The Pamir Earthquake of 18th February, 1911

Abstract

The Pamir earthquake of the 18th of February 1911, though of destructive violence in the central region and giving rise to long- distance records, would probably have passed without special notice had it not been for two circumstances : one, that it was accompanied by a landslip of exceptional dimensions, which dammed one of the principal drainage-valleys of the region, and gave rise to a permanent lake over 15 miles in length and 900 feet in depth; the other, that the late Prince Boris Galitzin formulated the conclusion that this landslip was the originating cause of the earthquake, and that this was an interesting and unique -instance of coincidence of epicentre and hypocentre. Attention has been recently drawn once more to this earthquake, and, although mistakes in Prince Galitzin's mathematical methods have been pointed out, the justice of his conclusion has been maintained; but this conclusion is so contrary to all other present knowledge of the character and behaviour of earthquakes, that a fuller examination of the evidence seemed desirable, and as this is not generally available, being published almost exclusively in the Eussian language, it has seemed desirable to record the facts, so far as they are available. Before dealing with the local observations and records of the earthquake, it will be well to refer briefly to Prince Galitzin^s paper.2 His conclusions were based primarily on the survey conducted in 1913 by Col. Spiiko, from which it was computed that the mass of the landslip amounted to between 7