Transverse Total Magnetic Field Gradiometer Marine Survey in Hawaii: The Quasi‐Analytic Signal Approach and Multi‐Channel Total Field Dipole Modeling

2009 ◽  
Author(s):  
Mikhail Tchernychev ◽  
Jeff Johnston ◽  
Ross Johnson
Keyword(s):  
Magnetic Field ◽  
Analytic Signal ◽  
Total Field ◽  
Total Magnetic Field ◽  
Dipole Modeling ◽  
Signal Approach

A TOTAL FIELD MAGNETOMETER FOR MOBILE OPERATION

Geophysics ◽  
1948 ◽  
Vol 13 (2) ◽  
pp. 209-214 ◽  
Author(s):  
Eugene Frowe
Keyword(s):  
Magnetic Field ◽  
High Sensitivity ◽  
Ferromagnetic Material ◽  
Magnetic Data ◽  
Recording Device ◽  
Total Field ◽  
Total Magnetic Field ◽  
Inductive Type ◽  
Continuous Field ◽  
Better Than

A magnetometer which measures the earth’s total magnetic field is described. The detector or measuring element of the magnetometer contains three mutually perpendicular elements, two of which are utilized to orient the third, which in turn operates a recording device to record the total magnetic field. The detector elements are of the inductive type and do not require ferromagnetic material to give them the high sensitivity required in geophysical work. The presence of a magnetic field in the region of the detector causes alternating currents to be generated in the detector elements. These currents are amplified to actuate motors which control the orienting and neutralizing functions of the magnetometer. A tape recorder gives continuous field readings. The accuracy of the magnetic data taken is better than five gammas.

Distinguishing buried alluvium from till by using detailed total-magnetic-field data

1990 ◽  
Vol 27 (4) ◽  
pp. 513-519
Author(s):  
Erik J. Schwarz
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Power Spectra ◽  
Total Field ◽  
Magnetic Field Data ◽  
Glacial Sediments ◽  
Total Magnetic Field ◽  
River Terraces ◽  
Magnetic Analysis ◽  
Lateral Extent

Total-magnetic-field and vertical-magnetic-gradient profiles are characteristically different over alluvial and glacial sediments. Positive magnetic anomalies elongated in the river-valley direction but not in the structural trend of the underlying bedrock indicate the occurrence of magnetite enrichments within the alluvium. No evidence for such anomalies is found in survey data obtained in gravel pits located in tills. The logarithm of the power of the total-field profiles over the river terraces plotted against spatial frequency is structured, which is indicative of the presence of magnetic sources of certain depth and width. However, the power spectra over till may also show similar features if high-frequency bedrock anomalies are present in the data, so these spectra are not a reliable means of distinguishing between buried alluvium and till. The results show that magnetic analysis allows the discrimination between buried tills and alluvium in which magnetite concentrations of considerable lateral extent were formed.

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