Earthquake Case Studies

Guatemala, 4 February 1976

This earthquake was a crucial experience for many agencies involved in disaster
assistance. Some major blunders were committed and some innovative plans in
builder education to construct earthquake-resistant houses were pioneered.
The disaster pushed attention to the urban and rural poor's weakness to exploitation by the landlords of Guatemala, and on some aid agencies who pursued policies they probably now regret, or acknowledge as important 'learning experiences'.

The earthquake killed 22,000 people living in unsafe houses in the rural highlands of Guatemala as well as within squatter settlements in Guatemala City. The upper and middle classes were left unharmed. This was the first major earthquake worldwide recognized as having such a selective impact, hence its tabloid nickname as the 'class-quake'.

Vulnerability variations in the Guatemalan case can clearly been detected. Firstly there was a strong ethnic factor at work. People who died in the highlands were not only poor but were indigenous Mayan Indians. In Guatemala City the death was concentrated in the slums. Secondly, it was difficult for either indian or urban
squatters to obtain assistance from the government.

The forces that led to so many people living in unsafe conditions, and the political
forces that controlled disaster aid, mirrored society at large. Guatemala unusually
had a high degree of awareness in these social problems, and the post-disaster relief
and rehabilitation became a political battleground. In the words of a contemporary
journalist:
    In this well-known fault zone the rich houses have been built to
    costly anti-earthquake specifications. The poorest housing, on the
    other hand, are in ravines or gorges which are highly susceptible to
    landslides after earthquakes. The city received proportionately little aid
    because it is governed by the most radical opposition tolerated in Guatemala,
    the Frente Unido de la Revolucion, a social democratic coalition. Its leader
    Manual Colon Arguetta was wounded by an unknown gunmen on 29 March. One city
    official, Rolando Andrade Pelia, was shot two weeks after the
    earthquake after suggesting that the homeless should be encouraged to
    rebuild on unoccupied private land.

In 1989, thirteen years after the earthquake, an author revisited Guatemala City
to determine vulnerability of the people there. In many ways matters now seem more
positive. While houses are still on the steep slopes, they are not as congested or
precarious. Many of the urban poor who lost their homes and managed to survive the
earthquake left the most dangerous slopes for other sites a short distance away.
This illegal 'invasion' took place from the day of the earthquake onwards, and ever
since the barrio has been known as '4th of February'. When survivors first 'invaded'
safer sites, there were a large number of newsmen visiting the city to report on the
disaster and authorities ignored the influx of displaced families. Eventually, perhaps
due to the force of numbers linked to sustained political pressure,
the government granted occupiers a legal title to their land. However, there is no evidence that the builders of these houses had any knowledge of earthquake-resistant construction. So although their sites are safer from earthquake-induced landslides, flash-floods, and eviction orders, their dwellings remain dangerous. In fact the risk houses collapsing may have increased. Illegally sited houses were generally built out of lightweight materials, including corrugated iron sheet roofing, but when they were legalized many families began to build in heavy materials such as reinforced concrete which is likely to cause greater damage than structures built of lighter materials.

Also, while there is some evidence of progress in Guatemala City, there
remains a very depressing picture of political repression linked to reconstruction
activity in the rural highlands of Guatemala. There, in the early 1980s, tens of
thousands of highland Indians were killed by the military in disputes over
expropriation of Indian land.

Oxfam America was one of the many NGOs that was heavily involved in the
reconstruction programmes based on co-operative activity. In 1982, they pub-
lished an account of the reign of terror that ensued, including a series of
interviews with local leaders:
    'The earthquake tore open many holes in the social fabric which had
    already been stretched thin. The rich and those in power came out richer
    and the poor came out poorer, and differences and inequalities became
    more visible. More protest led to more repression to contain the forces of
    change. Those in power do not want to share the wealth'. 'I think this
    region has become the target for increased repression and violence against
    the population. ..(since) many people in this area were very active in
    reconstruction efforts after the earthquake.'

Miculax and Schramm wrote a case-study of the long-term consequences of one
of the Housing Education programmes in 1989, thirteen years after the
earthquake:
    A terribly unfortunate negative consequence of these improvements in
    community organisation should be noted. During the 'violence' of the
    1980s, individuals who had developed their personal capacities during the
    post-disaster relief project were seen as 'troublemakers'. Many were
    killed by the army and others sought exile in neighbouring countries.

