Sunday, April 17, 2011

Whitsundays Earthquakes

Update 7pm Tuesday 19 April 2011 
At 5.38pm today, a M3.2 Aftershock was detected 20km South of the original Saturday quake. It was 65km WSW of Bowen and 30km North of the Collinsville Coal Mine. It appears to have occurred very close to the surface, but those details were unavailable at the time of this story.



Update 1pm Monday 18 April 2011
Saturdays earthquake has been upgraded to M5.3
Geoscience Australia has relocated the locations of the epicentres of the quakes - see below (click any of these images to enlarge).


6pm Sunday April 17 2011
The Whitsundays felt its first significant Earthquake at 3.31pm Saturday April 16, 2011. I was fortunate to be in the Chemist at the Whitsunday Shopping Centre at the time. The quake was a steady rumble lasting about 15 seconds, peaking at around 12 seconds in. (Click images to enlarge).


I did a quick look around the Shopping Centre and found no damage. People were carrying on as usual within 30 seconds of the quake - power, phones, internet & electronic banking remained online.

Eyewitnesses in Jubilee Pocket reported the quake as One or two bangs and then rumble. One eyewitness swears he heard it  2 seconds before the quake was felt, coming over the mountain (to the NW, the mountain behind Airlie Beach, between Jubilee Pocket & Cannonvale).

The quake was first measured at M5.2, then some media reported M5.4 (as did we), but the consensus now seems to be M5.2 .  It's epicentre was 60km West of Bowen and 10km (10,000m / 6.21mi) deep.


The first local aftershock was One hour 35 minutes later, 26km South of the original quake,  and 16.2km (10.07mi) deep - it was 30km North of the Collinsville Coal Mine. The US Geological Service says it was M4.7, however the Australian Geological Service says it was M4.0 . We do not know which one is correct.

As at 6pm Sunday April 17 2011, Geoscience Australia recorded:

Time
Magnitude

Update
Sat 3.31pm
    5.2

5.3
Sat 5.07pm
    4.0 GA

(4.7 USGS)

4.1
Sat 11.07pm
    3.2

3.2
Sun 1.33am
    3.4

3.4
Sun 11.36am
    3.3

3.2




All the earthquakes / tremors have been around the same area on the Northern Whitsundays border - between Collinsville, Bowen and Ayr, just south of the Burdekin River.

Sources:
US Geoscience
Geoscience Australia
Google Earth

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