Seismic strain and seismogenic stress regimes in the crust of the southern Tyrrhenian region

An investigation has been performed to identify and characterize the seismic deformation zones active over the last decades in the region of Italy that has experienced the strongest seismicity during the last centuries. The study is based on the estimate of hypocenter locations, fault plane solutions, seismogenic stress and seismic strain tensor orientations carried out using the entire dataset of the national and local seismic networks, and the recently improved three-dimensional (3D) crustal velocity model of the study area. A series of simulation tests have been performed to evaluate the significance of the earthquake space distribution obtained and whether it was influenced by network geometry problems related to the sea and the lack of ocean bottom seismometers. In the sectors where hypocentral location was synthetically proved to be reliable, space distributions of earthquakes located with epicenter and focal depth errors less than 3 and 4 km, respectively, have been compared with local geology in order to identify seismogenic faults. The dataset of 32 fault plane solutions estimated with fault parameter errors less than 20° has been used to investigate space variations of seismogenic stress and seismic strain orientations over the study area. Stress was found to be uniform in the Messina Strait and southern Calabria where inversion of the available set of 11 fault plane solutions showed clear evidence of an extensional regime. The different orientations of the minimum compressive stress and strain found in this sector, together with the information available on local geology and tectonics, lead us to propose that the seismicity occurring over the last decades in the Messina Strait and southern Calabria was not in general produced at the main faults, but at minor faults activated by the main tectonic stress field acting in the area. To the west, in the sector including western Etna, the Nebrodi chain and the western Aeolian Islands, analysis of the available set of 16 fault plane solutions revealed a certain degree of stress heterogeneity with an apparent prevalence of north–south compression. This east to west change of stress–strain regimes is evaluated in the light of current hypotheses regarding the geodynamics of the study region

Occurrence and concentration of PAHs in clams and sediments of the marine coastal lagoon of Ganzirri (Italy). Extraction, GC-MS analysis, distribution and sources

The distribution of selected Polycyclic Aromatic Hydrocarbons (PAHs) in surface sediments and clams of marine coastal lagoons, called Ganzirri, located at the Sicilian coast of the, Messina's strait, has been investigated by GC/MS analysis with Selected Ion Monitoring (SIM) mode. The lagoon is characterized by abundant organic detritus, deriving from aquagenic and anthropogenic inputs. Anoxic/reduced conditions of sediments make them a preferential site for uptake and preservation of PAHs. From an eco-toxicological point of view, the aquatic ecosystem investigated appears to be moderately polluted. The investigations have been performed on the 16 PAHs recommended by US-EPA as priority pollutants to be monitored in the framework of environmental quality control. The sediment PAH concentrations ranged from 135 to 1650 mu g/kg dry matrix. The total concentrations of PAHs in clams ranged from 60 to 1427 mu g/kg d.w. The relative standard deviation (RSD) for all samples of the concentration replicates of individual compounds ranged from 10% to 25%. The resulting distributions and ratios of specific compounds have been discussed in terms of sampling location and origin of contaminants. The results obtained show that levels of contamination are not homogeneous throughout the stations. In the Ganzirri Lagoon, the bioavailability of hydrophobic organic compounds, such as PAHs, seems to be mainly governed by chemical characteristics of the contaminants. Pyrolytic compounds (penta- and hexa-aromatics) are not readily available. In contrast, petroleum hydrocarbons (some tetra-aromatics) are accumulated by clams to a great extent

Metals distribution in the organic and inorganic fractions of soil: a case study on soils from Sicily

AbstractThe content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, has been determined in the organic and inorganic fraction of eight soil samples from Sicily. A modified type-Tessier sequential extraction procedure has been used to recognize metals in five different fractions categorised as follows: (a) exchangeable metals, (b) metals bound to carbonates, (c) metals bound to iron and manganese oxides, (d) metals bound to organic matter, and (e) metals in residual fraction. The mineralogical composition of soils samples was characterized by X-ray diffraction. Humic substances were extracted by means of an alkaline extraction procedure. It has been found that both the mineralogical composition and the different content of humic fraction of organic matter in the soils investigated are responsible for the observed trace metal distribution. The obtained data show that a significant amount of trace metals is bound to the organic fraction where different binding sites are present simultaneously. In particular, Pb an..

