Determination of the influence of soil parameters and sample density on ground-penetrating radar: a case study of a Roman picket in Lower Bavaria

Ground-penetrating radar (GPR) surveys are very much influenced by the site-specific physical properties, soil parameters and the sample density of the radar pulses. According to the electromagnetic theory, the transmission and reflection of electromagnetic waves is dominated by the conductivity, dielectric permittivity and the soil moisture. Therefore, it is advisable to measure these parameters in advance of a GPR survey. Commonly, this is not possible directly with the standard common-offset GPR arrays. To overcome this problem, we adapted and applied a direct method called time-domain reflectometry to a selected case study of the Roman picket Hienheim at the Raetischer Limes in Lower Bavaria. Furthermore, we present some important results relating to the profile spacing and orientation of GPR surveys and the site-specific soil parameters. The location and the identification of the archaeological features were successful by all geophysical methods. However, the application of all these geophysical methods like magnetometry, resistivity and GPR in addition with aerial photography and Airborne Laserscanning exemplifies the advantages of an integrated survey to achieve a comprehensive result of an archaeological site. The Roman picket of Hienheim shows up differently in all results, as each one traces the archaeological remains according to a specific physical parameter. Resistivity and radar are best to resolve buried stone structures like the walls of the picket or stone-filled ditches. In contrary, magnetometry benefits of the magnetic contrast between the limestone walls and the surrounding soil.     

Ground Penetrating Radar in the Northern Great Lakes: A Trial Survey of a Contact Period Occupation in Marquette County,Michigan

ABSTRACT

Timing, inclement weather, and limited budgets can obstruct archaeological survey efforts. Here, we ameliorate some of these with use of ground penetrating radar (GPR) at the Goose Lake Outlet #3 (GLO#3) site (20MQ140). GPR surveys to guide survey and excavation efforts in these well-drained sandy soils are limited. GPR imagery exhibited false positives; however, shovel probes, subsequent site excavation, and artifact analysis led to numerous discoveries at this protohistoric site—including glass trade beads dating to the 1630s. These discoveries solidify evidence for some of the earliest European-made trade items in the region and provide further confirmation for placement of an Indian trail and ancient travel corridor between Lake Superior and Lake Michigan. Two ¹⁴C samples obtained from moose-bone in features with trade goods fall within the expected occupation range of 1633–1668 and 1615–1647. Several anomolies, possible hearth clusters were seen on the GPR imagery; however, many features remained invisible.     

Detecting and mapping buried buildings with Ground-Penetrating Radar at an ancient village in northwestern Argentina

We describe an archaeo-geophysical investigation performed near the Palo Blanco archaeological site, Catamarca, Argentina. A large area beyond the northern limit of the site was explored with the Ground-Penetrating Radar (GPR) method in order to detect new buildings. The exploration showed signals of mud-walls in a sector that was located relatively far from the previously known buildings. A detailed survey was performed in this sector, and the results showed that the walls belonged to a large dwelling with several rooms. The discovery of this dwelling has considerably extended the size of the site, showing that the dwellings occupied at least twice the originally assumed area. High-density GPR surveys were acquired at different parts of the discovered building in order to resolve complex structures. Interpreted maps of the building were obtained. Different characteristics of the walls were satisfactory determined, in spite of the low contrast of the dielectric constant at their interfaces and the noticeable spatial fluctuations of the signals due to wall collapses.     

Imaging Radar and Archaeological Survey: An Example from the Gobi Desert of Southern Mongolia

Abstract

The application of spaceborne imaging radar data to archaeological survey in arid regions was investigated at a study area in the Gobi Desert of southern Mongolia. A repertoire of computer enhancement regimens specific to archaeological applications was applied to RADARSAT imagery of the study area to reduce noise, detect lineaments, or otherwise enhance the data. The imagery was then georectified and integrated into a large area mosaic, creating detailed multi-layered image-maps that were used to direct ground exploration. During two field seasons with the Joint Mongolian-Russian-American Archaeological Expedition (JMRAAE) in 1997 and 1998, precise latitude/longitude information was obtained with Global Positioning Satellite (GPS) devices, establishing Ground Control Points with which to further georectify the image-maps. Both navigation and archaeological site selection were enhanced by hydrologic and topographic information in these satellite image-maps. The JMRAAE field team successfully located Palaeolithic cultural artifacts showing little or no surface expression, most often in association with ancient watercourses. The team was able to navigate accurately through the extreme desert terrain using the image-maps and GPS in this otherwise only minimally mapped area, thereby facilitating detailed archaeological reconnaissance and survey.     

