Powerful Vibro-Sources for Active Seismology and Deep Earth Sounding

Success of active seismology in deep probing of seismically-active zones depends on parameters of used sources. It is unacceptable to use strong explosions or powerful stationary vibration sources for this purpose because of ecologic reasons as well as poor spatial coverage. Low-power vibration sources (which are commonly used for seismic prospecting purposes) are also ineffective, because of low translucence aperture and small penetration depths. Field investigations using powerful (40-60 tons) transportable vibrators have been carried out by Siberian Branch of the Russian Academy of Sciences since 1989. For the period of 20 years, a considerable data volume is accumulated in various regions of Siberia (Sayan region, Altay-Sayan and Okhotsk-Chukotski regions). Use of powerful transportable vibro-sources was developed into effective working technology. Optimal transportation unit was developed for work in hard-to-reach areas on the base of high performance cross-country vehicles. Data processing revealed quality wave fields for both longitudinal and shear waves reflected from a reference boundary in the Erath crust and Moho which were recorded for 0 - 300-400 km source-receiver offsets. Data show high stability and repeatability. Many data sets were recorded using both explosions and vibro-sources at different offsets and in presence of tectonically active zones. A database of records registered in near-field zone was accumulated for various geology (from low-velocity sediments to crystal rocks). We present some examples of using powerful transportable vibrators, including deep sounding and monitoring data, recording equipment, and observation systems.