Geophysics From Terrestrial Time‐Variable Gravity Measurements

Abstract

In a context of global change and increasing anthropic pressure on the environment, monitoring the Earth system and its evolution has become one of the key missions of geosciences. Geodesy is the geoscience that measures the geometric shape of the Earth, its orientation in space, and gravity field. Time‐variable gravity, because of its high accuracy, can be used to build an enhanced picture and understanding of the changing Earth. Ground‐based gravimetry can determine the change in gravity related to the Earth rotation fluctuation, to celestial body and Earth attractions, to the mass in the direct vicinity of the instruments, and to vertical displacement of the instrument itself on the ground. In this paper, we review the geophysical questions that can be addressed by ground gravimeters used to monitor time‐variable gravity. This is done in relation to the instrumental characteristics, noise sources, and good practices. We also discuss the next challenges to be met by ground gravimetry, the place that terrestrial gravimetry should hold in the Earth observation system, and perspectives and recommendations about the future of ground gravity instrumentation.

Short‐Time Geodetic Determination of Aquifer Storage Coefficient in Taiwan

“…This scenario does not need a pumping well, thus greatly reducing the cost. In view of the current advancements in gravimeter accuracy, transportability, and resilience (Menoret et al, ; Van Camp et al, ), a successful S y estimation from such short‐time gravity measurements can be very likely.…”

“…This scenario does not need a pumping well, thus greatly reducing the cost. In view of the current advancements in gravimeter accuracy, transportability, and resilience (Menoret et al, 2018;Van Camp et al, 2017), a successful S y estimation from such shorttime gravity measurements can be very likely. silt/mud layer stretches from 41 to 45 m and a thin-layer sand from 56.5 to 76 m. Thus, we assume that the unconfined aquifer at Neicheng covers the depths from 0 to 41 m.…”

The gravity database for Belgium

“…By performing the measurements as described above, the drift on the gravimeter could be precisely determined while transient effects were avoided. We refer to Van Camp et al () for more information.…”

Resolving Geophysical Signals by Terrestrial Gravimetry: A Time Domain Assessment of the Correction‐Induced Uncertainty

“…Local hydrological effects contributing significantly to the variation of gravity are beyond the scope of this study. Contributions such as polar motion and length of day are not considered because of the agreement on correction procedures (Hinderer et al, ; Van Camp et al, ). Details on the uncertainty of some gravity processing procedures such as calibration of relative gravimeters can be found in Meurers () and Van Camp et al (), while the uncertainty of gap fillings and discontinuity corrections are to a certain extend discussed in Hinderer et al ().…”

“…These include monitoring of geothermal fields (Kao et al, 2014), CO 2 storage reservoirs (Sugihara et al, 2017), volcanoes (Carbone et al, 2017;Poland & Carbone, 2016), evapotranspiration rates (Güntner et al, 2017;, preseismic and coseismic changes (Imanishi et al, 2004;Vallée et al, 2017), or the definition of the kilogram (Stock, 2013). Many more applications of absolute and relative gravity measurements have been reviewed by Crossley et al (2013) and Van Camp et al (2017). Given the ongoing technological advancements in terrestrial gravimetry toward…”