Joint geophysical measurements to investigate the Rossano of Vaglio archaeological site (Basilicata Region,Southern Italy)

A high resolution geophysical survey was carried out in the archaeological site of Rossano di Vaglio (Basilicata Region, Southern Italy), where an important ancient sanctuary is located. It was built during the IV century B.C. and devoted to the goddess Mephitis. The sanctuary rises in an area affected by a multiple and retrogressive rototraslational landslide, historically and presently subject to reactivation. The main objective of this work was the identification of buried structures of archaeological interest in an area designated by the Archaeological Superintendence of the Basilicata Region. The study was performed by means of the use of high resolution geophysical surveys. In particular, we made use of the joint application of three highly sensitive and non-invasive geophysical techniques, namely the Geoelectrical, the Magnetic and the Ground Probing Radar (GPR) methodologies. In such a way, we obtained two important results: first, we provided the archaeologists with information about the limits of the areas to be excavated; second, we could verify in real time the reliability of the geophysical results. The experimental results showed four main magnetic anomalies in the area of study, in agreement with the GPR results obtained for the same target. Finally, a partial excavation test of the investigated area revealed a buried building structure, located in correspondence of an anomaly identified by means of the geophysical prospecting.     

MAPPING THE UNDISCOVERED RUINS OF POMPEII (NAPLES,ITALY) USING GROUND PENETRATING RADAR*

The ground penetrating radar (GPR) technique was tested in Pompeii, in an unexplored area where the Roman ruins are partially buried in the volcanic deposits. The method was also combined with time domain reflectometry (TDR) measurements to estimate the dielectric properties of the different volcanic units. In spite of the total thickness of the covering materials and the high signal attenuation measured in some layers, the radar was able to show a detailed image of the volcanic sediments and to locate the manmade structures hidden in the ash deposits. Moreover, the present study shows that the integrated use of GPR and TDR techniques could be successfully employed to evaluate the performance of the radar in specific terrains covering archaeological sites. Since it is unlikely that a large part of Pompeii will ever be excavated, GPR could be successfully used to produce detailed maps of the ruins still hidden in the subsurface, giving archaeologists the possibility of reconstructing the entire urban development of this unique ancient city.     

GPR survey at Lapa do Santo archaeological site,Lagoa Santa karstic region,Minas Gerais state,Brazil

In this work we present and discuss the results of a novel and timely GPR-2D and GPR-3D survey performed at an archaeological rock shelter site, Lapa do Santo, localized in the karstic region of Lagoa Santa, central Brazil. A total of 113 ground-penetrating radar profiles were acquired with 200 MHz and 400 MHz shielded antennas aiming in identifying geological and archaeological anomalies in order to assist archaeologists in an excavation program. The GPR results indicated clear geophysical anomalies characterized by hyperbolic reflections and areas with high amplitude sub-horizontal electromagnetic waves. The anomalies observed by GPR were confirmed by the excavation of test units, allowing the identification anthropogenic features such as a fire-hearth structure and wooden artifact, and natural features, such as, tree roots and rocky bodies such as speleothems, boulders and bedrock. The results showed the efficiency of GPR method in identifying potential buried archaeological targets in cave sites within a karstic area, and they oriented to archaeological excavations, reducing costs and increasing the probability of finding archaeological targets in the initial stages of a project.     

Methods for the extraction of archaeological features from very high-resolution Ikonos-2 remote sensing imagery,Hisar (southwest Turkey)

Archaeological research in the territory of Sagalassos is a multidisciplinary project covering scientific disciplines traditionally linked to archaeology and also new technologies such as very high-resolution remote sensing with sufficient radiometric and spatial resolution (<2.5 m). This paper focuses on the evaluation of GIS-, pixel- and object-based techniques for automatic extraction of archaeological features from Ikonos-2 satellite imagery, which are then compared to a visual interpretation of ancient structures. The study was carried out on the unexcavated archaeological site of Hisar (southwest Turkey). Although all techniques are able to detect archaeological structures from Ikonos-2 imagery, none of them succeed in extracting features in a unique spectral class. Various landscape elements, including archaeological remains, can be automatically classified when their spectral characteristics are different. However, major difficulties arise when extracting and classifying archaeological features such as wall remnants, which are composed of the same material as the surrounding substrate. Additionally, archaeological structures do not have unique shape or colour characteristics, which can make the extraction more straightforward. In contrast to automatic extraction methods, a simple visual interpretation performs rather well. The methods presented in this paper can be applied with variable success to archaeological structures composed of the same material as the surrounding substrate, which is often the case.     

