http://hdl.handle.net/2122/583 Search the Channel search http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/4060 Title: Effects of transient water mass redistribution associated with a tsunami wave on Earth’s pole path <br/> <br/>Authors: Pisani, A. R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Piersanti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Melini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Piatanesi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Soldati, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia <br/> <br/>Abstract: We have quantified the effects of a water mass redistribution associated with the propagation of a tsunami wave on the Earth’s pole path and on the Length-Of-Day (LOD) and applied our modeling results to the tsunami following the 2004 giant Sumatra earthquake. We compared the result of our simulations on the instantaneous rotational axis variations with the preliminary instrumental evidence on the pole path perturbation (which has not been confirmed) registered just after the occurrence of the earthquake. The detected perturbation in the pole path showed a step-like discontinuity that cannot be attributed to the effect of a seismic dislocation. Our results show that the tsunami induced instantaneous rotational pole perturbation is indeed characterized by a step-like discontinuity compatible with the observations but its magnitude is almost one hundred times smaller than the detected one. The LOD variation induced by the water mass redistribution turns out to be not significant because the total effect is smaller than current measurements uncertainties. Fri, 28 Sep 2007 22:58:59 GMT http://hdl.handle.net/2122/4059 Title: Cavola experiment site: geophysical investigations and deployment of a dense seismic array on a landslide <br/> <br/>Authors: Bordoni, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Haines, J.; Bullard Laboratories, Department of Earth Sciences, University of Cambridge, U.K.; Di Giulio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Milana, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Augliera, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Cercato, M.; Dipartimento di Idraulica Trasporti e Strade (DITS), Facoltà di Ingegneria, Università degli Studi di Roma «La Sapienza», Roma, Italy; Martelli, L.; Regione Emilia Romagna, Servizio Geologico Sismico e dei Suoli, Bologna, Italy; Cara, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Cavola Experiment Team; 0 <br/> <br/>Abstract: Geophysical site investigations have been performed in association with deployment of a dense array of 95 3-component seismometers on the Cavola landslide in the Northern Apennines. The aim of the array is to study propagation of seismic waves in the heterogeneous medium through comparison of observation and modelling. The small-aperture array (130 m×56 m) operated continuously for three months in 2004. Cavola landslide consists of a clay body sliding over mudstone-shale basement, and has a record of historical activity, including destruction of a small village in 1960. The site investigations include down-hole logging of P- and S-wave travel times at a new borehole drilled within the array, two seismic refraction lines with both P-wave profiling and surface-wave analyses, geo-electrical profiles and seismic noise measurements. From the different approaches a consistent picture of the depths and seismic velocities for the landslide has emerged. Their estimates agree with resonance frequencies of seismic noise, and also with the logged depths to basement of 25 m at a new borehole and of 44 m at a pre-existing borehole. Velocities for S waves increase with depth, from 230 m/s at the surface to 625 m/s in basement immediately below the landslide. Fri, 28 Sep 2007 22:58:59 GMT http://hdl.handle.net/2122/4058 Title: Morphology of F-region vertical E×B drifts in the African sector using ionosonde measurements <br/> <br/>Authors: Oyekola, O. S.; Department of Physics, College of Science and Technology, Covenant University, Canaanland, Ota, Ogun State, Nigeria; Oluwafemi, C. C.; Department of Physics, College of Science and Technology, Covenant University, Canaanland, Ota, Ogun State, Nigeria <br/> <br/>Abstract: F-region vertical velocities are derived from the ground-based ionosonde data for Ibadan (7.4°N, 3.9°E; dip 6°S: an equatorial station in the African zone), to study the general characteristics of electrodynamics of equatorial ionosphere, such as their variation with season, solar cycle, and magnetic activity at different local time sectors. The results show profound seasonal and geomagnetic effects. Except for equinoctial period, there is an excellent consistency in the magnitudes (nearly 20 m/s) and patterns of upward daytime F-region drifts at low and high solar activity periods. Evening F-region exhibits strong motion with absolute mean value for quiet-time (15 m/s) greater than on disturbed-time (10 m/s). The average downward quiet midnight-early morning hours sector value is well below than 10 m/s. The evening reversal time is earliest and latest during solstitial periods. Prereversal peak is season dependent and varies strongly with magnetic activity. We show that prereversal peak, daytime, and nighttime maximum drifts saturate at particular values of F10.7 cm solar radio flux index, effects not noticed with corresponding sunspot number. Our observations confirm several previous results from other equatorial sites utilizing different experimental techniques. Fri, 28 Sep 2007 22:58:59 GMT http://hdl.handle.net/2122/4057 Title: Historical earthquakes and damage patterns in Potenza (Basilicata, Southern Italy) <br/> <br/>Authors: Gizzi, F. T.; Istituto per i Beni Archeologici e Monumentali, CNR, Area della Ricerca di Potenza, Tito Scalo (PZ), Italy; Masini, N.; Istituto per i Beni Archeologici e Monumentali, CNR, Area della Ricerca di Potenza, Tito Scalo (PZ), Italy <br/> <br/>Abstract: This paper analyzes three historical seismic damage patterns in Potenza, the main town of the Basilicata Region, in Southern Italy. We refer to the 1826, 1857 and 1930 earthquakes, which hit the town with intensities ranging from VI-VII to VIII-IX MCS. In order to depict the seismic effects, we analyzed original documents, most of them never consulted before. The events have been located on an urban map of Potenza dating back to 1875. This research represents the starting point for further investigations, with the goal of highlighting the causes of the ‘anomalies’ in the distribution of the effects. Fri, 28 Sep 2007 22:58:59 GMT