Abstract: New subauroral 15 indices are proposed. They are based on a simple reproducible algorithm which relies on an as dense as possible network of magnetic observatories in each hemisphere. At first, the variation with time of local geomagnetic activity is determined at each magnetic station. Gathering all obtained stations' precomputed values, a normalization with corrected geomagnetic latitude is determined. Then, for each 15 min interval, magnetic activity on the horizontal component is averaged out over 15 min and corrected using this normalization, before a spline modeling of the longitudinal variation in each hemisphere is applied. Hemispheric and planetary 15 min indices are then computed by arithmetic means. Preliminary statistical results, from probability distribution function over a solar cycle and superposed epoch analysis during storms conditions, show, by comparison with am geomagnetic index series, that new 15 indices are reliable in describing subauroral magnetic activity. These new indices will suit any future user, allowing either to choose the spatial description (planetary versus hemispheric) and/or to choose the temporal resolution, knowing unambiguously all their strengths and caveats.

Abstract: The high frequency radars in the Super Dual Auroral Radar Network (SuperDARN) estimate the elevation angles of returned backscatter using interferometric techniques. These elevation angles allow the ground range to the scattering point to be estimated, which is crucial for the accurate geolocation of ionospheric measurements. For elevation angles to be accurately estimated, it is important to calibrate the interferometer measurements by determining the difference in the signal time delays caused by the difference in the electrical path lengths from the main array and the interferometer array to the point at which the signals are correlated. This time delay is known as tdiff. Several methods have been proposed to estimate tdiff using historical observations; these methods are summarised in this paper. Comparisons of the tdiff estimates from the different calibration methods are presented and sources of uncertainty discussed. The effect of errors in the estimated tdiff value on the accuracy of geolocation is evaluated and discussed. The paper concludes with a series of recommendations for both scientific SuperDARN data users and SuperDARN radar operators.

Abstract: Conduction of integrated seismo-geophysical studies in the Antarctic region is a challenge as well as very much warranted to explore the region for its better geo-scientific understanding. Seismogenesis and seismic potential of the Antarctic region have not yet been well understood because of lack of common consensus on various issues, besides its unique and complex geotectonic settings associated with intriguing landscape evolution of the Antarctic plate since the breakup of Gondwana, West Antarctic Rift System (WARS), different patterns of exhumation events that occurred between the Early Cretaceous and Cenozoic. The hostile climatic situation and inaccessibility of the region due to the huge spatial distribution of thicker ice sheets hindered the mission of conducting comprehensive seismo-geophysical studies for the Antarctic Peninsula due to severe constraints of installations of ground-based sophisticated seismo-geophysical equipments in the region. Several causative factors associated with natural and anthropogenic are found still enigmatic in the sense to unravel the fact how the genesis of earthquakes are related to the glacial-dynamics and glacial mass change-induced earthquakes (GMCIE). It has become important to decipher the role and contribution of the East and the West Antarctic microplates and West Antarctic rift systems (WARS) in seismogenesis using advanced methodologies of geosciences. Seismicity of the Antarctic continent region is confined to different tectonic blocks, distributed into the southern ocean, continental margin, Lutzow-Holm Bay, Antarctic Peninsula, and in the volcanic regions in and around Deception Island, which helped estimate the seismic structure of Antarctica. In this chapter, a comprehensive overview of seismo-geophysical studies has been made to understand seismo-geodynamical implications for the Antarctic region in light of the Plate Reconstruction and seismo-geophysical structures of Antarctica.