Comment on "Recent subsidence of the Venice Lagoon
from continuous GPS and interferometric synthetic
aperture radar" by Y. Bock, S. Wdowinski, A. Ferretti,
F. Novali, and A. Fumagalli
P. Teatini
Dept. of Civil, Environmental and Architectural Engineering,
University of Padova, Padova, Italy
L. Tosi
Institute of Marine Sciences, CNR, Venezia, Italy
T. Strozzi
Gamma Remote Sensing, Gumligen, Switzerland
Relative sea level rise, i.e., the combination of
land subsidence and the eustatic rise of the sea
level, is a major problem for the safety of Venice
since the 1970s [e.g., Gambolati et al., 1974;
Carbognin et al., 1977].
The most recent paper on the subject has been
published by Bock et al. [2012]. In this Comment
we (1) dispute the originality of the combined GPS
and InSAR method presented by Bock et al. [2012]
who missed some previous publication on the
subject; (2) contest their statement of possible
"bias" in our previous analyses which used similar
methodologies; (3) question the "precision of 0.1-0.2
mm/yr with respect to a global reference frame"
declared by the authors; and, (4) discuss on the
meaning of "stability" versus "subsidence" for a
coastal city like Venice settled above 1500-m
thick Quaternary unit with 20-30 m of Holocene
poorly consolidated lagoon deposits.
