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.

The nature of Early Palaeozoic Kwangsian orogenic event in the South China Block: constraints from detrital zircons in Cambrian strata

Abstract: The tectonic nature of Early Palaeozoic Kwangsian orogeny in the South China Block (SCB) is still debated, due to controversy whether there was a Cambrian ocean between the Yangtze Block and the Ca

Effect of antenna-surface distance on the radiation of a GPR antenna

Abstract: An experimental investigation was performed to analyze the influence of the proximity of a dielectric interface on the radiation of a GPR antenna. The experimental setup consisted of two 1.5 GHz resistively loaded transmit-receive antenna pairs. Data were obtained from one transmit-receive antenna pair as it was moved from a height of 29 cm to the dielectric surface at 1 mm increments. Direct transmission data were also obtained at the second antenna pair placed on the other side of the dielectric medium. Data were obtained from three different dielectric media possessing permittivities of 5.2, 10.6, and 80. Comparison of the frequency spectra of the direct-transmission waveforms for different transmitting antenna distances from the dielectric surface revealed a slight shift towards lower frequencies when the antenna enclosure was in contact with the surface. The direct-coupled waveform between transmitting and receiving antennas inside the same enclosure varied significantly over an antenna enclosure-surface distance range of 0 to 10 cm. the changes in the direct-coupling waveform appear to be largely due to the linear superposition of: (1) the direct arrival between the transmitting and receiving antennas, and (2) the surface reflection and associated surface reflection multiples. The waveform collected by the receiving antenna adjacent to the transmitting antenna was remarkably similar to the one-way transmitted waveform recorded at the receiving antenna on the other side of the block.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The analysis and application of simplified two-parameter moveout equation for C-waves in VTI anisotropy media

Abstract: Several parameters are needed to describe the converted-wave (C-wave) moveout in processing multi-component seismic data, because of asymmetric raypaths and anisotropy. As the number of parameters increases, the converted wave data processing and analysis becomes more complex. This paper develops a new moveout equation with two parameters for C-waves in vertical transverse isotropy (VTI) media. The two parameters are the C-wave stacking velocity (V C2) and the squared velocity ratio (γ vti ) between the horizontal P-wave velocity and C-wave stacking velocity. The new equation has fewer parameters, but retains the same applicability as previous ones. The applicability of the new equation and the accuracy of the parameter estimation are checked using model and real data. The form of the new equation is the same as that for layered isotropic media. The new equation can simplify the procedure for C-wave processing and parameter estimation in VTI media, and can be applied to real C-wave processing and interpretation. Accurate V C2 and γ vti can be deduced from C-wave data alone using the double-scanning method, and the velocity ratio model is suitable for event matching between P- and C-wave data.

Detection of land subsidence in Beijing, China, using Interferometric Point Target Analysis technique

Abstract: Land subsidence in Beijing is supposed to be caused by over-exploitation of ground water, which is leading to a rapid decline of water levels, drying out clay layers that finally result in land subsidence.

Dynamic changes of lakes and the geo-mechanism in Tibet based on RS and GIS technology

Abstract: Using the topographic data at the scale of 1:100000 in 1960´s, and Landsat MSS in 1970´s, Landsat TM in 1990´s, Landsat ETM+ in 2000´s, we carried out the survey of the lake distribution and its dynamic changes on Tibetan Plateau. The result indicates that there are 3 lakes within the area more than 1000km 2 , 74 lakes within area more than 100km 2 , 382 lakes within the area more than 10km 2 , 1260 lakes with the area more than 1km 2 , 6882 lakes within the area more than 0.1km 2 , and the total area of lakes is about 43186.4km on Tibetan Plateau. The area of lakes has taken place significantly changes during the past 30 years. The total area of lakes has increased 1610.01km 2 . The area of increased lakes are 157 lakes with in area more than 1km 2 , 5411 lakes within area more than 0.1km 2 and small lakes increased in hundreds and thousands. The area and amount of lakes increase most obviously in Qiangtang Plateau and Kunlun Mountains, and decrease most obviously in Qaidam basin, Hexi Corridor, Yellow River Basin, Yarlung Zangbo River Basin. The expanded and newborn lakes are distributed in the inner Plateau and disappeared and decreased lakes in the surrounding area of the Plateau. The increase and decrease of lake area has some related with climate changes, but mainly related to the local topography controlled by neo-tectonic. Keywords: Topographic map ÷ Landsat data ÷ lake ÷ lake area change ÷ Tibetan Plateau Tibetan Plateau is the most concentrated area of lake and wet land in China