scispace - formally typeset
Search or ask a question

Showing papers by "Geophysical Survey published in 2013"


Journal ArticleDOI
TL;DR: In this article, the results of time-dependent local earthquake tomography for the Kluchevskoy group of volcanoes in Kamchatka, Russia, were presented, and the results were supported by synthetic tests that recover a common 3D model based on data corresponding to different time windows.

100 citations


Journal ArticleDOI
TL;DR: In this paper, the spatial distribution of the epicenters, which either gather along well-delineated belts or in discrete swarms, is considered in detail for different areas of the rift system.

32 citations


Journal ArticleDOI
TL;DR: InSAR images from both ascending and descending orbital passes of Envisat and ALOS PALSAR satellites reveal a pre-eruption deformation signal at Kizimen volcano, Kamchatka, Russia, where an ongoing eruption began in mid-November, 2010 as mentioned in this paper.

24 citations


Journal ArticleDOI
TL;DR: Samoylenko et al. as mentioned in this paper interpreted a focused swarm of earthquakes as the start of a new ongoing eruption on the south flank (Tolbachinsky Dol) of Plosky Tolbachik volcano in east central Kamchatka, Russia.
Abstract: On 27 November 2012 at 1715 local time, a focused swarm of earthquakes was interpreted as the start of a new ongoing eruption on the south flank (Tolbachinsky Dol) of Plosky Tolbachik volcano in east central Kamchatka, Russia (Figure 1a) [Samoylenko et al., 2012]. Visual observations on 29 November showed ash shooting from two fractures as well as long, rapidly moving lava flows. Although the initial ash clouds reached 6 kilometers in height, subsequent ashfall has been limited to the area around the main vents, and no permanent settlements are in danger from advancing lava flows (the closest settlements are about 40 kilometers from the volcano). Including this eruption, six different volcanoes are presently active in Kamchatka.

18 citations


Journal ArticleDOI
TL;DR: In this paper, the authors carried out a magnetotelluric (MT) survey along a profile crossing the Median Tectonic Line (MTL) in western Shikoku, Japan.

17 citations


Journal ArticleDOI
TL;DR: The results of the observation of the geophysical disturbances in ionosphere, atmospheric electrical field, magnetic field, surface ozone and infrasound during the total solar eclipse of 1 August 2008 in Novosibirsk are presented in this article.

16 citations


Journal ArticleDOI
TL;DR: In this article, the ground roll noise is characterized by elliptical plane polarization, strong energy, low apparent velocity, and low frequency, and an adaptive polarization filtering method is presented to improve the data quality of converted waves and better identify and suppress the strong ground-roll interference in 3C seismic recordings on land.
Abstract: To improve the data quality of converted waves, and better identify and suppress the strong ground-roll interference in three-component (3C) seismic recordings on land, we present an adaptive polarization filtering method, which can effectively separate the groundroll interference by combining complex polarization and instantaneous polarization analysis. The ground roll noise is characterized by elliptical plane polarization, strong energy, low apparent velocity, and low frequency. After low-pass filtering of the 3C data input within a given time-window of the ground roll, the complex covariance matrix is decomposed using the sliding time window with overlapping data and length that depends on the dominant ground-roll frequency. The ground-roll model is established using the main eigenvectors, and the ground roll is detected and identified using the instantaneous polarization area attributes and average energy constraints of the ground-roll zone. Finally, the ground roll is subtracted. The threshold of the method is stable and easy to select, and offers good groundroll detection. The method is a robust polarization filtering method. Model calculations and actual data indicate that the method can effectively identify and attenuate ground roll while preserving the effective signals.

12 citations


Patent
David Cist1
29 May 2013
TL;DR: In this article, a visual output of data from a ground-penetrating radar is displayed on a visual medium, such as a display with a first exhibition of output from a higher frequency range antenna, a second exhibition from a lower-frequency range antenna (compared to the other antenna; see definition in the "detailed description"), and a transition area between the first and second exhibition having merged data from the lower frequency antenna and the higher frequency antenna.
Abstract: In an embodiment of the disclosed technology, a visual output of data from a ground-penetrating radar is displayed on a visual medium. The display has a first exhibition of output from a higher frequency range antenna, a second exhibition of output from a lower frequency range antenna (compared to the other antenna; see definition in the "detailed description"), and a transition area between the first and second exhibition having merged data from the lower frequency antenna and the higher frequency antenna. The depth range of the transition area may be varied based on optimal depth range of each antenna, such as manually by a viewer viewing the visual output, which may occur in real-time, that is, while operating the radar and viewing the visual output thereof. Or, the transition depth range and/or width of the transition region may be varied as part of post-processing.

