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The ~M6.8 1868 Hayward earthquake - 140 years later Tom Brocher and colleages U.S. Geological Survey Menlo Park, CA USGS Fact Sheet 2008-3019 Boatwright.

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Presentation on theme: "The ~M6.8 1868 Hayward earthquake - 140 years later Tom Brocher and colleages U.S. Geological Survey Menlo Park, CA USGS Fact Sheet 2008-3019 Boatwright."— Presentation transcript:

1 The ~M6.8 1868 Hayward earthquake - 140 years later Tom Brocher and colleages U.S. Geological Survey Menlo Park, CA USGS Fact Sheet 2008-3019 Boatwright & Bundock, USGS OFR 2008-1121

2 Lawson Report, 1908

3 1868 “the great San Francisco earthquake” The East Bay north of Oakland was very sparsely settled, and few reports of the earthquake are available. This region still consisted of large rancheros and cowboys. Boatwright & Bundock, USGS OFR 2008-1121

4 1868 “the great San Francisco earthquake” Found new reports to supplement Toppozada’s work Shaking intensities were strong from San Leandro south through Hayward towards Fremont They were weaker in Oakland and Mission San Jose Boatwright & Bundock, USGS OFR 2008-1121

5 Yu and Segall, JGR, 1996, used historical triangulation survey data to estimate1.9 m of co- seismic slip during the 1868 quake. Creep on the Hayward Fault, afterslip, and slip from other contemporary earthquakes make this a challenging problem.

6 ~M6.8 Oct. 21, 1868 Hayward earthquake 30 fatalities, 5 in San Francisco (7th most lethal California earthquake) $350,000 (in 1868 dollars) in damage in San Francisco alone Extensive damage in San Leandro, Hayward, and Fremont (total population less than 2000) Bay Area population was 260,000 (at 7 million, it is now 27 times larger) USGS Fact Sheet 2008-3019

7 Impacts of the 1868 Hayward earthquake

8 2 nd Alameda Co. Courthouse, San Leandro Society of California Pioneers Courthouse “At San Leandro the shock was more sensibly felt than at any other point on that side of the Bay. All the buildings were terribly shaken, adobes were thrown to the ground, brick structures, and even frame buildings were demolished. The Court House and County Jail were shaken down.” San Francisco Morning Call, 22 Oct. 1868

9 Haywards Hotel, Haywards, 1860s Society of California Pioneers Hotel Hayward was heavily damaged by the 1868 earthquake. “Practically not a house was left on its foundations…” “Many buildings were much damaged.” (Lawson Report, 1908).

10 Mission San Jose Library of Congress Bancroft Library Before After “The old Mission church, which was of adobe, was shaken down, as were several other buildings at the same place.” Lawson Report, 1908 Fremont

11 UC Berkeley, South Hall, built 1873 Stephen Tobriner, Bracing For Disaster, 2006. The 1868 quake impacted building design in the Bay Area through 1906

12 Residents noted the localization of damage to areas of made ground (landfill)

13 Bancroft Library Reinstein Clothing Factory, 314 California St. Settlement

14 Alameda Oakland Berkeley San Leandro 1868 “the great San Francisco earthquake” Despite the admonition to not build on landfill, the East Bay has added a substantial amount of landfill since 1868 and 1906. Boatwright & Bundock, USGS OFR 2008-1121

15 Alameda Oakland Berkeley San Leandro 1868 “the great San Francisco earthquake” Much of Alameda, the Oakland Airport, the Port of Oakland, and Emeryville are built on landfill. The liquefaction potential of this area was recently studied by Holzer et al. Emeryville Boatwright & Bundock, USGS OFR 2008-1121

16 X Phil Stoffer, A Green Guide to the Hayward Fault, 3dparks.wr.usgs.gov/ haywardfault

17 An Ominous Comparison

18

19 1868 Hayward Earthquake Commemoration Help commemorate the 140 th anniversary of the 1868 Hayward quake at 7:55 AM Tues. Oct. 21st in a brief public ceremony at the front steps of Mission San Jose, 43300 Mission Blvd., Fremont. Mission San Jose 1868alliance.org

20 Abstracts are due by August 15th see www.consrv.ca.gov/ cgs/news/eastbaycon ference.htm

21 1868alliance.org


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