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1.
This article aims to study the dynamic characteristics of soil in Bam, southeastern Iran. Fundamental frequency and amplification factor of soil sediment were estimated by microtremor measurement. This procedure was performed at 49 sites in the city. Two 120-second data were recorded at each site. Segmental cross spectra were applied to calculate spectrum, Nakamura's method (H/V) was used for analyzing data and fundamental frequency and amplification factor values were derived. Iso-frequency and iso-amplification maps of the city were prepared. Results show that soil type in Bam city is mainly stiff, although amplification factor is relatively large. There is a short period zone in northwest to southeast direction. Sediment depth was estimated using a correlation between fundamental frequency and sediment thickness. Results obtained from microtremors were compared to the geotechnical boreholes and it was shown that microtremors can be used for a rough estimation of sediment thickness. Damage distribution map of Bam due to the Bam earthquake on December 26, 2003 was prepared by both field and aerial investigation. Quality of buildings in Bam was evaluated, as a result a crude zoning map on the building quality was prepared. Finally, it was concluded that several factors have contributed to damage intensity variation; earthquake characteristics, local site effect, and buildings' quality. All mentioned parameters affected the damage variation.  相似文献   

2.
Earthquakes and microtremor records are used for estimating the site response of hard rock sites comprising four three-component seismic stations which operate as part of the Israel Seismic Network. The response functions are determined by implementing the horizontal-to-vertical component spectral ratio of earthquake shear-waves (receiver function estimates) and microtremors (Nakamura's estimate) observed simultaneously at the site. The sites of seismic stations ATZ (Mt. Atzmon), MBH (Mt. Berech) and MRNI (Mt. Meron) exhibit amplification attributed to topography effects. At ATZ, within the 1.3–2.0 Hz range, the amplification is in the order of factor 4. At MBH amplification levels of 3.0–3.5 are observed in the frequency range 1.5–4.0 Hz. Station MRNI exhibits a relatively strong amplification effect (up to 4) in the frequency range of about 2.5 to 3.5 Hz. Slight amplification around 5 Hz is observed at ATR (the proposed site for a nuclear power plant). These effects were correlated with the thickness of the weathered layer above unweathered chalk. A comparison between the amplification factor observed during earthquakes and those inferred from microtremors shows that these are, in general, in agreement. However, details of the spectral ratios from different microtremor recordings are not exactly the same. Differences appear mainly in the frequency at which the maximum amplification occurs. These observations demonstrate the usefulness of non-reference technique in estimating the topographical effects of ground shaking. These methods may be used in the process of seismic hazard assessment for ridges and mountain tops, common sites for settlements, communication relay stations, bridges, rope-drive and power transmission towers.  相似文献   

3.
Nakamura's technique has been widely discussed from the theoretical point of view. Very little information is available as far as the experimental, on-the-field standpoint is concerned. A series of experiments under controlled conditions were set up to assess the reliability and applicability range of this microtremor technique. Since this approach to microzonation is particularly appealing in urban environments, great care was devoted to evaluate the influence of factors such as anthropic noise, concrete or asphalt coverings and soil-structure interaction. Environmental factors (wind) and the influence of sensors were also considered. The results were compared with the seismic response from four earthquakes. The set of experiments shows that under proper measurement conditions Nakamura's technique provides stable and reliable results, but great care has to be devoted to avoid factors that may significantly and adversely affect the results.  相似文献   

4.
The city of Port Vila, Vanuatu, is located in one of the most active seismic regions on earth. Earthquakes are felt frequently and, due to very rapid plate convergence rates, return period of large earthquakes (M>6) in the New Hebrides Benioff zone can be less than 10 years. Even though Port Vila does not lie on an identified seismic fault zone, strong motions by nearby earthquakes have to be expected due to the city's geographical location close to the plate boundary of New Hebrides convergence zone. An accurate estimation of the seismic ground motion across the city is of prime importance for urban developments and mitigation of earthquake risk. Following many examples of monitored strong earthquakes in the current century, it is evident that the local site effects may have a dominant contribution to the intensity of damage and destruction. In this study we focussed on the first stage of associating site effects and seismic hazard by preparing a microzonation map for Port Vila. The seismic microzonation of the city has been carried out to provide a detailed map of the zones that exhibit site effects in terms of resonance frequencies and approximated amplification of the ground shaking. Having in mind that these data will be used in improving building design to sustain strong ground motions, our analysis is limited to the frequency band of 1–10 Hz, corresponding to the expected resonance of different types of buildings in Port Vila. The Nakamura technique has been used to estimate site amplification effects from single station noise recordings. Interestingly, excluding one site located on an old dump zone, the amplification factors at about the 100 sites surveyed in Port Vila remain below 3 with an average well below 2 in the 1 to 10 Hz frequency band. These results suggest that there is no significant Vs velocity change in consequently layered material and that the uppermost sedimentary layers in the surveyed down town area are relatively thin. These observations are in agreement with the mapping of limestone terraces throughout Port Vila area. However, both the surface geology and results from seismic zonation indicate a thicker (up to several tens of meters) sedimentary cover around the Bauerfield airport and in the Mele terrace zone. Low resonance frequencies (around and below 1 Hz) and amplification factor of the order of 5 were observed over this large area, immediately outside Port Vila. Any building development in this area should take these results into account.  相似文献   