In Guatemala 'political vulnerability' expanded as a direct consequence of
community development and leadership training specifically intended to reduce
vulnerability to economic factors or seismic hazards.

Mexico City, 19 September 1985

Many people were very surprised at the revealing of the epicentre of this earthquake, with a magnitude of Richter 8.1, to discover it was 350km away from Mexico City in the trench that lies off the west coast of Mexico. Evidence from records, however, indicates that the 1985 earthquake follows a pattern. In the twentieth century
alone, 34 major earthquakes with magnitudes ranging from Richter 7.0 to 8.4, have occurred in the subduction zone where the Cocos Plate is being thrust beneath the
North American Plate. This ruptured causing the earthquake in the Michoacan Gap (this is a seismic gap where no major earthquakes had occurred for some time, and therefore considerable stress had built up). It is likely that Mexico City is under even more threat
from the Guerrero Gap to the north-west of Acapulco. In the coastal states adjacent to the epicentre considerable damage was caused, however Mexico City incurred the greatest devastation.

After a transmission time of 1 minute, the earthquake waves arrived in Mexico City. Much of the city centre is built on an old lake bed, and this helps to explain the notorious Mexico City effect. Soft, high-water-content sediments within the lake bed cause an intensification of the vibrations of earthquake waves as they pass through them.

Over 10 000 people were killed, approximately 50 000 injured and 250 000 were made homeless. 770 buildings were destroyed out of 800 000 buildings in the city, although the total number damaged was 7400. Mexico City has a population of approximately 20 million (over 20 per cent of the population of Mexico), and is growing at 2.56 per cent per annum. It is clearly one of the world's most hazard-prone cities.

Armenia, 7 December 1988

This earthquake had a magnitude of Richter 7.0 and devastated large sections of the three Armenian cities of Spitak, Leninakan and Kirovokan. It appears to have resulted from a fault rupture on the southern side of the Caucasus mountains. As all of the
three cities were relatively close to the epicentre of the earthquake, serious damage was expected, not least because the area was not well prepared. The death toll is estimated at between 25 000 and 100 000. 80 per cent of the structures collapsed or
were seriously damaged in Leninakan; in Spitak all of the buildings were damaged; in Kirovakan damage was far less.

Loss of life and damage in Armenia appeared to have been disproportionate. A contributory factor was the soft sediments under Leninakan and Spitak but it was not the main one. Engineers summarised the situation:
    'The catastrophic earthquake that occurred on
    December 7,1988 brought about heavy damage to most
    buildings and structures in many cities and villages.
    Our initial results reveal that most frame and nine-storey panel
    buildings were completely destroyed. Stone buildings
    with no anti-seismic measures collapsed.'

A professor at a university in the USA has since written:
    'Clearly, with regard to earthquake hazards, the
    system of prefabrication and site assembly of structural
    components in use in Armenia was deeply flawed.'

Kobe, 17 January 1995

The was the most devastating earthquake to strike Japan since the Tokyo earthquake of 1923 when 143000 people were killed. The earthquake measured 7.2 on the Richter scale, its epicentre located on a shallow fault zone some 200km from the main plate boundary between the Philippine and Eurasian Plates. The strike-slip pattern of the earthquake is similar to the Lorna Prieta event, with as much as 2m of surface slip on Awaji Island south-west of the epicentre.

Nearly 5000 people were killed in the earthquake, and 250 000 were made homeless. It occurred at 5.45 am local time, and loss of life would have been much heavier if it had happened two or three hours later in the rush hour.

With a high level of earthquake awareness in Japan, the structure of modern buildings is designed to withstand the strains imposed by seismic shocks. Thus, most of the buildings built to these stringent specifications survived the tremors, but many older concrete buildings lacking this inbuilt protection collapsed. The worst devastation appears to have been in the traditional-style Japanese wooden houses, with whole floors collapsing into one another. Popular myth was that such buildings would survive in an earthquake, but experience in Kobe proved this to be untrue.

Considerable damage to the urban infrastructure inevitably occurred. The Hanshin Express Way collapsed in five places and the Bay Coast Highway failed over a section of reclaimed land. Lines for the high-speed 'bullet trains' collapsed at 36 places over a distance of 90km. Public utilities were damaged over a wide area, with water, electricity and gas supplies being disrupted. Supplies of gas to nearly 1 million households had to be discontinued because of the fire hazard.

'The Kobe disaster has been an important case study of how we cannot manage a crisis in Japan.' (Professor Masashi Nishihara, of the National Defence Academy).

