@Article{PadilhaAlveSilvEspi:2017:EfHuCr,
               author = "Padilha, Antonio Lopes and Alves, Livia Ribeiro and Silva, 
                         Graziela Belmira Dias da and Espinosa Sarmiento, Karen Viviana",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)}",
                title = "Effect of a huge crustal conductivity anomaly on the H-component 
                         of geomagnetic variations recorded in central South America",
              journal = "Earth, Planets and Space",
                 year = "2017",
               volume = "69",
               number = "1",
                month = "Dec.",
             keywords = "Crustal conductor, Geomagnetic observatory, Geomagnetic 
                         variations, Reflection of electromagnetic waves, Skin effect, 
                         South America.",
             abstract = "We describe here an analysis of the H-component of the geomagnetic 
                         field recorded in several temporary stations operating 
                         simultaneously in the central-eastern region of Brazil during 
                         nighttime pulsation events in 1994 and the sudden commencement of 
                         the St. Patrick's Day magnetic storm in 2015. A significant 
                         amplification in the amplitude of the geomagnetic variations is 
                         consistently observed in one of these stations. Magnetovariational 
                         analysis indicates that the amplification factor is period 
                         dependent with maximum amplitude around 100 s. Integrated 
                         magnetotelluric (MT) and geomagnetic depth soundings (GDS) have 
                         shown that this station is positioned just over a huge 
                         1200-km-long crustal conductor (estimated bulk conductivity 
                         greater than 1 S/m). We propose that the anomalous signature of 
                         the geomagnetic field at this station is due to the high 
                         reflection coefficient of the incident electromagnetic wave at the 
                         interface with the very good conductor and by skin effects damping 
                         the electromagnetic wave in the conducting layers overlying the 
                         conductor. There are some indication from the GDS data that the 
                         conductor extends southward beneath the sediments of the Pantanal 
                         Basin. In this region is being planned the installation of a new 
                         geomagnetic observatory, but its preliminary data suggest 
                         anomalous geomagnetic variations. We understand that a detailed MT 
                         survey must be carried out around the chosen observatory site to 
                         evaluate the possible influence of induced currents on the local 
                         geomagnetic field.",
                  doi = "10.1186/s40623-017-0644-0",
                  url = "http://dx.doi.org/10.1186/s40623-017-0644-0",
                 issn = "1343-8832",
             language = "en",
           targetfile = "padilha_effect.pdf",
        urlaccessdate = "25 abr. 2024"
}