Probabilistic assessment of earthquake insurance rates for buildings - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 790

Table 29.2 Subjective probabilities assigned to alternative assumptions

Subjective
probability Alternative assumptions

All earthquakes 0.5

Main shocks only 0.5

Incomplete catalog 0.4

Artifi cially completed catalog 0.6

Standard least squares regression in the computation of the
recurrence relationships

0.4

Maximum likelihood method in the computation of the
recurrence relationships

0.6

Attenuation relationship of Musson (2000) in its original form 0.5

Attenuation relationship of Musson (2000) converted to M w scale 0.5

Attenuation uncertainty is equal to σ I = 0.08 0.15

Attenuation uncertainty is equal to σ I = 0.49 0.60

Attenuation uncertainty is equal to σ I = 0.80 0.25

enveloping space windows of Gardner and Knopoff (1974), Savage and
Rupp (2000), and Kagan (2002). For the time windows, on the other hand,
average of the windows specifi ed by Gardner and Knopoff (1974) and
Savage and Rupp (2000) are utilized. Spatial and temporal aftershock
window sizes are based on the magnitude of the main shock. Foreshock
identifi cation is achieved by using magnitude dependent spatio-temporal
windows also.
Virtual seismotectonic source zones (i.e. geometrical confi gurations, such
as polygons/lines), within which seismicity is homogenized, are delineated
at regions of epicenter clustering, based on subjective judgment of experts.
The confi guration given by Bommer et al. (2002) is adopted with some local
modifi cations. For the earthquakes that cannot be related to any of these
seismogenic provinces, background seismicity regions are defi ned; all geo-
graphic areas/regions are covered by either well-defi ned faults, area/line
seismotectonic source zones, or background source zones. The resulting
seismic source zones and their geographical locations are shown in Fig. 29.2.
The seismicity map of Turkey showing the epicentral locations of earth-
quakes with M

4.0 since 1900 is given in Plate V (between pages 452 and
453). For the temporal distribution of earthquakes, the earthquake occur-
rence within a seismic source zone is assumed to follow the Poisson distri-
bution, whereas the probability distribution of earthquake magnitude is
described by the Gutenberg and Richter (1949) recurrence relationship.
The source specifi c constants of the Gutenberg-Richter recurrence rela-
tionship are estimated both by carrying out least squares regression analysis

≥