Seismic surveys are one of the most frequently used geophysical methods. They allow not only quick, but also the most reliable recognition of a vast area.
Sparker and Subbottom profilling methods applied by us allow for depth analysis of several dozen metres of the subsoil with simultaneous spatial examination of geological structures. They are based on measurement and analysis of artificially generated seismic waves.
The scope of knowledge gained by means of seismic surveys enables the execution of most projects at sea and in harbours. Apart from core drilling, it is one of the elements of later geological-engineering projects used for making foundations and laying foundations of future structures, including wind turbines.
VIBRATION RECORDING AND SEISMIC PROFILING
Recording of mechanically generated seismic waves on the ground surface leads to obtain an image of geological structures and allows to determine the structure and parameters of studied medium (changes of its density, fractures, faults, weathering). The UXO Marine team, depending on the purpose of survey and field conditions, uses up to several dozen channels simultaneously (geophones or hydrophones for subsurface surveys). The obtained geophysical data is processed using the most modern specialist software to prepare the final geological interpretation together with geophysical documentation.
WORK PLANNING: determine acquisition parameters, field conditions, sources of interference
SEISMIC DATA PROCESSING
SEISMIC SURVEYS USING REFLECTION TECHNOLOGY
Until recently, reflection seismic was only a basic tool for hydrocarbon (oil and gas) exploration. Currently, however, the spectrum of its applications is wider due to the possibility of obtaining a precise image of the geological structure of the area. The method is based on recording and processing of seismic waves – artificially induced and then reflected from the boundaries of geological layers.
The scope of application of the seismic reflection technique:
defining the limits of the course of the bedrock
determination of geological structure stratification
determination of geological structure layering
determination of water table level
monitoring the exploitation of deposits
assessment of ground stability, determination of fault zones, cracks, weakening.
REFRACTION SEISMIC SURVEY
The refraction seismic method is based on measuring the time of arrival of first ascensions. It is based on the phenomenon of seismic wave refraction at the boundary of media with different speed of wave propagation. Multichannel system of geophones records the time of arrival (“first breaks”) of the wave at different offsets from the source (artificially generated seismic wave). This makes it possible to create a model of the wave velocity distribution in the geological medium. This method is effective for detecting layers that have high wave velocity contrast.
Scope of application of refraction seismic:
defining the boundaries of the bedrock and the lithological differentiation of rocks
indication of fault zones, fractures, landslides, deformations in the ground and rock medium
determination of groundwater table level
determining the volume of rock massifs and classifying rocks by workability.