The INGV tectonomagnetic network: 2004?2005 preliminary dataset analysis

International audienceIt is well established that earthquakes and volcanic eruption can produce small variations in the local geomagnetic field. The Italian Istituto Nazionale di Geofisica e Vulcanologia (INGV) tectonomagnetic network was installed in Central Italy since 1989 to investigate possible effects on the local geomagnetic field related to earthquakes occurrences. At the present time, total geomagnetic field intensity data are collected in four stations using proton precession magnetometers. We report the complete dataset for the period of years 2004?2005. The data of each station are differentiated respect to the data of the other stations in order to detect local field anomalies removing the contributions from the other sources, external and internal to the Earth. Unfortunately, no correlation between geomagnetic anomalies and the local seismic activity, recorded in Central Italy by the INGV Italian Seismic National Network, was found in this period. Some deceptive structures present in the differentiated data are pointed out

The INGV tectonomagnetic network: 2004-2005 preliminary dataset analysis

It is well established that earthquakes and volcanic eruption can produce small variations in the local geomagnetic field. The Italian Istituto Nazionale di Geofisica e Vulcanologia (INGV) tectonomagnetic network was installed in Central Italy since 1989 to investigate possible effects on the local geomagnetic field related to earthquakes occurrences. At the present time, total geomagnetic field intensity data are collected in four stations using proton precession magnetometers. We report the complete dataset for the period of years 2004-2005. The data of each station are differentiated respect to the data of the other stations in order to detect local field anomalies removing the contributions from the other sources, external and internal to the Earth. Unfortunately, no correlation between geomagnetic anomalies and the local seismic activity, recorded in Central Italy by the INGV Italian Seismic National Network, was found in this period. Some deceptive structures present in the differentiated data are pointed out

Investigations on diurnal and seasonal variations of Schumann resonance intensities in the auroral region

Measurements of the magnetic component of the Schumann resonance in the frequency range 6-14 Hz were performed at high latitude location (TNB Antarctica; geographic coordinates: 74.7°S, 164.1°E; geomagnetic coordinates: 80.0°S, 307.7°E; LT=UT+13; MLT=UT8; altitude=28 m a.s.l.), during the two years 1996-1997. TNB is a particularly important observation site located in a region characterised by a high electromagnetic activity in the ELF and VLF bands. Moreover its remote location in Antarctica provides the important advantage that electromagnetic background noise is not corrupted by anthropogenic noise and that the continental lightning activity is very low. The combination of low additional anthropogenic electromagnetic radiation and low atmospheric noise in this area allows detailed investigations into wave generation and amplification in the polar ionosphere and magnetosphere not possible anywhere else in the world. This paper reports the study of the magnetic power of the 8 Hz Schumann resonance mode. For both the years considered diurnal and long-term seasonal variations were observed

The INGV tectonomagnetic network

The Italian Istituto Nazionale di Geofisica e Vulcanologia (INGV) tectonomagnetic network was installed in Central Italy since the middle of 1989 to investigate possible magnetic anomalies related to earthquakes. The network is part of the INGV L'Aquila Geomagnetic Observatory and is located in an area extending approximately in latitude range [41.6°–42.8°] N and longitude range [13.0°–14.3°] E. Actually the network consists of four stations where the total magnetic field intensity data are collected using proton precession magnetometers. New stations will be added to the network starting from the end of 2007. Here we are reporting the whole data set of the network's stations for the period 2004–2006. No significant anomaly in the local geomagnetic field correlated to the seismic activity has been found. Some considerations about misleading structures present in the data sets are reported

Investigations on diurnal and seasonal variations of Schumann resonance intensities in the auroral region

Measurements of the magnetic component of the Schumann resonance in the frequency range 6-14 Hz were performed at high latitude location (TNB Antarctica; geographic coordinates: 74.7°S, 164.1°E; geomagnetic coordinates: 80.0°S, 307.7°E; LT=UT+13; MLT=UT–8; altitude=28 m a.s.l.), during the two years 1996-1997. TNB is a particularly important observation site located in a region characterised by a high electromagnetic activity in the ELF and VLF bands. Moreover its remote location in Antarctica provides the important advantage that electromagnetic background noise is not corrupted by anthropogenic noise and that the continental lightning activity is very low. The combination of low additional anthropogenic electromagnetic radiation and low atmospheric noise in this area allows detailed investigations into wave generation and amplification in the polar ionosphere and magnetosphere not possible anywhere else in the world. This paper reports the study of the magnetic power of the 8 Hz Schumann resonance mode. For both the years considered diurnal and long-term seasonal variations were observed

