[meteorite-list] 2nd recovered U.S. fall of 2016 - more details
From: J Sinclair <john_at_meteoritecentral.com>
Date: Thu, 25 Feb 2016 13:56:17 -0500
The new science of meteorite recovery is amazing. The time and effort
of all is greatly appreciated.
Thanks Rob and to everyone else that are taking part in these great recoveries.
On Thu, Feb 25, 2016 at 1:22 PM, Matson, Rob D. via Meteorite-list
<meteorite-list at meteoritecentral.com> wrote:
> Hi All,
> Some further information about the circumstances leading to the successful
> meteorite recovery east of Lubbock, TX. First off, Mike Hankey deserves special
> notice since often the first indication we have of a new potential fall is the
> AMS website that he maintains. Marc Fries was the first to spot the nice
> Lubbock radar returns for this fall -- less than 18 hours after the event! I
> compiled those, and additional returns I found in the Amarillo radar, and
> then went on a search for seismic signatures or videos that could be used
> to pin down the time of the event. One Youtube video surfaced right away,
> taken from a dashcam on highway 183 near Euless, Texas:
> Pat Branch did some quick work measuring terminus angles, concluding that
> the vector lined up perfectly with the radar returns east of Lubbock. I soon
> located two more videos, one from some still undetermined location near
> Augusta, Kansas (east of Wichita) and some 580 km (!) from the fall:
> and another from a dashcam near Edmond, OK, north of Oklahoma City:
> Pat Branch was successful in contacting the driver of this car who provided
> his exact location. There are numerous landmarks in this video that allowed
> me to determine reasonably accurate starting and ending directions. Triangulating
> this video with the one from Euless led to a fairly steep fireball entry angle and
> a nearly due west trajectory.
> However, upper atmospheric winds were relatively strong (over 100 mph to
> the southeast,) and not surprisingly this is the trend we see in the radar returns.
> All that remained was to get an accurate time for the event so that meteorite
> masses could be estimated (based on the time delay between the fall and
> when various radar volumes were scanned). Unfortunately, none of the
> three videos above has a sufficiently accurate timetag.
> But here again Pat came to the rescue. Rob Ferguson (the provider of the
> Edmond, OK dashcam) emailed Pat telling him that the fireball was also
> captured by the Oklahoma Dept. of Emergency Management's tower cam,
> and that a friend of his (Putnam Reiter) works there and pulled the video for
> him. This has a great, unobstructed view of the event, being up on a tower
> some 200 feet! Most importantly, it has a very accurate timetag, being
> regularly synced with a NTP server. So we now knew the beginning of the
> event was at 3:44:08 UT (21:44:08 CST). I determined that the earliest radar
> returns of the fall were from Amarillo NEXRAD at 3:45:49.7, just 99 seconds
> after the beginning of dark flight (~21:44:11 UT). This was how we knew
> meteorites were on the ground for sure, since dust or even small pebbles
> can't fall that far in less than 2 minutes.
> Anyway, this is getting a bit long and I want to get these details out
> there sooner rather than later in order to credit some of the important
> players that made this all happen. Hopefully it gives you a sense of the
> amount of detective work goes into chasing down these falls, and how
> much of a team effort it is.
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Received on Thu 25 Feb 2016 01:56:17 PM PST