f P- and SV-wave velocity-depth profiles from 2-component recordings

For a great variety of engineering geophysical projects information about P- and Swave velocities is important. One way to get this information is the recording of standard Pwave lines and an extra excitation and recording of SH-waves. The value of this technique is proven; however, the separate excitation of SH-waves by inducing horizontal forces in the ground is sometimes difficult and time consuming. An alternative way of obtaining the equivalent information is to excite both P- and SV-waves by a single vertical force applied to the ground surface, and to record simultaneously the X- and Z-component of the ground motion. Applying this technique both P- and SV-waves are present in the records and they have to be separated by proper processing. The investigations presented here are an application of this alternative method, concentrating on direct and refracted waves. They are based on 2- and 3-layer synthetic data sets generated by elastic finite element calculations and on real data sets acquired in the course of investigations into large landslides in Austria within the scope of IDNDR. The topographical and ground conditions here would have made it very difficult to induce the horizontal forces in the ground required for the SH-technique.