Geology of the Lawrence Livermore National Laboratory site and adjacent areas
LLNL is underlain by a thick sequence of late Tertiary and Quaternary alluvial deposits overlying a complex basement of Mesozoic metamorphic rocks of the Franciscan Assemblage and late Mesozoic and Tertiary marine sedimentary rocks. The ancestral Greenville Fault separates the Franciscan basement terrain from the late Mesozoic and Tertiary basement. The late Tertiary and Quaternary alluvial deposits include lacustrine, alluvial fan, and stream channel deposits. Soil profiles and relative and absolute age data demonstrate that most of the near-surface materials beneath LLNL range in age from latest Pleistocene to 100,000 y or greater. A low net sedimentation rate is indicated by the data. Depths to groundwater beneath LLNL vary from about 13 m beneath the northeast corner of the laboratory to about 49 m beneath the southeast corner. Depths to water beneath portions of the laboratory where major buildings are located range from 18 to 30 m. LLNL is located in a seismically active region. Deformation of Quaternary materials and periodic seismicity support this conclusion. Historic seismicity has been experienced along the Calaveras and Greenville Faults that bound the Livermore Valley on the west and east, respectively, and also appears associated with the Las Positas Fault Zone. The Calaveras Fault is located approximately 17 km west of LLNL, and recently active strands of the Greenville Fault Zone are located approximately 1.1 km northeast of the laboratory. Geologic evidence demonstrates Holocene activity along strands of the Las Positas Fault Zone that lie about 90 m southeast of LLNL at their point of closest approach. Pavement fracturing at the intersection of Greenville Road and East Avenue suggests that a strand of the Las Positas Fault may be located about 15 m southeast of the southeast corner of the laboratory. Other potential sources of seismicity could affect LLNL. 126 references, 71 figures, 18 tables.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6050765
- Report Number(s):
- UCRL-53316; ON: DE85006872
- Resource Relation:
- Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
LAWRENCE LIVERMORE LABORATORY
GEOLOGY
SEISMICITY
GEOLOGIC FAULTS
GROUND MOTION
STRATIGRAPHY
TOPOGRAPHY
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
MOTION
NATIONAL ORGANIZATIONS
US AEC
US DOE
US ERDA
US ORGANIZATIONS
580100* - Geology & Hydrology- (-1989)
580201 - Geophysics- Seismology & Tectonics- (1980-1989)
510500 - Environment
Terrestrial- Site Resource & Use Studies- (-1989)