Expected Transportation Losses in an Earthquake

Bay Bridge damaged in 1989 Loma Prieta earthquake

Bay Bridge damaged in 1989 Loma Prieta earthquake Source: USGS

Following an earthquake or other natural disaster, our roads, highways, bridges and airports may be closed due to damage from liquefaction or fault displacement. This page will help you understand the extent of those closures in future earthquake scenarios. We have also developed tips to aid families in dealing with transportation disruptions.

Potential Road Closures in Future Earthquakes

Source: Riding Out Future Quakes, ABAG 2003 update
Checklist for planning for transportation disruptions
Read 2003 report excerpts or purchase the full 1997 documentation.

Note: Although the 2003 closure estimates are significantly different from 1997, and many estimates are significantly higher, the technical documentation and basis for these estimates has not changed significantly since the 1997 report.

Select a fault by clicking on the map or on one of the links below to view a map and table showing road closure causes, and additional planning information for individual earthquake scenarios. Scenarios in black involve multiple fault segments.

map of fault segments to select scenario. Monte Vista Greenville Mount Diablo Green Valley West Napa Maacama Rodgers Creek Nothern Hayward Southern Hayward Northern Calaveras Central Calaveras San Andreas (Santa Cruz Mountains) San Andreas (Peninsula) Northern San Gregorio San Andreas (North Golden Gate)

Table of Road Closures in Future Earthquakes

County Alameda Contra Costa Marin Napa San Francisco San Mateo Santa Clara Solano Sonoma Total
San Andreas – Entire Bay Area 146 30 77 3 429 315 250 6 75 1,332
N + S Hayward 1,081 268 28 2 214 16 99 10 16 1,734
Rodgers Creek – Entire Hayward 1,111 294 41 10 317 25 105 17 233 2,153

Basic Assumptions for Road Closure Models

These estimates include:

  • direct causes of closures, including faulting, liquefaction, landsliding, and shaking damage to bridges and highway interchanges; and
  • indirect causes of closures, including threat of building collapse or structural damage to highway and rail structures, small hazmat releases, water and gas pipeline leaks, and other miscellaneous closures.

Note that this modeling does not include:

  • secondary disasters (such as fires, toxic gas releases far larger than occurred Northridge or Loma Prieta, or dam collapse);
  • possible road closures created for emergency housing or public assistance centers; or
  • extensive landsliding due to soils being saturated with water associated with a very large winter storm.

Airports and Earthquakes

Experience at Narita International Airport During March 11, 2011 Japan Earthquake
Don’t Wing It!, ABAG 2000 – Purchase full report

Features answers to important issues: (1) How vulnerable are airports? (2) What will we need from airports for emergency response and economic recovery? (3) Is there a role for other airports? The report also includes recommendations from a workshop held on October 10, 2000.

Report excerpts

Transportation System Mitigation

Note that the number of road closures listed on these slides is slightly higher than those in the October 1997 report. This discrepancy is due to ABAG’s use of Oct. 1998 information from Caltrans on bridge and overpass retrofit status, versus Oct. 1996 information used in the October 1997 report.


ABAG’s efforts to model road closures were funded by Caltrans, the U.S. Geological Survey, and ABAG. Our recent efforts to plan for these closures and to collect “Ideas for Action” have been funded by a creative partnership of public and private organizations, including the California Governor’s Office of Emergency Services, ABAG, Pacific Gas and Electric Company and Pacific Bell.



Last updated: 09.17.2014