Ely, Christopher P Kennedy, Jeffrey R Christensen, Allen H 20241201 tabular digital data https://doi.org/10.5066/P9DJ23US This dataset represents the network-adjusted results of relative- and absolute-gravity surveys performed from 2019 to 2023 in and near Anza Valley, California. Relative surveys were done using a Zero Length Spring, Inc. Burris relative-gravity meter. Absolute-gravity surveys were done using a Micro-g LaCoste, Inc. A-10 absolute-gravity meter. The effect of solid Earth tides and ocean loading were removed from the data prior to network adjustment. Non-linear instrument drift was removed by evaluating gravity change during repeated measurements at one or more base stations. Vertical gradients between the relative- and absolute-gravity meters were measured at each station where both types of measurement were collected to correlate the measurements of the two instruments. Vertical gradients were measured using a relative-gravity meter and tripod set to the height of the absolute-gravity meter. Relative-gravity differences and absolute-gravity data were combined using least-squares network adjustment, as implemented in the software GSadjust (https://code.usgs.gov/sgp/gsadjust). Data are provided for 35 stations collected over 7 discrete surveys. Gravity data were collected to evaluate aquifer-storage change and aquifer-storage properties. Using the horizontal infinite-slab approximation, gravity data can be converted to a thickness of free-standing water (Pool and Eychaner, 1995). Because data are not corrected for soil-moisture variation, estimated storage changes include all storage change in the vadose zone. Gravity values at all stations are reported at land-surface elevation. Observed absolute-gravity values are also available in the Southwest Gravity Program Absolute Gravity Database (https://doi.org/10.5066/P984HN6J). 20200921 20230911 observed Complete None planned -116.7009 -116.6308 33.5400 33.5773 ISO 19115 Topic Category geoscientificInformation None Southwest Gravity Program California Water Science Center USGS Thesaurus gravitational field (earth) geophysics hydrogeology gravimeter measurement USGS Metadata Identifier USGS:61ae617ed34eb622f69a7276 None Anza Valley Riverside County California None. Please see 'Distribution Info' for details. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Jeffrey R Kennedy U.S. Geological Survey, SOUTHWEST REGION Hydrologist mailing address