Integration of geophysical surveys,ground hyperspectral measurements,aerial and satellite imagery for archaeological prospection of prehistoric sites: the case study of Vésztő-Mágor Tell,Hungary

An integration of geophysical surveys, ground hyperspectral data, aerial photographs and high resolution satellite imagery for supporting archaeological investigations at the multi-component Vészt?-Mágor Tell, located in the southeastern Great Hungarian Plain, is presented in this study. This is one of the first times that all these techniques have been combined and evaluated for retrieving archaeological information. Geophysical explorations, specifically magnetic gradiometry and ground penetrating radar methods, have revealed shallow linear anomalies and curvilinear rings at the Tell. The use of remote sensing images has confirmed the diverse anomalies with respect to geophysics through photointerpretation, radiometric and spatial enhancements. Moreover, several indices from ground hyperspectral data also have revealed stress vegetation anomalies. These integrated results were used to map the main areas of archaeological interest at the Vészt?-Mágor Tell and plan future excavations. It was found that these multiscalar data can be used efficiently for detecting buried archaeological features.     

Magnetic imaging and electrical resistivity tomography studies in a Roman military installation found in Satala archaeological site,northeastern Anatolia,Turkey

Satala is one of the last great military centers in the Roman East available for archaeological and historical investigations. This archaeological site is situated on the crossing of two singularly important routes in North-East Asia Minor. Only little archaeological fieldwork in and around Satala has so far been carried out, thus delimiting our knowledge of the site and its role within the Roman military structure of the East. In order to provide further data on the site, we carried out geophysical surveys including the application of magnetic and electrical resistivity techniques in an area north of the Sadak village. The geophysical surveys within this area (supposedly part of the Roman military camp) proceeded in two stages. The first stage saw magnetic gradiometer imaging studies being carried out on 2.1 ha, measured by a Geoscan FM-36 fluxgate gradiometer by using 0.5 × 1 m grid intervals. For the second stage a different geophysical technique was used—resistivity tomography. Resistivity data were collected using a number of combined 2D resistivity pseudosections in the eastern part of the area which contained very regular magnetic anomalies. The 3D data were obtained by the combination of all survey lines collected from 2D data sets, and thereafter the arranged data were processed by using the 3D robust inversion modified from the smoothness-constrained algorithm. Electrical resistivity tomography investigations revealed that the buried archaeological structures might be located near the surface, except for some structures found in the middle of the studied area. The archaeological structures were furthermore determined by realistic model sections and volumetric representations. Magnetic imaging and electrical resistivity tomography surveys show that the combined usage of these techniques advances the understanding of archaeological structures beneath the surface.     

Remote Sensing and Archaeological Prospection in Apulia,Italy

Abstract

When deployed in combination with ground control, archaeological surface survey, and environmental research, remote sensing based upon high-resolution multispectral satellite imagery allows large areas to be evaluated efficiently by a small team of researchers and contributes to a better understanding of an archaeological landscape. In 2007 and 2008, we analyzed ca. 100 sq km of imagery centered on L'Amastuola, Italy. Combining the evaluation of high-resolution multispectral imagery with concurrent ground control led to the discovery of 29 sites and significant off-site scatters during about four weeks of fieldwork. Our analysis indicates that most of the detected features reflect geological conditions amenable to past human habitation rather than subsurface archaeological remains. Earlier fieldwork by the Murge Tableland Survey (MTS) provided independent definitions for various types of sites and a large sample of sites and off-site scatters in the study area. Comparison of our remote-sensing guided efforts with the results of that survey suggests that our success rate is too high to be explained by random association and also illuminates the strengths and weaknesses of the respective methods, underscoring the need to integrate satellite image analysis with ground control and surface survey.     

