Magnetic fabric of Pleistocene continental clays from the hanging-wall of an active low-angle normal fault (Altotiberina Fault, Italy)

Anisotropy of magnetic susceptibility (AMS) represents a valuable proxy able to detect subtle strain effects in very weakly deformed sediments. During the last decades a large number of AMS studies have documented that in compressive tectonic settings the maximum susceptibility axes (i.e. the magnetic lineations) are parallel to fold axes (and thrust faults) and local bedding strikes, while in extensional regimes they are perpendicular to the normal faults and, thus, parallel to the strata dip directions. One of the most striking active tectonic structures of the northern Apennines is represented by the Altotiberina Fault (ATF), a NE-dipping low-angle normal fault bounding the High Tiber Valley. The ATF represents a primary detachment of the Plio-Quaternary extensional tectonics affecting the Apennine belt. The long-lasting activity of the ATF produced 5 km of total displacement and up to 1200-m-thick basin infill of syn-tectonic, sandy-clayey continental succession. Thus, the AMS analysis of the sediments lying above the ATF represents a unique opportunity to document the strain field affecting the hanging-wall of low-angle normal faults. We collected 129 oriented cores at 12 different localities within the High Tiber Valley, and measured the AMS with a spinner Multi-Function Kappabridge. Most of the sites show a magnetic fabric typical of sediments at the earliest stages of deformation, characterized by oblate AMS ellipsoids and a well defined magnetic lineation, while prolate AMS ellipsoids at two sites are suggestive of pervasive tectonic effects. The magnetic lineation is well-developed at all sites and 20 has a prevailing N-S direction. At five sites the bedding is tilted and the magnetic lineation is subparallel to local bed-strikes, implying that these sites underwent a maximum horizontal shortening along an E-W direction. At two sites the magnetic lineation is sub-perpendicular to the trend of the ATF, and may be related to extensional strain. Our results reveal the existence of both compressional and extensional structures at the hangingwall of the ATF, and suggest that the early Pleistocene sequence of the High Tiber Valley is arranged in gently, local folds (hardly visible in the field) ~N-S trending. We interpret these compressivestructures as the result of local superficial stress induced by irregularities of the fault plane at depth. Accordingly, the strain field we documented from the High Tiber Valley can not be used to infer the regional tectonic regime acting during the ATF activity. We conclude that the long-lasting debate on the extensional vs. compressional Plio-Quaternary tectonics of the Apennines orogenic belt should be revised evaluating the importance of compressional structures resulting by local effects

Magnetic fabric of Pleistocene continental clays from the hanging-wall of an active low-angle normal fault (Altotiberina Fault, Italy)

Anisotropy of magnetic susceptibility (AMS) represents a valuable proxy able to detect subtle strain effects in very weakly deformed sediments. In compressive tectonic settings, the magnetic lineation is commonly parallel to fold axes, thrust faults, and local bedding strike, while in extensional regimes, it is perpendicular to normal faults and parallel to bedding dip directions. The Altotiberina Fault (ATF) in the northern Apennines (Italy) is a Plio-Quaternary NNW–SSE low-angle normal fault; the sedimentary basin (Tiber basin) at its hanging-wall is infilled with a syn-tectonic, sandy-clayey continental succession. We measured the AMS of apparently undeformed sandy clays sampled at 12 sites within the Tiber basin. The anisotropy parameters suggest that a primary sedimentary fabric has been overprinted by an incipient tectonic fabric. The magnetic lineation is well developed at all sites, and at the sites from the western sector of the basin it is oriented sub-perpendicular to the trend of the ATF, suggesting that it may be related to extensional strain. Conversely, the magnetic lineation of the sites from the eastern sector has a prevailing N–S direction. The occurrence of triaxial to prolate AMS ellipsoids and sub-horizontal magnetic lineations suggests that a maximum horizontal shortening along an E–W direction occurred at these sites. The presence of compressive AMS features at the hanging-wall of the ATF can be explained by the presence of gently N–Strending local folds (hardly visible in the field) formed by either passive accommodation above an undulated fault plane, or rollover mechanism along antithetic faults. The long-lasting debate on the extensional versus compressive Plio-Quaternary tectonics of the Apennines orogenic belt should now be revised taking into account the importance of compressive structures related to local effects

Enantioselective HF loss promoted by resonant two photon ionization of supersonically expanded (R)-1-phenyl-2,2,2-trifluoroethanol clusters.

