Hakan Karsli
Karadeniz Technical University, Geophysics Eng., Department Member
- I am geophysical engineering and I work at Karadeniz Technical University in position of Professor. I have the Ph.D d... moreI am geophysical engineering and I work at Karadeniz Technical University in position of Professor. I have the Ph.D degree in Geophysics and my special topic or research are includes seismic reflection data processing, interpretation, near surface site characterization by seismic refraction, active and passive multichannel analysis of surface waves, joint inversion of seismic and electrical resistivtiy data, gravity data processing.edit
Aktif ÇKYDA yönteminde, sığ yeraltının güvenilir bir S-dalgası hız-derinlik profilini elde etmek için en önemli aşamalarından biri, geniş frekans aralığında sürekli ve yüksek ayrımlı bir dispersiyon eğrisinin elde edilmesidir. Bu... more
Aktif ÇKYDA yönteminde, sığ yeraltının güvenilir bir S-dalgası hız-derinlik profilini elde etmek için en önemli aşamalarından biri, geniş frekans aralığında sürekli ve yüksek ayrımlı bir dispersiyon eğrisinin elde edilmesidir. Bu makalede, tabaka (S- ve P-dalga hızları, yoğunluk ve kalınlık) ve veri toplama (kaynak ofseti-X0, alıcı aralığı-dx ve sayısı-N, serim boyu-L=(N-1)*dx) parametrelerinin, yüzey dalga alanının temel mod dispersiyon eğrisi üzerindeki etkileri, yapay atış verilerinin analizi ile incelenmiştir. Yapay veriler, tabaka yansıma/iletim katsayısı tekniği ile hesaplanan dispersiyon eğrisi kullanılarak, her bir alıcıda harmonik mod toplama tekniği ile oluşturulmuştur. Buna göre, düşük S-dalga hızlı ara tabakalar dispersiyon eğrisinin düşük frekans bölgesinde düşük hızlara kaymasına, yüksek hızlı ara tabakalar ise, dispersiyon eğrisinin yüksek frekanslarda sürekliliğinin bozulmasına (zig-zag etkisi) ve yüksek mod etkisi yanılgısına neden olabileceği gözlenmiştir. Kaynak o...
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ABSTRACTThe inversion of active surface‐wave data is highly affected by the non‐uniqueness of the solution. While a deterministic approach is generally chosen due to certain advantages, there is the risk of getting trapped in a local... more
ABSTRACTThe inversion of active surface‐wave data is highly affected by the non‐uniqueness of the solution. While a deterministic approach is generally chosen due to certain advantages, there is the risk of getting trapped in a local minima, especially when no a priori information is available about the sub‐surface geometry since the layer thickness is assumed fixed to a priori. The fixed‐layer thickness in a deterministic inversion of the active surface‐wave raises significant issues, such as the relevance of the initial model geometry (the thickness of the intermediate layer and the total depth of the initial model) and the equivalence problems. Thus, the inversion result is inherently not reliable, even in the case of the normal dispersion medium, and the result could be unachievable in challenging sub‐surface situations. These issues could be reduced by using a joint inversion approach. The present paper first presents examples of issues through four case histories in Trabzon, T...
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In a seismic trace the location of a reflector is indicated by a reflection wavelet which consists of a main lobe, indicating the location of the reflectors, surrounded by side lobes which add no extra information. Side lobes are result... more
In a seismic trace the location of a reflector is indicated by a reflection wavelet which consists of a main lobe, indicating the location of the reflectors, surrounded by side lobes which add no extra information. Side lobes are result from the lack of the low frequency content in a reflection wavelet. The aim of the study is to reduce side lobes by using the complex trace envelope and thus improve low frequency content of a seismic trace. The method is based on comparing the energies in the reflection events in a seismic trace, with the energies in the reflection events in the addition and subtraction of a seismic trace with the envelope trace. The resulting polarity table is applied to the envelope trace and the result is an envelope trace that has positive valued reflection events and negative valued reflection events in agreement with the corresponding reflection coefficient. The result is that the main lobe in the seismic trace is increased whereas the side lobes are diminished. Tests are done on synthetic and real data. Consequently low frequency content is improved and it may be stated that resolution and interpretability of the seismic data are increased.
