XGH1
Gold Hill Creepmeter

Site subject to temp-related diurnals

Electronic data feed started drift from LVDT calibrations between
5/16/14 & 9/10/15 and is questionable since then; Re-calib. needed;

In April 17, 1998, site was visited and it was observed that
the invar wire had slipped off the rocker arm. The wire was
restored to its proper place. However, when reconciling
the micrometer measurements in May 98 with a measurement
in November 97, these measurements implied a 0.3 MM Left
lateral movement; the telemetry data implied a 1.5 mm left
lateral movement. Thus, it is BELEIVED that the telemetried
data showing the large LL motion between Dec 97 and April 98
is BOGUS; The offset shown is late April in the data
below was installed to force the telemetried values
equal to the micrometer measurements; Later complilations
of this data may have the data from Dec 97 through late
April deleted.


June 8, 2004;  Noted that recent (last few years) of micrometer
and telemetry data seem to be inconsistant with original calibration
of 134 cnt/mm-RL slip. Performed a calibration of the instrument
by sliding wire on anchor end and measuring displacement on micrometer
and collecting the DCP counts; Calibration confirms original results.

Sept 28 2004 Parkfield EQ--- site stayed on scale

November 2006 swap-out electronics and DCP for a new version; Telemetry 
voltage range now 0-5v; scale factor is now 146 counts(mv) per mm 
fault slip (creep).

Nov 28, 2006 -- revised scale factor by 3% after comparing digital data
to aperiodic micrometer measurements. The archival data reflects this change
in scale factor

April 1, 2014 -- revised scale factor by 50% after comparing digital data
to aperiodic micrometer measurements. The archival data reflects this change
in scale factor

Data after Jan 2019 is probably bad due to lack of maintenance.

Times of possible offsets:
N 201405010420 Mechanism disturbed by animals causing offset & noise (AS) 
N 201409100140 Reset creepmeter wire (AS)
N 201510140110 Wire Reset (AS)
S N 201705092150 Ditto
N 201705092230 Ditto
S N 201705092240 Ditto
N 201712212010 Wire reset & battery change (AS)
S N 201712212020 Ditto
N 201804261700 Wire reset and LVDT shift (TLE) 

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)