Earthquake Shaking and Damage to Buildings

Misconception as a barrier to teaching about disasters

INTRODUCTION

This paper is a report on an exercise designed to reveal the extent of belief in the common myths about disasters held by members of four groups of students from the University of Massachusetts and three groups of trainee emergency workers from Italy.

METHODS

A questionnaire was administered in which students and trainees were asked to agree or disagree with 19 statements about disasters. These statements were based on common misconceptions about disasters and are at least statements untenable in statistical terms, if not downright wrong. In each case, a Likert scale was used to assess the strength of the students' and trainees' agreement or disagreement with the statements.

RESULTS

The results suggest that some of the misconceptions (for example, that panic and looting are widespread reactions to disaster) were strongly held, whereas others (for instance, that disasters cannot be managed) were less well-rooted. Despite years of refutation by experts, all groups firmly believed that dead bodies constitute a health hazard if they are not disposed of quickly. Attitudes to the proposition that technology offers a solution to the disaster problem were equivocal.

CONCLUSIONS

Though the results of the study by no means were homogeneous, students and emergency workers, on either side of the Atlantic, bring many of the same misconceptions that the mass media continually propagates. These beliefs represent a serious challenge for the instructor who wants to ensure that disasters and emergencies are not misconstrued.

Building collapse and human deaths resulting from the Chi-Chi Earthquake in Taiwan, September 1999

In this study, the authors attempted to determine factors associated with earthquake deaths in the great Chi-Chi Earthquake that occurred on September 21, 1999, in Taiwan. An isoseismal map was used to identify life-threatening hazards. The vertical peak ground acceleration of ground motion intensity was deemed the most appropriate index for the evaluation of building collapse and mortality. Mortality increased with the increase in earthquake intensity, and building collapse, approaching the epicenter. The greatest number of collapsed buildings and human deaths occurred between the Chelungpu Fault and the Shuantun Fault. Individuals 65 yr of age and older were the most vulnerable to the impact. The authors' findings suggest that improvements in earthquake-resistant building design and construction, as well as improved medical rescue for the elderly, could reduce the level of exposure to earthquake hazards.

The health effects of earthquakes in the mid-1990s

This paper gives an overview of the global pattern of casualties in earthquakes which occurred during the 30-month period from 1 September 1993 to 29 February 1996. It also describes some of the behavioural and logistical regularities associated with mortality and morbidity in these events. Of 83 earthquakes studied, there were casualties in 49. Lethal earthquakes occurred in rapid succession in Indonesia, China, Colombia and Iran. In the events studied, a disproportionate number of deaths and injuries occurred during the first six hours of the day and in earthquakes with magnitudes between 6.5 and 7.4. Ratios of death to injury varied markedly (though with some averages close to 1:3), as did the nature and causes of mortality and morbidity and the proportion of serious to slight injuries. As expected on the basis of previous knowledge, few problems were caused by post-earthquake illness and disease. Also, as expected, building collapse was the principal source of casualties: tsunamis, landslides, debris flows and bridge collapses were the main secondary causes. In addition, new findings are presented on the temporal sequence of casualty estimates after seismic disaster. In synthesis, though mortality in earthquakes may have been low in relation to long-term averages, the interval of time studied was probably typical of other periods in which seismic catastrophes were relatively limited in scope.