Three-dimensional image of seismic refraction tomography and electrical resistivity tomography survey in the castle of Occhiolà (Sicily,Italy)

A geophysical survey was carried out at the ruins of Occhiolà Castle (Sicily, Italy), a medieval village located at the north-western part of a hill named “Terravecchia” at 491 m asl. In order to map the archaeological structures (such as walls and burrows), Electrical resistivity tomography (ERT) and seismic-refraction tomography methods were used. The resistivity variations are known to correlate quite well with the lithology, thus providing important information for identifying the buried archaeological remains. On the other hand, seismic velocity variations provide information about the geometrical features of the remains. The two geophysical methods are used in an enjoined way to better aid the interpretation and evaluate the significance and reliability of the results obtained with each single method. The electrical and seismic data are displayed in three dimensions by using the iso-resistivity and iso-velocity surfaces, respectively. This allows us to effectively define the location of the anomalies present in the single electrical and seismic sections. The results obtained in the survey highlight the presence of structures of regular shape, probably due to features of archaeological interest.     

Applications of integrated geophysical method in archaeological surveys of the ancient Shu ruins

The Jinsha site is one set of excavated ruins of the ancient Shu state, late Neolithic, early Bronze Age. The archaeological survey of the site is especially important for study of Shu culture, because there is hardly any written record of this period. As technology progresses, more and more advanced techniques and equipment have been used to conduct archaeological surveys. In this study, four nondestructive methods of geophysical detection were used to locate ancient relics at the site. The validity of these different types of archaeological detection methods (method of high-density resistivity, induced polarization, multi-frequency electromagnetic, ground-penetrating radar and so on) and techniques were analyzed. And a multi-scale, multi-method detection system to non-destructive detection of cultural relics was established.     

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.     

Shallow geophysical survey at the archaeological site of San Miguel Tocuila,Basin of Mexico

A combined near surface geophysical survey conducted in San Miguel Tocuila show that geophysical methods offer the possibility to characterize and reconstruct the geometry of subsurface structures without destroying the deposits, providing a way to find solutions to the questions of archaeological or engineering significance. The survey consisted of the application magnetometry, seismic refraction tomography (SRT) and ground penetrating radar (GPR) within a depth range of 10 m. Before Spanier conquest San Miguel Tocuila was a very prominent suburb of the main Aztec ceremonial complex located on the eastern margin of Lake Texcoco, central Mexico, where several mounds known as Tlateles in Nahuatl language have been identified. Nowadays, the rapid expansion of Mexico City's metropolitan area within the last four decades has strongly influenced Tocuila's environment and has compromised several of its archaeological and ancient human settlements. This study shows how the high resolution imagining of non-invasive geophysical methodologies in addition with surface archaeological studies [Parsons, J.R., 1971. Prehistoric Settlement Patterns in the Texcoco Region, Mexico. Memoirs of the Museum of Anthropology, University of Michigan, Number 3] provide different kinds of information that characterize the subsoil and a buried structure. Based on the history of the ancient settlements in the zone and considering the characteristics of shape and height of the structure, we interpreted that the subsurface images obtained depict a buried Tlatel which corresponds to a ceremonial–civic center of Late Aztec times.     

New temple discovery at the archaeological site of Nysa (western Turkey) using GPR method

We carried out a ground-penetrating radar (GPR) study at specific sites around the Nysa city (western Turkey) to assess the potential of detection method and imaging of buried archaeological features. As a major educational and cultural Aegean city during the Hellenistic and Roman times, Nysa has been the focus of archaeological investigations for the last 100 yrs. Past and ongoing excavations have revealed major ancient buildings such as theatres, amphitheatres, a library and shops. However, it is suspected that the original city may have extended further and reached a larger size.     

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.     

Mapping of the Buried Yarmouth Roads Wreck, Isle of Wight, UK, using a Chirp Sub-Bottom Profiler

Remains of the 16th-century Yarmouth Roads wreck, buried in sediments, were imaged using high-resolution geophysical techniques. The remains appear as strong reflectors underlain by an acoustic blanking zone, which was used to create maps of the wreck material. Close survey line-spacing allowed the construction of contour maps and hull sections, which revealed that the bow and stern sections are tilted to port at different angles, implying that they are detached. The seismic data have enhanced our understanding of the site beyond what was known from conventional archaeological investigations and confirms that this wreck was once a large carrack.
© 2007 The Authors     

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.     

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.     

Contribution of the resistivity method to characterize mud walls in a very dry region and comparison with GPR

Mud walls are frequent in many archaeological sites, including sites located in semi-desert regions. In cases with buried walls, the geophysical methods can be useful tools for their investigation, since they provide maps of the subsoil in a non-invasive way and in relatively short times. This article deals with the characterization of mud walls in very dry soils through the resistivity method, discussing a methodology to satisfactorily apply the method in this kind of adverse environment and how to interpret the results. The case of the Palo Blanco archaeological site, a pre-Incaic village located in the NW region of Argentina, is analyzed.     

Detection of exposed and subsurface archaeological remains using multi-sensor remote sensing

Multi-sensor airborne remote sensing has been applied to the Itanos area of eastern Crete to assess its potential for locating exposed and known buried archaeological remains, and to delineate subsurface remains beyond the current limits of ground geophysical data in order to permit future targeted geophysical surveys and archaeological excavations. A range of processing techniques (e.g., Reed–Xiaoli anomaly detection) have been applied to the CASI, ATM and lidar data in order to detect anomalies based on the premise that buried remains are likely to alter the physical and chemical characteristics of the soil compared with those of the surroundings due to variations in soil depth and drainage. Through a combination of CASI, ATM and lidar data, surface remains have been classified and mapped effectively using an object-oriented approach. The detection of subsurface remains is more problematic; however, the thermal data is most promising in this respect. The value of capturing multi- or hyperspectral data at a high spatial resolution has been demonstrated as well as the additional benefits of combining these with airborne lidar.     

