1,721,120 research outputs found
A broadband two axis flux-gate magnetometer
No full textA broadband two axis flux-gate magnetometer was developed to obtain high sensitivity in magnetotelluric measurements. In magnetotelluric sounding, natural low frequency electromagnetic fields are used to estimate the conductivity of the Earth's interior. Because variations in the natural magnetic field have small amplitude(10-100 pT) in the frequency range 1 Hz to 100 Hz, highly sensitive magnetic sensors are required. In magnetotelluric measurements two long and heavy solenoids, which must be installed, in the field station, perpendicular to each other (north-south and east-west) and levelled in the horizontal plane are used. The coil is a critical component in magnetotelluric measurements because very slight motions create noise voltages, particularly troublesome in wooded areas; generally the installation takes place in a shallow trench. Moreover the coil records the derivative of the variations rather than the magnetic field variations, consequently the transfer function (amplitude and phase) of this sensor is not constant throughout the frequency range 0.001-100 Hz. The instrument, developed at L'Aquila Geomagnetic Observatory, has a flat response in both amplitude and phase in the frequency band DC-100 Hz, in addition it has low weight, low power, small volume and it is easier to install in the field than induction magnetometers. The sensivity of this magnetometer is 10 pT rms.JCR Journalope
Electromagnetic background noise at L’Aquila Geomagnetic Observatory
No full textIn this paper we analyze the electromagnetic background noise at
L’Aquila Geomagnetic Observatory during 2006 and 2007 in the frequency
band 1-100 mHz. In this band a pronounced daily variation is observed
both in the natural signals as well as in the artificial ones, giving
rise to the problem of separating different contributions of very similar
morphology. We analyzed periods when the local K index was approximately
zero, in correspondence with minimum of the magnetospheric and
ionospheric activity. We found that in our area the main source of artificial
noise is constituted by the DC electrified railways
Magnetic Tensorial Gradiometer
No full textThe vectorial gradiometry offers many advantages compared to scalar gradiometry in the exploration of the subsoil. The introduction of new differential quantities adds a new dimension for the identification of magnetic sources. The direct measurement of the differential tensor quantities in the process of inversion can significantly increase the quality of solutions and the ability to separate more effectively the various magnetic sources in the regions where the magnetic field is derivable from a simple scalar potential. This paper describes the development of a magnetic tensorial gradiometer system and its capabilities with emphasis on the design, testing and operation. The system has been constructed by employing two independent cubic coil sensors at a distance of 50cm. The system measures the nine tensor components Tij as well as the magnitude of the six magnetic components Bhk, in the range of +/-50000 nT with a bandwidth from DC to 10 Hz and a sensitivity of 10 pT/m. The sampling rate can be set from 1 Hz to 20 Hz. It has been shown that a gradiometer sensitivity of 10 pT/m is sufficient to detect even weak magnetic contrasts such as in archaeological applications.UnpublishedCapri, Italy3.8. Geofisica per l'ambienterestricte
Misure di campo elettrico e magnetico nella banda ULF presso l’Osservatorio Geomagnetico dell’Aquila.
No full text
Magnetic Tensorial Gradiometer
No full textThe vectorial gradiometry offers many advantages compared to scalar gradiometry in the exploration of the subsoil. The introduction of new differential quantities adds a new dimension for the identification of magnetic sources. The direct measurement of the differential tensor quantities in the process of inversion can significantly increase the quality of solutions and the ability to separate more effectively the various magnetic sources in the regions where the magnetic field is derivable from a simple scalar potential. This paper describes the development of a magnetic tensorial gradiometer system and its capabilities with emphasis on the design, testing and operation. The system has been constructed by employing two independent cubic coil sensors at a distance of 50cm. The system measures the nine tensor components Tij as well as the magnitude of the six magnetic components Bhk, in the range of +/-50000 nT with a bandwidth from DC to 10 Hz and a sensitivity of 10 pT/m. The sampling rate can be set from 1 Hz to 20 Hz. It has been shown that a gradiometer sensitivity of 10 pT/m is sufficient to detect even weak magnetic contrasts such as in archaeological applications.UnpublishedCapri, Italy3.8. Geofisica per l'ambienterestricte
The contribution of L'Aquila (Italy) Geomagnetic Observatory to MAGDAS project
No full textThe geomagnetic Observatory of L'Aquila (Italy) was founded by Istituto Nazionale di Geofisica e Vulcanologia (INGV) in 1958, on the occasion of the International Geophysical Year. It is the main Italian geomagnetic observatory.
Since 1999 L'Aquila Observatory belongs to the Intermagnet system, an International network grouping worldwide geomagnetic observatories able to provide Earth's magnetic field measurements according to precise quality standards.
Geomagnetic field measurements in L'Aquila are used to study the variations of the Earth's geomagnetic field, both of internal and external origin. In November 2008 a new magnetometer was installed in L'Aquila within the MAGDAS project, coordinated by SERC. The location of this installation can be useful to complete the MAGDAS monitoring system to study solar-terrestrial events.Published49-531.6. Osservazioni di geomagnetismo3.8. Geofisica per l'ambienteN/A or not JCRreserve
The contribution of L'Aquila (Italy) Geomagnetic Observatory to MAGDAS project
No full textThe geomagnetic Observatory of L'Aquila (Italy) was founded by Istituto Nazionale di Geofisica e Vulcanologia (INGV) in 1958, on the occasion of the International Geophysical Year. It is the main Italian geomagnetic observatory.
Since 1999 L'Aquila Observatory belongs to the Intermagnet system, an International network grouping worldwide geomagnetic observatories able to provide Earth's magnetic field measurements according to precise quality standards.
Geomagnetic field measurements in L'Aquila are used to study the variations of the Earth's geomagnetic field, both of internal and external origin. In November 2008 a new magnetometer was installed in L'Aquila within the MAGDAS project, coordinated by SERC. The location of this installation can be useful to complete the MAGDAS monitoring system to study solar-terrestrial events.Published49-531.6. Osservazioni di geomagnetismo3.8. Geofisica per l'ambienteN/A or not JCRreserve
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