We used a gPhone (serial number 90), the newest spring-type gravimeter manufactured by Micro-g LaCoste Inc., to acquire high-quality, continuous gravity records, both below-and aboveground. At a depth of 100 m, when the gPhone was situated under an uncon ned aquifer, the standard deviations of the residual gravity based on rst-and second-order curve ttings are 4.2 and 2.7 μGal, respectively. Some gravity decreases caused by rainfall were clearly observed, and unknown gravity variations may also have occurred. Alternatively, when the gPhone was placed aboveground on the ank of a high mountain, the standard deviation of the residual gravity was 1.7 μGal for both the rst-and second-order curve ttings. The rainfall amount and snow depth can explain most of the residual gravity. On the basis of these results, we propose to detect and correct hydrological gravity responses using multiple gravimeters to study gravity signals from deep within the earth.

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