1979 Ghaenat earthquakes
The 1979 Ghaenat earthquakes were a series of large earthquakes in Qaen County, Khorasan Province, northeast Iran, near the Afghanistan border. The first mainshock, known as the Korizan earthquake with a surface wave magnitude () of 6.6 and moment magnitude () of 6.8, struck on November 14, while the 7.1 or 7.2 Koli-Boniabad earthquake struck on Nobemver 27. The two mainshocks were assigned a maximum Modified Mercalli intensity of VIII ("Severe") and IX ("Violent") respectively. The earthquakes caused extensive damage throughout northeastern Iran, killed a total of 297 to 440 people and left at least 279 injured. The  pair of earthquakes in November was preceded by another large 6.7 or 6.5 shock on January 16, killing 200 people in the town of Bonzonabad. Earthquakes. The 6.6 or 6.8 earthquake of November 14 was the result of rupturing the Abiz Fault; a 20-km-long, north-south striking, right-lateral strike-slip fault at a shallow depth of 9.2 km. A maximum horizontal slip of 1 meter and some vertical displacements were recorded during field surveys after the earthquake. The southern section of the earthquake surface rupture would move once again during the 1997 Qayen earthquake. The Abiz Fault  with an approximate length of 125 km, is thought to have ruptured its entire length during large earthquakes in 1936 ( 6.0), 1997 ( 7.3), as well as the 1979 event, with no prior rupture before the 20th century. A major aftershock of the November 14 earthquake registered 6.0 or 5.9 on December 7 was initially thought to have caused a 15-km-long surface rupture to the north. The aftershock would have extended the rupture length of the Abiz Fault to a total of 35 km, but the additional research suggest the 15 km of new ruptures formed during a subevent  of the 7.2 mainshock. It is unlikely that the 15 km surface ruptures were attributed to the 5.9 mainshock, due to its moderate magnitude. The earthquake has been suggested to be on a separate north–south striking structure, away from the Abiz Fault. The November 27 7.1 mainshock occurred as a result of strike-slip faulting for a length of 60 km along the left-lateral Dasht-e-Bayaz Fault. The second mainshock had a hypocenter depth of 7.9 km. During the 7.1 mainshock, the northern termination of the first 6.6 ruptured further northeast to join the eastern section of  the second earthquake rupture. The second rupture is nearly perpendicular to the prior rupture. The same fault produced another deadly 7.1 earthquake in 1968 west northwest of the epicenter of the 1979 quake. The 1968 earthquake ruptured the western section for the fault for about 80 km in length. At least 10 km of the 1968 rupture was involved in the 1979 event. Impact. The earthquake damaged or destroyed mainly adobe-constructed buildings of the sun-dried clay type. Strong ground motion mainly of horizontal fashion caused many walls of these structures to completely detach from its roof, resulting in  a collapse. More recent construction of single-storey buildings suffered small damage and were mostly intact. In one village located along a hill, the most serious damage was observed at the summit, and appear to decrease in severity downhill, suggesting the seismic waves produced by the earthquake was amplified and reflected at higher elevations on the hill. This subjected structures at the top of the hill with more intense shaking than those on lower elevations. The second earthquake destroyed 10 villages. Survivors of the earthquakes were reocated to other areas while some damaged villages were rebuilt by the government in  the same place. Casualties. Between 280 and 420 lives were lost, with a further 279 injured in the November 14 earthquake. Many villages were also badly damaged in the earthquake. The earthquake struck at 5:51 local time (IST) when many adult villagers were outside their homes harvesting saffron. Most of the dead were reportedly young children left at home while their adult family members were working in the saffron fields. The second mainshock which was 7.1–7.5, only resulted in 20 additional deaths and injured 24 people. The death toll from the second earthquake was smaller due to the low population  density of the area when the quake struck.