9 citations


Journal ArticleDOI
TL;DR: In this paper, a downwelling radiance residual index (DRRI) was used to obtain LST and emissivity from IRI and AIRS data, respectively.
Abstract: Land surface temperature LST is one of the key state variables for many applications. This article aims to apply our previously developed LST retrieval method to infrared atmospheric sounding interferometer IASI and atmospheric infrared sounder AIRS data. On the basis of the opposite characteristics of the atmospheric spectral absorption and surface spectral emissivity, a ‘downwelling radiance residual index’ DRRI has been recalled and improved to obtain LST and emissivity. To construct an efficient DRRI, an automatic channel selection procedure has been proposed, and 11 groups of channels have been selected within the range 800–1000 cm−1. The DRRI has been tested with IASI and AIRS data. For the IASI data, the radiosonde data have been used to correct for atmospheric effects and to retrieve LST, while the atmospheric profiles retrieved from AIRS data have been used to perform the atmospheric corrections and subsequently to estimate LST from AIRS data. The differences between IASI-and Moderate Resolution Imaging Spectroradiometer MODIS-derived LSTs are no more than 2 K, while the differences between AIRS-and MODIS-derived LSTs are less than 5 K. Even though an exceptionally problematic value occurred –12.89 K, the overall differences between AIRS-estimated LST and the AIRS L2 LST product are no more than 5 K. Although the IASI-derived LST is more accurate than the AIRS-derived one, the convenient retrieval of AIRS atmospheric profile made this method more applicable. Limitations and uncertainties in retrieving LST using the DRRI method are also discussed.

7 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed a new C-wave moveout equation with two parameters for C-waves in vertical transverse isotropy (VTI) media, which can simplify the procedure for Cwave processing and parameter estimation in VTI 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.

4 citations


Book ChapterDOI
Kun Yu1, Ting Li1, Jie Chen1, Fang Wu1, Changkui Sun1 
01 Jan 2013
TL;DR: A method based on object feature extraction based on multi-level classification according to object’s principal feature at last is presented, which has been applied to data points obtained by mobile laser scanning system and results show that the proposed classification method is promising.
Abstract: Mobile laser scanning has many advantages compared to traditional survey technology. These characteristics make it possible to rapidly acquire large-area high-precision 3D spatial data for reconstruction of 3D model. In this paper, we focus on the classification and recognition of mobile laser scanning data. We present a method based on object feature extraction. The main workflow of this method is made up by extraction of geometric feature from scanning data,foundation of objects feature knowledge database, extraction of main feature by PCA (Principal Component Analysis) to match geometric features,multi-level classification according to object’s principal feature at last. This method has been applied to data points obtained by mobile laser scanning system; the experiment results show that the proposed classification method is promising.

Journal Article
Wang Meng1
TL;DR: In this article, the resampled multiple channels of records are translated, superposed and reaveraged by one time and multiple times of sleeper-to-sleeper periods to from the time space filter screen holding the interference information of sleepers.
Abstract: When the ground-penetrating radar(GPR) is used in exploration of railway subgrades,its records are severely interfered in data processing by direct-coupled waves from antennas,strong rail reflection,and diffraction and multiple waves caused by sleepers.Sleeper interference in raw records possesses the feature of space-time periodic distribution.In this paper,the resampled multiple channels of records are translated,superposed and reaveraged by one time and multiple times of sleeper-to-sleeper periods to from the time space filter screen holding the interference information of sleepers.It is seen that the time space filter screen can be used to well suppress the diffraction and multiple waves caused by sleepers and direct-coupled waves and strong rail reflections can also be suppressed at the same time.Numerical simulation and measured data processing show the time space filter screen algorithm has obvious effects in improving the SNR and resolution capability of abnormalities of the GPR records.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed main land slidecausing factors and evaluated stability of landslide by use of Rosenbluth method, the result indicated that the landslide was in extremely unstable stage.
Abstract: This paper studies the environmental geological problems of Dashikou landslide. The author analyzed main land slidecausing factors and evaluated stability of landslide by use of Rosenbluth method. The assessment result is 0.98. The result indicated that the landslide was in extremely unstable stage. The author predicted hazardcausing economic losses and casualties to human beings. Finally some methods and suggestions in risk management were advanced in this paper. Keywords: landslide; hazard; risk; management; assessment

Journal Article
Zhu De-bin1
TL;DR: In this article, a theoretical analysis was performed with the mobility and modal analysis theory to show the effects of the added mass and contact stiffness of the geophone on its response performance in frequency domain.
Abstract: As an example in seismic exploration,tailstock is suitable to those sites always difficult to install geophones with tail-cones,such as,a ballast site in railway.Here,a theoretical analysis was performed with the mobility and modal analysis theory to show the effects of the added mass and contact stiffness of the geophone on its response performance in frequency domain.An actual geophone with tailstock was used in model testing and field tests to the tests were consistent with those of the theoretical analysis from which the field tests is analyzed in contrast to show the influence of added mass and contact stiffness on an ideal bandwidth.It was proved that the tailstock detector is feasible for the real production.The essential characteristics of this kind of geophone with tailstock were described also.