Riding Out Future Quakes Results

	Road Closure Estimates and Maps

	Riding Out Future Quakes - 2003 UPDATE

What Are We Predicting Will Happen to Our Transportation System in Future Earthquakes?

ABAG has revised the estimates of road closures in future earthquakes to be consistent with the scenario probability information released by the U.S. Geological Survey in April 2003. The principal differences between this 2003 update and the 2002 version relate to likely earthquakes on three fault segments - the San Andreas Peninsula, the San Andreas Northern Golden Gate, and the Greenville fault segments.

Scroll down this page to view a summary table of estimated road closures for 18 different scenarios, as well as information on the basic assumptions that went into developing these estimates.

Click on a fault scenario below to view a map, table showing road closure causes, and additional planning information for individual scenarios. You should find that the most interesting scenarios are the ones involving multiple fault segments on the San Andreas and Hayward faults, as well as the faults near you.

Select a fault by clicking on the map or on one of the links below. Scenarios in BLACK involve multiple fault segments.

	San Andreas-North Golden Gate
	San Andreas - Peninsula
	San Andreas - Santa Cruz
	Entire San Andreas (1906 Quake)
	Rodgers Creek
	Rodgers Ck + North Hayward
	Northern Hayward
	Southern Hayward
	North + South Hayward
	Northern Calaveras
	Central Calaveras
	Maacama
	West Napa
	Concord/Green Valley
	Greenville
	Mount Diablo (thrust fault)
	San Gregorio
	Monte Vista (thrust fault)

SUMMARY TABLE: Predicted Road Closures for Bay Area Counties and Selected Earthquake Scenarios

COUNTY	Alameda	Contra Costa	Marin	Napa	San Francisco	San Mateo	Santa Clara	Solano	Sonoma	Total
San Andreas - Santa Cruz Mts.	24	10	3	0	44	9	64	0	1	154
San Andreas - Peninsula-Golden Gate	50	9	22	0	335	300	146	1	4	866
San Andreas - Northern Golden Gate	62	20	70	1	321	24	10	4	69	581
San Andreas - Entire Bay Area	146	30	77	3	429	315	250	6	75	1,332
No. San Gregorio	43	11	20	0	164	144	13	1	6	401
Southern Hayward	901	43	15	1	72	8	90	4	4	1,138
Northern Hayward	335	238	20	1	48	5	7	5	8	667
N + S Hayward	1,081	268	28	2	214	16	99	10	16	1,734
Rodgers Creek	54	34	20	4	48	3	3	12	223	402
Rodgers Creek - Northern Hayward	363	256	34	9	157	11	10	14	230	1,084
Rodgers Creek - Entire Hayward	1,111	294	41	10	317	25	105	17	233	2,153
Southern Maacama	8	3	1	3	6	0	1	1	53	74
West Napa	22	20	1	89	6	1	1	14	5	159
Concord-Green Valley	56	201	1	19	11	3	7	83	4	386
Northern Calaveras	180	107	1	1	11	3	53	6	1	363
Central Calaveras	51	10	1	0	11	4	132	1	1	210
Mt. Diablo Thrust	94	78	7	0	41	2	4	2	1	228
Greenville	70	47	1	1	6	1	4	6	1	138
Monte Vista Thrust	10	1	0	0	8	23	283	0	1	326

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 process does not include:

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

The values are aggregated from modeling performed on individual census tracts. As with most types of statistics-based modeling, total values are more accurate than values for specific counties or hazards.

ABAG, the Association of Bay Area Governments, is the regional planning and services agency for the nine-county San Francisco Bay Area. This road closure information was last updated by ABAG in April, 2003.

jbp 9/15/03