5.
The aim of this study was to apply Nakamura's technique to Valencia city center, after some preliminary tests in Barcelona. Previous studies of Barcelona had measured periods in restrictive conditions and in various types of material ranging from very soft soil (with a predominant period of approximately 2 s) to rock (0.3 s), and under different measurement conditions. The Valencia city center measurements were taken by using the distance from buildings and car and pedestrian traffic to construct a measurement grid that was as regular as possible. We also estimated possible soil-structure interaction to detect potential vulnerability.  相似文献   

6.
Perth is the largest city in Western Australia and home to three-quarters of the state's residents. In recent decades, there have been a lot of earthquake activities just east of Perth in an area known as the South-West Seismic Zone. Previous numerical results of site response analyses based on limited available geology information for PMA indicated that Perth Basin might amplify the bedrock motion by more than 10 times at some frequencies and at some sites. Hence, more detailed studies on site characterization and amplification are necessary. The microtremor method using spatial autocorrelation (SPAC) processing is a useful tool for gaining thickness and shear wave velocity (SWV) of sediments and has been adopted in many previous studies. In this study, the response spectrum of rock site corresponding to the 475-year return period for PMA is defined according to the probabilistic seismic hazard analysis (PSHA) based on the latest ground motion attenuation model of Southwest Western Australia. Site characterization in PMA is performed using two microtremor measurements, namely SPAC technique and H/V method. The clonal selection algorithm (CSA) is introduced to perform direct inversion of SPAC curves to determine the soil profiles of representative PMA sites investigated in this study. Using the simulated bedrock motion as input, the responses of the soil sites are estimated using numerical method based on the shear-wave velocity vs. depth profiles determined from the SPAC technique. The response spectrum of the earthquake ground motion on surface of each site is derived from the numerical results of the site response analysis, and compared with the respective design spectrum defined in the Australian Earthquake Loading Code. The comparison shows that the code spectra are conservative in the short period range, but may slightly underestimate the response spectrum at some long period range.  相似文献   

7.
On October 31 and November 1, 2002, two earthquakes of magnitude 5.4 and 5.3 hit the area at the border between the Molise and Puglia regions in Southern Italy. The damage pattern in the epicentral area qualified the quake as an intensity VII MCS event, although providing a notable exception relevant to the small village of San Giuliano di Puglia. Since the first macroseismic survey, it appeared clear that in S. Giuliano the intensity was two degrees higher with respect to three neighbouring villages located within a radius of 3 km. Soon after the quake, our team started a campaign of microtremor HVSR measurements (Horizontal to Vertical Spectral Ratio), then we installed accelerometers and carried out damage and geological surveys. Finally, we performed a geoelectrical tomography and two profiles of Vs velocity with depth using the NASW technique (Noise Analysis of Surface Waves). The preliminary observations indicate that ground motion amplification is present in S. Giuliano within the frequency band that may affect building. A strong velocity contrast 20 m deep causes the predominant peak. More amplification could be due to more complicated, 2D effects. As regards the damage pattern, it divides S. Giuliano in three zones showing different characteristics and seismic behaviour. A building-by-building survey is still under way to better evaluate vulnerability variations in different zones of the village. However, the acquired data so far is sufficient to propose site amplification as a possible cause of the damage enhancement observed in S. Giuliano.  相似文献   