Magnetic anomalies possibly linked to local low seismicity

During the last twenty years a time-synchronized network of magnetometers has operated in Central Italy along the Apennine chain to monitor the magnetic field anomalies eventually related to the tectonic activity. At present time the network consists of five stations. In the past only few anomalies in the local geomagnetic field, possibly associated to earthquakes, has been observed, not least because the network area has shown a low-moderate seismic activity with the epicentres of the few events with Ml≥5 located away from the network station. During 2007 two Ml≈4 earthquakes occurred in proximity of two stations of the network. Here we report the magnetic anomalies in the geomagnetic field that could be related with these tectonic events. To better investigate these two events a study of ULF (ultra-low-frequency) emissions has been carried out on the geomagnetic field components H, D, and Z measured in L’Aquila Observatory during the period from January 2006 to December 2008. We want to stress that this paper refers to the period before the 2009 L’Aquila seismic sequence which main shock (Ml=5.8) of 6 April heavily damaged the medieval centre of the city and surroundings. At present time the analysis of the 2009 data is in progress

Electromagnetic background noise at L'Aquila Geomagnetic Observatory

In 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

Electromagnetic field measurements in ULF-ELF-VLF [0.001 Hz─100 KHz] bands

We are reporting the technological and scientific objectives of the MEM project. The MEM project has been activated in the INGV Observatory of L'Aquila to create in Central Italy a network of observatories in order to monitoring the electromagnetic signals in the frequency band [0.001 Hz–100 kHz]. Some examples of the instrumentation developed in the frame of the project are reported. An innovative technique, based on the wide band interferometry is proposed to obtain detailed information concerning the several detected electromagnetic sources. Moreover, data from each station will be elaborated to investigate different sectors as the structure of ground electric conductibility, the electromagnetic phenomena connected with seismic activity, the separation of the electromagnetic fields originated in the Earth's interior and the electromagnetic phenomena originated in the magnetosphere, in the ionosphere and in the Earth-ionosphere cavity

The INGV tectonomagnetic network

The Italian Istituto Nazionale di Geofisica e Vulcanologia(INGV) tectonomagnetic network was installed in Central Italy since the middle of 1989 to investigate possible magnetic anomalies related to earthquakes. The network is part of the INGV L’Aquila Geomagnetic Observatory and is located in an area extending approximately in latitude range [41.6°–42.8°]N and longitude range [13.0°–14.3°] E. Actually the network consists of four stations where the total magnetic field intensity data are collected using proton precession magnetometers. New stations will be added to the network starting from the end of 2007. Here we are reporting the whole data set of the network’s stations for the period 2004– 2006. No significant anomaly in the local geomagnetic field correlated to the seismic activity has been found. Some considerations about misleading structures present in the data sets are reported

The INGV Tectonomagnetic Network: 2004 - 2005 Whole Dataset

It is well established that earthquakes and volcanic eruption can produce small variations in the local geomagnetic field. The Italian Istituto Nazionale di Geofisica e Vulcanologia (INGV) Tectonomagnetic Network was installed in Central Italy since 1989 to investigate possible effects on the local geomagnetic field related to earthquakes occurrences. At the present time, total geomagnetic field intensity data are collected in four stations using proton precession magnetometers. We report the complete dataset for the period of years 2004- 2005. The data of each station are differentiated respect to the data of the other stations in order to detect local field anomalies removing the contributions from the other sources, external and internal to the Earth. Unfortunately, no correlation between geomagnetic signal and the local seismic activity, recorded in Central Italy by the INGV Italian Seismic National Network, was found in this period. Some deceptive structures present in the differentiated data are pointed out. At the end, an application of an autoregressive model on the differentiated data is briefly discussed