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Apatodemus degiulii n. gen. et sp. (Rodentia, Muridae), a hitherto undescribed endemite from the Terre Rosse of Gargano (Late Miocene, Southeastern Italy)
No full textThe taxonomy of the murid that had been ascribed to the genus Apodemus from the late Miocene insular faunal assemblages of Gargano
(Southeastern Italy) is revised. Morphological and odontometric analyses of important new dental characters were undertaken. Our
investigations revealed substantial morphological differences from Apodemus. The rodent is therefore assigned to a new genus and
species, Apatodemus degiulii. The new species is characterised by a combination of advanced and primitive characters: moderately
brachyodont teeth, t7 present in all M1–2s, elongated and distally located t1 in M1, t1 often twinned in M1–2, and narrow labial
cingulid in lower molars associated to a well-developed tma. The genus Apatodemus actually includes two distinct species of different
age. A. degiulii is the oldest and is described here in detail. The other one, for the moment, is referred to as Apatodemus sp.: a more
comprehensive description of it will be presented in a future publication. Apatodemus sp. is a highly modified, endemic species, whereas
A. degiulii is slightly endemized. Despite the features of Apatodemus degiulii render difficult to asses its closest continental ancestor,
the species likely originated from some south-eastern European stock, in agreement with paleo-geographical reconstructions suggesting
periodic connections of the Abruzzo-Apulian paleobioprovince with the Balkan mainland. The age when the ancestor of Apatodemus
reached the Apulia Platform is still unclear. However, some lines of evidence suggest a probable arrival at the time of the MN13 unit
(latest Miocene)
Preliminary data on fossil rodents from the vertebrate sites Moncucco and Verduno (post-evaporitic Messinian, Piedmont, NW Italy)
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Inquadramento paleobiogeografico del NW Italia nel Miocene terminale: nuovi dati dai roditori fossili di Verduno (CN) e Moncucco (AT)
No full textMicroseismicity of an unstable rock mass:from field monitoring to laboratory testing
No full textThe field‐scale microseismic (MS) activity of an unstable rock mass is known to be an important tool to assess damage and cracking processes eventually leading to macroscopic failures. However, MS‐event rates alone may not be enough for a complete understanding of the trigger mechanisms of mechanical instabilities. Acoustic Emission (AE) techniques at the laboratory scale can be used to provide complementary information. In this study, we report a MS/AE comparison to assess the stability of a granitic rock mass in the northwestern Italian Alps (Madonna del Sasso). An attempt to bridge the gap between the two different scales of observation, and the different site and laboratory conditions, is undertaken to gain insights on the rock mass behavior as a function of external governing factors. Time‐ and frequency‐domain parameters of the MS/AE waveforms are compared and discussed with this aim. At the field scale, special attention is devoted to the correlation of the MS‐event rate with meteorological parameters (air temperature and rainfalls). At the laboratory scale, AE rates, waveforms, and spectral content, recorded under controlled temperature and fluid conditions, are analyzed in order to better constrain the physical mechanisms responsible for the observed field patterns. The factors potentially governing the mechanical instability at the site were retrieved from the integration of the results. Abrupt thermal variations were identified as the main cause of the site microsesimicity, without highlighting irreversible acceleration in the MS‐event rate potentially anticipating the rock mass collapse
Numerical modelling of wave attenuation through soil
No full textNumerical analyses of induced ground vibrations play an important role in assessing building safety and comfort. One of the major difficulties is related to the calibration of an adequate source model to be used in the numerical simulation. In this paper the attenua-tion of waves caused by drop load tests is considered to provide a general framework for the evaluation of vibration attenuation both with empirical laws and numerical simulations. A new equation to reproduce the source signal is suggested and used as input for a dynamic cou-pled consolidation Finite Element Analysis. The model is validated through comparison with field data obtained at a site in the vicinity of the Tower of Pisa, Italy, from geophones at various distances from the impact source. The calibrated numerical model is then used to study in detail the attenuation of waves from the source and assess the validity of empirical attenuation laws
Mechanical properties of microcrystalline branching selenite gypsum samples and influence of constituting factors
No full textThe high sedimentological variability of gypsum rocks has the effect that a univocal characterization of this material is not easy to establish. This is particularly true from the geomechanical point of view: when the mechanical properties of gypsum rocks are requested, it is therefore necessary to undertake detailed characterization analyses. Common facies of gypsum was observed in the Upper Miocene evaporitic succession (Messinian Salinity Crisis) within the whole Mediterranean Basin. In this work, mechanical tests were conducted on a site-specific facies, represented by the microcrystalline branching selenite. The tested samples came from the Monferrato area (northwestern Italy). Uniaxial compressive strength (UCS) tests were performed in order to obtain reference mechanical parameters. More rapid and economic point load test (PLT) and ultrasonic pulse velocity (UPV) measurements were additionally performed to verify their applicability as complementary/alternative methods for site characterization. Rock-type specific PLT-UCS and UPV-UCS relationships were established. A wide dispersion of the mechanical parameters was observed due to the heterogeneities of the studied material. Consequently, compositional, textural and microstructural observations on selected samples were performed. Two main material classes were recognized based on average grain size and total gypsum content, underlining the significant influence of the grain sorting on the measured mechanical properties. Keywords: Gypsum, Uniaxial compressive strength (UCS), Point load test (PLT), Mechanical properties, Geological heterogeneit
Numerical modelling of drop load tests
No full textAssessment of the attenuation of induced vibrations in the ground plays an important role in evaluating comfort and structural safety. Analytical and empirical wave attenuation relationships of increasing complexity and detail are presented in the paper, as well as a numerical model that accurately reproduces wave attenuation for a well-documented site, namely the one of the Tower of Pisa, Italy. A new source model is calibrated on near-field data and used as input for the dynamic coupled consolidation finite element analysis to achieve a satisfactory simulation. The accuracy of simpler analytical and empirical approaches is then comprehensively assessed through comparison with the validated numerical model and the field data obtained from geophones at various distances from the impact sourc
Detecting Slow Deformation Signals Preceding Dynamic Failure: A New Strategy For The Mitigation Of Natural Hazards (SAFER)
No full textFirst results from microseismic monitoring of a rockslide at Madonna del Sasso (Verbania, Italy)
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