Drilling for natural gas is preceded by geophysical surveys. What lies beneath the surface of the earth can be estimated using measurements of various forces: magnetism, gravity, or sound (seismic).
In late May and early June, an airplane was measuring the strength of the earth’s magnetic field across our region. The plane has twin engines on underslung wings and a polished metal skin. What is distinctive is the magnetometer that is housed in a boom projecting straight back from the tail for some ten feet.
During an aeromagnetic survey, the plane makes a series of closely-spaced, parallel flights north and south, flying low at a constant height above the ground. It flew out of the Sidney Municipal Airport for three weeks and has since moved on to its next job in Canada.
Airborne magnetic surveys are used to estimate the thickness of the sedimentary rocks, some of which hold natural gas.