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.

Nonlinear Damping: From Viscous to Hysteretic Dampers

Abstract: This paper is dedicated to a brief discussion on the nonlinear damping. We present the particular results for linear and nonlinear viscous dampers, for fractional damper and for the hysteretic damper . As a main purpose we consider the mathematical model of damper with hysteretic properties on the basis of the Ishlinsky-Prandtl model. The numerical results for the observable characteristics such as the force transmission function and the “force-displacement” transmission function are obtained and analyzed both for the cases of the periodic affection as well as for the impulse affection (in the form of \(\delta \)-function). The comparison of the efficiency of nonlinear viscous damper and hysteretic damper is also presented and discussed.

Direct Analytic Signal Interpretation of Potential Field Data Using 2-D Hilbert Transform

Abstract: Through the analysis of analytical signal concept, we point out that the analytic signal (AS) of potential field data is in fact the analytic signal of gradient data. As potential field gradient components meet 2-D Hilbert transform, we propose the concept of Direct Analytical Signal (DAS) to expend the total gradient method. The DAS of a potential field or its 2-D Hilbert transform has geophysical significance, especially for the gravity anomaly or magnetic anomalies at the pole. Based on the concept of the DAS, we also propose a series of enhancement methods for the DAS including the DAS amplitude (DASA), the DAS horizontal amplitude (DASHA), the improved Tilt angle (ITiA) and the improved Theta map (IThM). Theoretical models and digital aeromagnetic data processing show that this method is an effective method for data interpretation of aeromagnetic and airborne gravity surveys.

Highway Speed Ground Penetrating Radar System Utilizing Air-Launched Antenna and Method of Use

Abstract: Embodiments of the disclosed technology comprise an air-launched antenna system with interference-rejection technology that operates in analog hardware as well as by way of a digital filtering technique. Using an inline analog hardware filter combined with a digital filter, to determine transversal (and/or recursive) coefficients, in a calibration phase, a measurement system may be configured to remove interference and the effects (such as a delay or temperature variation) which result from use of an analog filter. In this manner, the resulting measurements of a composition of road surface are more accurate and useful.

Application of the double absorbing boundary condition in seismic modeling

Abstract: We apply the newly proposed double absorbing boundary condition (DABC) (Hagstrom et al., 2014) to solve the boundary reflection problem in seismic finite-difference (FD) modeling. In the DABC scheme, the local high-order absorbing boundary condition is used on two parallel artificial boundaries, and thus double absorption is achieved. Using the general 2D acoustic wave propagation equations as an example, we use the DABC in seismic FD modeling, and discuss the derivation and implementation steps in detail. Compared with the perfectly matched layer (PML), the complexity decreases, and the stability and flexibility improve. A homogeneous model and the SEG salt model are selected for numerical experiments. The results show that absorption using the DABC is considerably improved relative to the Clayton-Engquist boundary condition and nearly the same as that in the PML.

Petrology, geochemistry, and geochronology of mafic rocks from the Taoxinghu Devonian ophiolite, LongmuCo–Shuanghu–Lancang suture zone, northern Tibet: evidence for an intra-oceanic arc–basin system

Abstract: A newly discovered Devonian ophiolite located in the Taoxinghu area of central Qiangtang on the Qinhai–Tibet Plateau is described. The ophiolite consists of gabbro and diabasic dikes, and invasive cumulate gabbros-leucogabbros. The ophiolite has undergone greenschist facies metamorphism and minor deformation. Dating of the metagabbro by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb techniques yielded a weighted mean age of 367.2 ± 3.3 Ma (Late Devonian). Whole-rock geochemical analyses show that the rocks belong to the tholeiite series, with weak depletion in light rare-earth elements (LREEs), almost no Eu anomalies, weak enrichment in large-ion lithophile elements (LILEs), depletion in Nb and Ta, and weak negative Hf and Ti anomalies. These characteristics are similar to those of back-arc basin basalts. Together, these characteristics suggest that the rocks of the Devonian ophiolite formed by ~30% partial melting of spinel lherzolite, which was enriched by in...