45 miles per second is pretty good.
At 10:35pm on August 27, 1957 in Area U3d of the New Mexico Nuclear Test Site, the bomb was detonated. But instead of the expected small yield the bomb detonated with a yield approximately five orders of magnitude greater than expected (that’s about 100 000 times greater). The blast instantly vaporized the entire multi-ton concrete collimator and shot it up the tube as a multi-ton wave of vaporized matter at extremely high temperature, pressure, and velocity. The shaft had, in effect, become a enormous 500-foot long, four-foot wide gun barrel with the energy of billions of pounds of TNT released at one end and, at the other end, the now insignificantly small metal cap, about the equivalent of a bottle cap on the end of a naval gun.
As it happens, a very high speed film camera was recording the event and was expected to capture in slow motion the path and speed of any ejecta from the hole. Unfortunately, the camera, which had quite a wide view of top of the hole and and the area around and above, recorded the “manhole cover” on only one frame. There was no malfunction of the camera, it’s just that the “manhole cover” blasted out of sight so fast that the camera only saw it for one frame. Later calculations showed that the heretofore mundane four-foot metal disk had been launched at six times Earth’s escape velocity. That’s one hundred fifty thousand miles per hour. Forty-five miles per second. Nine times faster than the Space Shuttle, six times faster than the fastest moon rockets.
https://www.quora.com/What-is-the-fastest-speed-of-any-object-on-the-earth/answer/Talon-Torres?srid=hAm9&share=66667ee7