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ABSTRACT Layer thickness is important model parameter as far as S-wave velocity that contributes to Rayleigh phase velocity. But, S-wave velocity is only inverted parameters in the traditional Rayleigh-wave inversion process. Thus, using... more
ABSTRACT Layer thickness is important model parameter as far as S-wave velocity that contributes to Rayleigh phase velocity. But, S-wave velocity is only inverted parameters in the traditional Rayleigh-wave inversion process. Thus, using erroneous thickness information in inversion process will cause unreliable or non-unique S-wave velocity profile. However, layer thickness can be incorporated into process by the joint inversion approach to increase accuracy of sub-surface model. This study presents 1D joint inversion of Rayleigh fundamental mode curve with electric sounding data, to use layer thickness as variable in the inversion process, contrary from separate inversion of Rayleigh dispersion curve. The proposed method was tested on noise-free and Gaussian noisy synthetic data. Results demonstrate that reliable vertical shear velocity profile can be obtained by the joint inversion approach, even there is no a priori.
Research Interests: Geology and Rayleigh Wave
In this paper, an estimation-subtraction technique based on Wiener filtering of attenuating two low frequency high amplitude noises such as ground roll in land and swell noise in marine environments are performed. The Wiener filter design... more
In this paper, an estimation-subtraction technique based on Wiener filtering of attenuating two low frequency high amplitude noises such as ground roll in land and swell noise in marine environments are performed. The Wiener filter design is always realized between an actual output and a desired output in the manner of least squares. Thus, to design Wiener estimation filter, an imperfect model of the noise type is obtained from the data itself by application of a suitable low-pass filter based on the frequency characteristic the noise. Then I used the filter coefficients to estimate the real noise from the data. Finally, the noise estimate has been adaptively subtracted from the data in order to perform attenuation process. The applications of the proposed method to both land and marine datasets show encouraging results and also show that these kinds of filters are effective in preserving available signal band while greatly attenuating these high amplitude noises which mostly damage the reflection signals.
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... However, suppression of the noise during data acquisition is not attempted because overlapping subsurface coverage caused by overlapping receiver and source arrays on the surface result in decreased resolution (Coruh and Costain,... more
... However, suppression of the noise during data acquisition is not attempted because overlapping subsurface coverage caused by overlapping receiver and source arrays on the surface result in decreased resolution (Coruh and Costain, 1983). ...
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ABSTRACT Seismic data have still no enough temporal resolution because of band-limited nature of available data even if it is deconvolved. However, lower and higher frequency information belonging to seismic data is missing and it is not... more
ABSTRACT Seismic data have still no enough temporal resolution because of band-limited nature of available data even if it is deconvolved. However, lower and higher frequency information belonging to seismic data is missing and it is not directly recovered from seismic data. In this paper, a method originally applied by Honarvar et al. [Honarvar, F., Sheikhzadeh, H., Moles, M., Sinclair, A.N., 2004. Improving the time-resolution and signal–noise ratio of ultrasonic NDE signals. Ultrasonics 41, 755–763.] which is the combination of the most widely used Wiener deconvolution and AR spectral extrapolation in frequency domain is briefly reviewed and is applied to seismic data to improve temporal resolution further. The missing frequency information is optimally recovered by forward and backward extrapolation based on the selection of a high signal–noise ratio (SNR) of signal spectrum deconvolved in signal processing technique. The combination of the two methods is firstly tested on a variety of synthetic examples and then applied to a stacked real trace. The selection of necessary parameters in Wiener filtering and in extrapolation are discussed in detail. It is used an optimum frequency windows between 3 and 10 dB drops by comparing results from these drops, while frequency windows are used as standard between 2.8 and 3.2 dB drops in study of Honarvar et al. [Honarvar, F., Sheikhzadeh, H., Moles, M., Sinclair, A.N., 2004. Improving the time-resolution and signal–noise ratio of ultrasonic NDE signals. Ultrasonics 41, 755–763.]. The results obtained show that the application of the purposed signal processing technique considerably improves temporal resolution of seismic data when compared with the original seismic data. Furthermore, AR based spectral extrapolated data can be almost considered as reflectivity sequence of layered medium. Consequently, the combination of Wiener deconvolution and AR spectral extrapolation can reveal some details of seismic data that cannot be observed in raw signal or which lost during the previous processing.
