East Bay Hills

This article is about the East Bay Hills in California. For the East Bay Hills in Nova Scotia, see East Bay Hills (Nova Scotia).
East Bay Hills
East Bay Hills is located in California
East Bay Hills
East Bay Hills
Highest point
PeakSunol Peak[2]
Elevation2,182 ft (665 m)
Dimensions
Length36.8 mi (59.2 km) northwest-southeast from Carquinez Strait to Alameda Creek/Highway 84
Width7 mi (11 km) west-east
Geography
CountryUnited States
StateCalifornia
RegionCentral California
Range coordinates37°48′06″N 122°09′12″W / 37.80167°N 122.15333°W / 37.80167; -122.15333[1]

The East Bay Hills is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges in northern California, United States. They are the first range of mountains east of San Francisco Bay and stretch from the Carquinez Strait in the north to Alameda Creek/Highway 84 in the south, crossing both Contra Costa and Alameda Counties. Although not formally recognized by United States Geological Survey (USGS) Geographic Names Information System, the East Bay Hills is included as part of the Diablo Range[3] in its list of multiple GPS coordinates for the latter.

Geography and geology

The East Bay Hills runs northwest to southeast for approximately 36.8 miles (59.2 km) with its midpoint at 37° 48' 06" N, 122° 09' 12" W.[1] The tallest peak in the range is Sunol Peak whose summit elevation is 2,182 feet (665 m).[2]

The East Bay Hills consists of multiple named components, from north to south: Franklin Ridge,[4] then the Briones Hills,[5] the Berkeley Hills,[6] the San Leandro Hills[7] centrally, and Walpert Ridge[8] and Pleasanton Ridge[9] to the southwest and southeast, respectively, culminating near Alameda Creek/Highway 84.

Geologically, the East Bay Hills are bounded by the Calaveras Fault to the east and the Hayward Fault to the west.[10][11] The Hayward Fault merges into the Calaveras Fault in east San Jose in Santa Clara County, about 15 kilometres (9.3 mi) south of Fremont and the southern boundary of the East Bay Hills.[12]

The East Bay Hills are a major center of earthquakes and landslides due to the nearby major and minor fault zones.[13] Both the East Bay Hills and Mt. Diablo continue to rise 1.5 millimetres (0.059 in) a year, which extrapolates to 1.5 metres (4.9 ft) over 1,000 years assuming constant rate and negligible erosion.[14]

Ecology

Extensive public lands are conserved in the East Bay Hills by the East Bay Municipal Utilities District (EBMUD) and the East Bay Regional Park District.[15] The East Bay Hills have groves of coast redwoods (Sequoia sempervirens), making Alameda and Contra Costa Counties two of only four inland California counties to host these trees.[16] The largest coast redwood tree was reported in 1893 by William P. Gibbons (1812-1897), the American naturalist, physician and founding member of the California Academy of Sciences, who measured the hollow shell of a coast redwood in the Oakland Hills with diameter of 9.9 metres (32 ft) at chest height.[17]

Wildfire danger in East Bay Hills

The East Bay Hills has lost more homes to wildfires than almost all of the high risk Southern California counties combined as of 2000. The Oakland firestorm of 1991 ranked as the state's largest home loss from wildfire. Major increases in fire fuel load from flammable vegetation over the last century continue to increase the wildfire risk as grazed grasslands have yielded to brush and unmaintained pine or eucalyptus.[18] The East Bay Regional Park District is implementing vegetation treatments to reduce fire fuel loads on up to 2,280 acres (9.2 km2) in Contra Costa and Alameda Counties in the East Bay Hills.[19]

References

  1. ^ a b U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map Archived 2012-03-29 at the Wayback Machine, accessed July 6, 2024
  2. ^ a b "Sunol Peak". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
  3. ^ "Diablo Range". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
  4. ^ "Franklin Ridge". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
  5. ^ "Briones Hills". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
  6. ^ "Berkeley Hills". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
  7. ^ "San Leandro Hills". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
  8. ^ "Walpert Ridge". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
  9. ^ "Pleasanton Ridge". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
  10. ^ R. C. Crane (1995). "Geology of Mount Diablo Region and East Bay Hills". In E. M. Sangines; D. W. Andersen; A. B. Buising (eds.). Recent Geologic Studies in the San Francisco Bay Area. Vol. 76. Pacific Section, Society for Sedimentary Geology (S.E.P.M.). pp. 87–114. Retrieved July 3, 2024.
  11. ^ J. Ross Wagner; Alan Deino; Stephen W. Edwards; Andrei M. Sarna-Wojcicki; Elmira Wan (September 27, 2021). "Miocene stratigraphy and structure of the East Bay Hills, California". In Raymond Sullivan; Doris Sloan; Jeffrey R. Unruh; David P. Schwartz (eds.). Regional Geology of Mount Diablo, California: Its Tectonic Evolution on the North America Plate Boundary. Vol. 217. Geological Society of America. pp. 331–391. doi:10.1130/2021.1217(15). ISBN 978-0-8137-1217-8. Retrieved July 7, 2024.
  12. ^ E. Chaussard, R. Bürgmann, H. Fattahi, R. M. Nadeau, T. Taira, C. W. Johnson, I. Johanson (April 2, 2015). "Potential for larger earthquakes in the East San Francisco Bay Area due to the direct connection between the Hayward and Calaveras Faults". Geophysical Research Letters. 42 (8): 2734–2741. Bibcode:2015GeoRL..42.2734C. doi:10.1002/2015GL063575. Retrieved August 31, 2024.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ^ David Rogers and Christopher S. Alger (1989). William M. Brown, III (ed.). Geology, Geomorphology, and Landslide Processes of the East Bay Hills, San Francisco Bay Region, California in Landslides in Central California: San Francisco and Central California, July 20–29, 1989. Washington, D.C.: American Geophysical Union. p. 98. ISBN 978-0875906409.
  14. ^ David K. Smith (2021). "The geologic and tectonic history of the East Bay Hills, in The geology and paleontology of the Caldecott Tunnel's Fourth Bore". PaleoBios. 38. University of California Museum of Paleontology and California Department of Transportation. Retrieved August 30, 2024.
  15. ^ Lester B. Rowntree (1994). "Afforestation, Fire, and Vegetation Management in the East Bay Hills of the San Francisco Bay Area". Yearbook of the Association of Pacific Coast Geographers. 56. University of Hawai'i Press: 7–30. doi:10.1353/pcg.1994.0013. Retrieved July 7, 2024.
  16. ^ Sherwood D. Burgess (1951). "The Forgotten Redwoods of the East Bay". California History. 30 (1): 1–14. doi:10.2307/25156275. JSTOR 25156275. Retrieved July 7, 2024.
  17. ^ William P. Gibbons (August 1, 1893). "The Redwood in the Oakland Hills" (PDF). Erythea. 1 (8). Berkeley, California: 161–166. Retrieved August 24, 2024.
  18. ^ Hillside Fire Working Group (2001). Background Report: The East Bay Hills Wildfire Problem Statement (Report). East Bay Regional Park District. Retrieved August 30, 2024.
  19. ^ Ascent Environmental, Inc. (June 1, 2023). East Bay Hills Vegetation Treatment Project, CalVTP Project I.D. Number 2022-24 (PDF) (Report). Oakland, California: East Bay Regional Park District. Retrieved August 30, 2024.