M 5.9 - 38 km S of Mount Buller, Australia

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  • #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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Answers and Replies

  • #2
Baluncore
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Davenn, did you catch it?
How could Davenn miss it?
The movement was reported in real time on Melbourne talk back radio.
 
  • #3
StevieTNZ
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How scary for those Australians!
 
  • #4
Astronuc
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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
davenn
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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 sensors


cheers
Dave

Summary:: Magnitude upgraded to 5.9 from 5.8

Davenn, did you catch it?
 
  • #6
Melbourne Guy
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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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  • #7
Astronuc
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Sorry guys, been rather distracted, my Dad's funeral yesterday 23 Sept
My condolences to you and your family about your dad.
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/
 
  • #8
Melbourne Guy
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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
Astronuc
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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?
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
Melbourne Guy
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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:

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

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