Time independent seismic hazard analysis of Greece deduced from Bayesian statistics

Abstract

Abstract.A Bayesian statistics approach is applied in the seismogenic sources of Greece and the surrounding area in order to assess seismic hazard, assuming that the earthquake occurrence follows the Poisson process. The Bayesian approach applied supplies the probability that a certain cut-off magnitude of M s = 6.0 will be exceeded in time intervals of 10, 20 and 75 years. We also produced graphs which present the different seismic hazard in the seismogenic sources examined in terms of varying probability which is useful for engineering and civil protection purposes, allowing the designation of priority sources for earthquake-resistant design. It is shown that within the above time intervals the seismogenic source (4) called Igoumenitsa (in NW Greece and west Albania) has the highest probability to experience an earthquake with magnitude M ≥ 6.0. High probabilities are found also for Ochrida (source 22), Samos (source 53) and Chios (source 56).

A detailed seismic zonation model for shallow earthquakes in the broader Aegean area

“…Focal mechanisms illustrate the connection between earthquakes and specific known faults, the general and local stress field, as well as their relation with other possible faults not already known, whose existence we can often only hypothesize. The contribution of fault plane solutions in the progress of seismotectonic understanding in the broader Aegean/southern Balkan area is very important, as they historically allowed the determination of the reverse faulting zones of the convex part of the Hellenic Arc and Albanian coast (Papazachos and Delibasis, 1969), of the extension field in continental Greece and surrounding southern Balkan area (McKenzie, 1970(McKenzie, , 1972 and its continuation to the north of the North Aegean (Papazachos et al, 1979;Taymaz et al, 1991). Dextral strike-slip faults in the Cephalonia area and the North Aegean Trough (Galanopoulos, 1967;McKenzie, 1972) are some other examples of the important contribution of fault plane solutions.…”

“…Taymaz et al, 1991). 15 seismic zones have been defined for this region, with 10 of them located in the North Aegean Trough and the islands of the NE Aegean Sea.…”

“…Dextral strike-slip faults in the Cephalonia area and the North Aegean Trough (Galanopoulos, 1967;McKenzie, 1972) are some other examples of the important contribution of fault plane solutions. For the study area, reliable fault plane solutions have been calculated using different methods, such as P wave polarities from first motions for both long-period teleseismic records (Papazachos, 1961;Delibasis, 1968;Ritsema, 1974;McKenzie, 1972McKenzie, , 1978Anderson and Jackson, 1987;Kiratzi and Louvari, 2003) and local events (Hatzfeld et al, 1989;Hatzidimitriou et al, 1991), as well as body-wave inversion or teleseismic waveform modelling Langston, 1989, 1991;Taymaz et al, 1990Taymaz et al, , 1991Papadimitriou, 1993;Yilmazturk and Burton, 1999;Benetatos et al, 2004;Bene- , 2007). In the last 15 years, reliable fault plane solutions have been calculated by the use of high-quality broadband teleseismic data from international digital networks for strong earthquakes, including earthquakes of magnitude less than 5.5 (e.g.…”

“…N-E4 and N-E23 zones). Moreover, we also applied the maximum likelihood method (MLM) (Weichert, 1980) in order to calculate independently the b values for each one of the 113 shallow seismic zones. In order to examine the origin of the b value variability, in both cases, we studied the effect of the employed magnitude range of the complete data set for each zone (dM = M max − M min ) on the G-R estimation.…”

“…McKenzie, 1970McKenzie, , 1972, and (5) the strike-slip faulting zone starting from the western part of the Anatolian fault and its continuation in the North Aegean Trough (e.g. Taymaz et al, 1991) and the corresponding strike-slip zone in the central Ionian islands Papazachos et al, 1994).…”