Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site islenet.UUCP Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!petrus!bellcore!decvax!decwrl!Glacier!well!ptsfa!dual!islenet!bob From: bob@islenet.UUCP (Bob Cunningham) Newsgroups: net.physics Subject: Re: Weird Gravitational effects at Lake Delton Wisconsin Message-ID: <1516@islenet.UUCP> Date: Thu, 22-Aug-85 17:28:17 EDT Article-I.D.: islenet.1516 Posted: Thu Aug 22 17:28:17 1985 Date-Received: Mon, 26-Aug-85 01:28:10 EDT References: <974@sphinx.UChicago.UUCP> Organization: Hawaii Institute of Geophysics Lines: 26 Currently, instruments used in gravity surveys are sensitive to about one part in 10^8. Gravity prospecting is commonly used as a reconnaissance tool in oil exploration -- it's often cheaper than a seismic survey -- though it's usually employed as a secondary method for mineral exploration, although recently it's become more popular for detailed follow-up of magnetic and electromagnetic anomalies during integrated base-metal surveys. Even a quick survey (several neighborhood sites for reference + a few measurements at the point of interest) would surely detect objectively any thing like what you've observed. Still, it wouldn't be cheap. Several days (minimum) of a well-trained crew of several people. (Contact any oil company for details and a cost estimate :-). Having well-calibrated instruments is a must. On the other hand, if the anomaly (anomalies?) are as pronounced as you suspect, they're probably detectable using a simple pendulum (accurately measuring period, using the total number of cycles over a period of several hours), or some form of torsion balance. The precision would be much less than that of modern gravity meters, but probably sufficient to detect (or fail to) major changes in the gravity field up by the lake. The time, effort and expertise involved would be roughly equivalent to a good high school level science fair project. -- Bob Cunningham {dual|vortex|ihnp4}!islenet!bob Hawaii Institute of Geophysics