Structural Measurement Atlas
Atlas / States / California

California strike and dip data

98,381 structural measurements in California, digitized from 3,181 published geologic maps across 5 sources. Every row carries its azimuth, inclination, measurement type, location confidence and the citation of the map it came from.

Open California on the map

What kinds of measurement

The Atlas separates planar structures, recorded as a strike and dip, from linear ones, recorded as a trend and plunge. This is what California holds:

Measurement typeGeometryMeasurementsShare
Bedding Planar — strike and dip 47,65348%
Foliation Planar — strike and dip 31,93132%
Other Planar — strike and dip 6,8637%
Vein / dike Planar — strike and dip 3,6854%
Lineation (mineral, stretching) Linear — trend and plunge 2,4422%
Fault plane Planar — strike and dip 2,1522%
Cleavage Planar — strike and dip 1,9542%
Joint Planar — strike and dip 9981%
Slickenline Linear — trend and plunge 541<1%
Fold hinge / axis Linear — trend and plunge 162<1%

Where the data comes from

Each source is a survey, agency or program whose published mapping was harvested and reconciled into one schema. Rows are published only where the source's terms permit redistribution.

SourceMeasurementsShare
NGMDB legacy quads 60,94962%
NPS GRI parks 29,97230%
USGS data releases · MRDS 3,9734%
USGS NGMDB GeMS 3,4824%
Oregon DOGAMI (OGDC-8) 5<1%

Most-measured published maps

The individual quadrangles and data releases contributing the most measurements in California. The full citation for every map behind a selection ships in the sources.csv of any export.

Published mapYearScaleMeasurements
adapted from: Kinkel, A.R., Hall, W.E., and Albers, J.P., 1956, Geology and Base-Metal Deposits of West Shasta Copper-Zinc District, Shasta County, California: U.S. Geological Survey, Professional Paper 285, plate 1, scale 1:24,0002025 240004,045
Regional geologic map of San Andreas and related faults in Carrizo Plain, Temblor, Caliente and La Panza Ranges and vicinity, California: a digital database1999 1:125,0003,368
Geologic maps and structure sections of the southwestern Santa Clara Valley and southern Santa Cruz Mountains, Santa Clara and Santa Cruz Counties, California2001 1:24,0002,665
Geologic map and map database of the Oakland metropolitan area, Alameda, Contra Costa, and San Francisco Counties, California2000 1:50,0002,372
Geology of the Joshua Tree National Park geodatabase [San Bernardino and Riverside Counties, California]2015 1:12,0002,225
adapted from: Krauskopf, K.B., 1985, Geologic Map of the Mariposa Quadrangle, Mariposa and Madera Counties, California: U.S. Geological Survey, Geologic Quadrangle Map GQ-1586, scale 1:62,5002021 625002,185
Preliminary geologic map emphasizing bedrock formation in Contra Costa County, California1994 1:75,0002,020
Geologic map of the Weaverville 15' quadrangle, Trinity County, California2009 1:50,0001,923
adapted from: Moore, J.G., and Sisson, T.W., 1987, Geologic Map of the Triple Divide Peak Quadrangle, Tulare County, California: U.S. Geological Survey, Geologic Quadrangle Map GQ-1636, scale 1:62,5002022 625001,916
Preliminary digital geologic map of the Santa Ana 30' X 60' quadrangle, southern California1999 1:100,0001,900
Reconnaissance geologic map of the Hayfork 15' quadrangle, Trinity County, California2010 1:50,0001,719
Geologic map and map database of eastern Sonoma and western Napa Counties, California2007 1:100,0001,587
Preliminary digital geologic map of the Oat Mountain 7.5' quadrangle, southern California: a digital database1995 1:24,0001,586
Preliminary geologic map emphasizing bedrock formations in Alameda County, California: a digital database1997 1:75,0001,495
adapted from: Peck, D.L., 1980, Geologic Map of the Merced Peak Quadrangle, Central Sierra Nevada, California: U.S. Geological Survey, Geologic Quadrangle Map GQ-1531, scale 1:62,5002021 625001,474

Most-measured map units

Where a source recorded the geologic unit a measurement was taken on, the Atlas keeps it. These are the units carrying the most measurements in California.

Map unitAgeLithologyMeasurements
Lower part of the Great Valley sequence KJgvl Late Jurassic to Early CretaceousMarine sediment, mostly fine-grained407
Lithic graywacke fs2 Upper Jurassic and CretaceousMetasedimentary rock358
Phyllite-greenschist belt, Phyllite, with quartzite and metachert TrCp Triassic to CarboniferousMetasedimentary rock211
Altered basaltic rocks (greenstone) fg Upper Jurassic and CretaceousMeta-mafic rock141
Tev 135
Chert and minor interbedded siliceous shale and tuff fc Upper Jurassic and CretaceousChert129
Devil?s Gate amphibolite, Amphibolite and hornblende gneiss Pam PermianMetaigneous rock126
Lang-Halsted Sequence, Undivided DOsfl Devonian? to Ordovician?Metasedimentary rock112
Graywacke of Little Sulphur Creek (structural unit 1) fs1 Upper Jurassic and CretaceousMetasedimentary rock103
Phyllite-greenschist belt, Metachert with minor phyllite TrCc Triassic to CarboniferousMetasedimentary rock98
Clipper Gap Formation, Phyllite and metachert JTrc Early Jurassic and TriassicMetasedimentary rock88
Locally conglomeratic metagraywacke fms Upper Jurassic and CretaceousMedium and high-grade regional metamorphic rock, of unspecified origin86

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