Monterey Bay- Tularcitos fault zone, Tularcitos section (Class A) No. 62c
Last Review Date: 2001-06-08
citation for this record: Bryant, W.A., compiler, 2001, Fault number 62c, Monterey Bay- Tularcitos fault zone, Tularcitos section, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, https://earthquakes.usgs.gov/hazards/qfaults, accessed 12/15/2025 09:00 AM.
| Synopsis |
General:
Monterey Bay-Tularcitos fault zone is a complex, generally northwest-striking zone up to 15 km wide of dextral, dextral-reverse, and thrust faults (Greene and others, 1973 #1323; Dibblee, 1974 #4829; Clark and others, 1974 #6136; Rosenberg, 1993 #6158; Rosenberg and Clark, 1994 #6144). Detailed reconnaissance level mapping is by Greene and others (1973 #1323), Dibblee (1974 #4829), Clark and others (1974 #6136), McCulloch and Greene (1990 #5406), Rosenberg (1993 #6158), Rosenberg and Clark (1994 #6144), and Clark and others (1997 #6137). Rosenberg and Clark (1994 #6144) documented evidence of Holocene displacement along the Hatton Canyon, Sylvan Thrust, and Tularcitos faults. McCulloch and Greene (1990 #5406) mapped Holocene alluvium as offset along offshore traces of the of the Monterey Bay fault zone. Monterey Bay-Tularcitos fault zone lacks detailed studies and evidence of late Pleistocene and Holocene slip rates is poorly constrained. Dextral slip rates are not known. Rosenberg and Clark (1994 #6144) reported vertical slip rates that ranged from 0.02 mm/yr for the Navy fault (late Pleistocene vertical rate), to 0.4 mm/yr for the Sylvan Thrust fault (Holocene vertical rate). Post-Middle Miocene dextral slip rate of 0.3-1.5 mm/yr can be inferred for Tularcitos fault zone based on postulated dextral displacement by Graham (1976 #6155). However, timing of total dextral displacement is poorly constrained. Sections: This fault has 3 sections. |
| Name comments |
General: Section: Section name, proposed in this compilation, encompasses the Tularcitos fault zone. Tularcitos section extends from the vicinity of Snivleys Ridge were the Tularcitos fault branches into several northwest-trending splays southeast to the Jamesburg area where the Tularcitos fault branches into the Paloma fault. Fault ID: Refers to numbers 229 (Monterey Bay fault zone), 232 (Navy fault), and 236 (Tularcitos fault) of Jennings (1994 #2878) and number LO4 (Monterey Bay-Tularcitos fault zone) of Working Group on Northern California Earthquake Potential (1996 #1216). |
| County(s) and State(s) | MONTEREY COUNTY, CALIFORNIA <br> |
| Physiographic province(s) | PACIFIC BORDER <br> |
| Reliability of location |
Good Compiled at 1:100,000 scale. Comments: Locations based on digital revisions to Jennings (1994 #2878) and Rosenberg (2001 #6159) using original mapping by Fiedler (1944 #6140), Bowen (1969 #6133), and Dibblee (1974 #4829) at 1:62,500; mapping by Clark and others (1974 #6136), Bryant (1985 #6135), and Rosenberg and Clark (1994 #6144) at 1:24,000. <P> |
| Geologic setting | Generally northwest-striking zone of discontinuous faults located in the complexly deformed Salinian block bounded by the San Andreas [1] fault zone to the northeast and the San Gregorio [60] fault zone to the southwest. Monterey Bay-Tularcitos fault zone extends for about 84 km from about 6 km southwest of Santa Cruz, near the San Gregorio [60] fault, across Monterey Bay southeast to the Monterey Peninsula to near the crest of the Sierra de Salinas. Cumulative dextral and vertical displacement are not known. Graham (1976 #6155) postulated between 3.2 km and 16 km of dextral strike-slip displacement may have occurred along the Tularcitos fault zone, based on apparent dextral separation of distinctive beds in the Miocene Monterey Formation. Fiedler (1944 #6140) reported 380 m of post-Miocene up-to-north vertical displacement along the Tularcitos fault zone. <P> |
