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71.
72.
Mauro Coltorti Andrea Brogi Lorenzo Fabbrini Dario Firuzabadì Lapo Pieranni 《Natural Hazards》2011,59(1):191-208
The eastern side of the Mt. Amiata volcano is affected by a series of deep-seated gravitational slope deformations (DsGSDs).
The San Piero and the Podere Mezzavia DsGSDs affect the lower part of the slope. The main escarpments are located on the outer
edges of the lava flows, but the landslides mostly affect the pre-volcanic Ligurian Terrains. A deeper movement, possibly
exceeding 100 m in thickness, is evidenced by a long trench at the base of the main escarpment that indicates a sagging type
movement. This deeper movement is responsible for the activation of a series of superficial rock and mud flows that show evidence
of ongoing activity. The most likely location of the sliding surface is the tectonized contact between the Santa Fiora and
Argille a Palombini Fms within the Ligurian units, although the superficial landslides prevent our determining with certainty
if a clear-cut sliding surface already developed connecting the upper and the lower parts of the slope. These DsGSDs were
activated along the flanks of a larger movement that affects the lava flow units cropping out in the middle slope of the volcano.
A long main escarpment, secondary escarpments, trenches and borehole data suggest that the thickness could locally exceed
200 m and generate another sagging type movement. Up-slope and up-movement-facing counterscarps indicate the existence of
a listric elongated spoon-shaped compound embryonic sliding surface. This sagging, which hosts the towns of Abbadia San Salvatore
and Piancastagnaio, appears to be in a quiescent stage, according to preliminary monitoring with a global positioning system
(GPS) network. The downcutting of the river network along the softer Pliocene terrains of the Radicofani basin is enhanced
by the general uplift of the Apennines and seems to be the major factor in the activation of these DsGSDs. 相似文献
73.
Tiziano Boschetti Lorenzo Toscani Orfan Shouakar-Stash Paola Iacumin Giampiero Venturelli Claudio Mucchino Shaun K. Frape 《Aquatic Geochemistry》2011,17(1):71-108
The salt waters from the Emilia-Romagna sector of the Northern Apennine Foredeep have been investigated using major and trace
element and stable isotope (δ2H, δ18O, δ37Cl, δ81Br and 87Sr/86Sr ratio). Ca, Mg, Na, K, Sr, Li, B, I, Br and SO4 vs. Cl diagrams suggest the subaerial evaporation of seawater beyond gypsum and before halite precipitation as primary process
to explain the brine’s salinity, whereas saline to brackish waters were formed by mixing of evaporated seawater and water
of meteoric origin. A diagenetic end-member may be a third component for mud volcanoes and some brackish waters. Salinization
by dissolution of (Triassic) evaporites has been detected only in samples from the Tuscan side of the Apennines and/or interacting
with the Tuscan Nappe. In comparison with the seawater evaporation path, Ca–Sr enrichment and Na–K–Mg depletion of the foredeep
waters reveal the presence of secondary processes such as dolomitization–chloritization, zeolitization–albitization and illitization.
Sulfate concentration, formerly buffered by gypsum-anhydrite deposition, is heavily lowered by bacterial and locally by thermochemical
reduction during burial diagenesis. From an isotopic point of view, data of the water molecule confirm mixing between seawater
and meteoric end-members. Local 18O-shift up to +11‰ at Salsomaggiore is related to water–rock interaction at high temperature (≈150°C) as confirmed by chemical
(Mg, Li, Ca distribution) and isotopic (SO4–H2O) geothermometers. 37Cl/35Cl and 81Br/79Br ratios corroborate the marine origin of the brines and evidence the diffusion of halogens from the deepest and most saline
aquifers toward the surface. The 87Sr/86Sr ratio suggests a Miocene origin of Sr and rule out the hypothesis of a Triassic provenance of the dissolved components
for the analyzed waters issuing from the Emilia-Romagna sector of the foredeep. Waters issuing from the Tuscan side of the
Apennines and from the Marche sector of the foredeep show higher 87Sr/86Sr ratios because of the interaction with siliciclastic rocks. 相似文献
74.
We investigate the bounce cosmology induced by inhomogeneous viscous fluids in FRW space-time (non necessarily flat), taking into account the early-time acceleration after the bounce. Different forms for the scale factor and several examples of fluids will be considered. We also analyze the relation between bounce and finite-time singularities and between the corresponding fluids realizing this scenarios. In the last part of the work, the study is extended to the framework of f(R)-modified gravity, where the modification of gravity may also be considered as an effective (viscous) fluid producing the bounce. 相似文献
75.
Badini Lorenzo Ott Stephan Aondio Patrik Winter Stefan 《Bulletin of Earthquake Engineering》2022,20(11):5963-6006
Bulletin of Earthquake Engineering - In this study a timber-based integrated solution is presented to solve at once common issues affecting typical reinforced concrete (RC) existing buildings, such... 相似文献
76.
77.
78.
Hypsometric Analysis of Headwater Rock Basins in the Dolomites (Eastern Alps) Using High‐Resolution Topography 下载免费PDF全文
Lorenzo Marchi Marco Cavalli Sebastiano Trevisani 《Geografiska Annaler: Series A, Physical Geography》2015,97(2):317-335
Hypsometric curves and integrals are effective tools for rapid quantitative assessments of topography. High‐resolution digital terrain models derived from airborne LiDAR data have been analysed to study the hypsometry of small headwater rock basins (drainage areas up to 0.13 km2) in three study areas in the Dolomites (Eastern Alps) that have similar lithologies and climatic conditions. Hypsometric curves in the studied rocky headwaters display a variety of shapes and present remarkable differences between neighbouring basins. Hypsometric integrals show generally high values in the three study areas (>0.42, mean values between 0.51 and 0.65). The extent of the scree slopes located at the foot of rock basins in the three study areas is larger in the area with lower hypsometric integrals and indicates consistency between the development of basin erosion, which is shown by the hypsometric integral, and debris yield, represented by the extent of scree slope. No clear relations were observed between the hypsometric integrals and basin area and shape. When extending the analysis to larger basins, which encompass rocky headwaters and downslope soil‐mantled slopes, a negative correlation is found between the hypsometric integral and catchment area, suggesting that the scale independency of the hypsometric integral occurs essentially in headwater rock basins. Geomorphometric indices (residual relief and surface roughness) have contributed to interpreting the variability of surface morphology, which is related to the geo‐structural complexity of the catchments. 相似文献
79.
Ocean Dynamics - Wind-generated ocean waves are key inputs for several studies and applications, both near the coast (coastal vulnerability assessment, coastal structures design, harbor... 相似文献
80.
Fernando I. Rial Manuel Pereira Henrique Lorenzo Pedro Arias Alexandre Novo 《Journal of Applied Geophysics》2009,67(4):367
Since target reflections directly depend on the emitted pulse characteristics, a key factor for carrying out a successful GPR survey is to know as much as possible about the transmission features of the antennas used. This information is very important in order to choose the right antennas and set the appropriate configuration parameters for a specific survey. With this in mind this paper deals with the development of a set of laboratory experiments on the resolution capabilities of three bowtie antennas at frequencies of 500, 800 and 1000 MHz. Results from these measurements give a first estimation of the resolution of the antennas under test, showing the advantage of performing experiments rather than relying only on theoretical assumptions. The results are also expressed in terms of the central wavelength for each antenna and compared with some theoretical estimations proposed in the specialized bibliography. 相似文献