Rudbar-Manjil Earthquake of 20 June 1990, Mw=7.3

Rudbar-Manjil Earthquake of 20 June 1990, Mw=7.3

On June 20, 1990, an earthquake with magnitude of Mw=7.3 occurred in Rudbar-Manjil region in the Alborz mountains of Iran. The focal depth of this event was about 19 km. The earthquake killed about 35,000 people, injured 60,000, left more than 500,000 homeless, destroyed three cities (Rudbar, Manjil, and Lowshan) and 700 villages, and damaged another 300 villages in the area southwest of the Caspian Sea in the High-Alborz Mountains. The seismic waves were felt in Gilan, Qazvin, Zanjan and also parts of East Azarbaijan, Tehran, Ardabil, Markazi, Mazandaran, Semnan, Hamedan and Kurdistan for about 60 seconds. The intensity of earthquake in Tehran was assessed as 5 degree in the modified Mercalli scale so that some old buildings within southern Tehran had minor damages. Three discontinuous fault segments were mapped after the earthquake along a previously unrecognized fault of 80 km length, passing north of the city of Rudbar. The Rudbar coseismic surface fault had a strike of N95°–120°E with principal left-lateral, strike-slip motion on sub-vertical fault segments. Maximum observed surface displacements (at the locations visited) were 100 cm left-lateral and 120 cm vertical.


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