Page 15 - Visini_de Nardis_Lavecchia_2010

Int J Earth Sci (Geol Rundsch) (2010) 99 (Suppl 1):S243–S264 S257

other 200 100 60 on the completeness and quality of the seismological

by interval SBT ± 1600 ± 1680 ± 1820 record and those concerning the shape and size of the
seismogenic volume. We have tried to evaluate the stan-
calculated 200 80 20 dard deviations associated with our solutions following the
approach described in Papazachos and Kiratzi (1992),
those Completeness (year) ABT ± 1640 ± 1680 ± 1860 which allows the determination of the range of fluctuations
of the results considering all the possible random errors of
with the model parameters by means of a generator of Gaussian

1 noise type. Because the a, b, c and d parameters are cor-
Table work M \ 5.5 M \ 5.0 related, the covariance matrix, V, is non-diagonal. There-
fore, it has been necessary to compute the co-variances r ab
of Magnitude Classes 5.5 C B B r cd : the value of the correlation coefficient r ab , calculated
datasets This M 5.0 4.5 from our dataset, is 0.94, 0.96 and 0.84 for the ABT, SBT
and STC, respectively; the r cd is 0.95, as proposed by
earthquake Completeness (year) SBT 1000 1600 n.e. Papazachos and Kiratzi (1992). From Eq. 6, new parame-
ters have been obtained in each iteration in order to esti-
_
mate the alternative values of M o and the corresponding
the interval ABT 1000 1600 n.e. velocity tensor.
for (2006) 6.4 In the Table of Fig. 5, for each province, we have
(1987) al. B M \ 5.0 summarised the along-strike length (l 1 ), the average width
(l 2 ) and the average thickness of the seismogenic volume

_
al. et Magnitude M [ 6.4 M B B (l 3 ), the calculated average moment rate M o and the
et Pace classes 5.0 4.5 eigenvalues of the velocity tensor (k 1 , k 2 , k 3 ), measured in
Mulargia mm/year and the direction angles of the eigenvectors
expressed as trend and plunge.
The average cumulative scalar seismic moment rates

of Completeness (year) SBT 1700 1530 – M o calculated for the ABT, SBT and STC seismotectonic
_
method interval ABT 1700 1530 provinces are 5.2 9 10 23 dyne cm, 2.0 9 10 23 dyne cm.
the – 2.9 9 10 23 dyne cm, respectively.
In the ABT case, the velocity tensor eigensystem has
by 0.115 0.115 been calculated, assuming a seismogenic volume extending
paper Magnitude ± ± nearly 240 km along strike and nearly 60 km perpendicular
this classes 5.91 6.14 – to strike with an average thickness of 12.5 km above a
in basal thrust deepening westward from 0 to 25 km. The
obtained (year) SBT 1895 1700 1700 province is arcuate and convex eastward, but in the com-
putation an average NNW–SSE strike has been assumed.

times 2006) Completeness interval ABT 1871 1700 1700 Size and shape of the velocity tensor have been computed

from the moment tensor F ij from the focal mechanism
dataset in Table 2, which contains focal solutions of major
completeness al. et Pace Magnitude 0.115 ± 0.115 ± 0.115 ± and minor earthquakes. The computed shortening occurs at
an average rate of 0.3 ± 0.1 mm/year along a nearly
of 2004b; classes 5.22 5.45 5.68 N80°E direction.
In the SBT case, the velocity tensor eigensystem has
ranges been calculated, assuming a seismogenic volume extending
nearly 270 km along strike and nearly 60 km perpendicular
the MPS (2004a) (year) SBT n.e. 1920 1895 to strike with an average thickness of 12.5 km above a
of Group Completeness interval basal thrust deepening northward from 0 to 25 km. The
Comparison (Working CPTI group ABT n.e. 1920 1871 province is arcuate and convex southward, but in the
computation an average E–W strike has been assumed.

When the moment tensor F ij is computed from the entire
3 Magnitude 0.115 ± 0.115 ± 0.115 ± focal mechanism dataset in Table 2, shortening at an
Table authors Working classes 4.53 4.76 4.99 average rate of *0.1 mm/year along an average N–S
direction is calculated.

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