https://hal.archives-ouvertes.fr/hal-02498600/document

Application of non-invasive geophysical methods (GPR and ERT) to locate the ancient foundations of the first cathedral of Puebla, Mexico. A case study

This article discusses the urban landscape of Angamuco, located in the Purepecha (Tarascan) imperial heartland in western Mexico. Angamuco was occupied between the Late Preclassic through Late Post...

Urbanization and Imperial Integration at Angamuco, Michoacán, Mexico

Ground-penetrating Radar (GPR) sections commonly suffer from strong scattered energy and weak reflectors with distorted lateral continuity. This is mainly due to the gradual variation of mo...

Ground-penetrating radar data diffraction focusing without a velocity model

High-resolution 3-D GPR applied in the diagnostic of the detachment and cracks in pre-Hispanic mural paintings at “Templo Rojo”, Cacaxtla, Tlaxcala, Mexico

It is important to distinguish between two common defects, fatigue cracks and reflective cracks, and determine their locations (the top and bottom) in the highway pavement because they require individually targeted treatment measures. Ground Penetrating Radar (GPR) has the potential to detect cracks in the highway pavement due to the change of the electromagnetic properties of highway-pavement media, arising from the existences of cracks. By using a theoretical analysis and a numerical simulation, we compare the characteristics of corresponding radargrams, including the amplitude variation of diffracted waves with various models of presetting cracks inside the layered homogeneous media. For those fatigue cracks and reflective cracks extending to the road surface, the amplitude curves of direct ground wave can intuitively indicate the locations of the top of the cracks and qualitatively compare the width of these cracks. Furthermore, we find that the shape and pattern of diffraction hyperbolas of both types of cracks with bottoms at different locations are quite similar, but their amplitudes are significantly different. To be specific, for those cracks with the same width, the amplitude of diffracted waves generated by fatigue cracks is slightly higher than that generated by reflective cracks at the interface between the asphalt surface and the semi-rigid base layer. In contrast, the amplitude of the former is significantly lower than the latter at the interface between the semi-rigid base and the roadbed. We applied these findings to the interpretation of the field GPR data of a highway pavement in China, and successfully identified the locations of the cracks and corresponding types. Our model results and field results clearly show the efficiency of our findings in the detection of cracks for highway-pavement rehabilitation.

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Detection and Characterization of Cracks in Highway Pavement with the Amplitude Variation of GPR Diffracted Waves: Insights from Forward Modeling and Field Data

A three‐dimensional ground‐penetrating radar survey was performed on the altar wall, which faced the risk of collapse, of a 16th‐century church in Michoacan, Mexico. The ground‐penetrating radar survey with high‐frequency antennas aimed to locate structural cracks and texture arrangements, the latter through the interpretation of the patterns in the electromagnetic data. The results indicate that the superficially visible cracks or fractures, except for the lateral ones at each end of the wall, disappear at a depth of between 15 and 25 cm. The lower part of the wall below a height of 3.97 m presents an area with multiple diffractions, which suggests that the masonry is made of ‘stone and mud’ and the tilt appears precisely where the adobe wall starts. Using 1500 and 900 MHz antennas, the identified texture of the wall shows at least three leaves or layers with diverse materials and a wooden beam embedded in the wall. Additionally, the survey near the church with a 200 MHz antenna supports the hypotheses that local construction materials were used here. The results inspire us to continue applying ground‐penetrating radar, a non‐destructive method, to diagnose the walls and structures of historical monuments before any intervention.

GPR measurements to identify cracks and textural arrangements in the altar wall of the 16th‐century Santa Maria Huiramangaro Church, Michoacán, Mexico

This study presents the results of a GPR investigation carried out at the archeological site of Tingambato, in the state of Michoacan, Mexico. The aim of the study was to detect the presence of ancient buried structures, such as walls or graves and determine their geometry in order to help establish the timeline history of the site. It also aimed at producing amplitude maps and/or reflection profiles of the location and dimensions of burial targets. The survey was conducted in four areas using the 200 MHz antenna, and in one area the study was performed with a 900 MHz antenna.

GPR survey for the archaeological characterization of the Tingambato site, Michoacan, western Mexico

Summary Tingambato was one of the major archaeological sites in west Mexico (latitude 19°30′N, longitude 101°51′W at an elevation of 1930 m asl.) during the Classic period, but unfortunately we know little about its particular chronology. The geology of the site is dominated by recent volcanic activity (Pliocene/Quaternary) and the bedrock is composed of young volcanic basaltic-andesite, andesite and dacite rocks and the volcanic ejects develop soils characteristics classified as Andisols. In this study we present the results of GPR and ERT measurements performed on Tingambato site in 2017. We have defined new location areas for excavations which are planned to be held in September 2017.

J. Robles-Camacho

Papers

GPR measurements to identify cracks and textural arrangements in the altar wall of the 16th‐century Santa Maria Huiramangaro Church, Michoacán, Mexico

GPR survey for the archaeological characterization of the Tingambato site, Michoacan, western Mexico

Applying Gpr Amplitude Maps And Ert For Characterizing Archaeological Site Of Tingambato, Michoacan, Western Mexico