Micro-seismic monitoring after the shipwreck of the Costa Concordia at Giglio Island (Italy)

A micro-seismic network was used for monitoring the wreck of the Costa Concordia cruise ship, wrecked and run agrounded along the Giglio Island coasts during the night of 13 January 2012, until its removal. The seismic traces were processed by means of real-time and “a posteriori” procedures to detect transients that could be ascribed to wreck movements on the sea bed to integrate this information in an early warning system for assessing the wreck stability. After a first discrimination of the transients using amplitude criteria we proceeded to the localization of the detected signals to focus the attention only on the transients originated in the shipwreck resting area. The results showed that most of the events localized on the wreck were likely related to human work activities or sudden internal brittle failure but not to displacements on the seafloor. Instead, the displacements are associated to the impact on the vessel of great sea storms which approach were well correlated with the increasing seismic noise at low frequency. The carried out procedures based on this unique dataset represent an opportunity to test seismic monitoring techniques also in not usual engineering context to support emergency management activities.     

Urbanization effects on shoreline phytobenthos: a multiscale approach at lake extent

To understand how littoral biota respond to anthropogenic disturbances, limnologists seek to detect the scale at which patterns and processes occur. We conducted an extensive study on the shoreline phytobenthos of Lake Garda (Italy) with the following main objectives: (i) to examine the importance of urbanization for species distribution within a set of hierarchical spatial scales (10¹–10⁴ m), and then (ii) to test the spatio-temporal interactions on a reduced set of scales (10¹–10² m, and 10¹–10² days). Results showed that most of the variation in most abundant species and habitat characteristics occurred at the spatial scale of 10¹–10² m. Species richness was positively related with microheterogeneity, but the relationship occurred only at low urbanization and not at highly-urbanized sites where artificial shores were less heterogeneous. The similarity of species assemblages was regulated by two interacting processes, one operating at a fine spatial scale (10² m), reflecting the physical-habitat requirements of the species, and the other one operating at a broader scale (10⁴ m) in relation to the N–S nitrogen gradient. Overall, time explained 73 % of the total variation of species assemblages, space 7 %, and 20 % was explained by the interaction between space and time (the patch scale, 10s of m, and area scale, 100s of m, interacted with the finest temporal scale, 10s of days). This interaction might be explained by the process of species recruitment operating at different rates at the two spatial scales. Since the largest variation in species assemblages was at the temporal scale (due to the seasonal succession of phytobenthos), we recommend collecting at least one sample per season when monitoring littoral habitats.     

南加州地壳的伴随层析成像

使用基于伴随方法的反演策略,研制出了南加州地壳的三维地震模型。该模型涉及到16次层析成像迭代,需要6800次波场模拟和总计80万个中心处理单位小时。与南加州地震中心给出的最初三维模型比较,该新的地壳模型揭示了更强的非均匀性,包括±30%的局部变化。模型说明了诸如沉积盆地和横跨断层的构造反差的浅部特征。也揭示了深部的地壳特征,从而帮助重建诸如俯冲捕获洋壳碎块的南加州构造。新模型有助于对地震危险性做出更实际而准确的评估。     

Pairs of pulsars (PSR) and the origin of PSR

The results of research on pairs of PSR which were possibly components of disrupted binaries, seem to advance further arguments in favour of the idea, suggested by some authors, that most of PSR were formed in binary systems.     

Implications of spatial heterogeneity for management of marine protected areas (MPAs): examples from assemblages of rocky coasts in the northwest Mediterranean

Marine protected areas (MPAs) are increasingly used as a management tool to preserve species and habitats. Testing hypotheses about the effectiveness of MPAs is important for their implementation and to identify informative criteria to support management decisions. This study tested the general proposition that MPAs affected assemblages of algae and invertebrates between 0.0 and 0.5 m above the mean low water level of rocky coasts on two islands in the Tuscan Archipelago (northwest Mediterranean). Protection was concentrated mainly on the west coasts of the islands, raising the possibility that neither the full range of assemblages nor the relevant scales of variation were properly represented within MPAs. This motivated the comparison of assemblages on opposite sides of islands (habitats). The effects of MPAs and habitat were assessed with a multifactorial sampling design; hypotheses were tested about differences in structure of assemblages, in mean abundance of common taxa and in univariate and multivariate measures of spatial variation. The design consisted of three replicate shores for each condition of protected and reference areas on the west side of each island and three unprotected shores on the eastern side. Assemblages were sampled independently four times on each island between June 1999 and January 2001. At each time of sampling two sites were selected randomly at each of two tidal heights to represent midshore and lowshore assemblages on each shore. Estimates of abundance were obtained using non-destructive sampling methods from five replicate 20x20 cm quadrats at each site. Results indicated differences among habitats in structure of assemblages, in mean abundance of common taxa and in univariate and multivariate measures of spatial variation at the scale of shores. Most of these patterns were inconsistent with the predicted effect of management through MPAs. The data suggest that designation of MPAs in the Tuscan Archipelago should proceed through management of multiple shores and types of habitat selected to guarantee protection to a representative sample of assemblages and to the processes responsible for maintenance of spatial patchiness at different scales. This study also shows that considerations of spatial heterogeneity are important to underpin management decisions about the number, size and location of MPAs.     

First ENA observations at Mars: ENA emissions from the martian upper atmosphere

The neutral particle detector (NPD) on board Mars Express has observed energetic neutral atoms (ENAs) from a broad region on the dayside of the martian upper atmosphere. We show one such example for which the observation was conducted at an altitude of 570 km, just above the induced magnetosphere boundary (IMB). The time of flight spectra of these ENAs show that they had energies of 0.2-2 keV/amu, with an average energy of ∼1.1 keV/amu. Both the spatial distribution and the energy of these ENAs are consistent with the backscattered ENAs, produced by an ENA albedo process. This is the first observation of backscattered ENAs from the martian upper atmosphere. The origin of these ENAs is considered to be the solar wind ENAs that are scattered back by collision processes in the martian upper atmosphere. The particle flux and energy flux of the backscattered ENAs are and , respectively.