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Tonga Eruption

Talk about the weather
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ConligWX
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Re: Tonga Eruption

Post by ConligWX »

Altocumulus wrote: Tue 18 Jan 2022 4:24 pm I wanted to check back through the graphs to see if I'd had a similar spike in the data, but on my localhost/charts display I have 12 hours of data on display. Only "All" is emboldened, the other 3 options are greyed out.

I assume there's a way to check back on previous days, or have I lost the opportunity without a lot of work - Historic Charts option is way too coarse.

I've looked back on our seismometer, but nothing appears to show beyond the background noise.
change your graph hours to 96 that will give you 4 days worth of data in the charts. settings, station settings, Graphs
Regards Simon

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Re: Tonga Eruption

Post by BeaumarisWX »

Tony Beaumaris, Tasmania (AUS)

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Re: Tonga Eruption

Post by HansR »

@BeaumarisWX: thanks, nice reading, It may take some time before comment because of difficulty level and not being available for some days ;)
The second link gives me a 502 bad gateway error.
Hans

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Altocumulus
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Re: Tonga Eruption

Post by Altocumulus »

ConligWX wrote: Tue 18 Jan 2022 8:44 pm
Altocumulus wrote: Tue 18 Jan 2022 4:24 pm I wanted to check back through the graphs to see if I'd had a similar spike in the data, but on my localhost/charts display I have 12 hours of data on display. Only "All" is emboldened, the other 3 options are greyed out.

I assume there's a way to check back on previous days, or have I lost the opportunity without a lot of work - Historic Charts option is way too coarse.

I've looked back on our seismometer, but nothing appears to show beyond the background noise.
change your graph hours to 96 that will give you 4 days worth of data in the charts. settings, station settings, Graphs
Thanks Simon.

I had a 1 hPa spike rise at 1820 on Saturday against a general fall trend, and a 1 hPa dip at 0220 on Sunday.
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Re: Tonga Eruption

Post by billy »

some ... belated ... Western Australian observations.

The main eruption occurred at ~ 12:20 (15/01/2022) WA time (WST = +8 UTC). The first pressure wave arrived almost precisely 6 hours later (left arrow, black) at 18:20 WST. We are 6859 km from the volcano so that gives a speed of 1,143 km/hr. The barometric disturbance lasted a little over an hour.

The second arrow (from the left - red) at 17:10 (16 Jan) WST marks the pressure wave that came the long way around to Perth via Tonga's antipodean point ... 33,216 km, giving a speed of 1,145 km/hr (almost too close to the first estimate given the rough calculations being made here :roll: ).

I thought it might be interesting to stretch all this and "read the tea leaves" to see if the waves could be detected going around a second time (ignoring interference etc). The primary/direct wave seems to appear again at 06:10 (17 Jan ... right black arrow) ... that's 36 hours after it arrived the first time and equates to a speed of 1,113 km/hour (distance of a full lap of the earth is about 40,074 km). So it's seems to have slowed a bit.

As for the other side of the wave - for us the component headed ENE from Tonga and coming to us from the west, there is also a blip (right red arrow) at 04:10 on18 Jan which might be a second coming :twisted:. This is 35 hours since that front arrived the first time and equates to a speed of 40,074 / 35 = 1,144 km/hr.

Tonga.jpg
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Altocumulus
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Re: Tonga Eruption

Post by Altocumulus »

That's some shock wave, just slightly faster than the speed of sound and, it seems, comparable with estimates on Krakatoa.

Very interesting calculations - here in NE Scotland I have to use a bit of licence to see anything really beyond the first two waves.
Last edited by Altocumulus on Thu 20 Jan 2022 9:43 am, edited 1 time in total.
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Re: Tonga Eruption

Post by sutne »

just slightly faster than the speed of light
Or maybe speed of sound?
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Re: Tonga Eruption

Post by billy »

Just a little slower than sound ;)
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Re: Tonga Eruption

Post by Altocumulus »

Flip - too early in the morning !!!! :bash:
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Re: Tonga Eruption

Post by apple8 »

Given that the pressure wave spreads in all directions from one point and the planet is more or less round, hypothetically is there a point where they all meet and what happens there?
Altocumulus
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Re: Tonga Eruption

Post by Altocumulus »

apple8 wrote: Fri 21 Jan 2022 5:46 am Given that the pressure wave spreads in all directions from one point and the planet is more or less round, hypothetically is there a point where they all meet and what happens there?
One would suspect, much like the tide and waves on the sea - in opposite directions, there's an amplification.
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