(R)-1-Phenyl-2,2,2-trifluoroethanol and its hydrogen bonded adducts with achiral (water, tetrahydrofuran) and chiral solvent mols. ((R)- and (S)-butan-2-ol, (R)- and (S)-3-hydroxy-tetrahydrofuran) have been ionized by resonant two-photon absorption. The presence of photofragments, attributable to the occurrence of a hydrogen fluoride loss reaction, has been interpreted with the aid of theor. predictions at the DFT level of theory with the inclusion of dispersive terms. The HF elimination process takes place by a mechanism involving the preliminary C.alpha.-H hydrogen transfer to an hydroxyl oxygen assisted by the solvent mol. which is followed by extrusion of the HF mol. The calcd. energy barriers depend on the type of solvent as well as on its configuration and are consistent with the obsd. fragmentation ratios

Verification of Precipitation Forecasts from Two Limited-Area Models over Italy and Comparison with ECMWF Forecasts Using a Resampling Technique

Abstract This paper presents the first systematic limited area model (LAM) precipitation verification work over Italy. A resampling technique was used to provide skill score results along with confidence intervals. Two years of data were used, starting in October 2000. Two operational LAMs have been considered, the Limited Area Model Bologna (LAMBO) operating at the Agenzia Regionale Prevenzione e Ambiente-Servizio Meteorologico Regionale (ARPA-SMR) of the Emilia–Romagna region, and the QUADRICS Bologna Limited Area Model (QBOLAM) running at the Agenzia per la Protezione dell'Ambiente e per i Servizi Tecnici (APAT). A 24-h forecast skill score comparison was first performed on the native 0.1° high-resolution grids, using a Barnes scheme to produce the observed 24-h accumulated rainfall analysis. Two nonparametric skill scores were used: the equitable threat score (ETS) and the Hanssen and Kuipers score (HK). Frequency biases (BIA) were also calculated. LAM forecasts were also remapped on a lower-resolution grid (0.5°), using a nearest-neighbor average method; this remapping allowed for comparison with ECMWF model forecasts, and for LAM intercomparisons at lower resolution, with the advantage of reducing the skill score sensitivity to small displacements errors. LAM skill scores depend on the resolution of the verification grid, with an increase when they are verified on a lower-resolution grid. The selected LAMs have a higher BIA compared to ECMWF, showing a tendency to overforecast precipitation, especially along mountain ranges, possibly due to undesired effects from the large-scale and/or convective precipitation parameterizations. Lower ECMWF BIA accounts for skill score differences. LAMBO precipitation forecasts during winter (adjusted for BIA differences) have less misses than ECMWF over the islands of Sardinia and Sicily. Higher-resolution orography definitely adds value to LAM forecasts

Verification of precipitation forecasts from two limited-area models over Italy and comparison with ECMWF forecasts using a resampling technique

This paper presents the first systematic limited area model (LAM) precipitation verification work over Italy. A resampling technique was used to provide skill score results along with confidence intervals. Two years of data were used, starting in October 2000. Two operational LAMs have been considered, the Limited Area Model Bologna (LAMBO) operating at the Agenzia Regionale Prevenzione e Ambiente- Servizio Meteorologico Regionale (ARPA-SMR) of the Emilia–Romagna region, and the QUADRICS Bologna Limited Area Model (QBOLAM) running at the Agenzia per la Protezione dell’Ambiente e per i Servizi Tecnici (APAT). A 24-h forecast skill score comparison was first performed on the native 0.1° high-resolution grids, using a Barnes scheme to produce the observed 24-h accumulated rainfall analysis. Two nonparametric skill scores were used: the equitable threat score (ETS) and the Hanssen and Kuipers score (HK). Frequency biases (BIA) were also calculated. LAM forecasts were also remapped on a lowerresolution grid (0.5°), using a nearest-neighbor average method; this remapping allowed for comparison with ECMWF model forecasts, and for LAM intercomparisons at lower resolution, with the advantage of reducing the skill score sensitivity to small displacements errors. LAM skill scores depend on the resolution of the verification grid, with an increase when they are verified on a lower-resolution grid. The selected LAMs have a higher BIA compared to ECMWF, showing a tendency to overforecast precipitation, especially along mountain ranges, possibly due to undesired effects from the large-scale and/or convective precipitation parameterizations. Lower ECMWF BIA accounts for skill score differences. LAMBO precipitation forecasts during winter (adjusted for BIA differences) have less misses than ECMWF over the islands of Sardinia and Sicily. Higher-resolution orography definitely adds value to LAM forecasts

Molecular and supramolecular chirality: R2PI spectroscopy as a tool for the gas-phase recognition of chiral systems of biological interest.

