2021 Mansfield earthquake
An earthquake struck approximately 53 kilometres SSE of the town of Mansfield (in the vicinity of the township of Woods Point), in the Victorian Alps of Australia on 22 September 2021, at 09:15 local time. The earthquake measured 5.9 on the moment magnitude scale. The earthquake caused minor structural damage in parts of Melbourne and left one person injured. The earthquake was also felt in New South Wales, Australian Capital Territory, South Australia and Tasmania. The earthquake was substantially stronger than the 1989 Newcastle earthquake that measured 5.6 and killed 13 people. Tectonic setting The Australian landmass is situated in the Australian Plate, far from any known active plate boundary, where most of the world's earthquakes occur. Such earthquakes at the plate boundary are known as interplate earthquakes. In Australia, earthquakes occurring within the Australian Plate are known as intraplate earthquakes because they happen within a tectonic plate rather than at the boundary. The earthquake is situated in the Lachlan Fold Belt, an orogenic belt consisting of folded and faulted strata. This zone formed as a result of plate convergence occurring at the eastern boundary of the supercontinent Gondwana during the Neoproterozoic. From the Neoproterozoic to Early Devonian, the region was dominated by thrusting and some rifting. Crustal deformation were later accommodated by predominantly strike-slip faulting in the Devonian. One of the major strike-slip faults accommodating this deformation is the Baragwanath Transform; a transform fault. Rifting also occurred in this period, leading to volcanism. By the Middle Devonian, the Baragwanath Transform became extinct. The Governor Fault marks the northern margin of the Mebourne Zone, and southern margin of the Tabberabberan Orogeny, and is characterised by strike-slip movement. The Governor Fault is a large intraplate fault that runs from mid-western New South Wales, along part of the Murray River bed and cutting through Central North Victoria near Barmah to the Victorian Alps near Mount Buller (near the quake epicentre) down toward the Gippsland Basin near the coast at Saint Margaret Island. Tectonically this fault separates the Melbourne and Tabberabberan structural zones. An earthquake of magnitude 6.0 or larger strikes Australia about once every six to ten years, based on the seismological data collected over the past 150 years. The last known magnitude 6.0 quake in Australia occurred in 2016 in the Northern Territory. That earthquake occurred as a result of shallow reverse faulting within the Australian Plate. The largest earthquake in Australia was the mainshock of the 1988 Tennant Creek earthquakes which consisted of an 6.7 quake preceded by two > 6.0 foreshocks. Earthquake According to the U.S. Geological Survey, the earthquake was the result of strike-slip faulting at a shallow depth of 12 km, while Geoscience Australia placed the depth at 10 km. The European-Mediterranean Seismological Centre reported the focal depth at 2 km. A preliminary insight of the quake of such magnitude suggest a rupture along a fault measuring 5 km long and 3 km wide. The geological fault involved has been identified as the western reaches of Governor