Source Effects on the Spectral Characteristics of Strong Ground Motions Recorded in Bucharest Area During Vrancea Earthquakes of 1986 and 1990

The August 30, 1986 (M_W ?=?7.1) and May 30, 1990 (M_W ?=?6.9) Vrancea intermediate-depth earthquakes, despite their almost similar magnitudes, have produced very different spectral contents as shown by the strong ground motions recorded in Bucharest and its surroundings. The differences can be attributed to different epicentral distances and to different values of the stress drop. The characteristics of the seismic ground motions recorded in Bucharest area in the 1986 and 1990 seismic events are discussed in the context of (a) the source characteristics of the two earthquakes and (b) the local soil conditions in Bucharest. Furthermore, an attempt is made to determine the soil factors S defined in EN 1998-1 EN 1998-1. 2004. Design of Structures for Earthquake Resistance – Part 1: General Rules, Seismic Actions and Rules for Buildings, CEN.  [Google Scholar] for the Bucharest area, based on the strong ground motion dataset recorded during the two seismic events.     

The Early Bronze Age settlement of Fidvár,Vráble (Slovakia): reconstructing prehistoric settlement patterns using portable XRF

This paper presents first results of chemical analyses of sediment samples from the Early Bronze Age (EBA) settlement Fidvár near Vráble (Slovakia). Large-scale geomagnetic prospection revealed detailed architectural remains of a fortified settlement. Other structures such as an earthwork of the linear pottery culture and at least two Roman march camps were found too. An Auger programme provided sediment samples of different depths, A) from an EBA house and the outer fortification ditch, B) from a potential metal workshop area as indicated by surface finds, and C) from an area located in the settlement's centre. The samples were analysed by a portable X-ray fluorescence (pXRF) spectrometer in order to investigate the vertical and horizontal distribution of chemical signatures. The comparison of geophysical data and three-dimensional chemical patterns gives us the opportunity to determine the human impact and to reconstruct activity patterns. The potentials and limits in the application of pXRF in archaeological soil chemical surveys are evaluated by systematic comparisons with high resolution laboratory measurements, including atomic absorption spectrometry (AAS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The pXRF analyses can be reproduced well and show a good accuracy. Whilst (p)XRF analyses reflect the total composition of archaeological soil samples, the results of the AAS and ICP-OES analyses are fundamentally influenced by the acid digestion or extraction methods used. The pXRF analyses of the Vráble soils showed typical patterns of human occupation. For example, there are strong positive correlations between phosphorous, strontium and calcium. Phosphorous shows an enrichment in pathways and the fortification ditch. It is less strongly enriched within the sediments of house structures. Similar results apply to calcium and strontium distribution. But compared to the respective concentrations in sediment samples from the ditch they show a considerably higher variation in samples associated with house structures; that is, individual samples of sediments from house structures contained high concentrations of both, calcium and strontium. The deposits of an area that according to surface finds was thought to represent a potential metal workshop did not show indicative chemical signatures. Targeted excavations confirmed the absence of such as workshop. Finally it was shown that the refill history of the innermost fortification ditch (sample area D) and the overall cultural occupation sequence at the site correlate strongly with the chemical signatures of the respective ditch profile. The systematic variation of key elements along the profile opens up an entirely new perspective for interpreting the site's history. Overall, the study shows the great potential of pXRF as valuable part of an archaeological survey toolkit.     

A charcoal-rich horizon at Ø69, Greenland: evidence for vegetation burning during the Norse landnám?

It is often assumed that the colonisation of Greenland by Norse settlers in c. A.D. 985 had a sudden and dramatic effect on the environment, involving substantial vegetation clearance and environmental degradation. Consequently, it has been argued that charcoal-rich horizons, visible in many sections in Greenland, represent the initial burning of the vegetation by Norse farmers to create land suitable for agriculture. In this study a charcoal-rich layer, visible in a modern drainage ditch beside the Norse farm of Ø69, was analysed using archaeobotany, sedimentary analysis and radiocarbon dating to test the date and formation processes of the horizon. It is demonstrated that the charcoal-rich layer at Ø69 was not derived from in situ vegetation burning in the 10th century and concluded that the layer was probably formed by the addition of midden material to the infields around Ø69 in the 13th and 14th centuries cal AD, perhaps as part of a soil amendment strategy. It is argued that caution must be exercised when interpreting charcoal-rich horizons as time-specific chronological markers in palaeoenvironmental sequences in Greenland.     