8.
Abstract

The many intersecting issues that arise when deciding whether to shelter an archaeological site should be approached using a values-based methodology, one that has demonstrated its validity arid practical worth in conservation over recent decades. Nonetheless, pitfalls abound in the decision-making process and in establishing effective conservation criteria which should be based principally on a thorough understanding of the threats to the resource and the specific deterioration mechanisms operating, with the objective of creating a shelter that will preserve the site's identified values. An aspect that has received almost no attention in the past is evaluation of a shelter's performance, both qualitative and quantitative, in preserving the site. It is urged that this receive priority when establishing the conservation criteria during the initial phases of a sheltering project. Issues are illustrated from a range of diverse sites, including a number of published shelters. The paper first looks at the examples of the Laetoli (Tanzania) and Lark Quarry (Australia) trackway sites in the context of decision-making and conservation criteria, and then discusses two examples of evaluation: one quantitative, using an experimental shelter and the other discussing publications on a petroglyph site shelter.  相似文献   

9.
《巴勒斯坦考察季》2013,145(3):199-216
Abstract

In 1894 the Garden Tomb Association concluded the purchase of a small property outside of the Old City of Jerusalem. The site in question was known as 'Skull Hill' or 'Gordon's Calvary' and was reputed to be the real site of the burial place of Jesus. This case study of a land transaction in Ottoman Jerusalem reveals several important themes from the period. The purchase by foreigners of sites in Palestine was a circuitous process that sometimes involved the intervention of foreign consuls and it sheds light on the Ottoman land laws. The Garden Tomb, a unique property, was part of a larger process of the development of new holy places in Palestine by Europeans. Lastly, the association that purchased the site was primarily funded, initiated and run by notable English women, illustrating their increasing involvement in 19th century religious and activist movements.  相似文献   

10.
ICAHM redivivus!     
Abstract

The measures employed in a current Siberian rock art conservation project are briefly described; and preliminary results are examined. The future development of the project is considered, and specific noninterventionist methods are suggested in an effort to contain contamination of the rock art, and so to avoid the destruction of its remaining research potential. The main site among the series of sites being discussed has suffered extensive damage from rock art recorders, as well as intentional vandalism by residents of the district's villages. In view of the steepness of most of the sites, access modifications are considered to be the most effective measures of alleviating anthropic damage. A number of less serious threats can be mitigated by fairly simple measures of altering the conditions threatening the rock art. Such measures of minimal intervention are listed. Although the paper deals with a particular region, climate, demography and geology, the underlying management philosophy may be much more widely applicable.  相似文献   

11.
This report presents results of a reanalysis addressing the presence of Paget's disease (Osteitis deformans) in the pre‐contact Safety Harbour Briarwoods site (8PA66), a burial mound in Pasco County along Gulf coast Florida, dating around 1000–1500 AD. Due to the paucity of published histological and radiological analyses as well as the suspect nature of this Paget's disease report, a new study was conducted. The diagnosis was suspect for three reasons. First, the original diagnosis was based on five skeletal fragments from five different burials making the results questionable. Secondly, Paget's disease is very similar to treponemal disease and can possibly be misdiagnosed. The characteristic histological mosaic pattern found in Paget's disease provides the most definitive differential diagnosis. Thirdly, Paget's disease is found primarily in European populations and this is a pre‐contact site. Histological sections from the suspected Pagetic bones were analysed for the presence of the mosaic pattern. Macroscopic and microscopic analyses were unable to support or deny the presence of Paget's disease due to the fragmentary nature of the skeletal elements as well as extensive diagenesis resulting from exposure to the environment. The presence of Paget's disease could not be confirmed or refuted at Briarwoods due to extensive taphonomic damage. However, it is suggested that the presence of treponemal disease should be investigated because although not originally reported, the presence of saber‐shin tibiae consistent with this disease are present at this site. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

12.
Abstract

In today's society it is recognized that all people, regardless of disability, should be welcomed at heritage sites. As mobility impairments are one of the most common types of disability faced by visitors to heritage sites, this study will look at how the changing views on disability discrimination have affected heritage sites by reviewing current legislation and comparing it with visits to heritage sites in the UK and the US. For this purpose, site visits looking at adaptations for mobility impairments were carried out at fifteen sites in the UK and six sites in the US. There are additionally three case studies: a comparison between a UK and a US early nineteenth-century naval vessel, a site with traditional adaptation methods, and one that has creatively designed access. Overall, both the UK and the US have adopted similar methods for creating disabled access. Yet, the research shows that although many sites have designed some type of access, there is no conformity as to how this access is achieved. In addition, many sites use the loopholes in legislation to ensure that little is changed in the physical material. In the end, it is evident that more must be done to find a compromise between accessibility and preservation.  相似文献   

