Introduction

The Bay Area Regional Deformation (BARD) network of continuously operating Global Positioning System (GPS) receivers monitors crustal deformation in the San Francisco Bay area (``Bay Area") and northern California (Murray et al., 1998). It is a cooperative effort of the BSL, the USGS, and several other academic, commercial, and governmental institutions. Started by the USGS in 1991 with 2 stations spanning the Hayward fault (King et al., 1995), BARD now comprises more than 70 permanent stations (Figure 7.1, Tables 7.1 and 7.2). The principal goals of the BARD network are: 1) to determine the distribution of deformation in northern California across the wide Pacific-North America plate boundary from the Sierras to the Farallon Islands; 2) to estimate three-dimensional interseismic strain accumulation along the San Andreas Fault (SAF) system in the Bay Area to assess seismic hazards; 3) to monitor hazardous faults and volcanoes for emergency response management; and 4) to provide infrastructure for geodetic data management and processing in northern California in support of related efforts within the surveying and other interested communities.

Figure 7.1: Operational BARD stations (dark triangles) in northern California (top) and in the San Francisco Bay area (bottom), including an 18-station network near the Long Valley Caldera (LVC) and a 14-station network near Parkfield (PKFD). In the oblique Mercator projection expected Pacific-North America relative plate motion is parallel to the horizontal. Circled stations use continuous real-time telemetry. The small black triangles near BRIB are the experimental L1 stations. Light triangles are PBO and Nucleus (previously existing continuous stations now part of PBO) stations operating in July 2005.
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Among others, BARD includes 14 stations near Parkfield along the central San Andreas Fault, and 17 near the Long Valley caldera near Mammoth. The BSL maintains 22 stations [including 2 with equipment provided by Lawrence Livermore National Laboratory (LLNL) and UC Santa Cruz). Other stations are maintained by the USGS (Menlo Park and Cascade Volcano Observatory], LLNL, Stanford Linear Accelerator, UC Davis, UC Santa Cruz, Hat Creek Radio Observatory, U. Wisconsin, Haselbach Surveying Instruments, East Bay Municipal Utilities District, the City of Modesto, the National Geodetic Survey, Thales, Inc., and the Jet Propulsion Laboratory. Many of these stations are part of larger networks devoted to real-time navigation, orbit determination, and crustal deformation.


Table 7.1: Currently operating stations of the BARD GPS network maintained by the BSL and by the BSL/USGS/SCIGN in the Parkfield region. Receivers: A = Ashtech, T = Trimble. See Table 3.2 for telemetry codes and for BSL sites collocated with seismic stations. Data from other agencies retrieved or pushed by FTP or from the Web.
Code Latitude Longitude Start Receiver Maint. Telem. Location
BRIB 37.91940 -122.15255 1993.58 A-Z12 BSL FR Briones Reservation, Orinda
CMBB 38.03418 -120.38604 1993.92 A-Z12 BSL FR Columbia College, Columbia
DIAB 37.87858 -121.91563 1998.33 A-Z12 BSL FR Mt. Diablo
FARB 37.69721 -123.00076 1994.00 A-Z12 BSL R-FR/R Farallon Island
HOPB 38.99518 -123.07472 1995.58 A-Z12 BSL FR Hopland Field Station, Hopland
LUTZ 37.28685 -121.86522 1996.33 A-Z12 BSL FR SCC Comm., Santa Clara
MHCB 37.34153 -121.64258 1996.33 A-Z12 BSL FR Lick Obs., Mt. Hamilton
MODB 41.90233 -120.30283 1999.83 A-Z12 BSL NSN Modoc Plateau
MOLA 37.94657 -122.41992 1993.75-2002.22 T-SSE BSL   Pt. Molate, Richmond
MONB 37.49892 -121.87131 1998.50 A-Z12 BSL FR Monument Peak, Milpitas
MUSB 37.16994 -119.30935 1997.83 A-Z12 BSL R-Mi-FR Musick Mt.
OHLN 38.00742 -122.27371 2001.83 A-uZ BSL FR Ohlone Park, Hercules
ORVB 39.55463 -121.50029 1996.83 A-Z12 BSL FR Oroville
OXMT 37.49936 -122.42432 2004.12 A-uZ BSL FR Ox Mt., Half Moon Bay
PKDB 35.94524 -120.54155 1996.67 A-Z12 BSL FR Bear Valley Ranch, Parkfield
POTB 38.20258 -121.95560 1998.92-2005.12 A-Z12 BSL FR Potrero Hill, Fairfield
PTRB 37.99640 -123.01490 1998.58 A-Z12 BSL R-FR Point Reyes Lighthouse
SAOB 36.76530 -121.44718 1997.58 A-Z12 BSL FR San Andreas Obs., Hollister
SBRN 37.68622 -122.41044 2003.18 A-uZ BSL FR San Bruno Mt., Brisbane
SODB 37.16640 -121.92552 1996.33 A-Z12 BSL R-FR Soda Springs, Los Gatos
SUTB 39.20584 -121.82060 1997.33 A-Z12 BSL R-FR Sutter Buttes
SVIN 38.03318 -122.52632 2003.89 A-uZ BSL R-FR St. Vincents, San Rafael
TIBB 37.89087 -122.44760 1994.42 A-Z12 BSL R Tiburon
YBHB 41.73166 -122.71073 1996.75 A-Z12 BSL FR Yreka Blue Horn Mine, Yreka
CAND 35.93935 -120.43370 1999.33 A-Z12 USGS R-FR Cann, Parkfield
CARH 35.88838 -120.43082 2001.58 A-Z12 USGS R-FR Carr Hill 2, Parkfield
CARR 35.88835 -120.43084 1989.00-2003.31 A-Z12 JPL   Carr Hill, Parkfield
CRBT 35.79161 -120.75075 2001.67 A-Z12 USGS R-FR Camp Roberts, Parkfield
HOGS 35.86671 -120.47949 2001.50 A-Z12 USGS R-FR Hogs, Parkfield
HUNT 35.88081 -120.40238 2001.58 A-Z12 USGS R-FR Hunt, Parkfield
LAND 35.89979 -120.47328 1999.33 A-Z12 USGS R-FR Lang, Parkfield
LOWS 35.82871 -120.59428 2001.58 A-Z12 USGS R-FR Lowes, Parkfield
MASW 35.83260 -120.44306 2001.58 A-Z12 USGS R-FR Mason West, Parkfield
MIDA 35.92191 -120.45883 1999.75 A-Z12 USGS R-FR Mida, Parkfield
MNMC 35.96947 -120.43405 2001.58 A-Z12 USGS R-FR Mine Mt., Parkfield
POMM 35.91991 -120.47843 1999.75 A-Z12 USGS R-FR Pomm, Parkfield
RNCH 35.89999 -120.52482 2001.58 A-Z12 USGS R-FR Ranchita, Parkfield
TBLP 35.91741 -120.36034 2001.67 A-Z12 USGS R-FR Table, Parkfield



