High-sensitivity EM prospecting technique based on measurement of three magnetic components of the natural EM field
Typical users of fifth-generation multifunctional equipment, which was put on the market in the late 1990s, showed a preference for a relatively high number of sites measuring two horizontal electric components, and only limited numbers of sites measuring five components of the natural EM field. Five-component measurements were used as local reference sites to calculate apparent resistivity using two horizontal magnetic components for normalization of electric components. Use of the vertical magnetic field was limited mainly to regional surveys. The principal reason for this approach was to lower costs and increase productivity by eliminating the expensive magnetic field sensor, which also requires a relatively longer time for installation in the field compared with the grounded electric-field sensors. As well there are a lot of areas in the world with surface conditions that create significant difficulties for reliable vertical magnetic sensor installation, such as severe winter conditions (frozen ground).Phoenix Geophysics (Toronto, Ontario, Canada) now sells and uses in surveys precision tripods for magnetic sensors. Highly accurate tripods with a special plastic case for each sensor are manufactured by Toronto-ba sedAdvanced Geophysical Operations and Services Inc. (AGCOS). These tripods have several advantages:accurate positioning for one, two, or three magnetic sensors, thermo-stabilization of the sensors, wind resistance,and reduced time for installation, deinstallation, and transportation to the next site.This approach to natural magnetic-field measurement considerably increases accuracy of measurement and productivity. This method, called the many-3H technique has become popular in Canada and Russia due to high sensitivity, high productivity at any time of the year, and suitability for frozen areas and areas covered by rocks with high resistivity. The first industrial kimberlite discoveries in 15 years in the Arkhangelsk region of Russia were made in 2005 using this technique.
Magnetotellurics magnetic sensor precision tripod natural EM field many 3-H
Leo Fox Olex Ingerov Alex Golyashov Igor Ingerov Alex Kolin
Phoenix Geophysics Ltd., AGCOS, Toronto, Ontario, Canada
国际会议
The 19th International Workshop on Electromagnetic Induction in the Earth(第十九届国际地球电磁感应学术研讨会)
北京
英文
965-970
2008-10-23（万方平台首次上网日期，不代表论文的发表时间）