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ABSTRACT Interpreting a post-stack seismic section is difficult due to the band-limited nature of the seismic data even post deconvolution. Deconvolution is a process that is universally applied to extend the bandwidth of seismic data.... more
ABSTRACT Interpreting a post-stack seismic section is difficult due to the band-limited nature of the seismic data even post deconvolution. Deconvolution is a process that is universally applied to extend the bandwidth of seismic data. However, deconvolution falls short of this task as low and high frequencies of the deconvolved data are either still missing or contaminated by noise. In this paper we use the autoregressive extrapolation technique to recover these missing frequencies, using the high signal-to-noise ratio (S/N) portions of the spectrum of deconvolved data.I introduce here an algorithm to extend the bandwidth of deconvolved data. This is achieved via an autoregressive extrapolation technique, which has been widely used to replace missing or corrupted samples of data in signal processing. This method is performed in the spectral domain. The spectral band to be extrapolated using autoregressive prediction filters is first selected from the part of the spectrum that has a high signal-to-noise ratio (S/N) and is then extended. As there can be more than one zone of good S/N in the spectrum, the results of prediction filter design and extrapolation from three different bands are averaged.When the spectrum of deconvolved data is extended in this way, the results show higher vertical resolution to a degree that the final seismic data closely resemble what is considered to be a reflectivity sequence of the layered medium. This helps to obtain acoustic impedance with inversion by stable integration. The results show that autoregressive spectral extrapolation highly increases vertical resolution and improves horizon tracking to determine continuities and faults. This increase in coherence ultimately yields a more interpretable seismic section.
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Structural and stratigraphic hydrocarbon (oil, gas) traps that develop in complex geological environments are formed in regions subjected to tectonically deformation or where there are impermeable rocks in the lateral direction and... more
Structural and stratigraphic hydrocarbon (oil, gas) traps that develop in complex geological environments are formed in regions subjected to tectonically deformation or where there are impermeable rocks in the lateral direction and accumulate significant amounts of hydrocarbons. Reflections from the subsurface media including such traps indicate highly complex behaviour. Therefore, understanding seismic wave propagation in such environments provide important contributions to the interpretation stage. In this study, the modeling of structural and stratigraphic hydrocarbon traps was carried out with exploding reflector (ER) technique. The most important advantages of the method is that the seismic source is located at the reflective interfaces and recorded by the receivers at the surface with the one way travel time. Therefore, as a result of the calculation, directly zero offset sections could be obtained. Numerical calculation of the seismic waves propagated from the source was made...
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Harmonic noise in seismic data is a single frequency noise caused by power line within the data acquisition systems and generally filtered by classical notch filter. However, the notch filter would attenuate all recorded data around notch... more
Harmonic noise in seismic data is a single frequency noise caused by power line within the data acquisition systems and generally filtered by classical notch filter. However, the notch filter would attenuate all recorded data around notch frequency at especially 50 Hz (or 60 Hz) and so leads to loss available information that explains fine details in the seismic data. On the other hand, iterative trimmed and truncated mean filter method locally applied in spectral domain (LITTM) is a signal protector filter and is very effective to remove the harmonic noise in the signal. In this study we proposed to compare the quality of migrated sections after removing the harmonic noise by using classical notch and LITTM filters. We tested the applicability and reliability of the LITTM filter in removing the single frequency harmonic noise on synthetic data set and then applied it to a marine data from Turkey. When comparing the outputs from classical notch and LITTM filters, we found that the LITTM filter strikes a balance between the removing harmonic noise and protecting available frequencies. Our experiments show that the LITTM filter can effectively be used to eliminate other spike-like noise within the bandwidth of the data.