| Length (km) | This section is 32 km of a total fault length of 84 km. |
| Average strike | N56°W (for section) versus N44°W (for whole fault) |
| Sense of movement |
Right lateral
Comments: Fiedler (1944 #6140) reported about 380 m of post-Miocene vertical displacement (up-to-north). Graham (1976 #6155) postulated between 3.2 km and 16 km of dextral strike-slip offset may have occurred along the Tularcitos fault, based on an apparent dextral offset of distinctive beds of the Miocene Monterey Formation. <P> |
| Dip |
70° to 85°
Comments: Dip angles observed in outcrops range from (Bryant, 1985 #6135). <P> |
| Paleoseismology studies | <P> |
| Geomorphic expression | Traces of the Tularcitos fault generally are not well-defined and are delineated by geomorphic features such as vague tonal lineaments, aligned benches and saddles. A significant portion of the northern Tularcitos section is located along the Carmel River valley and drainages that cross traces of the Tularcitos fault are not offset in a dextral or vertical sense (Bryant, 1985 #6135; Rosenberg, 1993 #6158). <P> |
| Age of faulted surficial deposits | Fault offsets Mesozoic (Cretaceous?) crystalline basement rocks, Tertiary sedimentary rocks, late Pleistocene alluvium, and early Holocene colluvial deposits (Dibblee, 1974 #4829; Clark and others, 1974 #6136; Rosenberg and Clark, 1994 #6144). |
| Historic earthquake | |
| Most recent prehistoric deformation |
latest Quaternary (<15 ka)
Comments: Timing of most recent paleoevent is not well-constrained. Rosenberg and Clark (1994 #6144) mapped offset Pleistocene terrace deposits and 7.78 ka (conventional 14C age) colluvium. <P> |
| Recurrence interval | |
| Slip-rate category |
Between 0.2 and 1.0 mm/yr
Comments: Weber (1984 #6160) inferred a post-Miocene vertical slip-rate of 0.08-0.2 mm/yr, based on postulated post-Miocene 1200 m vertical displacement. Rosenberg and Clark (1994 #6144) calculated a late Pleistocene to Holocene vertical slip-rate of 0.13 mm/yr, based on a 1 m vertical displacement of 7.78 ka (conventional 14C age) colluvium. Late Quaternary dextral component of slip is not known. Graham (1976 #6155) postulated between 3.2 km and 16 km of post Middle Miocene dextral offset. This infers a long term dextral slip-rate between 0.3 mm/yr and 1.5 mm/yr for the Tularcitos fault. However, timing of total dextral displacement is poorly constrained. Poorly constrained slip rate assigned to the entire fault by Petersen and others (1996 #4860) for probabilistic seismic hazard assessment for the State of California was 0.5 mm/yr (with minimum and maximum assigned slip rates of 0.1 mm/yr and 0.9 mm/yr, respectively. |
| Date and Compiler(s) |
2001
William A. Bryant, California Geological Survey |
| References | #6151 Beal, C.H., 1915, The geology of the Monterey quadrangle, California: Stanford, California, Stanford University, unpublished M.S. thesis, 88 p., scale 1;62,500.<br><br>#6133 Bowen, O.E., Jr., 1969, Geologic map of the Monterey quadrangle: California Division of Mines and Geology open-file map, scale 1:62,500.<br><br>#6135 Bryant, W.A., 1985, Faults in the southern Monterey Bay area, Monterey County, California: California Division of Mines and Geology Fault Evaluation Report 167 (microfiche copy in California Division of Mines and Geology Open-File Report 90-11).<br><br>#6136 Clark, J.C., Dibblee, T.W., Jr., Greene, H.G., and Bowen, O.E., Jr., 1974, Preliminary geologic map of the Monterey and Seaside 7.5-minute quadrangles, Monterey County, California, with emphasis on active faults: U.S. Geological Survey Miscellaneous Field Studies Map MF-577, scale 1:24,000.