Fault slip rates for the active External Dinarides thrust-and-fold belt

We present estimates of slip rates for active faults in the External Dinarides. This thrust-and-fold belt formed in the Adria-Eurasia collision zone by the progressive formation of NE-dipping thrusts in the footwalls of older structures. We calculated the long-term horizontal velocity field, slip rates and related uncertainties for active faults using a thin-shell finite element method. We incorporated active faults with different effective fault frictions, rheological properties, appropriate geodynamic boundary conditions, laterally varying heat flow and topography. The results were obtained by comparing the modeled maximum compressive horizontal stress orientations with the World Stress Map database. The calculated horizontal velocities decrease from the southeastern External Dinarides to the northwestern parts of the thrust-and-fold belt. This spatial pattern is also evident in the long-term slip rates of active faults. The highest slip rate was obtained for the Montenegro active fault, while the lowest rates were obtained for active faults in northwestern Slovenia. Low slip rates, influenced by local active diapirism, are also characteristic for active faults in the offshore central External Dinarides. These findings are contradictory to the concept of Adria as an internally rigid, aseismic lithospheric block because the faults located in its interior release a part of the regional compressive stress. We merged the modeling results and available slip rate estimates to obtain a composite solution for slip rates

Stress in Europe with confidence limits

This article has been accepted for publication in Geophysical Journal International ©: The Authors 2003. Published by Oxford University Press on behalf of The Royal Astronomical Society. All rights reserved.In this study, we modify and extend a data analysis technique to determine the stress orientations between data clusters by adding an additional constraint governing the probability algorithm. We apply this technique to produce a map of the maximum horizontal compressive stress (S_Hmax) orientations in the greater European region (including Europe, Turkey and Mediterranean Africa). Using the World Stress Map dataset release 2008, we obtain analytical probability distributions of the directional differences as a function of the angular distance, θ. We then multiply the probability distributions that are based on pre-averaged data within θ<3° of the interpolation point and determine the maximum likelihood estimate of the S_Hmax orientation. At a given distance, the probability of obtaining a particular discrepancy decreases exponentially with discrepancy. By exploiting this feature observed in the World Stress Map release 2008 dataset, we increase the robustness of our S_Hmax determinations. For a reliable determination of the most likely S_Hmax orientation, we require that 90% confidence limits be less than ±60° and a minimum of three clusters, which is achieved for 57% of the study area, with small uncertainties of less than ±10° for 7% of the area. When the data density exceeds 0.8×10^-3 data/km2, our method provides a means of reproducing significant local patterns in the stress field. Several mountain ranges in the Mediterranean display 90° changes in the S_Hmax orientation from their crests (which often experience normal faulting) and their foothills (which often experience thrust faulting). This pattern constrains the tectonic stresses to a magnitude similar to that of the topographic stresses.This work was supported by the DPC-INGV 2008-2010 S1 project, the EU-FP7 project “Seismic Hazard Harmonization in Europe” (SHARE; Grant agreement no. 226967), and project MIUR-FIRB "Abruzzo" (code: RBAP10ZC8K_003).Published3.1. Fisica dei terremoti3.3. Geodinamica e struttura dell'interno della Terra4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionaleJCR Journalpartially_ope

Determining rheology from deformation data: The case of central Italy

The study of geodynamics relies on an understanding of the strength of the lithosphere. However, our knowledge of kilometer-scale rheology has generally been obtained from centimeter-sized laboratory samples or from microstructural studies of naturally deformed rocks. In this study, we present a method that allows rheological examination at a larger scale. Utilizing forward numerical modeling, we simulated lithospheric deformation as a function of heat flow and rheological parameters and computed several testable predictions including horizontal velocities, stress directions, and the tectonic regime. To select the best solutions, we compared the model predictions with experimental data. We applied this method in Italy and found that the rheology shows significant variations at small distances. The strength ranged from 0.60.2 TN/m within the Apennines belt to 216 TN/m in the external Adriatic thrust. These strength values correspond to an aseismic mantle in the upper plate and to a strong mantle within the Adriatic lithosphere, respectively. With respect to the internal thrust, we found that strike-slip or transpressive, but not compressive, earthquakes can occur along the deeper portion of the thrust. The differences in the lithospheric strength are greater than our estimated uncertainties and occur across the Adriatic subduction margin. Using the proposed method, the lithospheric strength can be also determined when information at depth is scarce but sufficient surface data are available

Stress in Europe with confidence limits

In this study, we modify and extend a data analysis technique to determine the stress orientations between data clusters by adding an additional constraint governing the probability algorithm. We apply this technique to produce a map of the maximum horizontal compressive stress (S_Hmax) orientations in the greater European region (including Europe, Turkey and Mediterranean Africa). Using the World Stress Map dataset release 2008, we obtain analytical probability distributions of the directional differences as a function of the angular distance, θ. We then multiply the probability distributions that are based on pre-averaged data within θ<3° of the interpolation point and determine the maximum likelihood estimate of the S_Hmax orientation. At a given distance, the probability of obtaining a particular discrepancy decreases exponentially with discrepancy. By exploiting this feature observed in the World Stress Map release 2008 dataset, we increase the robustness of our S_Hmax determinations. For a reliable determination of the most likely S_Hmax orientation, we require that 90% confidence limits be less than ±60° and a minimum of three clusters, which is achieved for 57% of the study area, with small uncertainties of less than ±10° for 7% of the area. When the data density exceeds 0.8×10^-3 data/km2, our method provides a means of reproducing significant local patterns in the stress field. Several mountain ranges in the Mediterranean display 90° changes in the S_Hmax orientation from their crests (which often experience normal faulting) and their foothills (which often experience thrust faulting). This pattern constrains the tectonic stresses to a magnitude similar to that of the topographic stresses

