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.

Enhanced target imaging in 3D using GPR data from orthogonal profile lines

Abstract: Continuing improvements in computer technology have made 3-D imaging a standard GPR interpretation technique. The most common data collection methodology for 3-D imaging involves collection of data along parallel profile lines. The data are then often migrated and concatenated into a 3-D file. A 3-D image generated from the file is manipulated to detect linear and finite-size targets. The detection of linear and finite-size targets can be enhanced by creating images generated from data collected along orthogonal profile lines. The fact that the minimum angle formed between the long axis of a linear target and one of the orthogonal profile lines is 45 degrees enhances the detection of a linear target because in at least one profile line direction the reflection from the linear target will form the familiar hyperbola and a series of hyperbolas concatenated from parallel profile lines are readily observed in the 3-D image. Perhaps the most beneficial aspect of using bi-directional data is the ability to perform spatial filtering operators to improve detection of linear targets. Background removal filters applied to parallel profile line data will generally erase reflections from pipes or rebar that trend parallel to the direction of the profile lines. Comparisons of the data visualization capabilities between one-direction and orthogonal profile line data collected on reinforced concrete and on a buried pipe test site clearly show the advantages of imaging using orthogonal profile line data on both small and large scales.

RS+GCPs select basic information of landslide

Abstract: Based on practice over 20y's landslide RS investigation, this paper introduces the main RS+GCPs information resources, what's the basic information of landslide and the relation among RS resolution and possible recognized minimum landslide(PRML) and different scale landslide RS investigation. RS data can be divided into three types of panchromatic, Multi-spectral, SAR, based on spectral characteristics, and two types of arero and satellite based on sensors, that is the main and most important information resources. GCPs mainly comes from topographic map, GPS measurement and DEM made of stereo pair of aero or satellite image or by means of InSAR.Only ortho-mage processed by means of geometric correction and geographic coordinate register is the base for investigating landslide.The basic landslide information consists of elements of landslide and its developing environment. There are about 16 elements for an entire landslide,which are:sliding mass, boundary, scarp, terrace, tongue, sliding axle, bulge, tension fracture, shear fracture, fan type fracture, bulge fracture, fracture edge, depression on the back, sliding surface, sliding zone, sliding bed. Not every landslide has above 16 elements but sliding mass and scarp is at least the basic elements for any landslide. There are 3 basic geological environment factors for producing a landslide,that are ① material which can be evolved sliding surface, ② frail surface or zone making parts of slope separate from original slope, ③space for landslide moving ahead. Otherwise, induced environment factors including human beings' activities data should be investigated and collected as well.Up till now most of landslide RS investigation uses aero-photos. The space resolution of aero-photo is depends on the film's quality for distinguishing maximum line pairs/mm, the lens' properties and the contrast of objects and environment.Apart from the image quality and space resolution, the possible recognized minimum landslide-PRML is related to kinds, typicality and contrasts of landslide.Generally speaking each single element of landslide which should at least cover 10×10 pixels can then be recognized clearly and the entire landslide can be recognized at least cover 10×20×2 pixels according to practices. Different regions and landslides have different PRML. Through statistics the landslide at least covering (1?000) pixels can then be primarily analyzed qualitatively and quantitatively, and at least coving (2?000) pixels can then be analyzed qualitatively and quantitatively in detail, so that different scale landslide RS investigation needs different space resolution of image.

Interpolation, smoothing, and differentiation of gravity anomalies

Abstract: Numerical methods are examined whereby gravity anomalies observed at randomly distributed points may be transformed into a continuous harmonic function on a level surface. The interpolated value at a height z at the origin is found from the observed values gi at distances heights ζi and representing areas ai by a linear summation The weighting functions fi are derived from the Fourier-Bessel integral expansion of the gravity anomaly field, and are designed to act as low pass filters. Two cases are considered: the first is a sharp cut-off filter, where the frequency v has an upper limit ω, so that the frequency response is 1 for 0 ⩽ v ≪ ω and 0 for v > > and the second is an exponential filter of theoretical frequency response exp(−v 2/ω2) for which Differentiation of these formulae with respect to z yields the higher vertical derivatives directly from the observed anomalies. The methods include allowance for local variations in the density of observation points, and are designed to prepare data f...

Monitoring of landslide deformation based on the coherent targets of high resolution InSAR data

Abstract: Landslides are a kind of typical natural disaster in China, which pose serious threats to civil lives, property and living environment. Therefore, the identification, monitoring and prevention of landslides have been considered as a long-term geological work for the public welfare. In this article, 8 TerraSAR-X high resolution strip-map mode images, acquired in the period from January to March 2012 and covering Fanjinping landslide in Zigui county, Hubei province, were used to test the usability in monitoring the deformation of single landslide. The results of two-pass DInSAR sketched the region and the shape of the deformation field of Fanjiaping landslide. Corner reflectors’ linear deformation rate using CRInSAR method could be approximately validated by the in-situ GPS measurements. From the coherent pixels’ linear deformation rate map, it was inferred that the deformation could be more obvious in the tail of the Muyubao landslide while the lowest frontier of this landslide might prevent the slide. Due to its shorter revisiting period and high bandwidth,,the high resolution TerraSAR-X images can keep better coherence than previous satellite SAR data in the test area and provide basic guarantee to monitor the deformation of single landslides.

The Tolud Burst of Seismicity and the Earthquake of November 30, 2012 (MC = 5.4, MW = 4.8) that Accompanied the Start of the 2012‒2013 Tolbachik Eruption

Abstract: This paper reports a study of the Tolud earthquake sequence; the sequence was a burst of shallow seismicity between November 28 and December 7, 2012; it accompanied the initial phase in the Tolbachik Fissure Eruption of 2012‒2013. The largest earthquake (the Tolud earthquake of November 30, 2012, to be referred to as the Tolud Earthquake in what follows, with KS = 11.3, ML = 4.9, MC = 5.4, and MW = 4.8) is one of the five larger seismic events that have been recorded at depths shallower than 10 km beneath the entire Klyuchevskoi Volcanic Cluster in 1961‒2015. It was found that the Tolud earthquake sequence was the foreshock–aftershock process of the Tolud Earthquake. This is one of the larger seismicity episodes ever to have occurred in the volcanic areas of Kamchatka. Data of the Kamchatka seismic stations were used to compute some parameters for the Tolud Earthquake and its largest (ML = 4.3) aftershock; the parameters include the source parameters and mechanisms, and the moment magnitudes, since no information on these is available at the world seismological data centers. The focal mechanisms for the Tolud Earthquake and for its aftershock are consistent with seismic ruptures at a tension fault in the rift zone. Instrumental data were used to estimate the intensity of shaking due to the Tolud Earthquake. We discuss the sequence of events that was a signature of the time-dependent seismic and volcanic activity that took place in the Tolbachik zone in late November 2012 and terminated in the Tolud burst of seismicity. Based on the current ideas of the tectonics and magma sources for the Tolbachik volcanic zone, we discuss possible causes of these earthquakes.