1975
DOI: 10.1029/ja080i022p03141
|View full text |Cite
|
Sign up to set email alerts
|

Superconducting magnetometer measurements of geomagnetic activity in the 0.1- to 14-Hz frequency range

Abstract: A high-sensitivity superconducting magnetometer has been used to measure geomagnetic activity at Stanford, California, in the 0.1-to 14-Hz frequency range. The measurements, which covered the 2-month interval January 26 to March 26, 1974, consistently show a minimum of activity in the interval 3-7 Hz, where conventional measurement systems are likely to be limited by their internal noise. At frequencies, below the minimum, in the range 0.1-3 Hz, there is typically a monotonic decrease of background activity wi… Show more

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...
1
1
1
1

Citation Types

1
13
0

Year Published

1977
1977
2012
2012

Publication Types

Select...
7
2
1

Relationship

3
7

Authors

Journals

citations
Cited by 32 publications
(14 citation statements)
references
References 31 publications
1
13
0
Order By: Relevance
“…By using a superconducting magnetic field gradiometer [Fraser-Smith, 1983] of appropriate design as the measurement system, the cancellation technique could be incorporated automatically into the measurement. Then, depending on the spatial uniformity of the upper atmosphere signals, the spatial variation of the earthquake signals, and the internal noise of the gradiometer '(whiCh is likely to be extraordinarily small compared with the internal noise typically measured in con-ventional ULF measurement systems [e.g., Buxton and Fraser-Smith, 1974; Fraser-Smith and Buxton, 1975]), substantial increases in range might be achieved.…”
Section: Discussionmentioning
confidence: 99%
“…By using a superconducting magnetic field gradiometer [Fraser-Smith, 1983] of appropriate design as the measurement system, the cancellation technique could be incorporated automatically into the measurement. Then, depending on the spatial uniformity of the upper atmosphere signals, the spatial variation of the earthquake signals, and the internal noise of the gradiometer '(whiCh is likely to be extraordinarily small compared with the internal noise typically measured in con-ventional ULF measurement systems [e.g., Buxton and Fraser-Smith, 1974; Fraser-Smith and Buxton, 1975]), substantial increases in range might be achieved.…”
Section: Discussionmentioning
confidence: 99%
“…Besides man-made disturbances, naturally occurring geomagnetic fluctuations constitute a significant source of noise, especially at low frequencies. Below 1 Hz, the spectral density of such field variations can exceed 1 p T/&Hz (Fraser-Smith and Buxton, 1975). However, inside a shielded room and measured with a gradiometer (see Sec.…”
Section: Instrumentation For Magnetoencephalographymentioning
confidence: 99%
“…So the role of background noise is crucial in the research of seismogenic signals. The anthropogenic electromagnetic noise, such as power lines, DC railways, factories, etc., generates signals whose amplitude is often higher than those of tectonic origin and in the same frequency band (Lanzerotti et al, 1990;Fraser-Smith et al, 1975, 1978. These sources of noise which vary in frequency and time, are local in nature, so they could be difficult to distinguish from anomalous signals of tectonic origin (Fraser-Smith et al, 1978).…”
Section: Local Electromagnetic Background Noisementioning
confidence: 99%