Introduction
In the morning of 26 december 2003 the world woke up
to news of an earthquake in Iran, in which an entire city
was reported to have been destroyed and tens of thou-
sands of people killed—illustrated with a pair of pictures
of the ancient Bam Citadel, known as the »arg-e Bam,« a
site that was claimed to be the largest earthen structure
in the world. The »after« picture (fig. 2) showed a sea of
rubble where layer upon layer of undulating earthen
walls had once been—like a child’s sand castle on the
beach after it had been kicked down by rude kids. soon
this pair of pictures became the unwitting symbol for
the sudden annihilation of approximately 30,000 people
estimated to have died in the earthquake. Unfired earthen
construction—how can it possibly be safe? Isn’t it time that
it should be banned outright?
However, the images of the destruction of this historic
earthen structure hid the real truth of this earthquake—
namely that almost all of the over 30,000 people who died
in the earthquake, died in collapsed modern buildings!
even within the arg itself, those parts that had remained
abandoned and unrestored for as long as 150 years suffered
very little damage. The worst damage was concentrated
in those parts that had been restored and reconstructed
over the previous half-century.
Bam had only 7,000 residents in 1968, but it had grown
to 100,000 by the time of the earthquake. It was the new
buildings housing this expanded population that killed
Randolph Langenbach
Understanding What Works: Learning from Earthquake Resistant
Traditional Construction
almost all of the 30,000. Many of the new buildings did
have adobe walls, as unfired earthen construction remains
a common way of building here as it does in many desert
areas of the globe, but their roofs frequently were con-
structed of steel and fired brick. lacking any fasteners
to secure them to the walls, the roofs collapsed onto the
occupants. The earthquake also collapsed modern mul-
tistory steel frame structures, which were more common
here than reinforced concrete buildings.
all of this raises important questions in the fields of
disaster mitigation and historic preservation. does an
indisputably weak material (unfired clay) automatically
result in construction that is unacceptably vulnerable to
earthquakes? Can any form of traditional construction with
the historically available materials of earth, timber, stone,
and brick ever meet any reasonable modern standards of
earthquake safety? Indeed, how does one determine what
is acceptable risk?Earthquakes
earthquakes are unique among natural disasters because
they come with very little or no warning. When the shak-
ing begins, people can only take cover in the spot where
they find themselves. Thus in areas where the tectonic
plates shift, earthquakes engender a level of consternation
that is out of proportion to their frequency and the risk toFig. 1. The Arg-e Bam before the earthquake (photo courtesy
Iran Tourism Organization)
Fig. 2. The Arg-e-Bam, exactly the same view after the earth-
quake (photograph © Randolph Langenbach)