<br><br>#6137 Clark, J.C., Dupre, W.R., and Rosenberg, L.I., 1997, Geologic map of the Monterey and Seaside 7.5-minute quadrangles, Monterey County, California—A digital database: U.S. Geological Survey Open-File Report 97-30, map scale, scale 1:24,000.<br><br>#4829 Dibblee, T.W., Jr., 1974, Geologic maps of the Monterey, Salinas, Gonzales, Point Sur, Jamesburg, Soledad, and Junipero Serra 15-minute quadrangles, Monterey County, California: U.S. Geological Survey Open-File Report 74-5021, 7 sheets, scale 1:62,500.<br><br>#6140 Fiedler, W.M., 1944, Geology of the Jamesburg quadrangle, Monterey County, California: California Journal of Mines and Geology, Report XL of the State Mineralogist, v. 40, no. 2, p. 177-250, scale 1:62,500.<br><br>#6154 Galliher, E.W., 1930, A study of the Monterey Formation, California, at the type locality: Stanford, California, Stanford University, unpublished M.S. thesis, 29 p., scale 1:62,500.<br><br>#6155 Graham, S.A., 1976, Tertiary sedimentary tectonics of the central Salinian block of California: Stanford, California, Stanford University, unpublished Ph.D. dissertation, 510 p., 1 pl.<br><br>#6156 Greene, H.G., 1970, Geology of southern Monterey Bay and its relationship to the ground water basin and salt water intrusion: U.S. Geological Survey Open-File Report, 50 p.<br><br>#1323 Greene, H.G., Lee, W.H.K., McCulloch, D.S., and Brabb, E.E., 1973, Faults and earthquakes in the Monterey Bay region, California: U.S. Geological Survey Miscellaneous Field Studies Map MF-518 (U.S. Department of the Interior and U.S. Department of Housing and Urban Development Basic Data Contribution 58), 14 p. pamphlet, 4 sheets.<br><br>#2878 Jennings, C.W., 1994, Fault activity map of California and adjacent areas, with locations of recent volcanic eruptions: California Division of Mines and Geology Geologic Data Map 6, 92 p., 2 pls., scale 1:750,000.<br><br>#5406 McCulloch, D.S., and Greene, H.G., 1990, Geologic map of the central California continental margin, Map No. 5A (Geology), <i>in</i> Green, H.G., and Kennedy, M.P., eds., Geology of the central California continental margin: California Division of Mines and Geology California Continental Margin Geologic Map Series, Area 5 of 7, scale 1:250,000.<br><br>#4860 Petersen, M.D., Bryant, W.A., Cramer, C.H., Cao, T., Reichle, M.S., Frankel, A.D., Lienkaemper, J.J., McCrory, P.A., and Schwartz, D.P., 1996, Probabilistic seismic hazard assessment for the State of California: California Department of Conservation, Division of Mines and Geology Open-File Report 96-08 (also U.S. Geological Open-File Report 96-706), 33 p.<br><br>#6158 Rosenberg, L.I., 1993, Earthquake and landslide hazards in the Carmel Valley area, Monterey County, California: San Jose, California, San Jose State University, unpublished M.S. thesis, 123 p., scale 1:24,000.<br><br>#6159 Rosenberg, L.I., 2001, Geologic resources and constraints, Monterey County California—A technical report for the Monterey County 21st Century general plan update program: Monterey County Environmental Resource Policy Department Open-File Report, 167 p., 10 sheets, 1 CD-ROM with ArcView shape files.<br><br>#6144 Rosenberg, L.I., and Clark, J.C., 1994, Quaternary faulting of the greater Monterey area, California: Technical report to U.S. Geological Survey, under Contract 1434-94-G-2443, 27 p., scale 1:24,000.<br><br>#6160 Weber, G.E., 1984, New San Clemente Dam, Geotechnical investigation of faulting in the "Knothole" area: Santa Cruz, California, Rogers E. Johnson and Associates, consulting report for Monterey Peninsula Water Management district, 17 p., 1 pl.<br><br>#1216 Working Group on Northern California Earthquake Potential (WGNCEP), 1996, Database of potential sources for earthquakes larger than magnitude 6 in northern California: U.S. Geological Survey Open-File Report 96-705, 40 p. |