Reflection and Refraction Seismics

Ruden Geo Services, together with its partner GeoExpert from Switserland, offers hybrid seismic surveying, which is a combination of high-resolution reflection seismic profiling with the technique of refraction seismic tomography inversion, the two most common modern surface geophysical surveying disciplines in civil engineering. In 2017 we launched multi-channel systems, with an unrestricted amount of stations (more than 500), ensuring we can also offer 3D-seismics on-land.

An impact, or controlled vibrations, generated at the earth’s surface, produces a seismic source signal, which penetrates the sub-surface as a semi-spherical wave front. At the boundaries between layers, physically defined by acoustic impedance contrasts, the seismic waves are reflected and refracted. The reflected and refracted signals are recorded at the surface by acoustic sensors (geophones).

Reflection seismic profiling as well as refraction diving wave tomography, when applied as the sole prospection methods, have their undisputed merits in their performance, but unfortunately also some shortcomings, depending on the objectives of each individual survey. Therefore, it is desirable to combine their data acquisition and interpretation procedures.

Thanks to the recent technical advances implemented in modern seismic recording instrumentation, the data acquisition for both methods can now be combined into one single operation, which results in a substantial reduction of the costs for field work. This allows tapping the full potential of the information contained in the data by an appropriate joint data processing procedure.

Although the results of the reflection seismic data processing and the refraction tomography evaluation are based on the same data set, they are completely independent from each other, which enhances the reliability of a joint interpretation. The latter is further assisted by a suitable presentation of two results whereby the drawbacks of one method are compensated by benefits of the other.

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