Geophysical Survey

About: Geophysical Survey is a facility organization based out in Obninsk, Russia. It is known for research contribution in the topics: Geology & Seismology. The organization has 308 authors who have published 256 publications receiving 3067 citations. The organization is also known as: Federal State Institution of Science Geophysical Survey of the Siberian Branch of the Russian Academy of Sciences.

Sliding correlator for nanosecond pulses

Abstract: A digital sliding correlator having means for producing a series of time-shifted stored copies of a digital character, means responsive to said shifted, stored copies of the character for multiplying said shifted, stored copies by the input signal or the sign-inverted counterpart of the input signal, a first set of integrators and a second set of integrators, means for supplying to the first set of integrators first portions of said multiplied signals and for supplying to said second set of integrators second portions of said multiplied signals, and means for combining the outputs of said integrators.

Range information from signal distortions

Abstract: An electromagnetic signal having originally the time variation of a rectangular pulse is transmitted into a medium with conductivity σ. It is distorted by the medium to a signal f(σ,d,t) if it traveled the distance d from a transmitter to a scattering or reflecting object and the same distance d back to the transmitter. The time variation f(σ,d,t) of the distorted signal can be calculated for any conductivity σ and distance d. Using the conductivity σ known from previous measurements, the returned, distorted signal f(t) is compared with computed distorted signals f(σ,d,t) for various distances d. The computed signal f(σ,d,t) that is most similar to the actually received signal f(t) determines the distance d to the scattering or reflecting object. The comparison between the computed, distorted signals and the actually received signal is done by cross-correlations. The peak amplitude or the energy of the received signal becomes unimportant if cross-correlation is used, which means the physical size or radar cross-section of the scattering or reflecting object becomes unimportant.

Seismic evidence for a mantle plume oceanwards of the Kamchatka–Aleutian trench junction

Abstract: SUMMARY A non-linear iterative P-wave traveltime tomography has revealed a mantle plume originating at a depth of nearly 1000 km, rising across the 600 km discontinuity, and deflecting subhorizontally in the uppermost mantle presumably by shear flow due to the overlying moving plate. Data from the Geophysical Survey of Russia (1955–1997) were inverted jointly with the catalogues of International Seismological Centre and USGS National Earthquake Information Centre (1964– 1998). The result shows a 300–500 kmwide cylindrical low-velocity anomaly (yx2 per cent) that extends from a depth of greater than 900 km to shallower than 200 km. The anomaly is almost vertical at depths up to y400 km and rises obliquely to the north up to y200 km under the ocean floor near the northern end of Emperor seamounts. Above y300 km depth a subsidiary anomaly extends subhorizontally to the NW in fair agreement with the direction of movement of the Pacific Plate. The overlying seafloor is characterized by anomalously high heat flow, which may be attributed to the thermal effect of the mantle plume.