The development of the INGV tectonomagnetic network in the frame of the MEM Project

Abstract

Abstract. In the middle of 1989, the INGV (Italian Istituto Nazionale di Geofisica e Vulcanologia) installed in Central Italy a network of magnetic stations in order to investigate possible relationship of the local magnetic field with earthquakes occurrences. Actually the network consists of four stations, where the total magnetic field intensity data are being collected using proton precession magnetometers. Here we are report on the actual state and the future developments of the network. In the frame of the MEM (Magnetic and Electric fields Monitoring) Project, new stations will be added to the network by the end of 2007. The results of the test campaigns carried out in the sites chosen to widen the network are also discussed. Moreover, the 2006 complete data set of the network is also reported. Concerning the data analysis, a new approach is also discussed that takes into account the inductive effects on the local geomagnetic field by means of the inter-station transfer functions time variations analysis.

The INGV tectonomagnetic network

“…Afterwards, some test campaigns have been carried out to check the electromagnetic background noise level of the new sites. The results of these tests have shown that only BRT and VVL sites are suitable for the installation of a geomagnetic station, whereas the VVL background noise is too high for this purpose and this site has been rejected (Masci et al, 2007). Actually we are searching for a new site to fill the gap between the AQU and the CVT stations.…”

“…1 the locations in Central Italy of the stations are reported. The sampling rate of each station is set to 15 min except for the AQU Observatory in which the sampling rates are 1 min and 1 s. At the beginning of 2006, in the frame of the MEM (Magnetic and Electric fields Monitoring) Project, it has been decided to upgrade the network (Masci et al, 2007 Three potential sites as station locations were chosen at the end of 2006. Figure 1 shows the locations of these sites: Barete (BRT), Duronia (DUR) and Villavallelonga (VVL).…”

Magnetic anomalies possibly linked to local low seismicity

“…6 the daily means of the total magnetic field differences for the couple of stations AQU-CVT in the period JD = 2006. Unfortunately in this period MDM station was off for technical problems (Masci et al, 2007), so we can show only the differences AQU-CVT. A 3 days running average of the differences is reported to better show the differences trend.…”

“…Usually only large earthquakes (Ml≥5) generate evident electromagnetic anomalies. Moreover, coseismic anomalies are larger than preseismic and postseismic events because the observed coseismic effects are due to the release of the accumulated crustal stress during the entire earthquake duration, whereas the preseismic signals are due to a small fraction of the accumulated energy release (Mueller and Johnston, 1998 (Masci et al, 2006(Masci et al, , 2007. At present time, the network stations are: L'Aquila (AQU), Monte di Mezzo (MDM), Civitella Alfedena (CVT), Leonessa (LEO) and Duronia (DUR).…”

Multi-point ground-based ULF magnetic field observations in Europe during seismic active periods in 2004 and 2005

“…Many authors reported about the importance and difficulties of discriminating man made noise, e.g. Harada et al (2004), Villante et al (2004) and Masci et al (2007). Less influence due to man made noise is expected during the nighttime hours which is the reason why we selected the local midnight time period for detailed analysis as described in Sect.…”