International Collaboration and Training for the Assessment and Mitigation of Seismic Hazard in Iran

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Iran is one of the most earthquake-prone countries in the world. In the past 50 years, there have been five major earthquakes that have each killed more than 10,000 people, the most recent being the earthquake that devasted the city of Bam in December 2003. Almost every year there is an earthquake that does significant damage to people and property, e.g. the Zarand earthquake that occurred in February 2005. The first step in attempting to reduce the damage caused by earthquakes is to assess the likelihood of an earthquake occurring in a given area. Earthquakes occur by slip on faults within the earth's crust. They are caused by the relative motion of crustal blocks on each side of the fault. Initially friction holds the fault locked; however, with time, the bending of the rocks either side of the fault grows until it exerts a force that overcomes the friction on the fault. The rocks on either side of the fault then slip rapidly relative to each other radiating seismic waves and causing severe shaking of the ground nearby. A number of observations can be made to assess the likelihood of a future earthquake. Locating all the active faults is an essential starting point. This is not as easy as it might seem in a country like Iran where many of the faults do not reach the surface and remain hidden below ground. However, movement of the earth's surface in past earthquakes produces characteristic features in the land surface, particularly the pattern of streams and rivers around the fault, and these features can allow us to find faults whose existence had not previously been recognized. Measurements made by instruments on satellites orbiting the earth play an important role in this search. The satellites in the Global Position System can be used to measure small movements - a few millimetres to a couple of centimetres per year - and so allow us to detect the bending of rocks around the faults. Repeated observations using radar satellites also measure the slow ground motions occurring in between earthquakes. The most effective way to estimate how frequently earthquakes have occurred in the past is to combine satellite measurements with geological observations made on the ground in areas at risk. The task of carrying out an extensive programme of such measurements for Iran is a huge one. The Geological Survey of Iran (GSI) is the primary agency with responsibility for assessing earthquake hazard in Iran, but it lacks the expertise to undertake such a programme. However, the members of the Centre for the Observation and Modeling of Earthquakes and Tectonics (COMET) are expert in these types of observation, and COMET investigators have worked for many years with the GSI on many aspects of the science of mountain building (tectonics) and earthquakes. The purpose of this proposal is therefore to bring young Iranian scientists to the UK, where they will be trained within COMET in the appropriate techniques and learn from members of COMET by working with them. Another part of the proposal is for an international meeting that would bring together geologists and geophysicists making the observations on which the hazard assessment is based, and people concerned with planning for major earthquakes and mitigating their impact, from several such countries in order to share experiences and develop a common approach to communicating our results to local communities and regional authorities. The role of education in reducing the impact of major earthquakes is not to be underestimated. In the case of the recent large earthquake off Sumatra (26/12/2004), the existence of such earthquakes in that region in the past were well recognized and the effects that such an earthquake would produce were understood. If this information had been successfully communicated to local communities and to regional authorities, then, while the earthquake could not have been predicted or prevented, its damaging after effects could have been significantly reduced.