13.
ABSTRACT

South Africa's northern Namaqualand coastal desert is the southern extension of the Namib. Today, this region is semi-desert with patchy subsistence resources and scarce, unpredictable rainfall. Yet this ancient desert landscape possesses residues of human activity stretching back into the Middle Pleistocene, evidenced by heavily weathered surface finds, including handaxes and Victoria West cores. Such old finds in so harsh an environment raise important questions: how do human movements into this area relate to local palaeoenvironmental changes, and how has this relationship changed through time? While no dated Middle Pleistocene sites presently exist to reconstruct the earliest hominin dispersals, several late Pleistocene sites now have chronostratigraphic sequences that can be brought to bear on these questions. This article presents chronological and subsistence-settlement data for one such site, Spitzkloof A Rockshelter in northern Namaqualand's rugged Richtersveld. Humans are shown to have visited the site very sporadically between ~50,000 and 17,000 cal BP. Unlike most of the subcontinent, the most intensive occupations occur during early Marine Isotope Stage 2, when multiple proxies suggest enhanced humidity associated with intensified winter rainfall. We examine these data using the region's better-developed Holocene archaeological record to create predictions about the earliest coastal desert dwellers.  相似文献   

14.
We approach from a new standpoint the problem of estimating seismic hazard for some towns and villages located in Val d'Agri area (Southern Italy) that in the past have been affected by several seismic events. The estimates are carried out using a method that is based on the analysis of site seismic history extracted from macroseismic catalogues. To study the influence of site effects two different procedures have been performed: in the first, seismic hazard estimates have been deduced from epicentral data only, in the second, intensity data actually observed at the site are also considered. The difference between the two estimates can be correlated with local variations of seismic response due to local geological features which are responsible for possible cases of amplification. In order to validate the presence of such correlation, seismic hazard estimates have been compared to site amplification measurements obtained by using the HVSR (Horizontal to Vertical Spectral Ratio) technique. Our findings reveal a good correlation between seismic hazard enhancements and the presence of site amplification effects. The application of this kind of analysis to the Val d'Agri area has pointed out that the joint estimates of site seismic hazard enhancement and HVSR measurements could be a helpful tool to identify problems related to seismic microzonation.  相似文献   

15.
INAA at Manchester began almost by chance, and amid scepticism, with a request for help from the university's Department of Archaeology in the early 1970s. Over the years, the method of selecting pottery to be sampled was refined from the simple assumption that sherds found at a site were typical of those made there, to a greater focus on kiln sites and wasters. An important element in Manchester's approach was that this was a teaching department: in the quarter‐century during which the laboratory practised INAA over 6000 samples were analysed in a wide range of projects by postdoctoral researchers, Ph.D. students and even final‐year undergraduates. Although there were sometimes problems of comprehension on both sides, close collaboration with archaeologists encouraged methodological comparisons, and often INAA was seen as an additional weapon in the archaeologists’ arsenal as much as a developing scientific technique. The university's place as the inventor of the computer encouraged the development of statistical programs, which in turn facilitated ready collaboration and exchange of information with other laboratories, such as those at Bonn and Berkeley.  相似文献   

16.
Understanding the dynamic behaviour of soil in the Anchorage basin in southcentral Alaska is essential for seismic hazard assessment of this highly seismically active region. The analysis of site responses for 40 sites from weak-motion and strong-motion data with amplitudes less than 0.1 g showed a strong influence of subsurface geological conditions on the characteristics of ground motion. Particularly, the sites in the central part of the city, including the downtown area, showed prominent resonance peaks around 1 Hz with amplification values up to about 4. The numerical analysis, based on one-dimensional multi-layer soil models shows that site response characteristics, and especially aforementioned peaks, are largely related to the thick, soft layer of Quaternary deposits, particularly cohesive fades of Bootlegger Cove Formation. The computed transfer functions for soil profiles of six representative sites are in accord with the site responses in the frequency range from 1 to 5 Hz. There is no significant change in amplification values below 2 Hz corresponding to large-amplitude (up to 0.38 g) ground motions; however, above 2-3 Hz the amplification values are greatly reduced in this case.  相似文献   