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.     

Non-invasive archaeological exploration in stratigraphically complex rural settings: an example from Ferento (Viterbo, Italy)

This paper presents the results of a ground penetrating radar (GPR) survey conducted in the rural area of the ancient city of Ferento near Viterbo (Northern Latium, Italy), where the visible ruins testify an uninterrupted history from the Etruscan to the Medieval period. The soil covering the ruins has been intensively ploughed, cultivated and used for pasture over the centuries, and is characterised by a high content of clay minerals. In this scenario, the use of GPR is particularly difficult due to both possible ‘false positive anomalies’ and strong signal attenuation. In order to reconstruct the geometrical shape and size of the geophysical anomalies related to a medieval dwelling, multi-profile GPR data were collected in two different areas, using radar equipped with 250-MHz antennas. 2D and pseudo-3D migrated maps were created and signal velocity analysis was performed to estimate the target depths. Despite the clayey-calcareous material, the results show a good signal penetration and allow a clear reconstruction of the shape of the buried ruins, confirming that the anomalies are due to medieval buildings located at a depth in agreement with what was observed on the archaeological stratigraphy. Furthermore, our study suggests that in radar data interpretation, caution should be used if the surveyed area was subjected to prolonged and intensive agriculture.     

Identifying of buried archaeological remains with ground penetrating radar,polarized microscope and confocal Raman spectroscopy methods in ancient city of Nysa,Aydin – Turkey

The aim of this study was to image buried remains and appoint buried Hellenistic street system, and identify minerals and rock types of the ancient city of Nysa, one of the most important historical sites of Turkey. This study used polarized microscope and confocal Raman spectroscopy (CRS) ground penetrating radar (GPR) method, to identify the buried remains, rock types and minerals.     

Integrating pedological and geophysical methods to enhance the informative value of an archaeological prospection – The example of a Roman villa rustica near Regensburg,Germany

Geophysical prospection techniques are widely used to visualize the buried past. Various methods such as magnetometry, electric resistance mapping and electric resistivity tomography and ground penetrating radar yield different results. The use of all three techniques in combination with aerial photography interpretation and pedological mapping is highly effective, but it requires a multi-layer approach. This paper presents such a multi-layer approach carried out at a site with buried remnants of a Roman villa rustica in southern Germany. The integration of the various results into a geographical information system leads to a geocodation of all outcomes and a final archaeological interpretation. Several buildings in different states of preservation, different kinds of ground floors both with and without hypocausts, perimeter walls and kilns could all be detected. The soil mapping results helped in the geophysical interpretation by outsourcing soil erosion and accumulation areas. It is shown that none of the employed methods could have supplied all the compiled information on their own, and the strengths and weaknesses of each method is discussed in order to point out the implications for archaeologists.     

Integrated geophysical surveys for the subsurface mapping of buried structures under and surrounding of the Agios Voukolos Church in İzmir,Turkey

This work presents the results of the integrated usage of geophysics in the Agios Voukolos Church, one of the unique Orthodox constructions in ?zmir. The surveys had two main objectives: to define subsurface characteristics inside and around the church and search for possible structural damage such as cracks and fissures, that may exist in the subfloor of the church. Magnetic gradiometry, ground penetrating radar and electrical resistivity tomography were used in the investigations; this study is the first indoor application of magnetic gradiometry. The studies revealed that several suspicious relics and crypts might have existed under the floor of the church. In addition, investigations of the courtyard area indicated potential buried structures under the settling area of the church. This study demonstrates the importance of the integrated usage of non-destructive geophysical techniques in searching for possible hidden subsurface structures in standing historical buildings. In addition, magnetic gradiometry might be useful in indoor studies, assuming that there are no important magnetic sources near the site.     

Reduction of topography effect in inductive electromagnetic profiles: application on coastal sambaqui (shell mound) archaeological site in Santa Catarina state, Brazil

We present results of electrical conductivity profiles obtained with inductive electromagnetic geophysical method in Santa Marta archaeological site, Santa Catarina State, southern Brazil. This site is a sambaqui (shell mound), in which several human occupation remains are found during pre-colonial period such as buried lithic and bone artifacts, fire-place, etc. Most of these mounds include as well many human burials, which, in many cases, point to funerary ritual as a main agency for mound building. A set of profiles of apparent electrical conductivity and magnetic susceptibility was acquired in two sites aiming the identification of geophysical anomalies with potential interest for excavation. To enhance conductivity data, we applied an effective procedure to remove topographical effects in the apparent conductivity measurements, which are rather conditioned by the presence of a variable water table depth or conductive sediment layer. A linear dependence among conductivity values and the site elevation provided a simple linear model to remove the influence of topography. Corrected electric conductivity maps substantially improved the definition of anomalies, many of them rather subtle in raw data images. Corrected maps also show a better adherence with magnetic susceptibility maps, both of them identifying archaeological structures of interest: a well-structured fire-place and a concentration of ceramic fragments.     

我国考古和文物保护工作中物探技术的应用

20世纪80年代以来,物探技术在考古和物保护方面应用越来越多,在古墓探查、大型古建筑地下遗存现状探查、重要古建基础状况探查、古遗迹断代等方面,地球物理技术都找到了发挥作用的机会。本通过地球物理技术在云冈石窟、龙门石窟、克孜尔石窟、北京故宫紫禁城、嵩岳寺塔、古泗州城遗址、风阳明中都等的物理探查实例,以及查找古墓、古遗迹断代等方面的工作,介绍了我国在考古和物保护领域应用地球物理技术的进展,并指出了物探在用于考古和保时的特点和展望。     

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.