The trend in gravity exploration in the past years indicates the rather remarkable fact that a method of low resolving power (the gravity meter) has replaced one of higher resolving power (the torsion balance). This is entirely due to the superior speed of the former and suggests an instrument and procedure in which observation time is reduced by (1) reduction in number of quantities measured; (2) use of a reference direction near that of the maximum effect; (3) elimination of the torsionless position as unknown; (4) reduction in period, with compensating increase in optical sensitivity; (5) stabilization of thermal conditions. These objectives are attained by (1) measuring the profile components of gradients and curvature values, preferably at right angles to the assumed strike; whereby, for an ideal two‐dimensional feature, also the vertical gravity gradient is obtained, and the vertical and horizontal gravity components may be calculated by integration; (2) by holding the torsionless position constant with temperature control; (3) by decreasing the period and observation time to 3–4 minutes, and (4) by using a beam arrangement which will give the gradient in only one azimuth, and the profile gradient of the horizontal gravity component in a second azimuth if desired. Latitude and terrain corrections are also somewhat simplified by the proposed procedure.
Spatiotemporal variations in vertical gravity gradients at the Campi Flegrei caldera (Italy): a case for source multiplicity during unrest?
