author = "S{\'a}nchez Juarez, Sa{\'u}l Alejandro and Kherani, Esfhan Alam 
                         and Klausner, Virg{\'{\i}}nia and Paula, Eurico Rodrigues de and 
                         Meneses, Francisco de",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Universidade do Vale 
                         do Para{\'{\i}}ba (UNIVAP)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Universidad Aut{\'o}noma de Nuevo 
                title = "Geomagnetic and Ionospheric Disturbances During Moderate Seismic 
                         Events in South America",
                 year = "2019",
         organization = "AGU Fall Meeting",
             abstract = "Seismic-Triggered-Travelling-Ionospheric-Disturbances (SAIDs) can 
                         be generated by seismic activity. Earth displacement due to 
                         earthquakes causes effects on the atmosphere up to 300 km in 
                         height, including the ionosphere region, as a result of the 
                         coupling of the Lithosphere Atmosphere Ionosphere interfaces. In 
                         fact, in the atmosphere, effects are amplified by up to 4 orders 
                         of magnitude, because atmospheric density decreases exponentially. 
                         We use data from magnetometer and GPS stations located in the 
                         South America region. For the time series, spectral analysis 
                         techniques based on the Continuous Wavelet Transform (CWT) and 
                         Hilbert-Huang Transform (HHT) were used. For the moderate 
                         earthquake (Mw=6.3) using GPS receiver data, we detect the 
                         Travelling Ionospheric Disturbances that are associated with an 
                         acoustic wave with a velocity of 0.8 km/s and with slower (0.3 and 
                         0.2 km/s) velocities that may be associated with gravity waves. 
                         Favorable preconditioning offered by non-seismic MSTIDs 
                         contributes to the rise of the seismic detectable level. Using 
                         magnetometer networks, we detect SAIDs in the form of geomagnetic 
                         disturbances that have propagation velocities greater than the 
                         velocity of the primary and secondary waves recorded by 
                         seismographs, and due to the very high velocities, these 
                         disturbances may be associated mainly to the shear or oblique 
                         Alfv{\'e}n waves.",
  conference-location = "San Francisco, CA",
      conference-year = "09-13 dec.",
             language = "en",
           targetfile = "sanchez-geomagnetic.pdf",
        urlaccessdate = "26 jan. 2021"