17.
This article discusses British pioneer in birth control and palaeobotanist Marie Stopes' visit to Saint John New Brunswick's ‘Fern Ledges’ as an important historical episode for feminist geography. By considering the relationship between Stopes' inquiries into plant sex and human sex, this article explores feminist and queer studies' constructions of ‘natural’ bodies alongside environmental constructions of ‘natural’ environments. Stopes' work is useful in showing how early twentieth century plant-breeding and human sexual politics intersected through understanding sex as a perfectible technique for producing better bodies across plant, animal and human boundaries. This argument is developed along three significant sites that show how dynamic relationships between bodies and places are mutually constituted. The first site focuses on early twentieth century evolutionary thought which made it possible to conceive of linkages between plants and humans in their sexual lives. The second site is Stopes' experience of place in the ‘Fern Ledges’ through a palaeobotanical investigation of plants, which were read ‘backwards’ through human social categories of kinship, family, race and nation. The final site is an examination of Stopes' popular sex manuals as ecological texts that give specific attention to plant agency in shaping narratives of human sexual politics.  相似文献   

18.
Although written sources indicate that falconry or hawking was very popular already in early medieval Poland, there is no hard zooarchaeological evidence that would support it. So far, only two studies based on animal remains suggested hawking in medieval Poland. The purpose of this study was to examine all published zooarchaeological reports from all archaeological sites in Poland and check for possible clues of hawking. Altogether, 281 remains of 12 species of diurnal birds of prey were recorded from 38 sites (49 time‐site units) in Poland beginning from the Middle Ages onward. The most frequently found was the goshawk Accipiter gentilis followed by the white‐tailed eagle Haliaeetus albicilla and the sparrowhawk Accipiter nisus. Clues of possible hawking include high status of sites, occurrence of species used in falconry outside their natural ranges, preponderance of females, the presence of sub‐adult specimens and others. It is suggested that surface damage observed on prey bones done by the hawks' beaks and claws may be an extra evidence of hawking. The present study strongly supports the notion that hawking was a very popular activity in medieval Poland. In the future, medieval bone assemblages should always be checked for clues of hawking. The present study may also be used as a source of raw data for other analyses because it includes detailed information on birds of prey from all zooarchaeological reports published so far in Poland. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

19.
Defining the extent of human activity around settlement sites is of particular significance in archaeology as it may define peripheral activity areas and thus the site's boundary. In Near Eastern archaeology, site boundaries are usually defined by the presence of architectural and other macroscopic archaeological remains. Here we use the phytolith concentrations and morphotype assemblages, as well as changes in the mineralogical composition of the sediments in and around the small Iron Age site of Izbet Sartah in central Israel to determine the site boundaries. The site has a shallow stratigraphy and highly bioturbated sediments. Coincidental changes in the clay/quartz ratio and phytolith concentrations define the boundary between high and low impact anthropogenic activities. This boundary is generally some 20 m away from the architectural remains. In addition, we note that the phytoliths in the site's core show clear evidence of having been affected by chemical dissolution (i.e., diagenesis), while those in the vicinity of the site's boundary have undergone severe diagenesis. These observations indicate that phytolith diagenesis will affect site boundaries determination, as well as phytolith-based reconstructions of activity areas. We propose that phytolith preservation depends on the initial amount of available silica, the depth of burial with respect to the active root area of modern vegetation, and the presence of fresh phytoliths in the soil.  相似文献   

20.
India has one of the world's largest and most significant bodies of rock paintings and engravings, yet not a single rock art site or image has been directly and accurately dated using radiometric techniques. Here we report on results from the Billasurgam Cave complex near Kurnool in southern India. Although this cave complex has been investigated archaeologically since the late 1800s, it was not until 2008 that a large petroglyph, consisting of the remains of three nested diamond designs on a stalactite, was noted. In order to determine if this petroglyph had been made recently, flowstone was sampled from on top of and below the engraving. Radiocarbon dating revealed a mid-Holocene age of about 5000 cal BP for the petroglyph, but we cannot rule out the possibility that the engraving is several centuries younger. Similar nested diamond designs at some rock painting sites and on a chert core elsewhere in India have been assumed to be Mesolithic. Our result is consistent with this hypothesis, although we note that it also consistent with the creation of the petroglyph in the early Neolithic. We conclude that the Billasurgam engraved diamond design was probably made by Mesolithic foragers of the Kurnool region and is the oldest surviving form of rock art yet directly dated in southern India.  相似文献   

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