A comparison of surface magnetic data and MAGSAT data over Italy and its surroundings

A new composite map of magnetic surface (MAGSURF) anomaly for Italy and its adjacent region has been derived from sea and ground surveys on the basis of an improved definition of the Italian Magnetic Reference Field and its t emporal change. Spectral analysis of the MAGSURF anomaly field shows a regi onal scale energy in the wavelength range 145-500 hm, due to the presence o f various crustal sources. The regional MAGSURF anomaly map shows poor corr elation with the corresponding MAGSAT scaler anomaly map, whose power spect rum reveals wavelength components in the range 300-700 lan. The MAGSURF dat a are upward-continued to an elevation of 100 lan for comparison with MAGSA T satellite data, downward-continued to the same altitude of 100 lan and lo w-pass filtered for wavelengths larger than 500 km. Upward-continued surfac e data and downward continued satellite data show good morphological simila rity for wavelengths in the range 300-500 lan at an altitude of 100 lan. Sa tellite data permit the characterization of magnetic signatures due to sour ces located in the middle-lower crust of Sardinia, Lombardia, Molise and Da lmatia, while further surface regional anomalies are connected with upper c rust bodies of Mid Tyrrhene and East Sicily. (C) 1999 Elsevier Science Ltd. All rights reserved.