Bonsoir Arnauld - When I stumbled into Clube and Napier's work and others in 1997 was when I realized that the NASA rates from asteroid population were too low. Its cometary and comet fragment impacts, and the small fragments are damned hard to find.
I think Shoemaker's final paper out of Canada had better rates. The ones that I came up with were just from historical/myth-historical materials, but with archaeological confirmation - i.e. for the YD impacts there's quarry usage data. E.P. Grondine Man and Impact in the Americas --- On Sun, 11/15/09, The Tricottet Collection <tricottetc...@live.com> wrote: > From: The Tricottet Collection <tricottetc...@live.com> > Subject: RE: [meteorite-list] Tunguska rates > To: "E.P. Grondine" <epgrond...@yahoo.com>, "MeteoriteList" > <meteorite-list@meteoritecentral.com> > Date: Sunday, November 15, 2009, 3:01 AM > > Hi E.P. et al., > > actually, what the journalist of BI wrote is inaccurate. > You can read in our report that we used 1 per 1000 years as > our preferred value, following the most up-to-date > frequency-size distribution [Brown et al, 2002], but we also > tested 1 per 200 years [Shoemaker, 1983] and noted that the > rate could be far higher if hypotheses from geomythology and > related were to be verified. > > Best, > > ArnaudM > > > > > Date: Sat, 14 Nov 2009 18:20:11 -0800 > > From: epgrond...@yahoo.com > > To: meteorite-list@meteoritecentral.com > > Subject: [meteorite-list] Tunguska rates > > > > Hi Arnauld, all, > > > > The problem is that Tunguska type blasts have been > occuring recently (for the last 5,000 years) at a rate of 1 > per 100 years, not 1 per 1,000. Whether this represents a > short term phenonmenon or the long term rate is not > currently known. > > > > I used to put together catalogues of "known and > suspected impacts", you may want to google that, and if you > have not bought a copy of "Man and Impact in the Americas" > yet, well, it is the best available recent impact rate data > for the Americas. > > > > E.P. Grondine > > Man and Impact in the Americas > > > > > > > > ______________________________________________ > > http://www.meteoritecentral.com > > Meteorite-list mailing list > > Meteorite-list@meteoritecentral.com > > http://six.pairlist.net/mailman/listinfo/meteorite-list > > > > > _________________________________________________________________ > Windows 7: I wanted simpler, now it's simpler. I'm a rock > star. > http://www.microsoft.com/Windows/windows-7/default.aspx?h=myidea?ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_myidea:112009 ______________________________________________ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list