[meteorite-list] Peru Again!! Ubinas, Peru volcanic bomb

From: Charles O'Dale <codale0806_at_meteoritecentral.com>
Date: Wed, 17 Oct 2007 16:28:31 -0400 (EDT)
Message-ID: <942786.35375.qm_at_web88004.mail.re2.yahoo.com>

Just to add some more mystery to the latest crater/pit in Peru issue - there is a
crater in northern Quebec that is very similar in size and shape whose origin is
still an issue - Merewether.

http://epod.usra.edu/archive/epodviewer.php3?oid=315776

http://www.ottawa.rasc.ca/articles/odale_chuck/earth_craters/merewether/index.html

Chuck
Ottawa, Canada


> Date: Tue, 16 Oct 2007 20:12:18 -0700 (PDT)
> From: drtanuki <drtanuki at yahoo.com>
> Subject: Re: [meteorite-list] Peru Again!! Ubinas, Peru volcanic bomb
> block crater- Smithsonian Institution-INGEMMETstudy
> To: "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>,
> meteorite-list at meteoritecentral.com
> Message-ID: <805067.54890.qm at web53212.mail.re2.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> Hi Sterling and List,
> Sterling has hit the nail exactly on the head! No or
> little impactor was left in the crater. They will
> still finishing messing up the Carancas impact crater
> anyway or the rain will finish it off, either way it
> is likely gone....
> Happy always to read your posts. I was lucky to
> just find these photos tonight while searching for HE
> bomb craters in Osaka.
> No satellite imagery data has been located of the
> Carancas impact crater following the event, too bad.
> Best Regards, Dirk Ross...Tokyo
>
> --- "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
> wrote:
>
> > Hi, Dirk, List,
> >
> > The picture of the 2-meter "bomb" shows there
> > no distinction between an impact pit (which is what
> > this is) and a true crater, formed by an explosion.
> > The shape (but not the size) is the same for both.
> > The object's mass is up to 10 tons, but the velocity
> > was low, probably no more than 100 m/sec (depends
> > on how high it was tossed out of the volacano). A
> > "pit" is a low-energy event; a crater is not, but
> > the
> > shape's the same.
> >
> > The geometry of the pit or crater is very close
> > to that perfect conical shape of the mathematical
> > crater models with their 3:1 width-to-depth. But
> > since
> > it's the energy that determines the crater, you
> > could
> > have gotten the same crater that was produced by
> > ten tons at 100 m/sec with 100 kilos at 1000 m/sec,
> > or 1 kilo at 10,000 m/sec.
> >
> > It's a picture like this that demonstrates the
> > true
> > silliness of the idea that a "ten-ton monster" is
> > hiding
> > in the Carancas crater. The URL's a picture of a
> > ten-meter crater (OK, pit) with a ten ton impactor
> > sitting in it. Does it look to you like it's hiding?
> > I think
> > we'd have noticed a ten-monster in Carancas... if it
> > was intact!
> >
> >
> > Sterling K. Webb
> >
> ---------------------------------------------------------
> > ----- Original Message -----
> > From: "drtanuki" <drtanuki at yahoo.com>
> > To: <meteorite-list at meteoritecentral.com>
> > Sent: Tuesday, October 16, 2007 8:01 PM
> > Subject: [meteorite-list] Peru Again!! Ubinas,Peru
> > volcanic bomb block
> > crater- Smithsonian Institution-INGEMMETstudy
> >
> >
> > Hi List,
> > Thought some of you might be interested in seeing
> > another crater in Peru. Take a look at the photo
> > page
> > at least! Best Regards, Dirk Ross...Tokyo
> >
> >
> > Main Page:
> >
>
http://www.volcano.si.edu/reports/bulletin/contents.cfm?issue=3110&display=complete
> >
> >
> > Photo:
> >
> >
> http://www.volcano.si.edu/volcanoes/region15/peru/ubinas/3110ubi7.jpg
> >
> > Figure 14. Ubinas eruptions in May 2006 ejected
> > volcanic bombs, seen here in their impact craters. A
> > 2-m-diameter bomb (top), struck ~ 200 m from the
> > crater. A crater containing a large, partly buried,
> > smooth-faced bomb is seen in the bottom photo.
> > Numerous bucket-sized angular blocks appear on the
> > far
> > side of the impact crater. Two geologists stand
> > adjacent a ~ 2-m-long block that ended up on the
> > impact crater's rim. The bomb fragments were of
> > andesitic composition. Top photo from Salazar and
> > others (2006); bottom photo from INGEMMET website.
> > ______________________________________________
Received on Wed 17 Oct 2007 04:28:31 PM PDT