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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Geophysics and Geophysical Exploration
Journal Basic Information
Journal DOI :
Korean Society of Earth and Exploration Geophysicists
Editor in Chief :
Volume & Issues
Volume 16, Issue 4 - Nov 2013
Volume 16, Issue 3 - Aug 2013
Volume 16, Issue 2 - May 2013
Volume 16, Issue 1 - Feb 2013
Selecting the target year
Robust and Optimum Weighted Stacking of Seismic Data
Ji, Jun ;
Geophysics and Geophysical Exploration, volume 16, issue 1, 2013, Pages 1~5
DOI : 10.7582/GGE.2013.16.1.1
Stacking in seismic processing plays an important role in improving signal-to-noise ratio and imaging quality of seismic data. However, the conventional stacking method doesn`t remove random noises with various distributions and outliers up to a satisfactory level. This paper introduces a robust and optimum weighted stack method which shows both robustness to outlier noises and optimum in removing random noises. This was achieved by combining the robust median stacking with the optimum weighted stacking using local correlation. Application of the method to synthetic data showed that the proposed method is very effective in suppressing random noises with various distributions including outliers.
Effective Wavefield Separation of Reflected P- and PS-Waves in Multicomponent Seismic Data by Using Rotation Transform with Stacking
Jeong, Soocheol ; Byun, Joongmoo ; Seol, Soon Jee ;
Geophysics and Geophysical Exploration, volume 16, issue 1, 2013, Pages 6~17
DOI : 10.7582/GGE.2013.16.1.6
Multicomponent seismic data including both P- and PS-waves have advantages in discriminating the type of pore fluid, characterizing the lithologic attributes and producing the high resolution image. However, multicomponent seismic data recorded at the vertical and horizontal component receivers contain both P- and PS-waves which have different features, simultaneously. Therefore, the wavefield separation of P- and PS-waves as a preprocessing is inevitable in order to use the multicomponent seismic data successfully. In this study, we analyzed the previous study of the wavefield separation method suggested by Jeong and Byun in 2011, where the approximated reflection angle calculated only from one refernce depth is used in rotation transform, and showed its limitation for seismic data containing various reflected events from the multi-layered structure. In order to overcome its limitation, we suggested a new effective wavefield separation method of P- and PS-waves. In new method, we calculate the reflection angles with various reference depths and apply rotation transforms to the data with those reflection angles. Then we stack all results to obtain the final separated data. To verify our new method, we applied it to the synthetic data sets from a multi-layered model, a fault model, and the Marmousi-2 model. The results showed that the proposed method separated successfully P- and PS-reflection events from the multicomponent data from mild dipping layered model as long as the dip is not too steep.
S-Wave Velocities Beneath Jeju Island, Korea, Using Inversion of Receiver Functions and the H-κ Stacking Method
Jeon, Taehyeon ; Kim, Ki Young ; Woo, Namchul ;
Geophysics and Geophysical Exploration, volume 16, issue 1, 2013, Pages 18~26
DOI : 10.7582/GGE.2013.16.1.18
Shear-wave velocity (
) structures beneath two seismic stations, JJU and JJB on the flanks of the volcano Halla on Jeju island, Korea, were estimated by receiver-function inversion and H-
stacking applied to 150 teleseismic events (
) recorded since 2007.
waves converted at the Moho discontinuity does not appear clearly for northwesterly back-azimuths (
) at station JJU and southeasterly back-azimuths (
) at station JJB. This may be due to a gradual velocity increase at Moho or heterogeneity within the crust. The
models derived by inversion of receiver functions indicate a distinct low velocity layer (
; LVL) within the crust and a gradual increase in
in the depth interval of 30 to 40 km. Within the radius of 18 km beneath station JJB, the LVL occurs at depths of 14 ~ 26 km and the `Moho` (
) is at 34 km depth. Ten kilometers to the west, within the radius of 16 km beneath station JJU, both the LVL and the Moho are significantly shallower, at depths of 14 to 24 km and 30 km, respectively. H-
analyses for stations JJU and JJB yield estimated crustal thickness of 29 and 33 km and
ratios of 1.64 and 1.75, respectively. The lesser
ratio was derived for rocks nearest to th peak of the volcano.
A 3D Magnetic Inversion Software Based on Algebraic Reconstruction Technique and Assemblage of the 2D Forward Modeling and Inversion
Ko, Kwang-Beom ; Jung, Sang-Won ; Han, Kyeong-Soo ;
Geophysics and Geophysical Exploration, volume 16, issue 1, 2013, Pages 27~35
DOI : 10.7582/GGE.2013.16.1.27
In this study, we developed the trial product on 3D magnetic inversion tentatively named `KMag3D`. Also, we briefly introduced its own function and graphic user interface on which especially focused through the development in the form of user manual. KMag3D is consisted of two fundamental frame for the 3D magnetic inversion. First, algebraic reconstruction technique was selected as a 3D inversion algorithm instead of least square method conventionally used in various magnetic inversion. By comparison, it was turned out that algebraic reconstruction algorithm was more effective and economic than that of least squares in aspect of both computation time and memory. Second, for the effective determination of the 3D initial and a-priori information model required in the execution of our algorithm, we proposed the practical technique based on the assemblage of 2D forward modeling and inversion results for individual user-selected 2D profiles. And in succession, initial and a-priori information model were constructed by appropriate interpolation along the strke direction. From this, we concluded that our technique is both suitable and very practical for the application of 3D magentic inversion problem.
