The fact that each year thousands of people in seismically active parts of the world are killed or injured due to major earthquakes urges for continuous efforts in order to lessen the size of the catastrophe. Technical achievements made in recent years have made it possible to install an Earthquake Warning System (EWS) that can issue alarm a few seconds before the damaging waves reach the area. The main idea behind such systems is to make use of the difference between the propagation velocity of S-waves, and radio waves to issue earthquake alarm before arrival of the destructive part of the seismic waves. As the efficiency of an EWS depends on many factors, each area must particularly be studied in order to determine if such a system would be appropriate or not. In this paper EWS has been studied as a complementary measure against earthquake in Iran a country with more than 100,000 casualties due to earthquakes in recent decades. A simplified method has also been suggested for comparing the costs of the project with the economical advantages of it. Using the suggested method it has been shown that an EWS would be both economical and efficient in some parts of the country.
Obviously the most efficient way of facing earthquake is to design and build all buildings according to earthquake codes. The experience from the past major earthquakes, especially the 20 June1990 earthquake of Rudbar-Tarom show that if the structures are designed and constructed according to the codes, they would generally survive such events. On the other hand the limitations in time and economic resources makes the reconstruction of all buildings that are in poor condition an unrealistic solution for near future why unconventional measures must be found.