Virginia Cartography Volume 37; A Bibliographical Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1898 Excerpt: ...been felt. Here the abbreviation S. F. stands for San Francisco. When necessary the name of the county is added for convenience. Fourth, the intensity of the shock, expressed either in common language or in terms of some arbitrary scale. Professor Rockwood, in indicating the intensity, has used the adjectives: 1, very light; 2, light; 3, moderate; 4, strong; 5, severe; 6, destructive; but has added a Roman numeral to indicate the intensity, according to the Rossi-Forel scale, adopted by Swiss and Italian seismologists. In Professor Rockwood's papers, very light is II or III; light, IV; moderate, V or VI; strong, VI or VII; severe, VIII; destructive, IX or X. Fifth--A brief reference to the source of information, so that in nearly all cases the original record can be consulted, if desired. Exceptionally heavy shocks, such as those of 1865, 1868 and 1872, are treated with much more fullness than the lighter ones. I strongly recommend the use of the Rossi-Forel scale, on account of the definiteness of the classification and because of the comparative regularity of the gradations. In order to make it better known in California, I reprint it here: The Rossi-FoKEL Scale. I. Microseismic shock--recorded by a single seismograph, or by seismographs of the same model, but not putting seismographs of different patterns in motion; reported by experienced observers only. First proposed by Rossi in Archives den Sei. Phyt. et Nat., IV, p. 371 (1880), and qnite independently by Forel, ibid., VI, p. 461. After comparing hundreds of published accounts of California earthquakes, I have found that the words here printed in italics (which form no part of the Rossi.Forel scale as proposed by its authors) are frequently employed by California observers. They are here ...