A 4.0-kilometre (2.5 mi) deep earthquake measuring a magnitude (Mw) of 6.2 struck southeastern Afghanistan on 22 June 2022 at 01:24:36 AFT (on 21 June 2022 at 20:54:36 UTC). The earthquake had a maximum Modified Mercalli intensity of IX (Violent). There were between 1,052 to 1,163 deaths and 1,627 to 2,976 injured in Afghanistan and Pakistan. The worst affected provinces in Afghanistan were Paktika, Paktia, Khost, and Nangarhar. Casualties and damage also occurred in Pakistan's Khyber Pakhtunkhwa. At least 10,000 homes collapsed or were severely damaged. The earthquake's shallow hypocenter, proximity to populated areas, and low building quality all contributed to its destructive effects. Shaking was felt over 500 km (310 mi) away by at least 119 million people, including Pakistan's Punjab and parts of India and Iran.
Earthquake
More than 7,000 people in Afghanistan have been killed by earthquakes in the past decade, averaging 560 deaths a year. A major earthquake in 2015 in northeast Afghanistan killed more than 200 people in the country and neighboring Pakistan. In 2008, a magnitude 6.4 earthquake in western Pakistan killed 166 people and destroyed several villages from triggered landslides. Thousands died when earthquakes struck the country in 2002 and 1998.
Tectonic setting A large portion of Afghanistan is situated in a broad zone of continental deformation within the Eurasian plate. Seismic activity in Afghanistan is influenced by the subduction of the Arabian plate to the west and the oblique subduction of the Indian plate in the east. The subduction rate of the Indian plate along the continental convergent boundary is estimated to be 39 mm (1.5 in)/yr or higher. Transpression due to the plates interacting is associated with high seismicity within the shallow crust. Seismicity is detectable to a depth of 300 km (190 mi) beneath Afghanistan due to plate subduction. These earthquakes beneath the Hindu Kush are the result of movement on faults accommodating detachment of the subducted crust. Within the shallow crust, the Chaman Fault represents a major transform fault associated with large shallow earthquakes that forms the transpressional boundary between the Eurasian and Indian plates. This zone consists of seismically active thrust and strike-slip faults that have accommodated crustal deformation since the beginning of the formation of the Himalayan orogeny. Seismicity is also recorded beneath the Sulaiman Range and Spīn Ghar. These earthquakes tend to display strike-slip faulting due to its abundance and high deformation rate.
Characteristics The United States Geological Survey (USGS) recorded the shock as 6.0 Mww at 4 km (2.5 mi) depth. It released an energy yield equivalent to 475,000 tons of TNT— 37 times more powerful that the atomic bomb dropped over Hiroshima. The European-Mediterranean Seismological Centre reported the magnitude at 5.9 Mw, and the Global Centroid Moment Tensor recorded 6.2 Mw at 15.1 km (9.4 mi) depth. India's National Centre for Seismology recorded the event as M 6.1 at 10 km (6.2 mi) depth. The earthquake occurred in proximity to the North Waziristan–Bannu Thrust Fault Zone. From inferring InSAR data, the earthquake rupture process was complex; initiating along a primary northeast–southwest striking fault plane and triggering ruptures on three secondary fault planes branching outward. A maximum slip of 2 m (6 ft 7 in) occurred at 2 km (1.2 mi) depth and the rupture was concentrated within a 10 km (6.2 mi) × 8 km (5.0 mi) area along the fault. The primary fault displayed strike-slip displacements while the three secondary structures displayed oblique-thrust or strike-slip displacements. The rupture propagated northeast–southwest for 15 km (9.3 mi) from the epicenter. It produced surface ruptures with a maximum displacement of 78.4 cm (30.9 in).
Intensity
A maximum Modified Mercalli intensity of VIII (Severe) was estimated by the USGS. According to the USGS Prompt Assessment of Global Earthquakes for Response service, there was a 35 percent probability of shaking-related fatalities between 100 and 1,000. The service also stated that the disaster was potentially widespread. Approximately 13,000 people were within the zone of intensity VIII, and 30,000 people were exposed to VII (Very strong) shaking. Intensity VII shaking was felt in Paktika's Gayan District, while intensity V–VI (Moderate–Strong) was felt in Barmal District. An evaluation of damaged homes—of the clay brick type—and seismic effects reported by villagers indicate a maximum Modified Mercalli intensity of VIII–IX (Severe–Violent) around the rupture area.
Aftershocks One hour after the mainshock, a mb 4.5 aftershock occurred 6 km (3.7 mi) south of the mainshock epicenter. Another aftershock measuring mb 4.2 was recorded on 24 June. It killed five people and wounded 11 more in Paktika, Afghanistan. The strongest aftershock occurred on 18 July, measuring Mww 5.1, centred in Zerok District, Paktika Province. Seven hours later, a mb 4.3 aftershock occurred south of the previous event. The Mww 5.1 aftershock injured at least 44 people and destroyed 600 homes which were previously damaged by prior earthquakes. A spokesman for Afghanistan's Disaster Management Ministry said fewer casualties were expected as it occurred during the day, unlike the mainshock which struck at night. Mohammad Amin Huzaifa, a provincial government spokesman, said Paktika experienced more than 30 aftershocks. On 22 August, a mb 4.6 aftershock struck at a depth of 35.9 km (22.3 mi), destroying several homes in Ster Giyan. On 23 August, a magnitude 4.6 aftershock caused several houses previously damaged by the mainshock in Gayan District to collapse.
Impact
… excerpt ends here. Continue reading the full article.
