This paper presents application of multi- geophysical approach for detection of a cavern between two lanes of Rijeka - Zagreb highway in Croatia. Applied geophysical methods were ground penetrating radar (GPR) and seismic refraction method. While the ground penetrating radar method gave information of the degree of karstification of rock mass under the highway, seismic refraction gave an estimation of cavern dimensions. Basic principles of both methods are given in paper as well as the results of investigation works which consisted of 21 GPR profiles and one seismic refraction profile. Also, cavern remediation works, which are based on results on investigation works, are presented in paper.

Riparian meadow systems in the Central Great Basin are of interest because they support the majority of ecosystem diversity in the region. The riparian meadows are highly dependent upon groundwater levels, thereby making them vulnerable to fluctuations. These systems are actively degrading due to incision of the streams, resulting in a lowered water table and modification of the associated ecosystems. Geologic controls, such as bedrock geometry and sediment variability, are important in the meadows because of their control on the overall system. The current hypothesis is that the sediments associated with side-valley alluvial fans and fault-related bedrock steps interact to constrict ground water flow. Seismic reflection data and seismic refraction tomography data were collected to analyze bedrock structure and topography from 10 to 80 meters depth, while ground penetrating radar (GPR) data were collected to determine the stratigraphic variability in the upper 10 meters. These data were integrated to provide a comprehensive interpretation of the upper 80 meters of the subsurface. Seismic reflection data were processed to identify the bedrock surface. This surface was then correlated with the seismic refraction tomography to extend the bedrock surface across the meadow complexes. The large volume of GPR data were interpreted by classifying radar facies based on the characteristics of the radar reflectors. These facies (in conjunction with borehole information) confirm and exte

Abstract Two geophysical techniques—ground‐penetrating radar (GPR) and seismic refraction—were assessed for their capabilities in reconnaissance studies of soil characteristics, depth to the water table, and depth to bedrock beneath surficial deposits in mountainous terrain. Ground‐penetrating radar had the best near‐surface resolution in the upper 2 m of the profile and provided continuous interpretable imagery of soil profiles and bedrock surfaces. Where thick colluvium blankets side slopes, the GPR could not consistently define the bedrock interface. In areas with clayey or shaley sediments, the GPR is also more limited in defining depth and is less reliable. Seismic refraction proved useful in determining the elevation of the water table and depth to bedrock, regardless of thickness of overlying material, but could not distinguish soil‐profile characteristics. Although both techniques provide adequate information for reconnaissance purposes, these techniques have a greater probability of success in areas where there is some subsurface information. Independent use of any one method is advised only where ground control is well documented.

Abstract We performed a geophysical survey in Mirabello, a village of Emilia Romagna Region of Northern Italy, to study the soil affected by the ML 5.9 earthquake of 2012, specifically the formation of surface ruptures by sand ejection due to the liquefaction of shallow subsurface layers. The investigation was carried out using ground penetrating radar and seismic reflection/refraction techniques. This work confirms the importance of electromagnetic waves to map the shallow subsurface extent of fractures and liquefied sand bodies, while the high-resolution seismic reflection profile allowed us to map the fractures at depth. The result obtained by tomographic inversion of first arrivals of seismic data has been compared with a ground penetrating radar section acquired in the same place, furnishing complementary information for the interpretation of the section.

As transport routes, power networks, communication lines and human habitats expand in mountain valleys, the risks associated with landslides are growing on a yearly basis. To minimize these risks, there is a need to identify and characterise mountain slopes that are susceptible to failure. We assess the potential and limitations of geophysical techniques for investigating potentially unstable mountain slopes. Our assessments are based on two case studies involving mountain permafrost in form of a rock glacier and a steep rock slope well below the occurrence of permafrost. The internal structure of the rock glacier is delineated with a combination of seismic refraction tomography, geoelectrical tomography and ground penetrating radar measurements, whereas the steep rock slope is characterized with 3D seismic and ground penetrating radar measurements in combination with microseismic investigations.

The use of ground probing radar has increased significantly in the past few years and so too have the new applications for which it has proved suitable. For some time shallow seismic reflection and refraction surveys have been the main tools for geophysical investigation. There is therefore a strong background in seismic techniques and thus tend to be chosen preferentially to radar methods. The seismic reflection and radar techniques do however have much in common and the results are displayed in the same manner as a time/distance cross-section appearing similar to a geological cross-section. The time section in both cases may only be converted to depth sections when the velocity of seismic/electro-magnetic signal propagation within each medium of the resolved layers is known.