On June 21, 1990, an earthquake measuring 7.7 on the Richter scale struck northwestern Iran, killing up to 50,000 people.

A moderately strong, 5.1-magnitude earthquake struck in Iran on Friday, according to the United States Geological Survey. The temblor happened at 9:19 p.m. Iran time about 22 miles southwest of Semnan,

The earthquake has now triggered a wave of speculations about whether Tehran has tested a nuclear weapon. It has also sparked concern because it struck near a city with a space and missile complex.