Service Description: This report presents a map and database of Quaternary deposits and liquefaction susceptibility for the urban core of the San Francisco Bay region. It supercedes the equivalent area of U.S. Geological Survey Open-File Report 00-444 (Knudsen and others, 2000), which covers the larger 9-county San Francisco Bay region. The report consists of (1) a spatial database, (2) two small-scale colored maps (Quaternary deposits and liquefaction susceptibility), (3) a text describing the Quaternary map and liquefaction interpretation (part 3), and (4) a text introducing the report and describing the database (part 1). All parts of the report are digital; part 1 describes the database and digital files and how to obtain them by downloading across the internet. The nine counties surrounding San Francisco Bay straddle the San Andreas fault system, which exposes the region to serious earthquake hazard (Working Group on California Earthquake Probabilities, 1999). Much of the land adjacent to the Bay and the major rivers and streams is underlain by unconsolidated deposits that are particularly vulnerable to earthquake shaking and liquefaction of water-saturated granular sediment. This new map provides a consistent detailed treatment of the central part of the 9-county region in which much of the mapping of Open-File Report 00-444 was either at smaller (less detailed) scale or represented only preliminary revision of earlier work. Like Open-File Report 00-444, the current mapping uses geomorphic expression, pedogenic soils, inferred depositional environments, and geologic age to define and distinguish the map units. Further scrutiny of the factors controlling liquefaction susceptibility has led to some changes relative to Open-File Report 00-444: particularly the reclassification of San Francisco Bay mud (Qhbm) to have only MODERATE susceptibility and the rating of artificial fills according to the Quaternary map units inferred to underlie them (other than dams ? adf). The two colored maps provide a regional summary of the new...

Service ItemId: 950d3bfa37154eecae0d0666f3765c9c

Has Versioned Data: false

Max Record Count: 2000

Supported query Formats: JSON

Supports applyEdits with GlobalIds: False

Supports Shared Templates: True

All Layers and Tables

Layers:

• quaternary_deposits_2006_1037 (14)

Description:

Copyright Text:

Spatial Reference: 102643 (2227)

Initial Extent:

XMin: 6073396.91057568
YMin: 1965883.90453121
XMax: 6084005.1197093
YMax: 1974677.55157618
Spatial Reference: 102643 (2227)

Full Extent:

XMin: 6061653.23538639
YMin: 1869941.92972507
XMax: 6233713.30301097
YMax: 2006867.52103081
Spatial Reference: 102643 (2227)

Units: esriFeet

Child Resources:   Info   SharedTemplates

Supported Operations:   Query   ConvertFormat   Get Estimates