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4.7 Geology,Soils,and Seismicity r range from I(earthquake not felt)to XII (damage nearly total). Earthquakes on the various active and potentially active San Francisco Bay Area and Central Valley fault systems can produce a wide range of ground shaking intensities within the project area. r TABLE 4.7-2 MODIFIED MERCALLI INTENSITY SCALE(ABRIDGED) .. Average Intensity Peak Value Intensity Description Accelerationa I Not felt except by a very few persons under especially favorable circumstances. <0.0017 g II Felt only by a few persons at rest,especially on upper floors on buildings. <0.014 g Delicately suspended objects may swing. r III Felt quite noticeably indoors;especially on upper Floors of buildings,but many c 0.014 g people do not recognize it as an earthquake. IV During the day felt indoors by many,outdoors by few.At night,some awakened. 0.014-0.039 g Dishes,windows,doors disturbed;walls make cracking sound. V Felt by nearly everyone,many awakened.Some dishes,windows,etc.,broken;a 0.039-0.092 g few instances of cracked plaster;unstable objects overturned. V1 Felt by all,many frightened and run outdoors.Some heavy furniture moved;minor 0.092-0.18 g fallen plaster or damaged chimneys.Damage slight. VII Everybody runs outdoors.Damage negligible in buildings of good design and 0.18-0.34 g _ construction;slight to moderate in well-built ordinary structures;considerable in poorly built or badly designed structures;some chimneys broken. VIII Damage slight in specially designed structures;considerable in ordinary substantial 0.34-0.65 g buildings,with partial collapse;great in poorly built structures.Panel walls thrown .. out of frame structures.Fall of chimneys,factory stacks,columns,monuments, walls. IX Damage considerable in specially designed structures;well-designed frame 0.65-1.24 g structures thrown out of plumb;great in substantial buildings,with partial collapse. X Some well-built wooden structures destroyed;most masonry and frame structures >1.24 g destroyed with foundations;ground badly cracked.Rails bent.Landslides considerable from riverbanks and steep slopes.Shifted sand and mud.Water splashed(slopped)over banks. XI Few,if any,(masonry)structures remain standing.Bridges destroyed.Broad >1.24 g fissures in ground.Underground pipelines completely out of service.Earth slumps and land slips in soft ground.Rails bent greatly. XII Damage total.Practically all works of construction are damaged greatly or >1.24 g destroyed.Waves seen on ground surface.Lines of sight and level are distorted. Objects are thrown upward into the air. a g is gravity=980 centimeters per second squared.Acceleration is scaled against acceleration due to gravity or the acceleration with which a ball falls if released at rest in a vacuum(1.0 g).Acceleration of 1.0 g is equivalent to a car traveling 100 meters(328 feet) from rest in 4.5 seconds. r SOURCE: Bolt(1988),CGS(2003b). ` The closest known active fault to the proposed project site is the segment of the Great Valley (GV) thrust fault system designated GV07, located approximately 4.5 miles southwest of the r r RMC Pacific Vernalis Quarry Mining and Reclamation Project 4.7-5 ESA/203015 Draft Environmental Impact Report May 2006 I•