October 2018 Chapter Meeting

Fault Rupture Hazard Investigations for the Los Angeles Aqueduct System: Owens Valley to the San Andreas

Speaker: Scott Lindvall, CEG | Senior Principal Geologist | Lettis Consultants International, Inc.

When: October 23, 2018 | 12:00 – 1:00 PM

Where: Aviator’s Restaurant | 6151 Freeport Blvd, Sacramento, CA 95822

RSVP at http://www.aegsacto.org/meetings/signup/

The Los Angeles Aqueduct System delivers water from the Owens Valley to over 4 million residents within the City and is owned and operated by the Los Angeles Department of Water and Power, the largest municipal utility in the U.S. The first aqueduct was completed in 1913 and extends southward through the seismically active Owens Valley, across the Garlock and San Andreas faults, and into the faulted and folded Transverse Ranges.
The alignment crosses both the strike-slip 1857 ~M7.8 San Andreas and 1872 ~M7.5 Owens Valley historic earthquake ruptures. The southern terminus of the aqueduct at the Van Norman Complex in the northern San Fernando Valley was impacted by both the 1972 M6.6 San Fernando and 1994 M6.7 Northridge reverse earthquakes. This presentation will provide a brief history and overview of the Los Angeles Aqueduct, discuss historic earthquake ruptures and geology along the aqueduct alignment, and detail four recent seismic hazard investigations of key elements of the aqueduct system to address the hazard of surface fault rupture. From north to south, these facilities include Tinemaha Dam, North Haiwee Dam, South Haiwee Dam, and Elizabeth Tunnel. Tinemaha Dam is located along the 1872 rupture of the Owens Valley fault. North and South Haiwee Dams are located near the southern end of 1872 rupture, in an area of broad distributed faulting. The 5-mile-long Elizabeth Tunnel crosses the San Andreas fault zone near Lake Hughes.