RF Rossi-Forel
MM Modified Mercalli

ROSSI-FOREL INTENSITY SCALE (as modified by Holden, 1898)

Holden's comments: "First proposed by Rossi in Archives des Sci. Phys. et Nat., IV, p. 371 (1880), and quite 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 \fIitalics\fR (which form no part of the Ross-Forel scale as proposed by its authors) are frequently employed by California observers. They are here printed for convenience. When any one is describing the effect of a shock he should employ the numerals I, II, III, etc., of the Rossi-Forel scale. When, on the other hand, one is reading an account of a California earthquake and seeking to assign the proper R.F. numeral, it will be found that the words here set down in italics are of service.

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.

II Shock reported by several seismographs of different patterns; reported by a small numbers of persons who are at rest. \fIA very light shock.\fR

III Shock reported by a number of persons at rest; duration or direction noted. \fIA shock; a light shock\fR

IV Shock reported by persons in motion; shaking of movable objects; doors and windows, cracking of ceilings. \fIModerate; sometimes strong; sharp; light.\fR

V Shock felt generally by every one; furniture shaken, some bells rung, \fIsome clocks stop. Smart; strong; heavy; severe; sharp; quite violent; some sleepers waked.\fR

VI General awakening of sleepers; general ringing of bells; swinging of chandeliers; stopping of clocks; visible swaying of trees; some persons run out of buildings; \fIwindow glass broken. Severe; very severe; violent.\fR

VII Overturning of loose objects; fall of plaster; striking of church bells; general fright, without damage to buildings; \fInausea. Violent; very violent\fR

VIII Fall of chimneys; cracks in the walls of buildings.

IX Partial or total destruction of some buildings.

X Great disasters; overturning of rocks; fissures in the surface of the earth; mountain slides.

	MODIFIED MERCALLI TO ROSSI-FOREL EQUIVALENCE
		      (From Richter, 1958, Elementary Seismology)

		      Modified Mercalli	Rossi-Forel
		      0			0
		      I			I
		      II		II
		      III		III
		      IV		IV 1/2
		      V			V 1/2
		      VI		VI 1/2
		      VII		VII-VIII
		      VIII		VIII 1/2
		      IX		IX
		      X-XII		X

MODIFIED MERCALLI INTENSITY SCALE OF 1931 (ABRIDGED) From the Modified Mercalli Intensity Scale of 1931 by Harry O. Wood and Frank Neumann (BSSA, vol 21, #4, 1931)

I Not felt except by a very few under especially favorable circumstances.

II Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing.

III Felt quite noticeably indoors, especially on upper floors of buildings, but many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibration like passing of truck. Duration estimated.

IV During the day felt indoors by many, outdoors by few. At night some awakened. Dishes, windows, doors disturbed; walls made cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably.

V Felt by nearly everyone; many awakened. Some dishes, windows, etc., broken; a few instances of cracked plaster; unstable objects overturned. Disturbance of trees, poles and other tall objects sometimes noticed. Pendulum clocks may stop.

VI Felt by all; many frightened and run outdoors; Some heavy furniture moved; a few instances of fallen plaster or damaged chimneys. Damage slight.

VII Everybody runs outdoors. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable in poorly built or badly designed structures; some chimneys broken. Noticed by person s driving motor cars.

VIII Damage slight in specially designed structures; considerable in ordinary substantial buildings with partial collapse; great in poorly built structures. Panel walls thrown out of frame structures. Fall of chimneys, factory stacks, columns, m onuments, walls. Heavy furniture overturned. Sand and mud ejected in small amounts. Changes in well water. Disturbed persons driving motor cars.

IX Damage considerable in specially designed structures; well designed frame structures thrown out of plumb; great in substantial buildings, with partial collapse. Buildings shifted off foundation. Ground cracked conspicuously. Underground pipe s broken.

X Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations; ground badly cracked. Rails bent. Landslides considerable from river banks and steep slopes. Shifted sand and mud. Water splashed (slo pped) over banks.

XI Few, if any (masonry), structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipe lines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly.

XII Damage total. Waves seen on ground surfaces. Lines of sight and level distorted. Objects thrown upward into the air.

