Distant Deep Earthquake ON Seismic Hazard in Serbia

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2nd PROJECT WORKSHOP
Distant Deep Earthquake Impact
on Seismic Hazard in Serbia
Slavica Radovanović
Seismological Survey of Serbia
NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries
Vrancea earthquakes
Seismic waves generated from the Vrancea seismoactive
zone are of great interest not only for Romania, but also
for the neighboring countries due to their social and
economical impact on these territories.
Since 1900, the maximal seismic intensity registered so far
is degree X on the MSK scale in 1940, while the area
that experienced the degree VI and VII (severe ground
motion and building damage) includes Romania, the
Republic of Moldova, a large part of Bulgaria and southwestern Ukraine and east part of Serbia.
The strong intermediate-depth earthquakes1940, Mw=7.7;
1977, Mw=7.4; 1986, Mw=7.1; 1990, May 30, Mw=6.9;
1990, May 31, Mw=6.4; and 2004, Mw=6.0. are largely
felt in Serbia and caused extensive damage in east parts
of the country.
NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries
DATA
The data were obtained from the catalogue of macroseismic data. The
“Macro-catalogue of Serbia” for the period 306–2006 (6818 pages
with 30,480 earthquakes) was compiled by different scientists in
different time intervals; in 1940, the author was Jelenko Mihajlović.
As demonstrated by the analysis performed during the compilation of
the Balkan catalogue (Shebalin et al., 1972), Mihajlović modified the
used macroseismic scale over time, i.e., he inconsistently applied
the Rossi–Forel and then the Mercalli scales.
Therefore damage field reports for Serbian territory given in the Macro
catalogue until 1950, including the 1940 Vrancea event, have been
reinterpreted using the MSK and European Macroseismic scales
After 1964, the MSK scale is used in Serbia.
NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries
Sample page from the Macro-catalogue of Serbia for the
.
1940 Vrancea earthquake
NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries
DATA
Earthquake 1940, Mw=7.7
NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries
Local soil map based on EC-8
NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries
Hazard map TNRC=475y
Soil modification
NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries
1977th Vrancea eqNis time history of acceleration
Se (cm/s^2) .
Elastic response spectra horizontal components
artificial acceleration from distant earthquake
soil type C vs=260m/s
and
NIS acceleration
damping 5%
180
160
140
120
100
80
60
40
20
0
0.00
Nis-X
Nis-Y
syn-Vrancea Nis-x
syn-Vrancea-Nis-y
1.00
2.00
3.00
4.00
T (sec)
NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries
Synthetic acceleration for 1940th
Vrancea eq East Serbia
Elastic response spectra horizontal components
artificial acceleration from distant earthquake
soil type C vs=260m/s
and
NIS acceleration
damping 5%
250
Se (cm/s^2) .
Nis-X
200
Nis-Y
syn-Vrancea-ES-x
150
syn-Vrancea-ES-y
100
50
0
0.00
1.00
2.00
T (sec)
3.00
4.00
CONCLUSION
The effect of intermediate-depth Vrancea earthquakes on
all buildings and structures, which have a long oscillation
period and are located on soft and unconsolidated soil, is
evident in the spatial distribution of the macroseismic
effects of the 1940 Vrancea earthquake.
The question remains whether the probabilistic approach,
which is to be adopted, is able to account for the significant
effect of distant earthquakes (such as the ones in Vrancea)
in the area of East and Central Serbia.
NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries
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