often examined in detail in the literature, even though
they are useful for the evaluation of the possible damages in
structures. The widely used approach proposed by Cornell and McGuire is
implemented taking into account: (a) the seismotectonic model proposed
by Seismic Hazard Harmonization in Europe (SHARE), (b) an earthquake
catalogue for the instrumental period and (c) Ground Motion Prediction
Equations (GMPEs) proposed for the Greek territory. The computational
grid spacing for Messinia was set to 1 km, in order to accurately
calculate the hazard parameters and to reduce the bias of the results
through interpolation processes. For PGA and PGV, a logic tree approach
is considered, where every branch is a hybrid version of each GMPE
considering the percentage of the type (normal or non-normal) of focal
mechanisms for all zones of the seismotectonic model. The results show
an increase of the hazard values in the NW part of the study area, where
the Greek Building Code provides lower PGA values. In addition, hazard
curves in terms of PGA for multiple probabilities of exceedance in 50
years are determined for five major towns of Messinia, i.e. Kalamata,
Messini, Filiatra, Kyparissia and Pylos. Kyparissia has the higher
hazard in all probabilities of exceedance, which is in full agreement
with the PGA and PGV results. Pylos and Filiatra have intermediate to
high hazard, whereas Kalamata and Messini show intermediate hazard
values. Furthermore, the Uniform Hazard Spectrum (UHS) in terms of
Spectral Acceleration for the same towns is computed. The latter
provides essential information about the design parameters. Lastly, the
results are compared to the seismic histories of the five major towns in
terms of European Macroseismic Scale (EMS98) intensity, plotted for the
last 200 years.
Συγγραφείς:
Kaviris, George
Zymvragakis, Angelos
Bonatis, Pavlos
Sakkas,
Georgios
Kouskouna, Vasiliki
Voulgaris, Nicholas