Table 7.2: Currently operating stations of the BARD GPS network maintained by other agencies and by the USGS Cascade Volcano Observatory (CVO) in the Long Valley caldera region. Other agencies include: EBMUD = East Bay Mun. Util. Dist., UCD = UC Davis, SU = Stanford Univ., UCSC = UC Santa Cruz, UWisc = U. of Wisconsin, City = City of Modesto (see also Table 2.1). Data from other agencies retrieved or pushed by FTP or from the Web.
Code Latitude Longitude Start Receiver Maint. Location
CHAB 37.72412 -122.11931 1992.00 A-Z12 USGS Chabot, San Leandro
WINT 37.65264 -122.14056 1992.00 A-Z12 USGS Winton, Hayward
EBMD 37.81501 -122.28380 1999.18 T-SSi EBMUD EBMUD, Oakland
QUIN 39.97455 -120.94443 1992.68 Rogue JPL Quincy
S300 37.66642 -121.55815 1998.48 T-SSi LLNL Site 300, Livermore
HCRO 40.81563 -121.46915 2003.50 T-SSi HCRO Hat Creek Radio Obs.
CHO1 39.43264 -121.66496 1999.50 A-Z12 NGS Chico
CME1 40.44177 -124.39633 1995.74 A-Z12 NGS Cape Mendocino
CMOD 37.64130 -121.99997 2000.76 T-SSi City Modesto
CNDR 37.89641 -121.27849 1999.27 A-Z12 NGS Condor, Stockton
PBL1 37.85306 -122.41944 1995.50-2004.19 A-Z12 NGS Point Blunt, Angel Island
PPT1 37.18167 -122.39333 1996.00 A-Z12 NGS Pigeon Point
SLAC 37.41652 -122.20426 2002.34 Leica SLAC Stanford Linear Accel. Center
SUAA 37.42691 -122.17328 1994.30-2003.10 A-Z12 SU Stanford University
THAL 37.35149 -121.93549 2003.00 A-uZ Thales Thales, Inc., Santa Clara
UCD1 38.53624 -121.75123 1996.38 T-SSi UCD UC Davis
UCSC 36.99279 -122.05219 2000.31-2002.67 T-SSi UCSC UC Santa Cruz
ZOA1 37.54305 -122.01594 2002.50 Novatel FAA Fremont
GR8V 36.39901 -120.41577 2003.04 T-5700 UWisc San Andreas Creeping Segment
MEE1 36.18690 -120.75860 2003.02 T-5700 UWisc San Andreas Creeping Segment
MEE2 36.18052 -120.76684 2003.03 T-5700 UWisc San Andreas Creeping Segment
QCYN 36.16116 -121.13748 2003.05 T-5700 UWisc San Andreas Creeping Segment
USBR 36.84257 -120.43567 2004.30 T-SSi CVWD Central Valley
CCID 36.73901 -120.35657 2004.30 T-NetRS CVWD Mendota, Central Valley
LNC1 38.84651 -121.35023 2003.51 A-Z12 NGS Lincoln
PLSB 38.68530 -121.76150 2004.14 Leica Haselbach Woodland
SHJB 38.81418 -121.29606 2003.22 Leica Haselbach Rocklin
TMSB 38.57078 -121.54922 2003.22 Leica Haselbach West Sacramento
BALD 37.78330 -118.90130 1999.67 A-ZFX CVO Bald Mt., LVC
CA99 37.64460 -118.89670 1999.67 A-ZFX CVO Casa 1999, LVC
CASA 37.64464 -118.89666 1993.00 Rogue JPL Casa Diablo, LVC
DDMN 37.74430 -118.98120 1999.67 A-ZFX CVO Deadman Creek, LVC
DECH 38.05150 -119.09060 2001.58 A-ZFX CVO Dechambeau Ranch, LVC
HOTK 37.65860 -118.82130 2001.67 A-Z12 CVO Hot Creek, LVC
JNPR 37.77170 -119.08470 1997.81 A-Z12 USGS Juniper, LVC
KNOL 37.65912 -118.97917 1998.58 A-ZFX CVO Knolls, LVC
KRAC 37.71330 -118.88050 2001.67 A-Z12 CVO Krakatoa-USGS, LVC
KRAK 37.71313 -118.88114 1994.73-2004.04 Rogue JPL Krakatoa, LVC
LINC 37.63719 -119.01729 1998.67 A-Z12 CVO Lincoln, LVC
MINS 37.65376 -119.06090 1995.92 A-Z12 USGS Minaret Summit, LVC
MWTP 37.64052 -118.94473 1998.58 A-ZFX CVO Mammoth Water Treat Plant, LVC
PMTN 37.83130 -119.05690 1999.67 A-Z12 CVO Panorama Mt., LVC
RDOM 37.67707 -118.89794 1998.58 A-ZFX CVO Resurgent Dome, LVC
SAWC 37.68990 -118.95310 2000.65 A-ZFX CVO Saw, LVC
TILC 37.61890 -118.86280 2000.65 A-Z12 CVO Tilla, LVC
WATC 37.66440 -118.65390 2001.67 A-Z12 CVO Waterson, LVC