Experimental evidence for mantle drag in the Mediterranean

What forces control active deformation in the Central Mediterranean? Slab-pull has long been debated, but no other hypothesis has been generally accepted. Here we analyze the role of shear basal tractions. By using a thin-shell modeling technique, we generated a large number of models that span different sets of boundary conditions from the literature; we then explored acceptable ranges of model parameters. We computed residuals between model predictions and several datasets of stress directions, GPS measurements and tectonic stress regimes that have been produced in recent studies, and then compared the best models obtained in the presence of tractions with those obtained in the absence of tractions. For all tested boundary conditions and all considered datasets, our results show that the only successful models are those with significant basal shear traction exerted by eastward mantle flow

Earthquake rates inferred from active faults and geodynamics: the case of the External Dinarides

The goal of earthquake rate models is to define the long-term rate of seismicity above an established magnitude threshold. No earthquake rate models exist for the External Dinarides, although this area is prone to frequent earthquakes that have significant impacts on natural and human environments. In this study, we apply a tectonic/geodynamic approach to build a fault-based and a deformation-based earthquake rate model for the External Dinarides. The main difference between the two models is the inclusion of off-fault seismicity in the deformation-based earthquake rate model. We explore the impact of the moment-balancing uncertainties on the expected number of earthquakes above an established magnitude. The results show comparable earthquake rates for both input models. The slip rate, the elastic modulus and the seismogenic depth play important roles in the variability of earthquake rates, whereas the effects of the corner magnitude and the Gutenberg-Richter β parameter are insignificant. A comparison with the available historical seismic catalogue shows good agreement for MW>5.8 earthquakes

SHINE: Web Application for Determining the Horizontal Stress Orientation

Interpolating the orientation of the maximum horizontal compressive stress with a well-established procedure is fundamental in understanding the present-day stress field. This paper documents the design principles, strategies and architecture of SHINE (http://shine.rm.ingv.it/), a web-based application for determining the maximum horizontal compressive stress orientation. The interpolation using SHINE can be carried out from a global database or from a custom file uploaded by the user. SHINE satisfies the usability requirements by striving for effectiveness, efficiency and satisfaction as defined by the International Organization for Standardization (ISO) covering ergonomics of human-computer interactions. Our main goal was to build a web-based application with a strong “outside-in” strategy in order to make the interpolation technique available to a wide range of Earth Science disciplines. SHINE is an easy-to-use web application with a straightforward interface guaranteeing quick visualization of the results, which are downloadable in several formats. SHINE is offered as an easy and convenient web service encouraging global data sharing and scientific research collaboration. Within this paper, we present a possible use of SHINE, determining fault kinematics compatibility with respect to the present-day stress field

Micro-Raman characterizations of Pompei'smortars

The ancient town of Pompei offers a unique opportunity to study in detail many aspects of the every day life during the Roman early imperial age. The application of micro-Raman spectroscopy can be of great help in performing a reasonably rapid comparative analysis of the mortars, quite useful to ascertain the degree of uniformity of the technical recipes among the various building firms and the eventual technical evolution in the time; moreover, the individuation of minerals of specific geographical origins can give useful information about the extension of commercial intercourses. An example of a micro-Raman investigation on building materials is reported in this work, concerning the analysis of the mortars coming from different points of the wall in the 'The House of the Wedding of Hercules'. Remarkable differences between ancient and modern mortars are found, allowing a discrimination that can be useful in the case of historical building which underwent several restoration works. Copyright © 2008 John Wiley & Sons, Ltd

Decoration of nanovesicles with pH (low) insertion peptide (pHLIP) for targeted delivery

Acidity at surface of cancer cells is a hallmark of tumor microenvironments, which does not depend on tumor perfusion, thus it may serve as a general biomarker for targeting tumor cells. We used the pH (low) insertion peptide (pHLIP) for decoration of liposomes and niosomes. pHLIP senses pH at the surface of cancer cells and inserts into the membrane of targeted cells, and brings nanomaterial to close proximity of cellular membrane. DMPC liposomes and Tween 20 or Span 20 niosomes with and without pHLIP in their coating were fully characterized in order to obtain fundamental understanding on nanocarrier features and facilitate the rational design of acidity sensitive nanovectors. The samples stability over time and in presence of serum was demonstrated. The size, ζ-potential, and morphology of nanovectors, as well as their ability to entrap a hydrophilic probe and modulate its release were investigated. pHLIP decorated vesicles could be useful to obtain a prolonged (modified) release of biological active substances for targeting tumors and other acidic diseased tissues