Seismologist retreats from Flight 93 impact time

[Robb]

Just had this forwarded to me, from the notes page of the 9/11 report. I find this interesting, because if I recall correctly Will Bunch at the Philly News got another seismologist to re-do the work and also came up with 10:06, not 10:03, and didn't have any issues about signal-to-noise. Anyone have any thoughts?


168. Ibid., pp. 23Ð27.We also reviewed a report regarding seismic observations on September 11, 2001, whose
authors conclude that the impact time of United 93 was Ò10:06:05±5 (EDT).ÓWon-Young Kim and G. R. Baum,
ÒSeismic Observations during September 11, 2001,Terrorist Attack,Ó spring 2002 (report to the Maryland Department of Natural Resources). But the seismic data on which they based this estimate are far too weak in signal-to-noise
ratio and far too speculative in terms of signal source to be used as a means of contradicting the impact time
established by the very accurate combination of FDR, CVR,ATC, radar, and impact site data sets.These data sets
constrain United 93Õs impact time to within 1 second, are airplane- and crash-site specific, and are based on time
codes automatically recorded in the ATC audiotapes for the FAA centers and correlated with each data set in a
process internationally accepted within the aviation accident investigation community. Furthermore, one of the
studyÕs principal authors now concedes that Òseismic data is not definitive for the impact of UA 93.Ó Email from
Won-Young Kim to the Commission,ÒRe: UA Flight 93,Ó July 7, 2004; see also Won-Young Kim,ÒSeismic Obser-vations
for UA Flight 93 Crash near Shanksville, Pennsylvania during September 11, 2001,Ó July 5, 2004.