Earthquake Presentation
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The underlying geology of California causes most of
the problems.
Most of the areas are built on reclaimed soft soil.
The main problem comes around when the quake
occurs. The hard rock provides resistance to the stock
waves and they are impeded and reduced in intensity.
The clays and soft soils magnify the waves’ power and
can cause them to behave in various ways.
Buildings can simply sink, in fact, under their own
weight.
The acceleration of the 1989 earthquake was 4*6g but
it was propagated to 16*6 at the surface by the clay
soils.
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The region in which the earthquake occurred is
part of a broad seismic area, which stretches from
Turkey to the Arabian Sea.
Here, the Arabian landmass is slowly colliding
with the Eurasian plate.
The earthquake occurred along a small thrust
fault, directly under Spitak.
During the earthquake, the northeast – facing side
of the Spitak section rode up and over the
southwest – facing side.
The main shock occurred near the intersection
between Alavar fault and the Pambak – Sevan
fault.
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In Armenia people were mostly vulnerable, that’s why
they suffered so.
Most of the population lives in a high – risk
environment, because they cannot afford something
better and safer.
Land quality is poor
Lack of building regulations.
The majority of the people in Armenia cannot afford
to live in big houses. They are not very expensive but
even people who can afford to live in them, are also
under high risk because the quality of the houses is
cheap, and therefore they collapse easily.
Urbanisation, has also forced all the people to move to
the city which increases the risk.
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In San Francisco, the number of people that died
was much more smaller.
This shows that vulnerability was lower.
Using cutting edge technology, the people of San
Francisco have predicted the earthquake and
because San Francisco is an MEDC, they had been
able to prepare fully.
Another crucial fact, is that infrastructure in San
Francisco is not at all cheap, poor, or bad.
Most of the buildings in the city, especially the
high ones, are made to resist any dangerous
natural hazard, as much as possible.
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No seismic structure analysis was carried
out
Local power supplies were cut and the
government emergency radio system had
failed.
The earthquake was predicted
The areas that suffered were only the ones
that were in a high – risk surrounding.
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Very poor infrastructure
There was extremely low winter
temperatures.
Officials were not ready for a disaster of
this scale.
The Soviet government let in foreign aid
workers to help with the recovery.