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.

Seismic Zoning of Slovenia Based on Deterministic Hazard Computations

Abstract: Seismic hazard of the territory of Slovenia is estimated using a deterministic approach based on the computation of complete synthetic seismograms. The input data are the catalogues of earthquakes and fault plane solutions for Slovenia and surrounding regions. Structural models are defined based on available seismological and geophysical information, but are mainly constrained by surface-wave dispersion and 3-D tomographic modelling of the upper crust. Seismogenic zones are delineated considering geotectonic characteristics, fault plane solutions and distribution of earthquake hypocentres. Outside Slovenia seismogenic zones are extended up to distances from which they can considerably influence seismic hazard estimates.

NDE methods for quality assurance of new pavement thickness

Abstract: Accurate measurement of pavement thickness is an essential aspect of the quality assurance of new pavement construction. Current coring methods are time consuming and provide a very limited representation of the overall pavement structure. The objective of the work described in this paper has been to demonstrate the use of non-destructive evaluation (NDE) methods for rapidly determining the average pavement thickness on a newly constructed section to within 2.5 mm of the true value, without extensive reliance on cores. The effort has considered ground penetrating radar (GPR) and impact echo methods applied to both asphalt and concrete pavement, and has included laboratory and field-testing, with field correlations based on 172 cores. The results show that the 2.5 mm accuracy objective can be met for asphalt pavement, but that accuracy on concrete is limited to 4 mm. The paper describes the techniques that were evaluated, the testing that was conducted, and the results of correlation with core data.

Simultaneous inversion for velocity structure and hypocenters in Slovenia

Abstract: We use nearly 2100 P-wave arrival times from 166 local earthquakes to investigate the 3-D compressional velocity structure of the upper crust of Slovenia using the simultaneous inversion algorithm developed by (Michelini and McEvilly, 1991). Remarkable and stable features of the resolved model are the relatively high velocities in western Slovenia and the low velocities in central Slovenia, SE of the Ljubljana basin. The boundary between these two anomalies follows approximately the NNW-SSE direction that coincides with the general strike of the External Dinarides. We interpret this feature as the upper crustal expression caused by the tectonic processes occurring along the active margin of the Adria promontory/microplate.

Geophysical methods in geothermal prospecting in New Zealand

Abstract: The electrical resistivity method appears to be the most appropriate method of delineating geothermal waters in the New Zealand Volcanic Region. The early concept of structural control of heat loss (within reasonable drilling distance from the surface) appears invalid except in isolated instances. The prospecting methods used to delineate structure have failed to prove profitable in discovering heat sources.

Efficient driving circuit for large-current radiator

Abstract: An improved driving circuit for a large-current radiator avoids the need to dissipate large powers in the driving circuit by drawing a certain energy value from a power supply to a storage capacitor and then feeding this energy to the radiating antenna. A constant current source provides, when a switching circuit coupled to the radiator is opened, a current to counter the tendency of the radiator otherwise to maintain continuity of current through the switching circuit, keeping to a minimum the voltage across the switching circuit so that essentially no energy will need to be dissipated in the driving circuit. By choosing the stored energy value carefully one can make it just large enough to cover the radiated energy but leave essentially no energy to be dissipated in the radiator driving circuit.