Search results for "Geophysics"

Grassland fire effect on soil organic carbon reservoirs in a semiarid environment

2013

Abstract. The aim of this work was to investigate the effect of an experimental fire used for grassland management on soil organic carbon (SOC) stocks. The study was carried out on Hyparrhenia hirta (L.) Stapf (Hh) grassland and Ampelodesmos mauritanicus (Desf.) T. Durand & Schinz (Am) grasslands located in the north of Sicily. Soil samples were collected at 0–5 cm before and after the experimental fire, and SOC was measured. During the grassland fire, soil surface temperature was monitored. Biomass of both grasses was analysed in order to determine dry weight and its chemical composition. The results showed that SOC varied significantly with vegetation type, while it is not affecte…

Cool barnacles: Do common biogenic structures enhance or retard rates of deterioration of intertidal rocks and concrete?

2017

Sedentary and mobile organisms grow profusely on hard substrates within the coastal zone and contribute to the deterioration of coastal engineering structures and the geomorphic evolution of rocky shores by both enhancing and retarding weathering and erosion. There is a lack of quantitative evidence for the direction and magnitude of these effects. This study assesses the influence of globally-abundant intertidal organisms, barnacles, by measuring the response of limestone, granite and marine-grade concrete colonised with varying percentage covers of Chthamalus spp. under simulated, temperate intertidal conditions. Temperature regimes at 5 and 10 mm below the surface of each material demons…

Assessing vermetid reefs as indicators of past sea levels in the Mediterranean

2020

Abstract The endemic Mediterranean reef building vermetid gastropods Dendropoma petraeum complex (Dendropoma spp) and Vermetus triquetrus develop bio-constructions (rims) on rocky shorelines at about Mean Sea Level (MSL) and are therefore commonly used as relative sea-level (RSL) markers. In this study, we use elevations and age data of vermetid reefs to (1) re-assess the vertical uncertainties of these biological RSL indicators, and (2) evaluate the vertical growth rates along a Mediterranean east-west transect, in attempt to explain the differences found in both growth rates and uncertainties. In Israel, Differential Global Positioning System (DGPS) and laser measurements relative to the …

The Messinian Salinity Crisis deposits in the Balearic Promontory: An undeformed analog of the MSC Sicilian basins??

2021

International audience; The Messinian Salinity Crisis (MSC) is a controversial geological event that influenced the Mediterranean Basin in the late Miocene leaving behind a widespread Salt Giant. Today, more than 90% of the Messinian evaporitic deposits are located offshore, buried below the Plio-Quaternary sediments and have thus been studied mainly by marine seismic reflection imaging. Onshore-offshore records’ comparisons and correlations should be considered a key approach to progress in our understanding of the MSC.This approach has however not been widely explored so far. Indeed, because of the erosion on the Messinian continental shelves and slopes during the MSC, only few places in …

Structural architecture and active deformation pattern in the northern sector of the Aeolian-Tindari-Letojanni fault system (SE Tyrrhenian Sea-NE Sic…

2017

Framed in the current geodynamics of the central Mediterranean, the Aeolian-Tindari-Letojanni fault system is part of a wider NW-SE oriented right-lateral wrench zone which accommodates diverging motion between regional-scale blocks located at the southern edge of the Calabrian Arc. In order to investigate the structural architecture and the active deformation pattern of the northern sector of this tectonic feature, structural observations on-land, high and very-high resolution seismic reflection data, swath bathymetry data and seismological and geodetic data were merged from the Lipari-Vulcano volcanic complex (central sector of the Aeolian Islands) to the Peloritani Mountains across the G…

Reply to the comment on “Carbonate deposition and diagenesis in evaporitic environments: The evaporative and sulphur-bearing limestones during the se…

2016

Abstract Manzi et al. (in press) took the opportunity offered by our paper to repeat again all the set of ideas supporting an interpretative model of the Messinian Salinity Crisis (MSC), a model they assert to be valid for the whole Mediterranean basin. What emerges from reading this long comment may be summarized in one criticism of our article: we have not systematically applied their interpretative model to our data! The aim of our paper was not to promote their ideas, but to submit the results of more than 20 years of field studies and petrographical and geochemical analyses on Sicilian and Calabrian sequences of the Messinian “Calcare di Base”. It is out of our purpose to enumerate aga…

Evidence of Roman Earthquake Surface Faulting at Santa Venera al Pozzo (Catania, Southern Italy): a probable seismic event in 251 AD?

2018

The record of historical seismicity of Catania (Southern Italy) and its neighbourhood during the first millennium AD is largely incomplete due to the scarcity of sources reporting information on earthquake damage, whereas on the contrary numerous historical sources provide plentiful description of past Etnean eruptions affecting the Catania area. This study provides new insights on the Catania seismic history, which was struck by large earthquakes during its recent history (e.g. 1169, 1542, 1693, 1818 earthquakes). During the first millennium, the only documented earthquake occurred in 251 AD, a year before of the big Etna eruption of 252 AD (Guidoboni et al., 2014). This earthquake left we…

Physical identification of precious artefacts: their sonic imprint

2009

The Residual Shear Strength of the Shaly and Sandy Facies of the Opalinus Clay

2018

The paper presents a comprehensive laboratory campaign carried out with the aim to asses the residual strength of the Opalinus Clay. Ring shear tests with vertical effective stress up to 1 MPa were performed on remoulded samples of two different facies of the Opalinus Clay. Test results show that the «Shaly» facies is characterized by a low range of variation of residual strength while the strength of the «Sandy» facies is very sensitive to the variation of grain size distribution. Microstructural analyses (SEM) suggest that the difference in the observed mechanical behavior of the two facies can be related to different particles arrangements along the shear surfaces.

Life cycle environmental assessment of retaining walls in unsaturated soils

2022

Abstract Retaining structures above groundwater level support soils that are usually in a state of partial saturation and subject to the actions of atmospheric agents. The current design approach considers the possible extremes of soil conditions – either totally dry or totally saturated – but it neglects matric suction’s contribution to soil shear strength. This work aims to describe how unsaturated-soil mechanics of can positively influence the sustainability of retaining structures through a holistic, multidisciplinary, geotechnical, and environmental analysis. The geotechnical analysis allows to estimate the lateral earth pressure of a geostructure in both unsaturated and extreme soil c…