Magnitude 5.9 Earthquake Shakes Melbourne

by Flora Xia ’23

Source: BBC

Published Oct. 20th, 2021

A magnitude 5.9 earthquake struck the Australian city of Melbourne on Wednesday, September 22, shaking people and buildings throughout the region. Two aftershocks — smaller earthquakes that follow the main shock of the larger earthquake — were detected with magnitudes of 4.0 and 3.1. 

The Victorian State Emergency Service states that the earthquake’s epicenter was located near Mansfield, in the Australian state of Victoria, making it the largest in Victoria’s recorded history. The quake had a depth of about 6.5 miles, which is considered shallow, creating a potentially dangerous situation because of the damage it could have caused at the surface.

Fortunately, there were no immediate reports of damages or injuries.

Melbourne is Australia’s second largest city, home to around five million people. The country on average has an earthquake of magnitude 6.0 or higher every six to ten years; earthquakes of this magnitude are highly uncommon.

According to plate tectonics expert, Dr. Ben Mather, the magnitude 5.9 quake “likely occurred along the Governor Fault…that separates the Melbourne zone from the alpine region”.

Earthquakes typically take place along pre-existing fault lines, and Dr. Adrian McCallum, a senior lecturer in geotechnical engineering at the University of the Sunshine Coast, reported a large number of tectonic faults in Mansfield, shown in geological maps of Victoria.

Shocked Melbournians described the earthquake as “so scary” because “everything [was] rolling in front of our eyes.” Indeed, video footage showed crumbling buildings, knocked down walls, and panicked residents running into the streets of the city. Many individuals lost power, while others were forced to evacuate their buildings entirely.

Previously, the most devastating quake in Australia’s history was a magnitude 5.6 earthquake in 1989 that struck the city of Newcastle, resulting in the deaths of 13 people. The earthquake that occurred last month in Melbourne thankfully did not cause as much devastation because modern buildings have been fitted for certain levels of seismic resistance.

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