Ground‐Penetrating Radar Velocity Determination and Precision Estimates Using Common‐Midpoint (CMP) Collection with Hand‐Picking,Semblance Analysis and Cross‐Correlation Analysis: A Case Study and Tutorial for Archaeologists

The most crucial parameter to be determined in an archaeological ground‐penetrating radar (GPR) survey is the velocity of the subsurface material. Precision velocity estimates comprise the basis for depth estimation, topographic correction and migration, and can therefore be the difference between spurious interpretations and/or efficient GPR‐guided excavation with sound archaeological interpretation of the GPR results. Here, we examine the options available for determining the GPR velocity and for assessing the precision of velocity estimates from GPR data, using data collected at a small‐scale iron‐working site in Rhode Island, United States. In the case study, the initial velocity analysis of common‐offset GPR profile data, using the popular method of hyperbola fitting, produced some unexpectedly high subsurface signal velocity estimates, while analysis of common midpoint (CMP) GPR data yielded a more reasonable subsurface signal velocity estimate. Several reflection analysis procedures for CMP data, including hand and automated signal picking using cross‐correlation and semblance analysis, are used and discussed here in terms of efficiency of processing and yielded results. The case study demonstrates that CMP data may offer more accurate and precise velocity estimates than hyperbola fitting under certain field conditions, and that semblance analysis, though faster than hand‐picking or cross‐correlation, offers less precision.     

GPR and inductive electromagnetic surveys applied in three coastal sambaqui (shell mounds) archaeological sites in Santa Catarina state, South Brazil

In this article, GPR – Ground Penetrating Radar and inductive electromagnetic (EM38 equipment) results are presented for three archaeological sites of shell mounds located between Laguna and Jaguaruna cities, mid-southern coast of Santa Catarina state, Brazil. The Jabuticabeira II, Santa Marta IV, and Encantada III sites were studied. These sites consist of carbonate shell mounds built by societies that inhabited this region during the pre-colonial period (7.5–1.3 ky BP). Geophysical responses obtained in these archaeological sites had allowed the identification of anomalous regions related to archaeological point targets as well as continuous targets, correlated to the shell mound's structure and buried geologic features. GPR numerical modelling studies were done in order to evaluate the performance of the GPR method in relation to materials found in that environment, besides helping interpretations of real results. The synthetic GPR model was a good match with real data obtained in the field. So, the real and synthetic results serve as a reference guide to direct excavation activities in these archaeological and geological structures. In the Jabuticabeira II shell mound, lithic materials and burials were found amidst archaeological layers characterized by sediment rich in organic material, ferruginous concretions, and loose shells. In the Santa Marta IV archaeological site, a concentration of ceramic materials, burials and fireplaces were found. In the Encantada III site, a strong anomaly characterized by a hyperbolic reflection was related to the presence of a silicified tree root; a great example of ambiguity in shallow geophysics interpretation in archaeological applications. Results functioned as a guide to archaeological excavations, allowing cost and time reduction as well as contributing to improve the knowledge of these archaeological sites situated in southern Brazil.     

Cartographic,Geophysical and Diver Surveys of the Medieval Town Site at Dunwich,Suffolk, England

This paper presents the results of an integrated historical and geophysical survey of a medieval town lost through cliff recession and coastal inundation. Key objectives included evaluating historic maps in supporting the relocation and identification of major buildings, and applying integrated multibeam, side‐scan and sub‐bottom profiling to determine the location and extent of archaeological remains. The results demonstrate that cartographic sources from 1587 onwards can be a reliable source of data to guide geophysical survey. Integration of historical mapping with geophysical data enabled identification of the remains of two medieval structures, and the tentative identification of two others. © 2010 The Authors     

Integrated geophysical surveys at the archaeological site of Tindari (Sicily,Italy)

The results of geophysical survey carried out at the archaeological site of Tindari, located 70 km west-north-west of Messina (Sicily, Italy), are presented and discussed. The site is one of the most important archaeological sites, about 90 ha large, on the north-eastern side of Sicily and it was one of the last Greek settlements in Sicily. Keeping in mind the vastness of the site, according to the archaeologists an area, of about 1200 m² was selected, for a geophysical survey. Electrical resistivity tomography (ERT), including induced polarization (IP) measurements, and seismic refraction tomography were applied in the course of geophysical exploration in the area. The objective of this preliminary geophysical investigation was to verify the effectiveness of the technique for a spatial definition of the buried archaeological structures (mostly walls, columns, etc.) to determine their characteristics and to study the presence of collapsed columns within the zone of archaeological interest, in view of their application in the rest of the site, that, for obvious reasons, could not be entirely excavated in brief times. The geophysical data, visualized in 3D space, revealed a distribution of low-contrast shallow anomalies that indicate the presence of different types of buried structures in the surveyed area. Also, the probable accumulations of collapsed columns could be determined. These results confirm the hypothesis of a large northern extension of the archaeological site and provide useful information to design a more efficient excavation plan.     

