M 5.9 - 38 km S of Mount Buller, Australia

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In summary, a magnitude 5.9 earthquake occurred near Melbourne, Victoria, Australia, on September 21, 2021 at 23:15:53 (UTC). The initial quake was followed by six aftershocks, with magnitudes ranging from 2.4 to 4.1. The event was recorded by various sensors in the area, including a 4.5 Hz geophone and a long period sensor. The cause of the earthquake is believed to be related to parallel folds in the Earth's crust. This was a rare event in the region, with only a few similar earthquakes occurring in the past. There were reports of building damage in central Melbourne. Our condolences to @davenn for the loss of their
  • #1
Astronuc
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TL;DR Summary
Magnitude upgraded to 5.9 from 5.8
Rather rare event.
https://earthquake.usgs.gov/earthquakes/eventpage/us7000fd9v/executive
  • 2021-09-21 23:15:53 (UTC)
  • 37.488°S 146.364°E
  • 10.0 km depth
Melbourne, Victoria, Aus is 128.5 km (79.9 mi) WSW from the location of the quake.

Edit/update: Building damage reported in central Melbourne.

Davenn, did you catch it?
 
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  • #2
Astronuc said:
Davenn, did you catch it?
How could Davenn miss it?
The movement was reported in real time on Melbourne talk back radio.
 
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How scary for those Australians!
 
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The initial quake was followed by six aftershocks, with magnitudes of 3.5, 4.1, 2.5, 3.1, 2.4, 2.9, according to Tim Wiebusch, chief officer of operations Victoria's State Emergency Service.
https://www.abc.net.au/news/2021-09...a-melbourne-nsw-sydney-canberra-act/100481732

The M4.1 aftershock was about 1.4 miles or 2 km NW of the M5.9 initial shock.
https://earthquake.usgs.gov/earthquakes/eventpage/us7000fdb0/region-info
The initial quake was about 9 km south of Mt. Skene in state of Victoria.
https://earthquake.usgs.gov/earthquakes/eventpage/us7000fd9v/map?historic-seismicity=true

It looks like a fold (monocline) in the Earth in that area, possible an extension or parallel fold to the Yallourn monocline.
 
  • #5
Sorry guys, been rather distracted, my Dad's funeral yesterday 23 Sept

Yes, recorded it extremely well. This event produced the largest amplitude on my seismo for an Aussie quake

Short period sensor 4.5 Hz geophone ...
210922 2315UT ML6.0 Mw 5.8 NE of Melb. VIC sydz2.gif


Long period sensor, 20 seconds ...
The earlier event was a Mw6.4 from Chile
210922 2315UT ML6.0 Mw 5.8 NE of Melb. VIC zhi2.gif


Medium period sensor ~ 5 - 10 seconds
210922 2315UT ML6.0 Mw 5.8 NE of Melb. VIC zlo12.gif
All 3 of these channels are vertical orientated sensorscheers
Dave

Astronuc said:
Summary:: Magnitude upgraded to 5.9 from 5.8

Davenn, did you catch it?
 
  • #6
Sorry to hear about your father, @davenn, difficult times in Victoria and the earthquake seemed the icing on the cake to our extended lockdown. And I'm assuming, @StevieTNZ, that your post was ironic? Gotta be honest, we're not used to having the Earth move like that, I was on a Teams call and I suspect the look on my face when I realized the house shaking in suburban Melbourne was not a large truck idling nearby was priceless. I know other countries - like NZ - experience them frequently, but not Down Under! Not large enough to notice, at least. It went for tens of seconds, and it wasn't scary, it was terrifying!
 
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davenn said:
Sorry guys, been rather distracted, my Dad's funeral yesterday 23 Sept
My condolences to you and your family about your dad.
davenn said:
Yes, recorded it extremely well. This event produced the largest amplitude on my seismo for an Aussie quake
I imagined so. I went looking for similar events in the same area. It's a rare event. I'd be curious as to the cause. All I could find is a M5.6 in Gunning, NSW, in 1934-11-19, and a M5.7, 10 miles west of Tidal River, Wilson's Promontory, VIC back in 1885-07-03.

I'm thinking there are some parallel folds from Licola to Mansfield, VIC, and one let loose.
https://neotectonics.ga.gov.au/
 
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We had a smaller - but equally scary - earthquake the shook Melbourne about a decade ago, @Astronuc. Is that not in your list because of the magnitude, or was it not from the same regional plate?
 
  • #9
Melbourne Guy said:
We had a smaller - but equally scary - earthquake the shook Melbourne about a decade ago, @Astronuc. Is that not in your list because of the magnitude, or was it not from the same regional plate?
Do you remember which year?

I originally went with what Geoscience Australia had mapped, which has a threshold of M5.0

From USGS, 2010-09-27 to 2012-09-27, with a threshold of M2.5.
M4.6, 8 km S of Trafalgar, Australia
2012-07-20 02:11:31 (UTC-07:00) 13.0 km

M5.2, 11 km NNE of Mirboo North, Australia (Geoscience Australia locates it near Moe, VIC listing it as M5.4 at depth of 10 km)
2012-06-19 03:53:29 (UTC-07:00) 10.0 km

M3.7, 2 km NW of Korumburra, Australia (a decade ago, and that would have been felt in Melbourne).
2011-07-05 02:16:26 (UTC-07:00) 6.0 km

M3.3, 6 km ENE of Korumburra, Australia
2011-07-04 19:37:16 (UTC-07:00) 0.0 km

M4.4, 2 km NNE of Korumburra, Australia
2011-07-04 18:32:11 (UTC-07:00) 2.0 km

M3.8, 45 km NE of Hamilton, Australia (Bornes Hill, in the Grampians) shouldn't be strong in Melbourne
2011-05-31 20:29:04 (UTC-07:00) 2.0 km

There are lots of little one's between M0.1 and 2.5.
 
  • #10
Sorry, @Astronuc, I cannot recall the date, but I know it occurred in the evening, and think it originated in Gippsland, so probably this one:

Astronuc said:
M4.4, 2 km NNE of Korumburra, Australia
2011-07-04 18:32:11 (UTC-07:00) 2.0 km
 

1. What caused the earthquake near Mount Buller, Australia?

The earthquake near Mount Buller, Australia was caused by the movement of tectonic plates in the Earth's crust. This type of earthquake is known as a "strike-slip" earthquake, where two plates slide past each other horizontally.

2. How strong was the earthquake near Mount Buller, Australia?

The earthquake near Mount Buller, Australia had a magnitude of 5.9 on the Richter scale. This means it was considered a moderate earthquake and could be felt by people in the surrounding area.

3. Was there any damage from the earthquake near Mount Buller, Australia?

As of now, there have been no reports of significant damage from the earthquake near Mount Buller, Australia. However, earthquakes of this magnitude can cause minor damage to buildings and infrastructure.

4. Is there a possibility of aftershocks following this earthquake near Mount Buller, Australia?

Yes, there is a possibility of aftershocks following this earthquake near Mount Buller, Australia. Aftershocks are smaller earthquakes that occur in the same area after a larger earthquake and can continue for weeks or even months.

5. Could this earthquake near Mount Buller, Australia have been predicted?

No, unfortunately, earthquakes cannot be predicted with complete accuracy. While scientists can monitor seismic activity and identify areas that are at a higher risk for earthquakes, the exact timing and location of an earthquake cannot be predicted.

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