Multiple-event relocation of the main shock and aftershock epicenters and discontinuous surface ruptures recorded after the earthquake are compatible with northeastward movement on a southwest-dipping thrust , although maximum recorded displacements were less than would have been expected from the observed magnitude . This suggests that most of the slip did not actually reach the Earth 's surface but caused folding at the surface . A previously unmapped thrust with little surface expression , the Abdareh fault , has been identified from the disruption of earlier drainage systems by the growth of the fold in its hanging wall , and is thought to be responsible for the earthquake . Such structures are known as blind thrusts , and have been responsible for many destructive earthquakes in Iran and elsewhere . The geomorphological effects of this particular fold have been partly obscured by the presence of an earlier Neogene topography . The Qazvin region was hit by an even greater earthquake in 1962 , which killed 12,200 . In 1990 a rupture killed over 40,000 people , injured 60,000 , and left more than 500,000 homeless
rupture
1990 Manjil–Rudbar earthquake
2002 Bou'in-Zahra earthquake