Seismicity and Focal Mechanisms at the Calabro-Lucanian boundary along the Apennine chain (southern Italy)

The Calabro-Lucanian boundary is a complex geological zone marking the transition between the highly seismogenic tectonic domains of Southern Apennines and the Calabrian Arc. Historical catalogues include earthquakes with macroseismic effects up to VII-VIII MCS (CPTI WORKING GROUP, 2004) and paleoseismological investigations suggested that earthquakes of magnitude between 6.5 and 7 may have occurred in this area, between the 6th and the 15th century (MICHETTI et alii, 2000). More recently, on 9 September 1998, an earthquake of moment magnitude M5.6 occurred at the north-western margin of the Pollino massif (GUERRA et alii, 2005; ARRIGO et alii, 2006) and since the second half of 2010 the same region was interested by a noteworthy seismic activity characterized by several swarms with thousands of events with a maximum magnitude of 3.6

Synthesis, properties, antitumor and antibacterial activity of new Pt(II) and Pd(II) complexes with 2,2'-dithiobis(benzothiazole) ligand

Mono- and binuclear Pt(II) and Pd(II) complexes with 2,20-dithiobis(benzothiazole) (DTBTA) ligand are reported. [Pt(DTBTA)(DMSO)Cl]Cl 19CHCl3 (1) and [Pd2(m-Cl)2(DTBTA)2]Cl2 (2) have been synthesized and structurally characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, MS spectrometry and the content of platinum and palladium was determined using a flame atomic spectrometer. Two different coordination modes of 1 and 2 complexes were found; in both complexes, the coordination of Pt(II) and Pd(II) ions involves the N(3) atoms of the ligand but the binuclear complex 2, is a cis-chloro-bridged palladium complex. Evaluation of their in vitro antitumor activity against two human tumor cell lines human breast cancer (MCF-7) and hepatocellular carcinoma (HepG2); and their antimicrobial activity against Escherichia coli and Kokuria rhizophila was performed. Only complex 1 showed a dose- and time-dependent cytotoxic activity against the two tumor cell lines, associated to apoptosis and accumulation of treated cells in G0/G1 phase of cell cycle, while both 1 and 2 exhibited antimicrobial activity with complex 1 much more potent. The study on intracellular uptake in both MCF-7 and HepG2 cell lines revealed that only platinum of complex 1 is present inside the cells, suggesting a different mode of action of the two compounds. This was also in agreement with the results obtained for the antitumor and antibacterial activity

Testing the stability of moment tensor solutions for small earthquakes in the Calabro-Peloritan Arc region (southern Italy)

The aim of this study is to test the stability of moment tensor solutions for crustal earthquakes in the Calabro-Peloritan area (southern Italy). We used waveforms recorded by the Italian National Seismic Network managed by the Istituto Nazionale di Geofisica e Vulcanologia and the CAT-SCAN (Calabria Apennine Tyrrhenian - Subduction Collision Accretion Network) project. We computed the moment tensor solutions using the Cut And Paste (CAP) method. The technique allows the determination of the source depth, moment magnitude and focal mechanisms using a grid search technique. For the earthquakes investigated, we tried different station distributions and different velocity models. Results were also checked by computing the moment tensor solutions using the SLUMT grid-search method. Both methods (CAP and SLUMT) allow time shifts between synthetic and observed data in order to reduce the dependence of the solution on the assumed velocity model and on earthquake location errors. Comparisons have been made with the available published solutions. The final focal mechanisms were robustly determined. We show that the application of the CAP and SLUMT methods can provide good-quality solutions in a magnitude range not properly represented in the Italian national earthquake catalogues, and where the solutions estimated from Ponset polarities are often poorly constrained