44 research outputs found
H&RA Lacinia project – a multidisciplinary case study in the Crotone offshore (Calabria, Southern Italy) to develop good practices for studying triggerable seismicity and tsunamis
Detection of periodic structures through opaque metal layers by optical measurements of ultrafast electron dynamics
Ion distribution and ablation depth measurements of a fs-ps laser-irradiated solid tin target
The ablation of solid tin surfaces by an 800-nanometer-wavelength laser is
studied for a pulse length range from 500 fs to 4.5 ps and a fluence range
spanning 0.9 to 22 J/cm^2. The ablation depth and volume are obtained employing
a high-numerical-aperture optical microscope, while the ion yield and energy
distributions are obtained from a set of Faraday cups set up under various
angles. We found a slight increase of the ion yield for an increasing pulse
length, while the ablation depth is slightly decreasing. The ablation volume
remained constant as a function of pulse length. The ablation depth follows a
two-region logarithmic dependence on the fluence, in agreement with the
available literature and theory. In the examined fluence range, the ion yield
angular distribution is sharply peaked along the target normal at low fluences
but rapidly broadens with increasing fluence. The total ionization fraction
increases monotonically with fluence to a 5-6% maximum, which is substantially
lower than the typical ionization fractions obtained with nanosecond-pulse
ablation. The angular distribution of the ions does not depend on the laser
pulse length within the measurement uncertainty. These results are of
particular interest for the possible utilization of fs-ps laser systems in
plasma sources of extreme ultraviolet light for nanolithography.Comment: 8 pages, 7 figure
Evaluation of tsunamigenic hazard through numerical modeling from seismic and non-seismic sources in the Crotone offshore (Calabria, Southern Italy)
Tsunamis in the Mediterranean Sea can be considered among the major sources of hazard, both for the extension of the area that can be involved by the water impact and for the closeness of potential sources to the coast, which reduces dramatically the alert and evacuation time. Moreover, landslides, as other non-seismic tsunami sources, are often characterized by a lack of precursors (such as seismic shaking), a reason for which the ensuing waves are sometimes called “surprise tsunamis”
Soil deformation analysis through fluid-dynamic modelling and DInSAR measurements: a focus on groundwater withdrawal in the Ravenna area (Italy)
This study aims at assessing the deformation processes affecting an area NW of the
city of Ravenna (northern Italy), caused by groundwater withdrawal activities. In situ
data, geologic and structural maps, piezometric measurements, underground water
withdrawal volumes, and satellite C-band SAR data were used to jointly exploit two
different techniques: 1) fluid-dynamic and geomechanical modelling (by RSE S.p.A),
and 2) Differential Synthetic Aperture Radar Interferometry (DInSAR) analysis (by
CNR - IREA). The results of the comparative analysis presented in this work brought
new evidence about the contribution of groundwater withdrawal to the total subsidence
affecting the area during the 2000-2017 time interval. In particular, they show an
increase of the subsidence from year 2000 to 2010 and a decrease from year 2010 to
2017. These results are generally in line with groundwater withdrawal data that report
a reduction of the extracted water volumes during the considered temporal interval.
Meantime, they show a delay effect in the subsidence process, partially recovered
during the 2010-2017 thanks to a stabilisation of the extracted groundwater volumes.
The presented results shade new light on the groundwater withdrawal contribution to
the subsidence of the analysed zone, although further investigations are foreseen to
better clarify the ongoing scenario