The Earthquake Science Center is storing ~150 feet of core from the San Andreas Fault Zone (SAF), that had been collected by the Los Angeles Department of Water and Power (LADWP) at the Elizabeth Lake underground crossing of the aqueduct. LADWP is planning a seismic-safety upgrade of the tunnel crossing, and the drilling program was conducted to try to locate the active trace(s) of the SAF as closely as possible in the roughly 200-meter wide damage zone. We focused on collecting what had been tentatively identified as active, subsidiary fault traces in the damage zone of the SAF; the country rocks on either side of the fault are granodiorite and granite gneiss. We are storing 75 ~2-foot-long pieces of core, and basically serving as caretakers. There has been scientific interest in the core, and some subsampling has taken place, as noted in the spreadsheet below. The core pieces that we didn’t take are housed in a metal container in the Mojave Desert, where they will dry out and the more highly damaged materials will disintegrate.
The cores that we are housing come from 5 shallow (less than 500 feet), angled drillholes at the location: 34°40’16”N, 118°25’56”W. The holes are closely spaced in a NS traverse across the damage zone; the fault strikes essentially east-west in this area. The coring operations lasted from October, 2016 to February, 2017.
