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Yamazaki, Y.
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Yamazaki, Y.
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- PublicationRestrictedEquatorial ionospheric disturbances over the East African sector during the 2015 St. Patrick’s day stormDuring solar cycle 24, the St. Patrick’s Day storm on 17 March, 2015 was one of the most severe geomagnetic storms. Several research investigations have been done and are still ongoing about this storm since the dynamics of this storm differs on a global scale from one sector to another. This study examines the response of the equatorial ionosphere to the storm in the East African sector. Total electron content (TEC) data from ground stations are used to investigate the evolution of the Equatorial Ionization Anomaly (EIA) during the storm. The TEC observations show a reduced EIA during 18–20 March 2015, consistent with previous studies at other longitudes. Analyses of ground magnetometer data and the thermospheric composition data from the NASA/TIMED satellite reveal that the reduced EIA during the storm can arise from the combined effect of the disturbance dynamo and composition change.
115 8 - PublicationRestrictedClues from joint inversion of tsunami and geodetic data of the 2011 Tohoku-oki earthquake(2012-04-27)
; ; ; ; ; ; ; ; ;Romano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piatanesi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Lorito, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;D'Agostino, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Hirata, K.; Meteorological Research Institute, Japan Meteorological Agency, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan ;Atzori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Yamazaki, Y.; Department of Ocean and Resource Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA ;Cocco, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; ; ; ; The 2011 Tohoku-oki (Mw 9.1) earthquake is so far the best-observed megathrust rupture, which allowed the collection of unprecedented offshore data. The joint inversion of tsunami waveforms (DART buoys, bottom pressure sensors, coastal wave gauges, and GPS-buoys) and static geodetic data (onshore GPS, seafloor displacements obtained by a GPS/acoustic combination technique), allows us to retrieve the slip distribution on a non-planar fault. We show that the inclusion of near-source data is necessary to image the details of slip pattern (maximum slip ,48 m, up to ,35 m close to the Japan trench), which generated the large and shallow seafloor coseismic deformations and the devastating inundation of the Japanese coast. We investigate the relation between the spatial distribution of previously inferred interseismic coupling and coseismic slip and we highlight the importance of seafloor geodetic measurements to constrain the interseismic coupling, which is one of the key-elements for long-term earthquake and tsunami hazard assessment.340 26