[meteorite-list] norwegian fall

[Sterling K. Webb]

Hi, Bjorn,


    Thanks. There's nothing like local knowledge!
I lamented that the news photo didn't show us the
area below the spot, or some wider view, which
would have made this obvious.

    Did I identify you as Swedish in an earlier
post of mine? If so, apologies. A slight pause
while I remove my foot from my mouth (an old
expression).

    Chris, Mike, and company were correct,
then -- just a rock fall. I love digging into these
stories of great new falls and watch them slowly
unravel like a cheap sweater...

    This information (and the crazy translation
of the seismography page) makes an airburst
seem more likely, so I guess I'll go back to the
Melosh model and try to coax an airburst out
of it that can be heard 200 kilmeters away...

    I was most interested in the part that says,
"So it's a very usual phenomenon in this area,
which was associated unrightfully with the
exploding and rolling sounds between the
valley sides."  That is a great description of
a big airburst. But further, it implies a low
altitude for the source.

    If it was at 30 to 50 kilometers up (which
is where most of the airbursts I got in the
Melosh model were), the sound waves would
be mostly perpendicular to the flat valley floor
and bounce straight back up, attentuating the
echoes. But if it were at a lower altitude, the
shock waves would reverberate more in
the valley. (Google Earth shows the mountains
on either side as only 1000 meters or so, a
shallow valley with a flat bottom.)

    Giving up on impact, going for the airburst...


Sterling K. Webb
---------------------------------------------
----- Original Message ----- 
From: "Bjorn Sorheim" <astrogeo at online.no>
To: <meteorite-list at meteoritecentral.com>
Sent: Tuesday, June 13, 2006 1:26 PM
Subject: Re: [meteorite-list] norwegian fall


>
> In this article(norwegian)
> http://www.framtidinord.no/nyheter/article45150.ece
> it says in the heading (translated):
>
> ** A [rock] slide no meteorite. **
>
> (This story is also on the front page of www.framtidinord.no at the 
> moment).
>
> The location has been know to [many] locals since a month back.
> Many has turned to the newspaper with this information in the last days.
> Locals has known the slide since the snow disappeared at least one month 
> ago.
> Also a part of a local road in this Mosko vally taken by the slide is 
> visible
> to anyone going there.
> So it's a very usual phenomenon in this area, which was associated
> unrightfully with the exploding and rolling sounds between the vally 
> sides.
>
> Bjørn Sørheim,
> In Norway
>
> -----------------------------------------------
> Full norwegain text:
>
> Utglidning, ikke meteoritt
> Av  AV INGE BJØRN HANSEN
>
> Det er ikke en meteoritt som har forårsaket raset i fjellsiden i 
> Moskodalen i Reisadalen.
> Beboere i området bekrefter overfor Framtid i Nord at de har observert 
> arret i fjellsiden nesten helt siden den tiden snøen gikk tidligere i vår.
>
> En av dem som bekrefter at det ikke har slått noen meteoritt ned i 
> området, i alle fall ikke siste uka, er Håkon Rosengren. Han bor på den 
> gården som er nærmest utrasningsstedet i det som folk i dalen kaller 
> "Lillefjellet".
>
> Dette fjellet ligger i utløpet av Moskodalen. Fra gården han ser man rett 
> på bruddet i fjellsiden. Også veien raset har tatt er klart synlig.
>
> - Kona og jeg går tur i området nesten hver dag. Det rasområdet som var 
> omtalt som nedslagsfelt for sist ukes meteoritt i Nord-Troms er i alle 
> fall en måned gammelt, sier Rosengren, og er dermed en av mange som har 
> bekreftet dette overfor Framtid i Nord.
>
>
>
> At 11:03 13.06.2006, you wrote:
>>That has the look of a percussion mark, to me.
>>The shape is elipsoidal, the internal part is fractured, the envolving 
>>rock
>>seams, by contrast, healty.
>>It would be a strange rockslide.
>>Even if the scale of the scar is dificult to evaluate from the photo, a 
>>mass
>>of an average car falling at the final speed of a meteorite, would not let
>>more evidence on a granite surface than this, I think.
>>Big craters form when cosmic speed is maintained, with asteroid sized
>>bodies, but why are we expecting such a big thing?
>>AA
>>
>>
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>>
>
>
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