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

From: Laura _at_ CopperWired Studios <laura_at_meteoritecentral.com>
Date: Thu, 25 Feb 2016 17:22:11 -0500
Message-ID: <02f801d1701a$fa314a90$ee93dfb0$_at_copperwired.com>

Thank you to all of the great contributors that aid the in the recovery
methodology thru their true diligence and love of the science! Without
their help, this would be a near impossible task! Congratulations to all
involved!

Best Regards,
Laura Atkins
IMCA #4542

-----Original Message-----
From: Meteorite-list [mailto:meteorite-list-bounces at meteoritecentral.com] On
Behalf Of Matson, Rob D. via Meteorite-list
Sent: Thursday, February 25, 2016 1:22 PM
To: meteorite-list at meteoritecentral.com
Subject: [meteorite-list] 2nd recovered U.S. fall of 2016 - more details

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 05:22:11 PM PST