Oceanic and continental gravity investigations by Oregon State University

Abstract

Since 1962 the Department of Oceanography, Oregon State University, has obtained gravity measurements in the Hawaiian and Aleutian archipelagoes, along the continental margin of North America from San Francisco Bay, California, to Cape Spencer, Alaska, and in Oregon. From 1963 through 1968 approximately 37,000 measurements were made in the regions delineated in Figure 1. These measurements provided the basis for the construction of gravity anomaly maps and studies of selected crustal and subcrustal structures. Underwater gravity meter measurements were used in 1962 to establish a near‐shore marine gravity range along the northcentral Oregon Coast near Newport, Oregon [Rinehart and Berg, 1963]. The marine gravity range provides a gravity difference of approximately 60 mgal and an accuracy of 1 mgal with a 90% level of confidence. Traverses of the Newport gravity range were made at the beginning and end of all surface ship gravity surveys of the Department of Oceanography. Estimates of the uncertainty in surface ship gravity measurements due to meter nonlinearity and sea state and navigation quality were obtained from data collected over the marine gravity range and off Oregon and Northern California [Dehlinger, 1964a; Dehlinger et al., 1966a].