Keeping San Francisco Pedestrians Safe: Earthquake Update

Flashback to 1989 – The Loma Prieta (M6.9) quake struck just as the World Series was beginning in San Francisco.   Centered 50 miles south in the Santa Cruz Mountains, the temblor killed 63, collapsed an elevated portion of a freeway in Oakland and a portion of the Bay Bridge, sparked fires that burned much of San Francisco’s Marina district, leveled portions of Santa Cruz and Watsonville, and disrupted transportation and services for months. It left behind more than $6 billion in damages (over $9.5 billion).

Due to recent events, some scientists believe that the residents of the California coastline should be ready for another earthquake (as conditions are set for such) until at least March 26, 2011.  As most Californians already know, earthquakes and other natural disasters can cause severe destruction very quickly.   For example and without warning, pedestrians may suddenly be at risk when foundations of nearby buildings begin to crack, and the ground beneath them becomes unstable.  Falling objects are another immediate concern.  As a result, whether one is walking down the street, driving in a vehicle, or standing inside of a building and or home: it is critical to know what steps to take in order to ensure safety.  One of these steps may be simply to know where the hazard zones are.

CA.GOV offers the following advice on this frequently asked question: “How do I find out what earthquake hazard zone I live in?” There are four types of zone maps: Shaking, Fault Rupture, Seismic Hazard Zones for Liquefaction and Landslides, and Tsunami Inundation.

Ground shaking typically causes over 90 percent of all earthquake damage.  California has two shaking zones 4 and 3.  Zone 4 is located nearest to active earthquake faults and poses greater hazards than Zone 3.  See Figure 7 on page 7 of the Homeowner’s Guide at:http://www.seismic.ca.gov/pub/CSSC_2005-01_HOG.pdf.

Fault Rupture maps show 1,000 foot or so wide zones nearest active earthquake faults that have ruptured the earth.  For more information and to view these maps, please visit the California Geological Survey website at:http://www.consrv.ca.gov/cgs/rghm/ap/Map_index/index.htm.  Seismic Hazard Zone Maps show areas of land that might be prone to landslides, liquefaction or tsunami inundation.  These maps are available to view and download at: http://gmw.consrv.ca.gov/shmp/index.htm.  For copies, downloads, and information about the geologic hazards of California, please contact the California Geological Survey, (916) 445-5716 or online at http://www.consrv.ca.gov/cgs/index.htm.

In addition to the above information, residents should be aware of what precautions can be taken to avoid injury during an earthquake. FEMA has some helpful tips and the safety steps can be found here: http://www.fema.gov/hazard/earthquake/eq_during.shtm.