Appendix A. – Modified Mercalli Scale
- Not felt except by a very few under especially favorable circumstances. (I Rossi-Forel Scale.)
- Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing. (I to II Rossi-Forel Scale.)
III. Felt quite noticeably indoors, especially on upper floors of buildings, but many people
- During the day felt indoors by many, outdoors by few. At night, some awakened. Dishes, windows, doors disturbed; walls make creaking sound. Sensation like heavy truck striking building. Standing motorcars rocked noticeably. (IV to V Rossi Forel Scale.)
- Felt by nearly everyone, many awakened. Some dishes, windows, and so on broken; cracked plaster in a few places; unstable objects overturned. Disturbances of trees, poles, and other tall objects sometimes noticed. Pendulum clocks may stop.
(V to VI Rossi Forel Scale.)
- Felt by all, many frightened and run outdoors. Some heavy furniture moved; a few instances of fallen plaster and damaged chimneys. Damage slight. (VI to VII Rossi-Forel Scale.)
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 persons driving cars. (VIII Rossi-Forel Scale.)
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, fact01y stacks, columns, monuments, walls. Heavy furniture overturned. Sand and mud ejected in small amounts. Changes in well water. Persons driving cars disturbed. (VIII+ to IX Rossi-Forel Scale.)
- Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb; great in substantial buildings, with partial collapse. Buildings shifted off foundations. Ground cracked conspicuously. Underground pipes broken. (IX+ RossiForel Scale.)
- 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, slopped over banks. (X RossiForel Scale.)
- Few, if any, (masonry) structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipelines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly.
XII. Damage total. Waves seen on ground surface. Lines of sight and level distorted. Objects thrown into the air.
Bolt, Bruce A. Earthquakes. W.H.Freeman and Company. New York, 1988
Bishop William Ford Nichols. “A Father’s Story of the Earthquake of 1906.” San Francisco Museum of History, 2016
History channel. San Francisco 1906 Earthquake.
Holden, Edward S. Catalogue of Earthquakes of the Pacific Coast 1769 to 1897. Reprint from the Smithsonian Miscellaneous Collection No. 1087 for Distribution by the Lick Observatory. 1898
Insurance Journal. Earthquake coasts at $200B. (2015) govtech.com/local/Bay-Area-Infrastructure-is-Safer-but-Still-on-Shaky-Ground.html
Kircher. C. el al. When the Big One Strikes Again- Estimated Losses due to a Repeat of the 1906 San Francisco Earthquake. Earthquake Engineering Research Institute, ERRI (November, 2016)
Lawson, Andrew C and Chairman. The California Earthquake of April 18, 1906 Report of the State Investigation Investigating Commission. Carnegie Institution of Washington. 1908
Michigan Technological University, Magnitude measurements explained. 2007 geo.mtu.edu/UPSeis/intensity.html
San Francisco Funcheap com on-line. 1906 earthquake remembered, SF Funcheap com on-line. 2016 sf.funcheap.com/1906-quake-rememberance-lottas-fountain-sf/
State of California Dept. of Conservation and Geology. California Geological Survey: Remember ‘06 But Don’t Forget To Look Ahead And Be Prepared. 2006, conservation.ca.gov/index/news/2006%20News%20Releases/Pages/nr2006-04_1906_quake_reminder_to_prepare.aspx
State of California Dept. of Transportation. Transportation Management and Plans. (2016) dot.ca.gov/
Tocher, Don. Guide Book for Seismology Study Tour, Meeting of the International Union of Grodesy and Geophysics. University of California at Berkely 1963.
USGS. Earthquake Faults in detail.
USGS. Hayward Fault Model. (2016)
USGS. San Francisco 1906 simulation.
Walker, Bruce. Planet Earth Earthquake. Time Life Books. Alexandria, Virginia 1980
Wikipedia. Napa Valley Earthquake. 2014 en.wikipedia.org/wiki/2014_South_Napa_earthquake