A review. In life sciences, diastereomeric chiral mol./chiral receptor complexes are held together by a different combination of intermol. forces and are therefore endowed with different stability and reactivity. Detn. of these forces, which are normally affected in the condensed phase by solvent and supramol. interactions, can be accomplished through the generation of diastereomeric complexes in the isolated state and their spectroscopic investigation. This review presents a detailed discussion of the mass resolved Resonant Two Photon Ionization (R2PI-TOF) technique in supersonic beams and introduces an overview of various other technologies currently available for the spectroscopic study of gas phase chiral mols. and supramol. systems. It reports case studies primarily from the authors' recent work using R2PI-TOF methodol. for chiral recognition in clusters contg. mols. of biol. interest. The measurement of absorption spectra, ionization and fragmentation thresholds of diastereomeric clusters by this technique allow the detn. of the nature of the intrinsic interactions, which control their formation and which affect their stability and reactivity

Earthquakes in a fault system embedded in an elastic body subject to increasing shear stress

We consider the faults of an elastic body subject to an increasing stress and the stress field generated by slip on a fault. The slip along the fault releases the stress component parallel to the slip, but the component normal to the fault is not released and increases in time at the same rate as the shear affecting the body. The effect is an increase of the value of the force necessary to cause the subsequent slip; and, if the shear increases linearly, it causes an increase of the time intervals between the earthquakes on the fault, that is between the stress drop p and the slip s. The density distribution of p in a given time interval is computed; it is found that rigorously it is not a power law although it is a decreasing function of p. It is also seen that, as in the cases in which it was assumed that the component of the stress field locking the fault, after each earthquake, in the time interval to the next earthquake, would be anelastically released, the logarithm of the density distribution of the moments of the earthquakes is a linear function of log (M0 ) and a linear function of M in any time interval; M0 and M being the scalar seismic moment and the magnitude, respectively. Conditions for the existence of these linear relationships are discussed finding that a sufficient condition, when the range of p is not exceptionally large, is that the density distribution of p be of the type log (p), which includes the case when it is independent of the fault linear size l. The Gutenberg-Richter frequency-magnitude relationship and the conditions to obtain aftershocks and seismic swarms generated by this model are presented and discussed. In order to obtain the observed density distribution of earthquakes one or several hypotheses can be done: 1) the stress locking the faults, between successive earthquakes of the same fault, is released anelastically; 2) the density distribution of the sizes of the faults is such as to cause the logarithm of the density distribution of log (M0) and of M to be linear; 3) the density distribution of log M0 (M) is linear and the linearity factor is related to the density distribution of the stress drop and not to that of the linear dimensions of the faults

Linear and nonlinear post-processing of numerically forecasted surface temperature

International audienceIn this paper we test different approaches to the statistical post-processing of gridded numerical surface air temperatures (provided by the European Centre for Medium-Range Weather Forecasts) onto the temperature measured at surface weather stations located in the Italian region of Puglia. We consider simple post-processing techniques, like correction for altitude, linear regression from different input parameters and Kalman filtering, as well as a neural network training procedure, stabilised (i.e. driven into the absolute minimum of the error function over the learning set) by means of a Simulated Annealing method. A comparative analysis of the results shows that the performance with neural networks is the best. It is encouraging for systematic use in meteorological forecast-analysis service operations

Annotating Causality in the TempEval-3 Corpus

While there is a wide consensus in the NLP community over the modeling of temporal relations between events, mainly based on Allen\u2019s temporal logic, the question on how to annotate other types of event relations, in particular causal ones, is still open. In this work, we present some annotation guidelines to capture causality between event pairs, partly inspired by TimeML. We then implement a rule-based algorithm to automatically identify explicit causal relations in the TempEval-3 corpus. Based on this annotation, we report some statistics on the behavior of causal cues in text and perform a preliminary investigation on the interaction between causal and temporal relations