XVA1
Varian Creepmeter

Site defunct as of 11/1/17; wire broken/conduit caved due to fault offset;
remediated Feb. 2018

Site can have large seasonal affects...influence by winter rainfall...beware!!


The Sept 28, 2004 Parkfield Earthquake caused the wire to
stretch beyond the limits of the micrometer. (ie, the meter 'pegged')
Released tension on wire by feeding 25mm from the anchor end; Micrometer
read 13.06 mm; then slid anchor end so that micrometer read 4.14 mm.


It appears the both the 'Big Creep' counter gauge and electronics DO NOT
work properly. Counter gauge only shows 16 mm of extension;


November 2006 swap-out electronics and DCP for a new version; Telemetry 
voltage range now 0-5v; scale factor is now 140 counts(mv) per mm 
fault slip (creep).

Nov 28, 2006 -- revised scale factor by 2% after comparing digital data
to aperiodic micrometer measurements. The archival data reflects this change
in scale factor

Times of possible offsets:
N 201401290000 Wire reset (AS)
N 201505130210 Ditto

For more information, please consult:
Open-File Report 2024-1011, “Summary of Creepmeter Data from 1980 to 2020—Measurements Spanning the Hayward, Calaveras, and San Andreas Faults in Northern and Central California” https://pubs.usgs.gov/publication/ofr20241011

and
Open File Report 89–650, "Catalog of creepmeter measurements in California from 1966 through 1988" https://pubs.usgs.gov/publication/ofr89650

Many people have contributed to this project including:
Roger Bilham
Robert Burford
Sandy Schulz
Andy Snyder
Kate Breckinridge
Todd Erickson
Rich Liechti
Vince Keller
John Langbein

For questions, contact John Langbein (langbein@usgs.gov)