Laserfiche WebLink
<br /> <br />damaged. Some <br />pipes break. <br />MMI 9 Only very well <br />anchored contents <br />remain in place. <br />Poorly constructed <br />buildings collapse. <br />Well-constructed <br />buildings are heavily <br />damaged. <br />Retrofitted buildings <br />damaged. <br />Soft-story buildings <br />partially or <br />completely collapse. <br />Some well- <br />constructed <br />buildings are <br />damaged. <br />Poorly constructed <br />buildings are heavily <br />damaged, some <br />partially collapse. <br />Some well- <br />constructed <br />buildings are <br />damaged. <br />MMI 10 Only very well <br />anchored contents <br />remain in place. <br />Retrofitted buildings <br />are heavily <br />damaged, and some <br />partially collapse. <br />Many well- <br />constructed <br />buildings are <br />damaged. <br />Well-constructed <br />buildings are <br />damaged. <br /> <br />5.1.4 Earthquake Shaking Scenarios <br />In addition to this effort, ABAG and USGS have developed several shaking scenario maps <br />that depict shaking intensity for specific, plausible earthquake scenarios with a given <br />magnitude on a fault. These maps show possible levels of ground shaking throughout the <br />Bay Area in a single likely earthquake, taking into consideration the earthquake magnitude; <br />rupture location and direction; and soil conditions throughout the region. Sixteen <br />scenarios that could cause strong shaking in the Bay Area can be seen side-by-side. <br />Scenario maps are helpful to model the expected shaking of an individual event, but they do <br />not depict the likelihood of the event occurring or whether it is the most significant event <br />for a particular location. A Probabilistic Seismic Hazard Assessment (PSHA) Map <br />incorporates the likelihood of ground shaking from all nearby fault sources, and accounts <br />for the frequency of each event. The PSHA Map in Figure 3 illustrates the 10 percent or <br />greater chance in a 50 year period that each location on the map will exceed the MMI <br />shown at least once. <br />In terms of risk characterization, it is equivalent to a 500-year flood. A 10 percent in 50 <br />years hazard level was chosen as it most closely aligns to the levels of shaking used in the <br />current building code. Seismic hazard maps are not intended to be site-specific but depict <br />the general risk within neighborhoods and the relative risk from community to community. <br /> <br /> <br />