Repeat microgravity data from Tucson Basin and Avra Valley, Arizona, 2021
Dates
Publication Date
2021-09-23
Start Date
2020-11-16
End Date
2021-01-14
Citation
Landrum, M.T., 2021, Repeat microgravity data from Tucson Basin and Avra Valley, Arizona, 2021: U.S. Geological Survey data release, https://doi.org/10.5066/P952D0WL.
Summary
These data represent the network-adjusted results of relative- and absolute-gravity surveys. Relative-gravity surveys were carried out using two ZLS Corporation Burris relative-gravity meters. The effect of solid Earth tides and ocean loading were removed from the data. Instrument drift was removed by evaluating gravity change during repeated measurements at one or more base stations. Absolute-gravity surveys were carried out using a Micro-g LaCoste, Inc. A-10 absolute-gravity meter. Vertical gradients between the different measuring heights of the absolute- and relative-gravity meters were measured using a relative-gravity meter and fully-adjustable tripod, and used to correlate the measurements between the two instruments. Relative-gravity [...]
Summary
These data represent the network-adjusted results of relative- and absolute-gravity surveys. Relative-gravity surveys were carried out using two ZLS Corporation Burris relative-gravity meters. The effect of solid Earth tides and ocean loading were removed from the data. Instrument drift was removed by evaluating gravity change during repeated measurements at one or more base stations. Absolute-gravity surveys were carried out using a Micro-g LaCoste, Inc. A-10 absolute-gravity meter. Vertical gradients between the different measuring heights of the absolute- and relative-gravity meters were measured using a relative-gravity meter and fully-adjustable tripod, and used to correlate the measurements between the two instruments. Relative-gravity differences and absolute-gravity data were combined using a least-squares network adjustment, as implemented in the software GSadjust (https://doi.org/10.5066/P9YEIOU8). Information about the network adjustment is provided under Data Quality in the metadata.
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TAMA_AdjustedGravity_2021_tabular.xml Original FGDC Metadata
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TAMA_AdjustedGravity_2021_tabular.csv
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Purpose
Data were collected to evaluate aquifer-storage change in the Tucson Active Management Area. Using the horizontal infinite-slab approximation, gravity data (in units of acceleration, for example, m/s^2), are converted to a thickness of free-standing water, regardless of the depth to or porosity of the interval at which storage-change occurs. Data are not corrected for soil-moisture variation (that is, estimated storage changes include all storage change between the land surface and the aquifer).
