M 6.0 - 52 km NE of Bandar-e Lengeh, Iran

Tectonic Summary

This earthquake is part of a sequence of earthquakes on July 1, 2022, in southern Iran that began with a magnitude 6.1, followed by a magnitude 5.7 earthquake two hours later, and a magnitude 6.0 earthquake one minute after the magnitude 5.7 earthquake. Faulting mechanisms for these earthquakes indicate that slip occurred on reverse faults, either dipping to the north or to the south, as is common of seismicity in this region. The earthquakes occurred at shallow depths, and likely reflect active deformation within the Zagros Mountains that form along the southern region of Iran adjacent to the Persian Gulf. Earthquake sequences similar to this one have previously occurred in the Zagros Mountains, with a similar sequence having occurred as recently as November 2021.

Regional tectonics are dominated by the collisions of the Arabia plate with Eurasia; at the longitude of this event, the Arabia plate is converging towards the north-northeast at a rate of approximately 33 mm/yr with respect to the Eurasia plate. Arabia plate lithosphere is subducted beneath the Eurasia plate at the Makran Coast of Pakistan and Iran and becomes progressively deeper to the north.

Southern Iran is a highly seismically active region where earthquake sequences like those occurring on July 1, 2022, are relatively common. Earthquakes are caused by the active convergence between the Arabia and Eurasia plates that form the Zagros Mountains of southern Iran. The Zagros Mountains accommodates approximately one-half of the total plate convergence between Arabia and Eurasia. Although moderate magnitude earthquakes (magnitude 4-6) are common in this region, large (magnitude 7 or greater) earthquakes are rare, if at all present, and there is documented evidence of only one surface-rupturing earthquake in the Zagros. Most earthquakes in the Zagros occur as the result of reverse faulting similar to that which occurred in the July 1, 2022, earthquakes. This prior seismicity includes a sequence on November 14, 2021, that included earthquakes of magnitude 6.0 and 6.4. A magnitude 5.6 reverse faulting earthquake occurred approximately 100 km west of the July 1, 2022, sequence on June 25, 2022. Despite the moderate magnitude of these earthquakes and the observation that they rarely reach the surface, such earthquakes in Iran can cause significant damage owing to regional building approaches.