Seismic Risk
Yerevan as
well as practically all of the territory of Armenia is situated
in a seismically .active zone. The Magnitude of earthquakes
ranges up to M = 7.1 (according to historical and paleoseismic
estimations). Focal depth is, on average, 10 km. All sources are
located on the active faults, with an average slip rate of about
1 cm/year. The duration of destructive earthquakes may last one
minute under adverse ground conditions. The average recurrence
interval of large earthquakes (M > 5.5) is about 30-40 years.
The above-mentioned characteristics
of the seismic regime mainly indicate a high level of
seismic hazard, which is well reflected on the new map of
seismic zonation of the territory of Armenia. So far, as
that hazard was considerably understated in the past, the
seismic resistance of buildings and constructions, by
which the whole republic is built up, turned out to be
significantly below the level required for the real
seismic hazard. This fact, as a result of an absence of
state policy in the field of seismic risk reduction in
Armenia has led to the disaster in Spitak in 1988. The
rapid growth of population and the urbanization of the
territory have caused a higher level of seismic risk in
Armenia at the moment than at any time in the past.The strategy of seismic risk
in Armenia developed by the NSSP under the Government of Armenia,
unique for its structure and goals, was established in 1991 by
the project of Prof. Balassanian.
After eight years of
successful approbation, the Government of Armenia as a state
program confirmed the strategy in 1999.
Seismic Risk
Mitigation Strategy
Over the
centuries Armenia has suffered numerous destructive earthquakes
that caused tremendous damage to the nation.
Taking
into account the fact that the type of structures, design
standards, construction materials and practice of construction in
Yerevan are the same as those in the destroyed cities of Northern
Armenia and almost 40% of the population of the republic is
concentrated in the capital, it is not difficult to suppose that
the scope of probable destruction here would be extremely high.
Taking
into account the seismic risk to Yerevan and the seismic risk to
other cities and settlements in Armenia under the supervision of
Prof. S. Balassanian, a long term state program for seismic risk
mitigation in Armenia being drawn up by all the ministries,
departments, public and private organizations under the
coordination of NSSP was elaborated and adopted by the Government
and the President of Armenia in 1999.
The
above-mentioned program includes the following basic elements:
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Seismic Hazard Assessment (SHA).
-
Seismic Risk Assessment (SRA).
-
Seismic codes and standards.
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Seismic strengthening and upgrading of existing
buildings.
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Seismic construction.
-
Education of population.
-
Current Seismic Hazard Assessment (CSHA).
-
Early warning and notification (EWAN).
-
Emergency response and rescue operations.
-
Disaster relief and people rehabilitation.
-
Insurance.
State
disaster law and regulations.Responsible Governmental Agency for
seismic risk reduction in Armenia.
Since 1991, in
all aspects of that program, NSSP in collaboration with other
ministries and departments have carried out a lot of spade- work. (see more)
