Salton Sea Region Faults

Earthquake Fault Maps



Faults in Imperial County:

Salton Sea Faults Map

Salton Sea Faults Map


Imperial Valley Fault Map

Imperial Valley Faults Map


The Salton Sea and surrounding basin sits over the San Andreas Fault, Brawley seismic zone, Indio Hills fault zone, Imperial Fault Zone, and nearby and very large San Jacinto fault zone. Area geologists have estimated that previous flooding episodes from the Colorado River have been linked to increases in earthquakes along the area’s San Andreas Fault. Ground instruments were used to survey the Salton Sea's underwater faults during this study. During the geologic historic period when the basin was filled by the large Lake Cahuilla, (a larger inland sea), more earthquakes higher than magnitude 7 occurred about every 180 years, the last one occurring around the decades in the 1700s.

Computer stress models conclude that the normal faults in the area are vulnerable to special deviatoric stress loading by filling in of water. Currently, a risk still exists for an earthquake of magnitude 7 or 8 due to man lowering the huge natural aquifer tables in the region. Simulations also showed, in the Los Angeles area, shaking and thus damage would be more severe for a San Andreas earthquake that propagated along the fault from the south, rather than from the north due to fault directions, depth, and it being much closer than the 1857 mega quake. Such a large earthquake also raises the risk for soil liquefaction in the Imperial Valley filled in regions and sandy soils.

Salton Sea Earthquake Fault Map Resources

USGS 2014 Significant Earthquakes Archive
Find out if your home is in a seismic liquefaction or landslide area


Fault Attributes Key


NAME is an 80-character field for the name of the fault (including section name,
i.e., Denali fault, Holitna section). Fault and section are lower case.

CODE is a three-integer field.that defines certainty or reliability of field mapping
(integer one), time of most recent movement (integer two), and amount or rate of slip (integer three).
CODE is composite of the single integer fields ACODE, SLIPCODE, and FCODE
and determines the line type (fault trace) to be plotted.

NUM is a six-character unique USGS identifier that defines a fault or section id. Simple fault
ids are only numeric; section ids are alpha numeric.

AGE is the upper bounding time of the most recent surface-deforming earthquake. The allowable
choices are provided in a pull-down menu.

ACODE is the second integer in CODE and defines the upper bounding time of the most recent
surface-deforming earthquake.
Permissible values are between 1 and 6: 1=historic «150 years; red =cmyk 1096680);
2= post glacial (15,000 years; orange = cmyk 1 38 1000);
3 = late Quaternary «130,000 years; green> cmyk 1002500);
4 =middle and late Quaternary «750,000 years: blue > cmyk 1004440);
5 =Quaternary «1,600,000 years; black 5);
6 = Class B (black halftone)
In the text documentation, Quaternary faults (integer two, 1-5) are Class A structures. Questionable or
suspected structures are Class B (integer two, 6).

SLIPRATE is the assigned slip rate category.

SLIPCODE is the third integer in CODE and defines the assigned slip rate category. Permissible
values are between 1 and 4 and determines line width:
1=>5 mm/year (extra wide; .048):
2 =1-5 mm/year (wide; .0325):
3 =0.2-1 mm/year (medium; .025);
4 =<.2 mm/year (thin; .015)

SLIPSENSE is normal, reverse, strike slip, thrust

DIPDIRECTION is one of the eight quadrant dip directions for the entire fault or section, not the
individual arc. C = center E =east N_ =north NE =northeast NW =northwest S =south SE =southeast SW =
southwest W_ =west
SLIPDIRECT (we are not using that field anymore and can be left empty) FCODE is the first integer
in CODE and defines how well the fault is located and expressed in the landscape. Permissible values are

between 1 and 3:
1 = fault landforms are more continuous than discontinuous and mapping is accurate at
given MAPPEDSCALE (solid);
2 = fault landforms are more discontinuous than continuous and mapping is accurate at
given MAPPEDSCALE (dashed);
3 = location of fault is inferred (dotted)
FTYPE is one of three allowable choices provided in a pull-down menu: Well constrained (FCODE 1),
Moderately constrained (FCODE 2), and Inferred (FCODE 3)

MAPPEDSCALE is one of four allowable choices provided in a pull-down menu.
Mapped scale will control visualization of the fault at various scales.
1:24,000, fault should be more continuous than discontinuous and mapping is accurate at <10,000 scale.
1:50,000, fault should be more continuous than discontinuous and mapping is accurate at <25,000 scale.
1:100,000, fault could be more discontinuous than continuous and mapping is accurate at <50,000 scale.
1:250,000, fault location may be inferred or is poorly constrained.


Click on the fault lines for more information.
Note* The earthquake faults are color coded by unique name and section not type.

Data source: USGS
CCCarto is not responsible for data errors or omissions, use as reference only.
copyright cccarto.com



Other Earthquake Fault Maps:

Region Faults
Los Angeles Harbor Tsunami Threat

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