1974 Volume 20 Issue 3 Pages 133-142
In gravity measurements, it is naturally presumed that the gravity values obtained are disturbed by certain effects. A thorough investigation for those effects is an essential problem on gravity measurements. Experiments for investigating the following two kinds of characteristics of 9 LaCoste & Romberg gravimeters (G-29, 31, 34, 113, 124, 196, 210, 304 and 305) were cooperatively carried out at Mizusawa inFebruary 1974. (1) Calibration on scale factor of the gravimeters along the route between Mizusawa and Hachinohe (gravity difference 213.1 mgal). (2) Effect due to change of the outer temperature. The following conclusions were obtained through the present experiments. (1) Discrepancy among the scale factors of the 9 LaCoste & Romberg gravimeters was found to be about 2×10-4. Its amount was the same order as for the previous experiments. (2) Effect due to change of the outer temperature is different at each gravimeter. Generally speaking, reading value of the gravimeter increases at when the outer temperature decreases, and there are some phase lags between change of the outer temperature and response of the gravimeter's reading value. In field gravity measurements, it is, therefore, avoidable from effect due to change of the outer temperature in case when the gravity measurement was carried out within 10 minutes just after the gravimeter was taken out of its case.
