International gravimetric connections were carried out by means of 8 and 7 LaCoste & Romberg gravimeters (model G) at selected cities along the west and east sides of the Circum-Pacific zone in 1980 and 1981, respectively, and both sides were connected by Tokyo (Japan) and Santiago (Chile). A branched connection was extended from Christchurch (New Zealand) to McMurdo Sound (Antarctica) by means of 2 of the 8 gravimeters in 1980. Preliminary and additional connections were also carried out with 2 LaCoste & Romberg gravimeters (model G) to experience actual measuring environments and to directly link Tokyo with Santiago as rapidly as possible in 1979 and 1982, respectively. The maximum gravity difference in the present connections amounted to about 6.1 gals (=6.1 × 10-2 ms-2) . The purpose of these connections was to make a precise calibration of scale values of the gravimeters employed, to establish an up-to-date gravity net which is capable of detecting the time change of gravity along the Circum-Pacific zone, and to obtain data for the updating of the International Gravity Standardization Net 1971 (IGSN 71) in this annn The international gravimetric connections were executed among 34 cities mainly along the Circum-Pacific zone. In 25 among the 34 cities, local gravity measurements were made at 3 to 9 measuring stations. The total number of the measuring stations occupied was 187 of which 19 were temporary stations. After the data obtained were adjusted, a correction function for the scale value of each gravimeter given by the manufacturer was precisely determined as a function of counter value of the gravimeter. By applying the correction function thus obtained, the gravity value at each gravity station was recalculated and compared with either the corresponding value given on the IGSN 71 or the value determined by an absolute gravity measurement. The accuracy of the present international gravimetric connections was estimated to be better than f 0.03 mgals, and it was revealed that the gravity values at some stations given on the IGSN 71 seemed to involve some systematic errors with an order of 0.1 mgals.
