Subduction-related episodes of K-alkaline magmatism (15–0.1 Ma) and geodynamic implications in the north Tyrrhenian — central Italy region: a review

In the north Tyrrhenian region and adjoining shores of Alpine Corsica and central Italy, four magmatic phases (15–14; 8–6; 5–2; and 1.3–0.1 Ma) are present which consist prevailingly of either old acidic and lamproitic rocks or young (1.3–0.1 Ma) basic volcanics with potassic–ultrapotassic affinity (the rocks of the K and HK series of the Roman province, and the kamafugitic rocks). Composition, age and location of the igneous phases reveal a geochemical polarity oriented from west to east. The episodes of magmatic activity reflect the evolution of the geodynamic environment (ensialic plate convergence): backarc stretching and attenuation of an Alpine orogenic wedge were accompanied by the eastward roll-back and progressive steepening of the descending Adria plate. The latter process led to enhanced metasomatic modifications of the mantle wedge composition and to eruption of the large volumes of KS and HKS volcanic rocks in central Italy (0.6–0.1 Ma).     

Effects of inflationary bubbles on the polarization and temperature anisotropies of the cosmic microwave background

The broad X-ray iron line, detected in many active galactic nuclei, is likely to be produced by fluorescence from the X-ray-illuminated central parts of an accretion disc close to a supermassive black hole. The time-averaged shape of the line can be explained most naturally by a combination of special and general relativistic effects. Such line profiles contain information about the black hole spin and the accretion disc, as well as the geometry of the emitting region, and may help to test general relativity in the strong gravity regime. In this paper we embark on the computation of the temporal response of the line to the illuminating flux. Previous studies concentrated on the calculation of reverberation signatures from static sources illuminating the disc. In this paper we focus on the more physically justified case of flares located above the accretion disc and corotating with it. We compute the time-dependent iron line, taking into account all general relativistic effects, and show that its shape is of a very complex nature, and we also present light curves accompanying the iron line variability. We suggest that present and future X-ray satellites like XMM or Constellation-X may be capable of detecting features present in the computed reverberation maps.     

Biochemical Responses of European Sea Bass (Dicentrarchus labrax L.) to the Stress Induced by Off Shore Experimental Seismic Prospecting

The paper reports the results of an experimental seismic survey in the open sea by an air gun, carried out to evaluate the effects of air gun acoustic waves on marine animals. Air gun blast exposition was found to have a marked influence on confined Dicentrarchus labrax. Our data, in fact, demonstrated a biochemical response to acoustic stress induced by air gun blasts. Variations of cortisol, glucose, lactate, AMP, ADP, ATP and cAMP in different tissues of D. labrax, indicate that fish have a typical primary and secondary stress response after air gun detonations. Radiography indicates that air gun blasts do not induce any macroscopic effect on skeletal apparatus. The variations of biochemical parameters returned within physiological values within 72 h indicating a rapid recovery of homeostasis after acoustic stress and no mortality was observed.     

Preliminary prediction of damage to residential buildings following the 21st August 2017 Ischia earthquake

On August 21st, 2017, an earthquake with duration magnitude M_d?=?4.0 and epicentre in Casamicciola Terme hit Ischia island, in the South of Italy. This event caused two fatalities and dozens of injured people. Moreover, despite the low magnitude, the earthquake produced significant damages to masonry and reinforced concrete (RC) buildings, with some partial or complete collapse of structures, in a very limited area close to the epicentre, while even at small distance from the most damaged zone the earthquake was just felt by local people and tourists. In the days after the event, discussions concerning the destructive effects of such an earthquake arose in the scientific community—as also reported by local and national media. In this paper, the seismic history of Ischia island is recalled to show and explain the peculiarity of the August 21st earthquake, which is also described in terms of ground motion and response spectra characteristics. The results of the first surveys carried out in Casamicciola Terme are reported, together with appropriate pictures, to introduce and explain the observed damage state of masonry and RC buildings in the epicentral zone. Then, data from the 15th general census of the population and dwellings (ISTAT) is used to define vulnerability classes according to the classification of the European Macrosismic Scale (EMS-98) (Grünthal, 1998). Seismic damage scenarios are then evaluated combining macro-seismic intensity values obtained using an interpolation method starting from QUEST macro-seismic survey data (Azzaro et al., 2017 ) and fragility curves for A-to-D vulnerability classes and for five damage states, from DS0 (no damage) to DS5 (collapse) trough a Monte Carlo simulation technique. The distributions of Usable, Temporarily or Partially Unusable, and Unusable buildings, which are obtained by using relationships between damage and usability judgments obtained through post-earthquake damage data collected after past seismic events, result in very good accordance with those published in September 1st, 2017 by the Department of Civil Protection, regarding a dataset of about 600 buildings.     