Interpretation of Airborne Magnetic and Radioactive Data for the Uranium Deposit in Geumsan Area
Shin, Eun-Ju ; Ko, Kwangbeom ; An, Dongkuk ; Han, Kyeongsoo ;
Geophysics and Geophysical Exploration, volume 16, issue 1, 2013, Pages 36~44
DOI : 10.7582/GGE.2013.16.1.36
We conducted the airborne magnetic and radiometric survey for the characterization of the black shale related and pyrometamorphic uranium deposits distributed in Geumsan area. For the successful characterization of the uranium deposits, the general geological and structural geological features were investigated based on the lithological and linear feature analysis to individual magnetic and radiometric data as the first step. Lithological analysis from the magnetic reduction to the pole and downward continuation map revealed that prominent positive anomalies caused by black and dark gray slate member were clearly recognized as magnetic sources. These results indicate that magnetic survey, even though it is not a direct method for the detection of uranium, can be a useful tool in uranium detection. By the linear feature analysis based on 2nd vertical derivative and curvature map, two linearments corresponded the gray hornfels and black slate member were extracted and in succession, the additional uranium potential zone was inferred. Final discrimination whether uranium-rich or not was confirmed by radiometric and uranium anomaly map. From these analysis, we finally concluded that uranium deposit originated by pyrometamorphic process was confined near the intrusive area only. On the contrary, it was found that black shale related uranium deposit is distributed and extended through out the entire survey area with south-west to north-east direction. In addition, from the linear feature analysis based on radiometric total anomaly map, the typical discontinuous characteristics were recognized in areas where uranium-contained linearments cross the faults. From the above discussion, we concluded that airborne magnetic and radiometric survey are complementary to each other. So it is preferable to carry out simultaneously for the efficient data processing and fruitful interpretation.
Development of the Impulse Response Measurement System for Non-destructive Test of Slab Structure
Chung, Hojoon ; Lee, Heuisoon ; Oh, Seokhoon ; Song, Sung-Ho ;
Geophysics and Geophysical Exploration, volume 16, issue 1, 2013, Pages 45~52
DOI : 10.7582/GGE.2013.16.1.45
We developed a Impulse Response Measurement System, including hardware system and data analysis software, for non-destructive test of slab structure. And, we carried out impulse response measurements on the pavement to test performance of the system. In the field test, the developed system measured impulse response stably and showed parameters immediately. Test results showed that dynamic stiffness and average mobility varies significantly depending on the characteristics of the pavement materials. Some data showed anomalous values those reflect variations in pavement itself or subsurface ground. Developed system gives informations of conditions of slab structure easily and quickly. So, 2-D monitoring with the system will be helpful in maintaining various slab structures.
Microseismic Monitoring Using Seismic Mini-Array
Sheen, Dong-Hoon ; Cho, Chang Soo ; Lee, Hee Il ;
Geophysics and Geophysical Exploration, volume 16, issue 1, 2013, Pages 53~58
DOI : 10.7582/GGE.2013.16.1.53
It was introduced a seismic mini-array that could monitor microseismicity efficiently and analyzed seismic data obtained from the mini-array that was operated from December 19, 2012 to January 9, 2013. The mini-array consisted of a six channel data logger, a central 3 components seismometer, and a tripartite array of vertical sensors centered around the 3 components seismometer as an equilateral triangle with about 100 m aperture. All seismometers that had the same instrument response were connected a 6 channel data logger, which was set to record seismograms at a sampling rate of 200 sps. During the three weeks of campaign, a total of 16 microearthquakes were detected. Using time differences of P wave arrivals from the vertical components, S-P time from 3 components seismometers, and back azimuth from the seismic array analysis, it was possible to locate the hypocenter of the microearthquake even with one seismic miniarray. The epicenters of two nearest microearthquakes were a quarry site located 1.3 km from the mini-array. The records of quarry blasting confirmed the our analysis.
Extension for Downward Continuation of the Method of "Upward Continuation of Potential Field on Spherical Patch Area"
Na, Sung-Ho ; Chung, Tae Woong ; Shin, Young Hong ;
Geophysics and Geophysical Exploration, volume 16, issue 1, 2013, Pages 59~62
DOI : 10.7582/GGE.2013.16.1.59
We formerly reported a new method for the upward continuation of potential field on spherical patch area including Earth`s curvature, which has been neglected in most studies on rectangular area with flat Earth assumption. This new method is applicable to downward continuation as well by only assigning corresponding value for the ratio of two radii;
, i.e., target radius
versus datum radius
. In addition, the inherent problem of this method due to spherical surface geometry is described, and its one possible remedy is given.
Effects of a Frozen Layer on Near-Surface Seismic Data
Park, Iseul ; Han, Arim ; Kim, Ki Young ;
Geophysics and Geophysical Exploration, volume 16, issue 1, 2013, Pages 63~66
DOI : 10.7582/GGE.2013.16.1.63