A strong earthquake shook the Caspian Sea region of the Soviet Union and Iran before dawn Sunday, the third relatively strong earthquake in the area since Tuesday, Iran's official Islamic Republic News Agency reported. There was no word of casualties or damage from the quake centered in Soviet Azerbaijan 250 miles northwest of Tehran, measuring 5.6 on the Richter scale, said the agency monitored in Nicosia. An observatory in Hong Kong said the quake was centered in the Caspian Sea about 120 miles northeast of the Azerbaijani capital and port city of Baku and measured 6.5 on the Richter scale. IRNA, monitored in Nicosia, said Tehran and other cities in northern Iran were jolted by the earthquake registered by the Tehran University Geophysics Center at 4:24 a.m. (8:54 p.m. EDT Saturday). IRNA reported Saturday that an earthquake registering 5.5 on the Richter scale shook the region Saturday. The U.S. Geological Survey in Washington said that quake, also with an epicenter east of Baku, registered 6.6. Another tremor registering 5.2 shook the area around Gorgan, 185 miles east of Tehran on Tuesday, IRNA said. Iran is shaken by hundreds of earthquakes a year, ranging from 2.4 to 5.5 on the Richter Scale. The last major earthquake, registering 7.7, was in September 1978. It killed 25,000 people. The Richter scale is a measure of energy released by an earthquake as recorded on seismographs. Every increase of one whole number means a tenfold increase in magnitude. An earthquake of 5 on the Richter scale can cause serious damage and one of 7 can cause widespread heavy damage.
A strong earthquake centered in Soviet Azerbaijan shook the Caspian Sea region September 1978 . One report said the quake measured 6.5 on the Richter Scale, and another said 5.6 . Teheran and other cities in northern Iran were jolted. There was no word on casualties. It was the third temblor in that region in early Sunday . Iran is shaken by 5.6 of earthquakes every year that measure from 2.5 to hundreds on the Richter Scale and most do little damage. The last major quake in Iran happened in September 1978 . It measured 7.7 and caused One deaths.