温湿度对水井坊遗址的影响

为探讨引起水井坊遗址酒窖开裂、酥粉的主要病害根源,采用化学分析、X射线晶体衍射、温湿度监测等方法对水井坊遗址土样化学成分、矿物组成、监测点的温湿度变化、土样含水量与该点湿度的关系进行分析测试。结果表明:因二个监测点的小环境不同,温湿度变化对它们的影响也不相同,温湿度变化对L2的影响比对J8解剖坑要明显,结合L2周边酒窖和J8解剖坑的病害勘察,认为温湿度变化是引起遗址酒窖开裂、酥粉的主要因素。     

Environmental history in the Mediterranean world: cross-disciplinary investigation of cause-and-effect for degradation and soil erosion

Environmental history is a multidisciplinary enterprise united by shared interests in ecological change and the complex interactions between people and the environment. Its practitioners include expertise in the natural sciences, in history or archaeology, or in political ecology and related social sciences; but there is no agreement on a common agenda and limited success in bridging methodological and epistemological divisions that impede integrative and interdisciplinary research. World-systems history and environmental history also have overlapping interests in long-term change and matters of sustainability. The Mediterranean world sustained agricultural lifeways across some 8000 years, yet its environment has repeatedly been described as degraded, suggesting conceptual confusion between transformation and destruction. This paper is didactic in purpose and uses landscape histories for the Peloponnese and eastern Spain to show that the impact of recurrent, excessive precipitation events and of reduced quality of land cover are difficult to unravel, because they commonly appear to work in tandem. As a result (a) environmental change cannot be assumed or “predicted”, but must be studied inductively by experts with science skills, and (b) cause-and-effect relationships demand an understanding of ecological behavior, for which humanistic insights are indispensable. Social science models highlight systemic relationships from socioeconomic and structural perspectives, but are less suited to deal with the complexity of environmental change or the contingencies exemplified by human resilience. Near Eastern, Greek and Roman agronomic writings offer elite “voices” that speak to cumulative technological change, scientific understanding, and the context of intensification. Rural voices can be heard through ethnography, and in eastern Spain are extended into the past by archaeology and archival research. In the absence of structural constraints, they reveal collective decision-making with respect to a shifting repertoire of agricultural strategies that take into account market opportunities, demographic growth, finite resources and environmental problems. Such adaptability spells resilience, and “good farming” is culturally embedded as a civic responsibility, both in the ethnographic present and in the older, elite agronomic writings. But if the “moral economy” erodes in the wake of food stress, tax extortion, instability, insecurity, or ideological oppression, there is little incentive to pursue long-term strategies, so that behavior focuses on short-term survival. The context for this dialectic of poor versus good ecological management may be structural, but cause-and-effect in the traditional Mediterranean world ultimately depended on ecological and human resilience. Long-term sustainability is similarly non-predictive. It depends on people, rather than social theory.     

The legacy of past urban waste disposal on local soils

Many attributes of present day soils can only be explained by reference to land management in the historic past. This is particularly well expressed in the plaggen soils which occur extensively on the north European plain. These deepened soils owe their dominant characteristics to the application from the 12th century of turf materials, often impregnated with dung. Similar deepening of soils can result from the disposal of urban waste. This paper discusses the results of soil research focused on a small Scottish town (Nairn). A soil survey revealed topsoils of over 1 m overlying fluvioglacial sands and gravels; such deepening is explained by the use of town waste on the burgh's arable lands from at least the 17th century up until the mid-19th century when an integrated sewerage system was installed. Micromorphological study of this deepened topsoil revealed the presence of many small black carbonaceous particles. Oxygen:carbon ratios were calculated from microprobe results as a means of confirming the carbonaceous nature of these particles. Soil phosphorus was primarily concentrated on the perimeter of these particles. The high quality of present day soils on the edge of the town is explained by the disposal of waste material, which included much carbonised material. This paper is the first to highlight the importance and potential of examining the gradation in soils from urban to rural contexts.     

