Soviet scientists are trying to determine why the Armenian earthquake toppled whole cities and killed more than 40,000 people. One U.S. expert blamed much of the devastation on poorly constructed buildings.

Soviet seismologist Igor Nersesov told a news conference Saturday a commission was sent to the Armenian city of Leninakan to determine why three-quarters of the buildings in the city of 250,000 tumbled.Wednesday's quake measured 6.9 on the Richter scale and its epicenter was not far from the surface. A similar earthquake in Southern California would have killed about 1,000 people, acting state geologist Brian Tucker told The Associated Press in California on Friday.

Tucker, who spent two years in Armenia on a research project, blamed the high death toll on local construction, which tends to be loosely connected, unreinforced concrete slabs in the city or adobe in the villages.

Nersesov told reporters in Moscow that "with a duly organized scientific system of observation and research, we could have" predicted the quake.

He said a team of seismic experts also had been sent to Armenia in an attempt to predict aftershocks.

The latest seismic records for northwestern Armenia were destroyed in the quake along with the Institute of Seismology in Leninakan, Nersesov said. The institute had been researching earthquake-proof construction techniques.