The INGV tectonomagnetic network in central Italy. Fifteen years of observations and future developments: an update

Abstract

Tectonic events, as earthquakes and volcanic eruptions, may generate variations in the local geomagnetic field intensity. To detect possible effects related to seismic activity in central Italy, the INGV (Istituto Nazionale di Geofisica e Vulcanologia) installed a network of four magnetometers in 1989, in a region extending from 41° to 43° latitude N and 12° to 15° longitude E. The study area is characterized by active faulting and seismicity, and by historical destructive earthquakes. The total geomagnetic field intensity was synchronously sampled at the magnetometer sites since July 1989 and averaged on a daily basis. These values were then differentiated with respect to the data recorded at the permanent nearby National Geomagnetic Observatory of L’Aquila (42° 23’ N, 13° 19’ E). The aim of our work was to detect possible significant magnetic field variations of tectonic origin. Data have been regularly recorded for about 15 years with some interruptions due to instrumental temporary failures. This data set represents a long series of recordings that is valuable to characterize the local response of each station to the secular variation in a tectonically active area. In this paper we applied a new signal processing on data by means of a wavelet analysis to the differentiated geomagnetic records for the period 2000-2005. In an ongoing paper the same technique is extended back to the remaining ten years of data (1989-1999).