Thursday Crash Data-- It was very quick. According to minute by minute data posted by SoMch2Knw at TMF RMBS board (post #128134), about two minutes to reach the low, about five for the "recovery".
14:35 Open 44.44 High 44.46 low 44.29 Close 44.30 Vol 41,017
14:36 Open 44.29 High 44.30 low 44.02 Close 44.02 Vol 75,072
14:37 Open 44.03 High 44.06 low 42.28 Close 42.50 Vol 459,522
!!!
14:38 Open 42.50 High 43.00 low 34.02 Close 34.06 Vol 1,236,992
14:39 Open 34.02 High 34.35 low 29.52 Close 31.33 Vol 1,050,628
!!!
14:40 Open 32.55 High 34.12 low 29.57 Close 33.78 Vol 1,068,937
14:41 Open 33.82 High 38.00 low 33.76 Close 37.86 Vol 762,768
14:42 Open 37.92 High 39.34 low 33.27 Close 34.85 Vol 738,490
14:43 Open 34.65 High 38.22 low 34.55 Close 37.92 Vol 419,276
14:44 Open 37.95 High 38.66 low 37.00 Close 37.55 Vol 473,215
14:45 Open 37.55 High 38.08 low 36.70 Close 36.95 Vol 320,694