[meteorite-list] 2nd recovered U.S. fall of 2016 - more details

From: Darryl Pitt <darryl_at_meteoritecentral.com>
Date: Thu, 25 Feb 2016 13:41:11 -0500
Message-ID: <568295C8-5CE8-472A-8AA6-4CD0E8464EDD_at_dof3.com>

Hi,

Thank you so much for this email. I LOVE THIS.

Congratulations to all involved and with especial appreciation to those whose efforts helped to make this possible. Bravo!



On 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:
>
> https://www.youtube.com/watch?v=qMkeVGSlV7o
>
> 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:
>
> https://www.youtube.com/watch?v=YPDoZYfH4ko
>
> and another from a dashcam near Edmond, OK, north of Oklahoma City:
>
> https://www.youtube.com/watch?v=qPb7jrtX4p0
>
> 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.
>
> Cheers!
> Rob
>
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Received on Thu 25 Feb 2016 01:41:11 PM PST