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Research Interests: Geodesy, Geology, Geophysics, Seismology, Geodynamics, and 3 moreIonosphere, Geomatic Engineering, and Tec
Sismik veri-islem akisinin degismez bir asamasi olan dekonvolusyon islemi matematiksel olarak bir ters cozum islemidir ve yaygin olarak sismik verilerin zamansal ayrimliligini arttirmak icin kullanilir. Onkestirim dekonvolusyonu sismik... more
Sismik veri-islem akisinin degismez bir asamasi olan dekonvolusyon islemi matematiksel olarak bir ters cozum islemidir ve yaygin olarak sismik verilerin zamansal ayrimliligini arttirmak icin kullanilir. Onkestirim dekonvolusyonu sismik sinyaldeki yankilanmalari, salinimlari, kisa yollu ve hatta uzun yollu tekrarlilari sonumlemek icin yaygin olarak kullanilan istatistiksel bir dekonvolusyon turudur. Onkestirim dekonvolusyonunun uygulanabilirligi ve performansi iki onemli parametre olan kestirim uzakligi ve operator uzunluguna baglidir. Her iki parametre de sismik sinyalin oziliskisi analiz edilerek belirlenir. Genel olarak kestirim uzakligi cikis sinyalinin zamansal ayrimliligini kontrol eden parametredir. Kucuk secilirse zamansal ayrimlilik artar, ancak bu durumda birincil yansimalara zarar verebilir ve dolayisiyla Sinyal/Gurultu orani azalir. Operator uzunlugu ise onkestirim dekonvolusyonu ile suzulecek kismi ve performansi kontrol eden parametredir. Bununla birlikte, geleneksel of...
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Research Interests: Geology and Attenuation
First of all, I congratulate all the authors of the article. The presented article is extremely valuable in terms of including the microzonation studies and what kind of geophysical and geotechnical studies have been done in these... more
First of all, I congratulate all the authors of the article. The presented article is extremely valuable in terms of including the microzonation studies and what kind of geophysical and geotechnical studies have been done in these studies, and contains specificity. The data required for soil amplification and liquefaction, two of the three important stages of microzonation studies, were collected, processed and interpreted for the project area. When evaluated in this context, the article presented provides a very detailed base for studies on microzonation. By mapping all the data collected and evaluated within the scope of the project, the average shear wave velocity up to
Sismik veri-işlem akışının değişmez bir aşaması olan dekonvolüsyon işlemi matematiksel olarak bir ters çözüm işlemidir ve yaygın olarak sismik verilerin zamansal ayrımlılığını arttırmak için kullanılır. Önkestirim dekonvolüsyonu sismik... more
Sismik veri-işlem akışının değişmez bir aşaması olan dekonvolüsyon işlemi matematiksel olarak bir ters çözüm işlemidir ve yaygın olarak sismik verilerin zamansal ayrımlılığını arttırmak için kullanılır. Önkestirim dekonvolüsyonu sismik sinyaldeki yankılanmaları, salınımları, kısa yollu ve hatta uzun yollu tekrarlıları sönümlemek için yaygın olarak kullanılan istatistiksel bir dekonvolüsyon türüdür. Önkestirim dekonvolüsyonunun uygulanabilirliği ve performansı iki önemli parametre olan kestirim uzaklığı ve operatör uzunluğuna bağlıdır. Her iki parametre de sismik sinyalin özilişkisi analiz edilerek belirlenir. Genel olarak kestirim uzaklığı çıkış sinyalinin zamansal ayrımlılığını kontrol eden parametredir. Küçük seçilirse zamansal ayrımlılık artar, ancak bu durumda birincil yansımalara zarar verebilir ve dolayısıyla Sinyal/Gürültü oranı azalır. Operatör uzunluğu ise önkestirim dekonvolüsyonu ile süzülecek kısmı ve performansı kontrol eden parametredir. Bununla birlikte, geleneksel of...
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To investigate the crustal structure of the Archangelsky Ridge, gravity data obtained from the World Gravity Map (WGM2012) were analyzed using Total Horizontal Derivative (THD), Parker-Oldenburg (PO) inversion and Normalized Full Gradient... more
To investigate the crustal structure of the Archangelsky Ridge, gravity data obtained from the World Gravity Map (WGM2012) were analyzed using Total Horizontal Derivative (THD), Parker-Oldenburg (PO) inversion and Normalized Full Gradient (NFG) techniques. The THD method was applied to the Bouguer gravity after band-pass filtering in order to image the discontinuities. The maximum amplitude values of the THD were used to reveal the discontinuities caused by the density difference in the Archangelsky Ridge and its vicinity. In addition, the basement upper surface topography of the region was calculated and mapped with the inverse solution. Moreover, the presence of an uplift area in the northeast of the study area, as well as the elevation of the Archangelsky Ridge was determined. The depth to the Cretaceous aged sedimentary basement in the Sinop basin and on the Archangelsky Ridge approximately reaches 4 km and 1.6 km, respectively. The average upper surface depth of the basement is calculated as 5 km under the Eastern Black Sea Basin (EBSB). Finally, depth calculations were made using NFG method for the selected profiles and correlated with gravity inversion results. The depth results of the basement upper surface topography obtained from NFG and inversion methods are compatible with each other within ± 0.1 km error limits.
