The U. S. Geological Survey's Gravity program in California, Hawaii, Nevada, and Oregon
During the past 10 years, personnel of the U. S. Geological Survey have made about 14,000 observations of the Earth's gravity field in California, about 13,000 in Nevada, 3,400 in Oregon, and about 1,000 in the Hawaiian Islands. The total number of stations established in the four states is slightly in excess of 30,000.
California, Hawaii, Nevada, Oregon↗