A team of U.S. engineering and earthquake experts returned from Armenia earlier this month, bringing with them some answers and important new questions about the extraordinarily destructive shocks that hit the region in early December, killing more than 24,000 people. According to their findings, this tragic event offers some unique lessons that could reduce death tolls from future earthquakes, not only in Armenia but around the globe. Although many factors, including freezing temperatures, combined to make this event particularly deadly, team members agree that building inadequacies are the principal reason why the strong, but not huge, quake killed so many people. Engineers who examined the damage and rescue workers who cut through the wreckage searching for trapped people blame both design deficiencies and flawed construction practices for the collapsed buildings. The main shock, which registered a magnitude of 6.9, struck just north of the city of Spitak on Dec. 7, at 11:41 a.m. local time. Four minutes later, a magnitude 5.8 aftershock occurred. Since then, swarms of aftershocks as large as magnitude 5.0 have continued to emanate from a zone centered around Spitak, a leveled city that formerly held about 16,000 people. The rubble of reinforced concrete in cities around Spitak testifies that many of the newer nine-story buildings in this quake-prone region could not survive the one-two punch of the main shock and strong aftershock, while some older, shorter buildings fared better. Although the Soviets had adapted their standard building designs for use in this seismic area, they "are indicating that the earthquake was bigger than they had designed for," says Loring Wyllie, a co-leader of the team and a structural engineer who specializes in seismic-resistant building designs with H.J. Degenkolb Associates in San Francisco. Wyllie says regulations for the area required that buildings be constructed to survive tremors that would register 7 or 8 points on the 12-point Soviet scale. The Dec. 7 event hit 10 points. In spite of the quake's severity, many damaged buildings did stand, and examinations of these structures will help engineers determine which kinds of buildings can best survive strong shaking, Wyllie says. Historical records reveal that significant earthquakes have long struck this section of eastern Armenia. The area's most recent large tremors occurred during the mid-1920s and registered about magnitude 6, which corresponds to ap-