Between 1993 and 2001, the BSL acquired 29 Ashtech Z-12 and Micro-Z receivers from a variety of funding sources, including from federal (NSF and USGS), state (CLC), and private (EPRI) agencies. The network enhances continuous strain measurements in the Bay Area and includes several profiles between the Farallon Islands and the Sierra Nevada in order to better characterize the larger scale deformation field in northern California (Figure 7.1). Five sites have been equipped as part of the NSF-funded Mini-PBO project to establish collocated GPS, and borehole strainmeter and seismometer observatories in the Bay Area (see Chapter 8).

The number of continuous GPS stations in northern California is significantly increasing with over 250 new site installations planned by 2008 as part of the Plate Boundary Observatory (PBO) component of the NSF-funded Earthscope project. UNAVCO and researchers from BARD and the other regional networks, such as SCIGN, BARGEN, and PANGA, are funded by NSF to fold operation and maintenance of about 200 existing stations, which constitute the PBO Nucleus network, into the PBO array by 2008. Two BSL-maintained stations (SUTB and MUSB) are included in the PBO Nucleus network. The other BSL stations are either collocated with seismic instrumentation or are located near the San Andreas Fault where real-time processing of the GPS data for earthquake notification is a high priority. Another 23 northern California stations, including most of the Parkfield network, will be included in the PBO Nucleus, and we are working closely with UNAVCO to facilitate their transition to UNAVCO control.

Today, raw and RINEX data files from the BSL stations and the other stations run by BARD collaborators are archived at the BSL/USGS Northern California Earthquake Data Center (NCEDC) data archive maintained at the BSL (Romanowicz et al., 1994). The data are checked to verify their integrity, quality, completeness, and conformance to the RINEX standard, and are then made accessible, usually within 2 hours of collection, to all BARD participants and other members of the GPS community through Internet, both by anonymous FTP and by the World Wide Web (http://www.ncedc.org/ncedc/access.html#gps).

Many of the BARD sites are classified as CORS stations by the NGS, and are used as reference stations by the surveying community. We coordinate efforts with surveying community at meetings of the Northern California GPS Users Group and the California Spatial Reference Center. Data and ancillary information about BARD stations are also made compatible with standards set by the International GPS Service (IGS), which administers the global tracking network used to estimate precise orbits and has been instrumental in coordinating the efforts of other regional tracking networks. The NCEDC also retrieves data from other GPS archives, such as at SIO, JPL, and NGS, in order to provide a complete archive of all high-precision continuous GPS measurements collected in northern California.

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