earthquake risk may be even higher (Tavakoli and Ashtiany, 1999; CEST-JICA, 2000; EMI, 2006; Jafari, 2007).

Megacity earthquakes can jeopardize prosperity and social welfare, and so it is in our common interest to know more about them and learn how to work together to reduce societal risks. Iran’s long history provides a remarkable record of earthquake activity pertinent to this end (Ambraseys and Melville, 1982; Berberian, 1994). During the past 13 centuries, nine earthquakes with magnitudes greater than 7 have occurred less than 200 kilometers from Tehran. The last, in 1962, killed more than 12,000 people. Even much smaller, more frequent events can cause considerable damage. The magnitude-6.2 Firuzabad-Kojur earthquake, which struck a mountainous region 70 kilometers north of Tehran on May 28, 2004, killed 35 people, and preliminary assessments of its economic damage exceeded 125 billion rials.

As citizens of “earthquake country,” many of us at this workshop share an interest in the earthquake problem. My focus will be on its scientific dimensions. Of course, engineering conditions are no less important. In particular, I will outline some of the key areas where scientific collaboration among Iran, the United States, and other countries might lead to new understanding of earthquake behavior that can help reduce risk. My discussion is intended to support a broader thesis: the potential for scientific cooperation to address our common environmental problems—water and energy supply, pollution, climate change, ecological degradation, as well as earthquakes—can be a strong force for developing crosscultural understanding and improving international relations.

SEISMIC RISK ANALYSIS

Earthquakes proceed as cascades in which the primary effects of faulting and ground shaking induce secondary effects, such as landslides, liquefaction, and tsunamis. They set off destructive processes within the built environment, such as fires and dam failures (NRC, 2003). Seismic hazard can be defined as a forecast of



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