'The response to the earthquake of what many call the faceless and gigantic bureaucracy that controls Japan was dictated by territorialism, passivism and the inclination to follow precedent at times of emergency.' (Mr Tatou Takayama, a journalist for Japan’s largest selling daily newspaper, the Yomiuri Shimbun).

Many comments similar to those above suggest that the response to the Kobe earthquake by the authorities left much to be desired. Even in one of the most technologically advanced countries in the world, flaws in its hazard management procedures were exposed:

the authorities waited five hours before calling in the Self-Defence Force;
government officials debated for days whether to designate the Kobe area 'a Particularly Terrible Disaster' -a legal requirement necessary to clear the way for special emergency relief;
offers from the United States military stationed in Japan were discussed for two days before being accepted;
there is a lack of a single powerful central authority to co-ordinate relief work. At the moment a weak ministry outside the cabinet, the National Land Agency, co-ordinates emergency responses, but is so weak that local government tends to bypass it and go straight to the services themselves;
bureaucratic delays in accepting foreign offers of help, e.g. discussion of whether Swiss sniffer dogs should undergo the statutory period of quarantine and the initial refusal to accept foreign medical teams because they were not qualified to work as doctors in Japan.

The Kobe earthquake also raises some important issues concerning seismological prediction research and the construction of earthquake-proof buildings. The Japanese Government has designated ten regions for the intensive monitoring of earthquakes, one of which covers the cities of Kobe, Kyoto, Osaka and Nagoya and the tip of Awaji Island. The most intensive observations, however, have been concentrated in the Kanto and Tokai regions around Tokyo, even to the extent that researchers claimed that they could predict the next earthquake in that region. Although small-scale foreshocks occurred at the Kobe epicentre, their significance was not correctly interpreted or understood. Harumo Aoki, head of the Co-ordination Committee for Earthquake Prediction Research commented: 'We have repeatedly warned that the area around Kobe is riddled with active faults, but in practice only a few earthquakes have been felt, and the danger was not appreciated.’

Many experts now feel that the establishment of an effective and reliable earthquake prediction service is still a distant goal. More research on a strong ground motion, which will provide data on the level of a disaster in different areas is required, since it will enable relief teams and other emergency procedures to be targeted effectively in the areas most requiring assistance. Data on strong ground motion is vital to future work on the design of earthquake-proof buildings.

North-West Afghanistan , 30 May 1998

North-west Afghanistan lies in a seismic zone which runs through Central Asia, where
the Indo-Australian plate collides with the Eurasian plate. Earthquakes of magnitude 6.0 and above on the Richter scale are common in this area. The epicentre of this particular earthquake appears to have been near the remote village of Shari Basurk, close to the Turkmenistani boarder. It was registered with a magnitude of 6.9 on the Richter scale. It occurred four months after a similar event 500km to the east near the small town of Rostaq. Both areas are hundreds of kilometers from Kabul, the capital of Afghanistan, and lie in mountainous terrain, which is only penetrated by widely spaced airstrips,from which any rescue operations have to be organised.

Compared to the major urban areas affected by the 1988 earthquake in Armenia, areas such as the inaccessible mountains of Afghanistan suffer from a range of additional
problems in the immediate aftermath:

The earthquake struck in the afternoon of the 30 May 1998, and four aftershocks followed. The earthquake timing probably reduced the number of casualties since many people were not in their frail houses at the time. Maps of the area were inaccurate, and many of the villages were not even on the map used by the rescue organisations.

As is often the case in such areas, where people live in very primitive conditions, up to 25 villages were completely destroyed, and some of them are unlikely to be rebuilt.
Up to 100 villages were affected, an estimated 5000 people were killed and 95 000 rendered homeless.

The reports on the initial response of international organisations such as the United Nations and the International Red Cross were contradictory. In the period following the earlier earthquake in February 1998, it took five days for emergency supplies to reach the earthquake zone. However, in the second earthquake aid was arriving within hours according to some reports; other reports complained of long delays. Food and other supplies had been stockpiled after the previous Rostaq earthquake, and the United Nations had more than $1 million dollars in unused funds.

Nevertheless, the severe conditions encountered in the area slowed the relief activity.
Landslides blocked most of the already poor access roads into the worst hit region of Bandakhshan, two days drive away from the relief centre of Faizabad. The poor visibility hampered helicopter operations over north-west Afghanistan, and the adverse weather conditions caused flooding in the affected areas, further delaying the relief operation.