Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN><SPAN>When this layer is turned on, click on any area of the map to view the total population, occupied housing units, number of businesses, and number of employees exposed to each shaking intensity. These estimates are provided for the county clicked.</SPAN></SPAN></P><P><SPAN><SPAN>The Modified Mercalli Intensity (MMI) scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake on the earth’s surface, humans, objects in nature, and the building environment. The scale ranges from 1 (not felt) to 12 (total destruction), often expressed as Roman numerals I through XII. </SPAN></SPAN></P><P><SPAN> Following is a detailed description of MMI shaking intensity levels: </SPAN></P><P><SPAN> MMI 4: Vibration felt like passing of heavy trucks. Stopped cars rock. Hanging objects swing. Windows, dishes, doors rattle. glasses clink. In the upper range of IV, wooden walls and frames creak. </SPAN></P><P><SPAN> MMI 5: Pictures move. Felt outdoors. Sleepers wakened. Liquids disturbed, some spilled. Small unstable objects displaced or upset. Doors swing. Pictures move. Pendulum clocks stop. </SPAN></P><P><SPAN> MMI 6: Objects fall. Felt by all. People walk unsteadily. Many frightened. Windows crack. Dishes, glassware, knickknacks, and books fall off shelves. Pictures off walls. Furniture moved or overturned. Weak plaster, adobe buildings, and some poorly built masonry buildings cracked. Trees and bushes shake visibly. </SPAN></P><P><SPAN> MMI 7: Nonstructural damage. Difficult to stand or walk. Noticed by drivers of cars. Furniture broken. Damage to poorly built masonry buildings. Weak chimneys broken at roof line. Fall of plaster, loose bricks, stones, tiles, cornices, unbraced parapets and porches. Some cracks in better masonry buildings. Waves on ponds. </SPAN></P><P><SPAN> MMI 8: Moderate damage. Steering of cars affected. Extensive damage to unreinforced masonry buildings, including partial collapse. Fall of some masonry walls. Twisting, falling of chimneys and monuments. Wood-frame houses moved on foundations if not bolted; loose partition walls thrown out. Tree branches broken. </SPAN></P><P><SPAN> (MMI descriptions taken from quake.abag.ca.gov/shaking/mmi/plaintext/.) </SPAN></P></DIV></DIV></DIV>