Satellite Remote Sensing of Archaeological Vegetation Signatures in Coastal West Africa

This article discusses how archaeological sites in Sierra Leone, and by extension much of West Africa, can be identified through vegetation patterns (vegetation signatures) detectable in very high-resolution (VHR) multispectral satellite imagery. Settlement sites typically have a differing pattern of vegetation from the surrounding landscape, including concentrations of very large trees with sociocultural and historical significance: cotton (Ceiba pentandra) and baobab (Adansonia digitata). These features are conspicuous elements of the landscape both from the ground and in aerial imagery. Two complementary methods of using VHR multispectral satellite imagery are discussed in this paper: visual interpretation and semi-automated subpixel classification. These techniques are aiding ongoing archaeological survey of the Sierra Leone River Estuary. The impact of recently renewed industrial activity at a site of probable archaeological significance is also assessed through visually interpreted VHR satellite imagery.     

Evaluation of very high to medium resolution multispectral satellite imagery for geoarchaeology in arid regions – Case study from Jabali,Yemen

Archaeological research of the ancient Jabali silver mines (7th to 14th centuries ad) in northern Yemen is a multidisciplinary project covering scientific disciplines traditionally related to archaeology, a geological approach and new technologies such as very high resolution remote sensing. Mining companies envisage the development of the Jabali deposit for zinc ore. Some of the planned facilities, particularly a large open pit, will have a destructive impact on the old pits and processing heaps, already damaged by recent works. In the present study, remote sensing is used for a detailed survey of the impact of preliminary mining works from the early 1980’s with the aim to establish archaeological remains and to prioritize areas for future ground surveys, as well as for geological mapping. Results indicate that mapping using remote sensing in the visible to short wave infrared range has a great potential for the identification of gossans (iron caps) possibly related to archaeological remains. The phases of work in Jabali are clearly put into light by the study of a time series of Landsat data. Very high resolution QuickBird imagery appears particularly relevant for mapping most of the archaeological remnants, iron caps, as well as the 3D visualization of the mining site when drapped over a detailed digital elevation model.     

From conflict archaeology to archaeologies of conflict: remote survey in Kandahar,Afghanistan

ABSTRACT

Emerging from research with the Afghan Heritage Mapping Partnership, a multi-year project using satellite imagery to detect, record and manage archaeological heritage, this paper examines the potentials of remote-sensing to not only monitor archaeological material culture, but also contemporary materiality as it is violently (re)assembled through conflict. Through systematic remote-sensed archaeological survey using diachronic imagery in Kandahar, Afghanistan, this work expands archaeological understanding of an under-surveyed region while exploring the impact of the region’s expansive military infrastructural footprint on cultural heritage. Further, this research considers the long history of landscapes of control and successive military occupations. Remote survey allows for continued generation of archaeological data during conflict, thereby enabling more thorough heritage management. Finally, this survey demonstrates that, although remote aerial technologies have been criticized as tools of violence, surveillance and control, satellite imagery can be used analytically to generate new understandings of and challenges to military infrastructural reach.     

香港佛头洲遗址2004年考古调查简报

佛头洲原位于香港维多利亚港东面入口的一个小岛。文献记述该岛尚存古代税关遗址,1964年和1979年的调查发现"德怀交趾国遥通贡赋"石碑和建筑构件,但其具体年代难作定论。2004年的田野调查发现多座建筑遗迹,遗物则有瓦当和篆刻石柱等,可以确定该遗址保存清末时期的佛头洲税厂遗存,对于研究香港开埠初期猖獗的鸦片贸易、清末九龙关的沿革和新界拓展等问题提供重要的实物资料。     

Detection of archaeological crop marks by using satellite QuickBird multispectral imagery

The capability of satellite QuickBird imagery for the identification of archaeological crop marks is herein presented and discussed for two test sites located in the South of Italy. The selected sites, dating back to Middle Ages, were buried under surfaces covered by herbaceous plants characterized by a different phenological status (dry/green) when the satellite data were acquired.