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| Titel |
Seismic hazard assessment in Polyphyto Dam area (NW Greece) and its relation with the "unexpected" earthquake of 13 May 1995 (Ms = 6.5, NW Greece) |
| VerfasserIn |
K. Pavlou, G. Kaviris, K. Chousianitis, G. Drakatos, V. Kouskouna, K. Makropoulos |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 13, no. 1 ; Nr. 13, no. 1 (2013-01-25), S.141-149 |
| Datensatznummer |
250017538
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| Publikation (Nr.) |
 copernicus.org/nhess-13-141-2013.pdf |
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| Zusammenfassung |
Seismic hazard assessment and seismicity changes are investigated in the
Kozani–Grevena area, at the western margin of internal Hellenides in NW
Greece. The region is of great interest, since it was characterized by very
low seismic activity until 1995, when the "unexpected" Kozani–Grevena
earthquake (Ms = 6.5) occurred. This event is of significant importance for
Greece, since it, along with the 1999 Athens earthquake, initiated the
modification of the Greek Building Code. In order to detect any seismicity
changes, the seismicity of the region was divided into three time windows:
the first up to 1973, the second from 1900 to 1994 and the third covering
the entire instrumental period.
For the above mentioned time windows, seismic hazard assessment was performed
using the extreme values method. The results indicate an increase of the
peak ground acceleration (PGA)
values after the impoundment, with the exception of the area in the vicinity
of the NE edge of the Dam. Before the occurrence of the 1995 event, the
epicentral region also exhibited higher PGA values than before the
impoundment. The most significant increase in PGA values is observed SE of
the Polyphyto artificial lake, where the largest values are observed for the
second and the third period. The coincident increase in the number of
earthquakes and in the PGA values may be attributed to the impoundment of
the Polyphyto Dam.
The maximum expected magnitude is calculated by the extreme values method
and Gumbel's third asymptotic distribution. The results reveal similar
values of maximum expected magnitudes (Mmax = 6.5), independent of the
seismicity rate, indicating that the 13 May 1995 earthquake was not an
"unexpected" event, since the magnitude of an oncoming earthquake depends
mainly on the tectonics of the region and the characteristics of the active
faults. |
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