San Andreas Fault System in Southern California
Geologic Map of the US
Southern CA from the Space Shuttle
Fault Zone Study Area
San Gorgonio Pass
Southern California is home to nearly 24 million people and countless visitors who live, recreate, consume resources, and face the risk of natural hazards in the region. This project produces high-quality, multi-purpose geologic maps, databases, and reports that portray our understanding of the region’s four-dimensional geologic framework. We conduct stratigraphic, structural, geomorphological, geophysical, geochronological, and paleontological studies, and we assist other stakeholders in applying our findings toward establishing geologic context for diverse land-use management issues; for assessing water, mineral, and energy resources; and for understanding natural hazards.
The geologic and landscape evolution of southern California is framed by plate tectonic interactions between the North America and Pacific plates, leading most recently to the growth of the San Andreas Fault system. Our project studies are helping to document the evolving formation and deformation of crustal blocks—accompanied by the growth and subsequent disruption of mountain ranges and flanking basins—that record the magnitude, timing, and interactive roles of faults comprising this plate-margin system.
Science Issue and Relevance:
Plate-margin deformation leads either directly (through seismic events) or indirectly (by creating steep range-front relief) to high-risk of natural hazards in southern California, home to more than 24 million people. USGS and USGS-sponsored studies have made and continue to make essential contributions to our understanding of the overall geologic and tectonic framework for these hazards. Because the region contained crustal faults before the initiation of the San Andreas system, these studies will consider the full timespan of plate margin evolution. This will allow the greatest insight into the distribution of seismic hazards.
Methodology to Address Issue:
FEDMAP Geologic Mapping - FEDMAP Geologic Mapping advances nationwide geologic mapping and associated research as mandated by the National Geologic Mapping Act of 1992 (Public Law 102-285). The FEDMAP program produces world-class digital geologic maps and 3D framework models based on state-of-the art observation and scientific interpretation directed by high priority national issues.
Within the Fedmap framework we will
- Conduct geologic mapping, stratigraphic, geochronologic, and geophysical studies that contribute to our understanding of fault interactions in the San Andreas system in Southern California
- Conduct geomorphic mapping and carry out tectonic landform analyses that help us understand landscape evolution and hazards in southern CA, and
- Conduct paleontologic and paleogeographic studies in Eocene, Miocene, and Pliocene strata along the San Andreas fault
Southern California is home to nearly 24 million people and countless visitors who live, recreate, consume resources, and face the risk of natural hazards in the region. This project produces high-quality, multi-purpose geologic maps, databases, and reports that portray our understanding of the region’s four-dimensional geologic framework. We conduct stratigraphic, structural, geomorphological, geophysical, geochronological, and paleontological studies, and we assist other stakeholders in applying our findings toward establishing geologic context for diverse land-use management issues; for assessing water, mineral, and energy resources; and for understanding natural hazards.
The geologic and landscape evolution of southern California is framed by plate tectonic interactions between the North America and Pacific plates, leading most recently to the growth of the San Andreas Fault system. Our project studies are helping to document the evolving formation and deformation of crustal blocks—accompanied by the growth and subsequent disruption of mountain ranges and flanking basins—that record the magnitude, timing, and interactive roles of faults comprising this plate-margin system.
Science Issue and Relevance:
Plate-margin deformation leads either directly (through seismic events) or indirectly (by creating steep range-front relief) to high-risk of natural hazards in southern California, home to more than 24 million people. USGS and USGS-sponsored studies have made and continue to make essential contributions to our understanding of the overall geologic and tectonic framework for these hazards. Because the region contained crustal faults before the initiation of the San Andreas system, these studies will consider the full timespan of plate margin evolution. This will allow the greatest insight into the distribution of seismic hazards.
Methodology to Address Issue:
FEDMAP Geologic Mapping - FEDMAP Geologic Mapping advances nationwide geologic mapping and associated research as mandated by the National Geologic Mapping Act of 1992 (Public Law 102-285). The FEDMAP program produces world-class digital geologic maps and 3D framework models based on state-of-the art observation and scientific interpretation directed by high priority national issues.
Within the Fedmap framework we will
- Conduct geologic mapping, stratigraphic, geochronologic, and geophysical studies that contribute to our understanding of fault interactions in the San Andreas system in Southern California
- Conduct geomorphic mapping and carry out tectonic landform analyses that help us understand landscape evolution and hazards in southern CA, and
- Conduct paleontologic and paleogeographic studies in Eocene, Miocene, and Pliocene strata along the San Andreas fault