GNGTS 2015 - Atti del 34° Convegno Nazionale

100 GNGTS 2015 S essione 1.2 two parts of the basin cannot be simply imputed to different anthropogenic effects or to ground settlement (Teatini et al., 2011). The same pattern was highlighted by the results of repeated levelling measurements from 1897 to 1957 (Arca and Beretta, 1985), a period that preceded the strong increase of economic activities in the second half of the XX century. Such observations point out a dominant subsidence in the eastern Po Valley and a prevalent uplift in the western part of the valley. The similarity between the two vertical kinematic patterns, the actual obtained analyzing the GPS data and ones estimated using the data levelling acquired in the first half of XX century seems indicate that the effects of anthropogenic activities on the vertical movements it may be not only causes of this difference. This analysis suggests the existence of a tectonic contribution that produce a ��� ���������� ������ �� ��� ������� ������� �� ������� �� ���� ������� not negligible uplift in the eastern sector, as suggest to some authors (Cenni et al., 2013). ��� ���������� ������� ��� ������� ��������� ������� �� ��� ������� ������ The comparison between the present kinematic pattern in the eastern sector of Po Plain (Fig. 3) and the results obtained previously with different observation time span and/or techniques (Baldi et al., 2009, 2011; Bonsignore, 2007, 2008; Cenni et al., 2013; Teatini et al., 2013) indicates that the rates are stable or in some cases are decreasing. During the meeting we present the first results about a study regarding the time variation of the vertical velocity values observed in the Po Plain and possible correlations with tectonic processes, or other natural phenomena (e.g. changes in the rainfall trend) or anthropogenic activities. Acknowledgments. We are grateful to the following Institutions: ASI, ARPA Piemonte, FOGER (Fondazione dei Geometri e Geometri Laureati dell’Emilia Romagna), FREDNET – OGS, LEICA – Italpos, NETGeo – Topocon, Regione Abruzzo, Regione Friuli Venezia Giulia, Regione Liguria, Regione Piemonte, Regine Umbria – Labtopo (University of Perugia), Regione Veneto, RING-INGV, Provincia Autonoma di Bolzano (STPOS), Provincia Autonoma di Trento (TPOS), STONEX, which have kindly made available GPS recordings. The figures have been carried out by the Generic Mapping Tools (Wessel and Smith, 1998). References Arca S. and Beretta G.P.; 1985: Prima sintesi geodetica-geologica sui movimenti verticali del suolo nell’Italia Settentrionale. Boll. Geod. Sci. Aff., 44 , 125-156. Altamimi, Z., Métivier, L. and Collilieux, X.; 2012: ITRF2008 Plate Motion Model. Journal of Geophysical Research , 117 , Article ID: B07402. http://dx.doi.org/10.1029/2011JB008930. Baldi P., Casula G., Cenni N., Loddo F. and Pesci, A.; 2009: GPS-based monitoring of land subsidence in the Po Plain (Northern Italy). Earth Planet. Science Letts., 288 , 204-212, doi:10.1016/j.epsl.2009.09.023. Baldi, P., Casula, G., Cenni, N., Loddo, F., Pesci,A., Bacchetti, M.; 2011: Vertical ad horizontal crustal movements in Central and Northern Italy . Boll.Soc.Geol.It. (Ital. J. Geosci.), 52 , 4, 667-685. Fig. 3 – The present GPS vertical kinematic pattern in the Po Plain obtained considering the stations with an observation time span longer than 2.5 years. The contour map has been estimated using a geostatistical method over a regular spaced grid (15 km x 15 km). The magnitude of vertical rates can be deduced by the chromatic scale on the right.