2255 N. Gemini Dr.

Flagstaff AZ 86001 US 928-556-7087 jkennedy@usgs.gov Data were processed using least-squares network adjustment, as implemented in the software GSadjust (https://code.usgs.gov/sgp/gsadjust). Attribute accuracy is evaluated from the least-squares network adjustment results. Attribute accuracy is evaluated from the least-squares network adjustment results. Attribute accuracy is evaluated from the least-squares network adjustment results. Survey | Max. delta residual | Max. datum residual | Mean SD | Deltas | Deltas not used | Datums | Datums not used 2019-12-03 6.1 4.1 3.3 67 1 4 0 2020-09-21 12.9 7.9 4.2 75 1 5 0 2021-04-27 8.1 6.7 2.3 160 0 6 0 2021-08-31 5.6 6.0 2.1 140 0 5 0 2022-03-30 9.9 3.3 2.4 154 2 6 0 2022-11-01 8.5 7.6 2.2 69 0 10 0 2023-09-11 NA NA 5.0 0 0 10 0 Relative gravimeter scale factor(s) Survey | Meter | Scale factor | Scale factor S.D. (0 = specified S.F.) 2019-12-03 EB22A 1.001397 0.000266 2020-09-21 EB22A 0.999821 0.000236 2021-04-27 EB22A 0.999239 0.000190 2021-08-31 EB22A 0.999915 0.000162 2022-03-30 EB22A 0.999482 0.000201 2022-11-01 EB22A 0.999777 0.000138 No formal logical accuracy tests were conducted. Dataset is considered complete for its intended purpose, as described in the Purpose section. Station positions were identified using a combination of handheld and differential Global Navigation Satellite System surveys(GNSS). Positions obtained using differential GNSS are accurate to about 1 cm (about 0.000001 degrees). Positions obtained using handheld GPS are accurate to about 1.0 m (about 0.0001 degrees). The number of decimal places in the data file reflects the accuracy of the position source. All positions are reported in the NAD83 (epoch 2010.00) datum accessed through the National Geodetic Survey Online Positioning User Service (OPUS). Station elevations were using a combination of handheld and differential Global Navigation Satellite System surveys(GNSS). Elevations obtained using differential GNSS are accurate to about 3 cm. Positions obtained using handheld GPS are accurate to about 1.0 m. The number of decimal places in the data file reflects the accuracy of the position source. All elevations are reported in the NAVD8 (Geoid18) datum accessed through the National Geodetic Survey Online Positioning User Service (OPUS). U.S. Geological Survey 20240906 tabular digital data https://doi.org/10.5066/P984HN6J Digital and/or Hardcopy 202409061 publication date SGP-AGDB Absolute gravity data used in the network adjustment are published in this database. Relative-gravity were corrected for solid Earth tides, ocean loading, and instrument drifts. Gravity differences between stations were calculated. 20240905 Absolute-gravity data were collected and reviewed. Absolute-gravity values were transferred to the measuring-height of the relative-gravity meter using a measured vertical gradient. SGP-AGDB 20240905 Relative-gravity differences were combined with absolute-gravity data using least-squares network adjustment. The GSadjust software package (https://doi.org/10.5066/P9YEIOU8) was used for processing. 20240905 0.000001 0.000001 Decimal degrees World Geodetic System 1984 (WGS 84) WGS_1984 6378137.0 298.257223563 North American Vertical Datum of 1988 0.01 meters Explicit elevation coordinate included with horizontal coordinates Anza_AdjustedGravity_2019-2023.csv Comma Separated Value (CSV) file containing data. Producer Defined Station Station name Producer Defined Station name Latitude Latitude (North American Datum 1983; NAD83) National Geodetic Survey Online Positioning User Service (OPUS) 33.53998 33.57725 Longitude Longitude (North American Datum 1983, NAD83) National Geodetic Survey Online Positioning User Service (OPUS) -116.70092 -116.63078 Elevation Elevation (North American Vertical Datum 1988; NAVD88) National Geodetic Survey Online Positioning User Service (OPUS) 1168.12 1289.68 meters 2019-12-03_g Network-adjusted gravity, 2019-12-03 Producer Defined 979263124.0 979292924.5 microgal 0.1 2019-12-03_sd Network-adjusted gravity, 2019-12-03, standard deviation Producer Defined 1.9 5.0 microgal 0.1 2020-09-21_g Network-adjusted gravity, 2020-09-21 Producer Defined 979263161.3 979292897.6 microgal 0.1 2020-09-21_sd Network-adjusted gravity, 2020-09-21, standard deviation Producer Defined 1.8 6.1 microgal 0.1 2021-04-27_g Network-adjusted gravity, 2021-04-27 Producer Defined 979263156.3 979292921.3 microgal 0.1 2021-04-27_sd Network-adjusted gravity, 2021-04-27, standard deviation Producer Defined 1.3 3.8 microgal 0.1 2021-08-31_g Network-adjusted gravity, 2021-08-31 Producer Defined 979263134.3 979292909.1 microgal 0.1 2021-08-31_sd Network-adjusted gravity, 2021-08-31, standard deviation Producer Defined 1.5 3.1 microgal 0.1 2022-03-30_g Network-adjusted gravity, 2022-03-30 Producer Defined 979263138.3 979292906.3 microgal 0.1 2022-03-30_sd Network-adjusted gravity, 2022-03-30, standard deviation Producer Defined 1.4 4.4 microgal 0.1 2022-11-01_g Network-adjusted gravity, 2022-11-01 Producer Defined 979266386.5 979292898.7 microgal 0.1 2022-11-01_sd Network-adjusted gravity, 2022-11-01, standard deviation Producer Defined 1.3 3.2 microgal 0.1 2023-09-11_g Absolute gravity, 2023-09-11 Producer Defined 979266385.7 979285273.0 microgal 0.1 2021-09-11_sd Absolute gravity, 2021-09-11, standard deviation Producer Defined 3.0 3.0 microgal 0.1 U.S. Geological Survey - ScienceBase mailing and physical

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 USA 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P9DJ23US None 20250430 Jeffrey R Kennedy U.S. Geological Survey, SOUTHWEST REGION Hydrologist mailing address

2255 N Gemini Dr

Flagstaff AZ 86001 US 928-556-7087 jkennedy@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998