Rupture by damage accumulation in rocks

The deformation of rocks is associated with microcracks nucleation and propagation, i.e. damage. The accumulation of damage and its spatial localization lead to the creation of a macroscale discontinuity, so-called "fault" in geological terms, and to the failure of the material, i.e. a dramatic decrease of the mechanical properties as strength and modulus. The damage process can be studied both statically by direct observation of thin sections and dynamically by recording acoustic waves emitted by crack propagation (acoustic emission). Here we first review such observations concerning geological objects over scales ranging from the laboratory sample scale (dm) to seismically active faults (km), including cliffs and rock masses (Dm, hm). These observations reveal complex patterns in both space (fractal properties of damage structures as roughness and gouge), time (clustering, particular trends when the failure approaches) and energy domains (power-law distributions of energy release bursts). We use a numerical model based on progressive damage within an elastic interaction framework which allows us to simulate these observations. This study shows that the failure in rocks can be the result of damage accumulation

THE TEMPORAL DIMENSION IN A 4D ARCHAEOLOGICAL DATA MODEL: APPLICABILITY OF THE GEOINFORMATION STANDARD

In recent years, the interest of many researchers in various domains is triggered to move beyond the traditional border of twodimensionality and explore the possibilities of the third and even the fourth, temporal, dimension. The emerging research interest concerning 3D and 4D and the handling of these additional dimensions can bring many benefits to archaeology as well. A 4D GIS tailored to archaeological data would facilitate better insights and more complex analyses. Its basis must be a conceptual 4D archaeological data model, which pays attention to existing data models and standards. Although in some cases more complex, archaeological data are closely related to geography and geo-information. Since the temporal dimension is a, and possibly the most, substantial element in archaeological research, this paper focusses mainly on this dimension. In this paper, the applicability of the ISO 19108 geo-information standard on temporal information for archaeological data is investigated. For a set of common temporal categories, e.g. the excavation time, the appropriate description according to this standard is determined. This will indicate in which cases the internationally recognized standard is suitable for use in an archaeological data model. Furthermore, three versions of the West European archaeological time scale as temporal ordinal reference system are constructed. For the first version, the ISO 19108 structure is used, whereas the second and third are based on geological variants. The results of the performed analysis are favourable to the usability of the ISO 19108 standard in archaeology; however, other temporal standards or data models may yield up better results

The temporal dimension in a 4D archaeological data model: applicability of the geoinformation standard

Moving beyond the traditional border of two-dimensionality towards handling the third and even fourth, temporal, dimension in a GIS has been attracting many researchers. Archaeological data are inherently 3D and linked with time, which makes a 4D GIS tailored to archaeological data beneficial. Such a system would facilitate the handling of the three spatial and temporal dimension simultaneously and so enable better insights and more complex analyses. Its basis must be a conceptual data model, which pays attention to existing data models and standards. Therefore, this chapter focusses on the applicability of the ISO 19108 geoinformation standard to describe temporal information, which is a crucial aspect in archaeological research. For a set of six common temporal categories, e.g. the excavation time, the appropriate description according to this standard is determined. This will indicate in which cases the internationally recognized standard is suitable for use in an archaeological data model. Furthermore, part of the West European archaeological time scale is constructed as temporal ordinal reference system. For the first version, the NBN EN ISO 19108:2005 structure is used, whereas the second and third are based on geological variants. The results of the performed analysis are favorable to the usability of the ISO 19108 standard in archaeology; however, other temporal standards or data models may yield up better results

Collaborative network for district energy operation and semantic technologies: A case study

The growing interest toward renewable energies and alternative energy sources has led to the development of an increasingly complex district energy landscape with multiple agents and systems. In this new prospect, some frameworks such as USEF [1] or holonic multi-agent systems [2] propose new approaches, where, in the way of a Virtual Organisation Breeding Environment (VOBE) [3], diverse organizations cooperate on a long-term basis to run an energy system. This study focuses on the THERMOSS project, an EU-funded project that investigates the efficient operation of district heating and cooling networks, and demonstrates that such organisation can be integrated into the Collaborative Networks (CNs) paradigm. Additionally, a semantic approach is briefly introduced as a mean to support and improve data transfer and communication between the different entities of THERMOSS as a CN

Earthquake rupture dynamics frozen in exhumed ancient faults

Most of our knowledge about co-seismic rupture propagation is derived from inversion and interpretation of strong-ground-motion seismograms(1-3), laboratory experiments on rock(4,5) and rock-analogue material(6), or inferred from theoretical and numerical elastodynamic models(7-9). However, additional information on dynamic rupture processes can be provided by direct observation of faults exhumed at the Earth's surface(10). Pseudotachylytes (solidified friction-induced melts(11,12)) are the most certain fault-rock indicator of seismicity on ancient faults(13). Here we show how the asymmetry in distribution and the orientation of pseudotachylyte-filled secondary fractures around an exhumed fault can be used to reconstruct the earthquake rupture directivity, rupture velocity and fracture energy, by comparison with the theoretical dynamic stress field computed around propagating fractures. In particular, the studied natural network of pseudotachylytes is consistent with a dominant propagation direction during repeated seismic events and subsonic rupture propagation close to the Rayleigh wave velocit