Evaluating the use of IKONOS satellite imagery in lowland Maya settlement archaeology

This article presents an extensive evaluation, in several contiguous or near-contiguous areas, of the viability of IKONOS satellite imagery in detecting sub-canopy Maya settlement in Peten, Guatemala. Initial research in and around San Bartolo, Guatemala, led to the conclusion that IKONOS imagery could be highly effective in detecting and predicting Maya settlement of the Preclassic and Classic periods, in zones of dense occupation near swampy lowlands known as bajos. The pioneering methods at San Bartolo are applied here to other regions in the Maya lowlands, but with mixed or unpromising results. Preliminary evaluation indicates that local climate, geology, hydrology, topography, pedology, and vegetation differ dramatically in these other regions, with consequences for wider application of the settlement signature discerned at San Bartolo. Possible reasons for these difficulties are offered in this paper, along with ways to strengthen the use of multispectral imagery in archaeological survey of tropical forests.     

Evaluating soil resilience in long-term cultivation: a study of pre-Columbian terraces from the Paca Valley, Peru

This study evaluated the soil properties of pre-Hispanic stone-walled terraces by comparing soil quality along terraced catenas in the Paca Valley, a tributary of the Mantaro Valley, Peru. Micromorphological and bulk analyses of terrace soils revealed that despite terracing soil horizonation largely followed the catena. Upland terraced fields had deeper A-horizons with higher biotic activity than uncultivated controls, but less fine material and greater carbonate accumulation. Midslope fields were highly variable in depth and soil properties reflecting considerable substrate and anthropogenic variations in this growing zone. Silts and clay accumulated in valley bottom terraces where pedofeatures indicate an ongoing downhill movement of fine material. The distribution of soil separates down Paca hillsides demonstrates that terraces help moderate, rather than control, the erosion of key soil fractions required for long-term agricultural productivity. This study illustrates how the loss of fine material is partly mitigated by soil consolidation in dense topsoil peds, microaggregates and saprolite. These aggregates are retained by terraces and contribute to deep soil profiles. Nevertheless, many fields show signs of degradation, especially from insufficient organic matter amendment. In addition to farming itself, buried soils and associated artefacts in valley bottom fields indicate mass soil movement, a likely result of disruption caused by Inca road and terrace construction. The poor soil quality of many upland terraces also confirms that stone-walled terraces were constructed on mediocre substrates for farming, indicating a high labour investment for marginal agricultural returns in these areas. Overall, Paca Valley terraces improve topsoil retention and promote deep soil profiles. However, these fields present quite varied growing substrates. It is also apparent that over the last millennium, soil depletion from cultivation has compromised soil quality through loss of fine material and organic matter. Shifts in farming practice away from pre-Hispanic practices such as long-fallow and middening appear to exacerbate this trend.     

Geoarchaeological insights from a Roman age incineration feature (ustrinum) at Enconsta de Sant'Ana (Lisbon,Portugal)

Ustrina are incineration funerary structures that are relatively common in Roman age cemeteries. Salvage excavations at Encosta de Sant'Ana (Lisbon, Portugal) in 2002 brought to light a part of the necropolis of the Roman town of Olisipo, including some ustrina. One of them, designated Burial 1 during fieldwork, is analyzed here from a geoarchaeological viewpoint to understand the formation processes of such an archaeological feature, namely its construction technique, use and function. The study of site context and subsurface pedofeatures, and the application of archaeological soil micromorphology, revealed that the ustrinum was constructed digging a hollow in bedrock and building a mud-brick ridge around it, with raw material taken from the local bedrock. The structure was used at various times and remodelled at least once, and its base was not always thoroughly cleaned – according to the custom called “pars pro toto” by Roman authors – and probably left open when not in use.     

Ancient soil resources of the Usumacinta River Region,Guatemala

In this study we present the results of a combination of methods used to identify possible agricultural activity of the ancient Maya in the Usumacinta River Basin in Guatemala. These methods included stable carbon isotope analysis of bulk soil organic matter, soil profile investigations and a spatial model of gentle slopes and well-drained soils to identify favorable agricultural conditions. Stable carbon isotope analysis of bulk soil organic matter in particular offers potentially direct evidence of agricultural activity. The δ¹³C results suggest that there is a strong signature of C₄ plants, such as maize and tropical grasses, throughout the study area. Further, the current soil conditions and extent of relatively gently sloped areas are favorable to agriculture. Overall, the results are supportive of the hypothesis that the area, located between the polities of Piedras Negras and Yaxchilán, was agriculturally important to surrounding areas.