Abstract: Measuring of soil gas flux. Particularly a method of measuring soil gas concentration and emission flux during a period of post-compression of the earth's crust. The method includes observing gravitational acceleration on the surface of the earth, as defined by crustal tension and compression and as induced by the Sun and Moon, compensating for variation in acceleration due to geographic location of said observing, locating said crustal tension in the form of a bulge on the surface of the earth, then post-compression measuring of soil gas concentration and emission flux rate during both the long term (approximately 1 to 10 days) and short term (approximately 1 to 8 hours) of maximum soil gas emission.