Turbulent behaviour within a coastal boundary layer,observations and modelling at the Isola del Giglio

The hydrodynamics of coastal areas is characterized by the interaction among phenomena occurring at different spatial and temporal scales, such as the interaction of a large-scale ocean current with the local bathymetry and coastline, and local forcing conditions. In order to take into account all relevant phenomena, the study of the hydrodynamics of coastal zones requires a high-spatial and temporal resolution for both observations and simulation of local currents. This resolution can be obtained by using X-band radar, which allows simultaneous measurement of waves and currents in a range of 1–3 miles from the coastline, as well as high-resolution numerical models implemented in the area and configured through multiple nesting techniques in order to reach resolutions comparable to such coastal observations. Such an integrated monitoring system was implemented at the Isola del Giglio in 2012, after the accident of the Costa Concordia ship. Results can be used as a cross-validation of data produced independently by radar observations and numerical models. In addition, results give some important insights on the dynamics of the coastal boundary layer, both for what concerns the attenuation in the profile of the depth-averaged velocities which typically occur in turbulent boundary layers, as well as for the production, detachment and evolution of vorticity produced by the interaction of large-scale ocean currents with the coastline and the subsequent time evolution of such boundary layer. This transition between large-scale regional currents and the coastal boundary layer is often neglected in regional forecasting systems, but it has an important role in the ocean turbulence processes.     

Human‐induced hazardous debris flows in Carrara marble basins (Tuscany,Italy)

In Carrara marble basins, the long and intensive quarrying activities (which began in the first century BC ) have produced extensive dump deposits, locally known as ravaneti. Ravaneti are of such large dimensions and diffusion as to make them a widespread landform of the Apuane Alps (Tuscany). In recent years these quarry dump deposits have been affected by frequent debris flows, more than 50 in 1996/97. This phenomenon is the most significant currently active geomorphological process in this landscape. The evolution of quarrying techniques produced a variety of sedimentological compositions of ravaneti. The debris flows analysed involve only the surface layers where debris is mixed with fine material with a lower permeability (active ravaneti) than the coarser underlying debris (older ravaneti). The presence of different permeability layers causes a wetting front to move downwards. Source area observations indicate a soil slip movement in the initial phases of the failure. The transformation of landslides into debris flow occurs by means of both soil contractive failure and an increase of granular temperature. The morphological and sedimentological analyses of depositional lobes resulted in a classification of three types of lobe, based on fabric–morphometry relationships allowing the identification of different flow dynamics: (1) type A lobe (platy form), matrix‐supported and well developed fabric with general tendency of ab clast plane strikes to lie generally parallel to flow direction as a consequence of laminar flow; (2) type B lobe (elongated form), clast‐supported and random fabric as a consequence of both turbulent flow and coarser composition of starting material; (3) type C lobe, intermediate type A–B morphometry, tendency for ab clast plane to lie in a semi‐circle around the main flow direction determined by the presence of secondary flow lines divergent from it in the stopping phase. In Carrara marble basins, the anomalous frequency with which debris flows tend to be triggered by medium‐intensity rainstorms (about 30 mm h⁻¹ rainfall) is due to the recent increases in silt dump produced by modern quarrying techniques. This represents a significant example of debris flows as an environmental problem in major anthromorphized landscapes. Copyright © 2000 John Wiley & Sons, Ltd.     

Stern’s Review and Adam’s fallacy

The Stern Review has played an enormous role in making the world of business aware of the challenge of long-term climate change. In order to make real progress on the basis of this awareness, it is important to pay attention to the difference between human suffering and losses of gross domestic product (GDP). The Review has compared climate change to experiences of suffering like World War I. That war, however, hardly affected global GDP. The long-term damages to be expected from business-as-usual greenhouse gas emissions include loss of the coastal cities of the world over the next millennia. This would be an act of unprecedented barbarism, regardless of whether it would slow down economic growth or perhaps even accelerate it. Business leaders worried about climate change need to pay attention to the tensions between ethical and economic concerns. Otherwise, a credibility crisis threatens global climate policy. An important step to establish the credibility needed for effective climate policy will be to gradually move towards a regime where emission permits are auctioned, not handed out as hidden subsidies. The revenues generated by permit auctions should be used to establish a global system of regional climate funds.     

IFSAR-DEM在岩溶洼地探测中的应用——以薄荷省旁劳市沉降灾害评估为例

岩溶研究中,通常会使用高分辨率卫星图像和地理空间数据识别、描绘岩溶发育及相关地质灾害发生的地貌特征。本文旨在利用ArcGIS10.0确定干涉合成孔径雷达数字高程模型（IFSAR-DEM）识别、量化和描述岩溶洼地。这种半自动岩溶洼地/天坑探测方法采用水流模拟法,并结合（1）流域划分;（2）下沉填充法提取洼地特征;（3）下沉深度测量及分类;（4）使用2013年至2014年谷歌高光谱卫星图像和数字地形模型对探测到的岩溶洼地进行验证。该方法已在薄荷省旁劳市进行的评估中进行了预测试。使用国家测绘资源信息局（菲律宾）1991年的1:50 000比例尺地形图进行的初步封闭洼地分析,发现旁劳岛有15个天坑。利用5米高分辨率IFSAR-DEM,共探测到820个天坑,其中424个根据详细的地面实况进行了描绘,以验证了岩溶洼地的存在。地表实况包含天坑大小、形状和深度等基本形态测量分析以消除误报数据。阈值设定为沉降深度大于1米,孔径大于10米,从而最大程度精确区分实际的天坑。这种基于GIS的工具有助于生成高分辨率岩溶塌陷易发区图,继而指导当地规划者、工程师及决策者进行开发规划和土地利用。