Famous as the measurement is , it was beset by problems , not least of which was the haze created by the smoke from forest fires which blurred the mirror image . It is also probable that the intensively detailed work of the geodetic survey , with an estimated error of less than one part in 1 million , was compromised by a shift in the baseline arising from the Santa Barbara earthquake of June 29 , 1925 , which was an estimated magnitude of 6.3 on the Richter scale
Santa Barbara earthquake
1925 Santa Barbara earthquake
Albert A. Michelson