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Natural or ‘unnatural’ disasters: hitting the poor hardest
ANTONIO GUTERRAS, head of the UN Refugee Agency,
recently said that climate change is indirectly forcing large-scale
resettlement of populations, which reached 37.4 million in 2007, a rise
of three million. This shocking new statistic provides further evidence
that the world’s poor are the biggest sufferers of disasters, unnatural
or natural, whether in the USA after Hurricane Katrina, which was linked
to global warming effects (Socialism Today No.95, October 2005), or in
the ex-colonial countries devastated by the tsunami of 2004.
The death tolls after Katrina, the tsunami and, most
recently, the earthquake in China were made worse by the neglect and
indifference of governments to the plight of workers and the poor. The
high death toll of 70,000 in China was partly due to the lack of seismic
protection designed into buildings, despite strict existing regulations
requiring that this be done. In contrast, the major quake in California
in 1989, also in a densely populated area, resulted in only a handful of
victims, largely because of seismic building design.
The widespread indignation in China as a result of
the high death toll was fuelled particularly by the deaths of thousands
of school students trapped in poorly constructed buildings. This was
partly linked to the allegation made by Chen I-wan of the Committee of
Natural Hazard Prediction for the China Geo-Physics Society, that the
China Earthquake Administration (CEA) had received a warning of the
quake and not acted on it. Chen said that he personally sent a
prediction to the CEA of a scale six or seven quake in the Sichuan
province that would occur between May 2008 and April 2009. Weight is
added to Chen’s claim of official negligence if it is linked to a report
in Nature magazine in 1999 that 30 false earthquake alarms in the
previous three years had caused widespread economic disruption, and the
Chinese authorities clamped down on ‘unofficial predictions’ as a
result.
Leaving to one side for the moment the immediate
claims and counter claims, this controversy raises the more general
issue of whether prediction is a useful approach to addressing
earthquake threats or whether the only way of mitigating suffering is to
improve the infrastructure. This question is relevant in general terms
to other disasters like Katrina and, of course, the tsunami, which was
also caused by an earthquake.
Earthquake prediction has been subject of intense
scientific debate and controversy for decades. In 1975, prediction was
given a huge boost when, following extensive seismological survey and
research work, China successfully predicted the Haicheng quake
beforehand, and people stayed outdoors for several days despite the cold
weather. When it happened it was recorded as a massive scale nine event,
similar to the tsunami, and so thousands of lives were saved. The hope
created by this success was not borne out though, when the following
year 270,000 were killed in the Beijing area following an unpredicted
earthquake. Further doubt was sown by an analysis published in the
Journal of Applied Probability, in 2001, which found that prediction in
China was at a very preliminary stage, barely above a pure chance level.
Perhaps because of the limitations of ground-based
prediction methods, interest has been growing in using satellite
monitoring. Distinctive cloud formations were found above an active
fault in Iran 65-70 days before each of two large earthquakes occurred.
At the same time, thermal images of the ground showed the temperature
was higher along the fault. A theory was put forward by scientists from
a university in Henan, China, that hot gases could have caused water in
the clouds to evaporate.
Another idea was that ionisation may be involved,
since it has been demonstrated that when rocks are squeezed, positively
charged ions form in the air above them. (An ion is an electrically
charged particle.) Sceptics point out, though, that ions usually help to
form clouds, not disperse them. They also say that there are no physical
models that could explain why this phenomenon would occur two months
before a quake and then shut off and not occur again (New Scientist, 18
April 2008).
The fundamental problem with the science of
prediction is that the underlying mechanics and thermodynamics of the
behaviour of the earth’s crust are not sufficiently understood. For
example, laboratory simulations have shown that the sliding of tectonic
plates along fault lines seems to accelerate before the quake hits, but
it has proved impossible to detect this acceleration in real-life
situations. Consequently, prediction relies on statistical approaches
that, inevitably, will have a significant degree of uncertainty.
An alternative method being pursued in California
and Japan is to develop a system of early warning rather than
prediction. This relies on an extensive network of monitors on the major
fault lines, linked to a satellite system that gives an early warning.
So far, the usefulness of this (very expensive) approach is limited,
since it has been estimated that the ElarmS system developed at the
University of California would give only a 15-second warning of a
Richter scale five quake because seismic waves travel at six kilometres
(3.7 miles) per second. The exact warning time would depend on the
distance of populations from the epicentre – and even a short warning
time could allow some evacuation to take place – but the current
possibilities of this approach are clearly still limited. The
controversy that arose after the Sichuan disaster must be viewed in this
context, ie predicting the timing, location and size of earthquakes with
useful accuracy is not possible with scientific knowledge at its present
level.
Policies to save lives in earthquakes must be based
not on prediction data but on designing and building the infrastructure
to withstand the effects of the earth’s movement, as far as possible.
Protection can be provided by using quake-resistant materials that can
absorb greater quantities of energy than conventional materials before
they collapse following sudden shaking, thus giving more time for
evacuation, and building foundations can be designed to act as shock
absorbers, attenuating the movement of the earth’s crust.
It is true that these approaches are expensive to
implement in a poor country, but lower-tech measures can also be
effective. For example, it is well known that unreinforced concrete and
masonry is particularly susceptible to sudden collapse in an earthquake,
which is what appears to have happened in Sichuan. Just simply using
reinforced concrete more widely in this region, something there is no
shortage of in China generally in the current building boom, would have
made a big difference. For the poorest dwellings, even more basic
methods could also have saved lives, such as placing strips of
tear-proof fabric between the layers of adobe structures, essentially
tying the building together, giving crucial extra time before collapse.
Also, since they can withstand shaking more effectively, building wooden
structures rather than unreinforced concrete ones, would have been
preferable.
The Chinese regime is culpable not because it
ignored imprecise and unreliable predictions of possible disaster, but
because it failed to ensure that even simple and relatively cheap
measures were implemented that could have saved tens of thousands of
lives.
Pete Dickenson
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