Why You Should Be Ready for "The Big One"; Where to Get Ready if You Are Not

Monday, November 16, 2015

Too many Oakland and Rockridge residents today are unprepared for a major earthquake on the Hayward fault.

Although the City Council and Oakland Fire Department take the warnings seriously and have produced the disaster preparedness program "Communities of Oakland Respond to Emergencies" (CORE), community response has been lethargic.

Here is the scientific reality: Strong earthquakes occur with fairly regular frequency and magnitude. For the Hayward fault, that is a strong earthquake about every 140 years (plus or minus about 30 years) with a magnitude of 7.0 or greater on the Richter scale. Every 140 years is right NOW! Are residents and support services ready?

Oakland"s government still has much to do; Oakland citizens even more. Consider the following potential destruction that could paralyze the East Bay:

  • The ground rupture displacement of the fault zone is expected to be from two to six feet, the more likely being six feet. That means the lower, flat ground of Rockridge and the East Bay west of the fault is expected to lurch northward some six-and-a-half feet.
  • Freeway surfaces will probably be undrivable. The state has retrofitted highway overpasses to withstand known lateral and vertical accelerations, but few are designed for significant shear pressure. Imagine Montcair"s LaSalle Avenue and Park Avenue overcrossings on Highway 13 with their eastern footings on the Montclair side of the fault and their western footings on the Rockridge side. It is doubtful the structures could withstand six feet of lateral movement. The possible result will be the collapse of the overpasses onto Highway 13.
  • Moraga Road has been closed twice in the past because of recurring landslides. In an earthquake, a major part of the hillside could collapse, creating an earthen dam across the canyon.
  • Highway 24 is expected to experience significant damage to the Caldecott Tunnel approach, and there is concern about the strength of the two oldest bores. BART"s twin-bore tunnel is deeper and longer, and runs through the fault line face. Six feet of lateral displacement within the tunnels will likely result in long-term closure. Farther east, according to a study completed by the Orinda Fire Department, the city of Orinda is concerned about the overpass sections of Highway 24 near that city's BART station.

The United States Geological Survey (USGS) liquefaction zone charts identify the following areas as also possibly incurring significant damage due to their construction on fill or other unstable land:

  • San Francisco, Oakland, and San Jose airports, and the Port of Oakland.
  • Bay Bridge toll plaza.
  • I-80 (East) and I-580 (West), and parallel to the BNSF railroad mainline, from the toll plaza northward to beyond Golden Gate Fields.
  • I-880 (South) and parallel to the BNSF line, from near 16th Avenue to beyond the Coliseum.

The following Bay Area characteristics make many analysts feel the anticipated earthquake will be the largest single natural disaster to hit the U.S.:

  • 6-7 million people live near the fault; 4-5 million people live west of the fault line and will be severed from critical sources of supply.
  • All major highways; railroads; high tension power lines; water, natural gas, and petroleum pipelines - automotive fuel, aviation fuel, bunker oil, and others - cross the fault and are expected to be damaged.There will surely be no water pressure. The Association of Bay Area Governments (ABAG) predicts 5,500 water-line breaks in such a quake.
  • PG&E will likely experience downed power lines and ruptured gas mains all over the East Bay, bringing down high voltage lines on Claremont Avenue and Rockridge residential streets.
  • Leaking natural gas will create a hazard. In the 1999 Northridge earthquake, more than 600 underground natural gas pipeline ruptures caused leaks beneath the streets. A number of these leaks led to explosions, and broken gas lines within or connected to structures resulted in fires. With the disrupted water supply system, fighting these fires was difficult. At least 600 buildings burned.
  • Rockridge homes not properly seismically upgraded could be knocked off their foundations and their gas and water lines likely sheared.

Will citizens be able to evacuate? Not with all the roads possibly blocked, bringing those who try to drive to safety to a dead stop in a massive traffic jam that could last for days.

What Can You Do?

The best strategy is to be prepared, and to stay and hold your ground as long as possible. Oakland citizens need to read, learn and embrace the recommendations of the CORE program. Scheduled 2015 programs are concluding, but neighborhoods can request a local presentation at any time. See "How to Request a Core Class" at: http://www2.oaklandnet.com/Government/o/OFD/s/CORE/index.htm

The 2016 schedule will be available soon. Also, the United States Geological Service (USGS) web site has more earthquake information and a variety of links to other resources: http://www.usgs.gov/