This table lists short mnemonic identifiers for the sources used in the database. These appear in event summaries.

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Catalogs

BB Berg and Baker, 1963, Oregon Earthquakes, 1841 through 1958, BSSA, V. 53, No. 1, pp. 95-108

BRAD Bradford, Donald C., 1935, Seismic History of the Puget Sound Basin, BSSA, V. 25, No. 2, pp. 138-153

BYERL Byerly, Perry, 1952, Pacific Coast Earthquakes, Condon Lecture, pp. 33-38

HOLD1 Holden, Edward S., 1887, List of Recorded Earthquakes in California, Lower California, Oregon, and Washington Territory

HOLD2 Holden, E.S., 1898, A Catalog of Earthquakes on the Pacific Coast 1769-1897, Smithsonian Miscellaneous Collections, 1087

McA McAdie, Alexander C., 1907, Catalog of Earthquakes on the Pacific Coast: 1897 to 1906, Smithsonian Misc. Collections, Part of Vol. XLIX (No. 1721), Smithsonian Institution, Washington D.C., 64 p.

MILNE Milne, W.G., 1956, Seismic Activity in Canada, west of the 113th meridian 1841-1951: Canada Dominion Obs. Pub., V. 18, No. 7, pp. 119-146

RAS Rasmussen, Norman, 1967, Washington state earthquakes 1840 through 1965, BSSA V. 57, No. 3, pp. 463-476

SMITH Smith, W. D., 1919, Earthquakes in Oregon, BSSA, V. 9, n. 3, pp. 58-71

TA-OR Townley, S.D. and M.W. Allen, 1939, Descriptive Catalog of earthquakes of the Pacific Coast of the United States 1769 to 1928, Chapter II, Earthquakes in Oregon--1846-1928, BSSA, V. 29, No. 1, pp. 253-258.

TA-WA Townley, S. D. and M. W. Allen, 1939, Descriptive Catalog of Earthquakes of the Pacific Coast of the United States 1769-1928, Chap. III Earthquakes in Washington, 1883-1928, BSSA, V. 29, No. 1, pp. 259-268

USEQS U. S. Dept. of Commerce, 1973, Earthquake History of the United States, V. 41-1, revised ed., pp. 89-96

WWC Woodward-Clyde Consultants (1981), Historical Catalog (1841-1980) for the Pacific Northwest Region, unpublished catalog prepared for the Washington Public Power Supply System. Copy provided to UW in 1993.

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Newspapers

N- Newspapers from outside the Pacific Northwest area.

N-CA Any California newspaper,

N-OR Any Oregon Newspaper except the Portland "Oregonian"

N-Ore The Portland "Oregonian", N-OR is any other Oregon newspaper,

N-UCB Clippings from the U.C. Berkeley Seismographic Stations scrapbooks.

N-Vic Any Victoria, B.C. newspaper,

N-WaS The Olympia "Washington Standard"

N-WA Any Washington newspaper, other than the Olympia "Washington Standard"

N-WPP Newspaper clippings transcribed in the WPPSS documents.

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Other sources

BSSA Bulletin of the Seismological Society of America - articles or notes

CGR C.G. Rockwood - Published a short column on earthquakes in the American Journal of Science from 1878-1887

DIARY Diary entries documenting earthquakes

GCR Dissertation of G.C. Rogers (1983), who recalculated locations, felt area and magnitudes for some of Cascadia's larger earthquakes.

I-ORE An Index to an Oregon newspaper

I-WA An Index to a Washington newspaper

JOURN A periodical publication

MISC Other sources, published and unpublished.

MWR Monthly Weather Review. Comments on earthquakes were published along with weather reports by weather observers.

N-WPP Newspaper clippings transcribed in the WPPSS documents.

REID1 Unpublished notes of Henry Fielding Reid, noted seismologist - transcribed from microfilm obtained from the USGS Menlo Park lary.

REID2 Unpublished notes (part 2) of Henry Fielding Reid

WBR Weather Bureau Climatologic Records, National Archives microfilm of handwritten reports by weather observers.

WPPSS Documents from the Washington Public Power Supply System 'grey literature'. .