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Summary Integrated Geophysical Surveying has gain importance for landslide investigations, deciding the type of landslide, location of the possible sliding and failure zones, the interface between soil and bedrock, determining of... more
Summary Integrated Geophysical Surveying has gain importance for landslide investigations, deciding the type of landslide, location of the possible sliding and failure zones, the interface between soil and bedrock, determining of water-containing zones, and lithological variation in lateral and vertical direction. This study presents preliminary results of the evaluation of seismic refraction tomography (SRT), multichannel analysis of surface wave (MASW), electrical resistivity tomography (ERT) and microtremor (HVSR) data collected in from an active landslide where is located in Isiklar locality of Macka district in Trabzon province. From these data, 2D P-wave velocity and ERT sections, 1D S-wave velocity depth profile, and the values of predominant frequency and H/V amplitude of ground were obtained by using regular processes and inversion steps. Based on preliminary results, possible distribution of landslide materials in the horizontal and vertical directions was revealed and it is shown that the landslide materials with a thickness exceeding approximately 12 meters. Dominant materials of study area are composed of large and small blocky rocks and have a very complex structure. Moreover, the SRT and ERT sections show the presence of a valley-shaped structure and that the type of landslide is a combination of collapse-sliding.
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We describe a simple and fast filtering procedure which is locally applied in spectral domain and uses iterative trimmed and truncated mean filter method (LITTM), to cancel harmonic noise with 50 or 60Hz and its multiples caused by power... more
We describe a simple and fast filtering procedure which is locally applied in spectral domain and uses iterative trimmed and truncated mean filter method (LITTM), to cancel harmonic noise with 50 or 60Hz and its multiples caused by power line during the seismic data acquisition in land and marine. The procedure doesn’t require any reference signal or an estimate accurately the fundamental frequency of the harmonic noise, but only it should be determined the approximate frequencies of the noise on the amplitude spectra. Real land and marine data examples show that the harmonic noise is filtered well without damaging the available frequencies around the fundamental frequency and provide clean outputs for later processes. We expect this procedure may be a useful tool to recover the signal masked by power line noise in other geophysical data.
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Least Squares Migration (LSM) is well known migration methods, but it is very expensive because of time. There are many optimization methods to improve LSM results. In this paper, five optimization methods, LSQR, Shooting, Grafting,... more
Least Squares Migration (LSM) is well known migration methods, but it is very expensive because of time. There are many optimization methods to improve LSM results. In this paper, five optimization methods, LSQR, Shooting, Grafting, Gauss-Seidel and Conjugate-Gradient are applied to data (SEG/EAGE salt model) in order to obtain better migration results and to compare them in terms of quality, time and resolution. Tests have shown that the Gauss-Seidel method is the best method yields improved amplitude response, less time and higher resolution compared to others.
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Trabzon-Uzungol settlement and construction areas take place on landslide deposits which occurred due to an historical landslide. Shallow seismic reflection, seismic refraction first arrival tomography and MASW methods were used to reveal... more
Trabzon-Uzungol settlement and construction areas take place on landslide deposits which occurred due to an historical landslide. Shallow seismic reflection, seismic refraction first arrival tomography and MASW methods were used to reveal the soil structure and characterization of this deposit. The obtained P and S-wave velocity sections indicate the topographic change of the depth of the basic rock in ~ 13.5m in lateral direction. On the other hand, dynamic elastic parameters of that soil on the bedrock were calculated for geotechnical engineering studies. Despite the fact that the soil classification indicates variability from place to place, it was determined to be medium-stiff. However, all the obtained data are coherent to each other when the previous drilling studies in the study area and a geologic cross section including two wells with P and S-wave velocity sections are compared. Consequently, it is thought that all this information will contribute to the engineering studies planned for Uzungol to be done safely without damaging the environment and will be a scientific base for the future studies. Also, the contribution of the use of refraction first arrival tomography and MASW methods together are indicated to determine the soil structure and characters safely in this study.
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The high-quality interpretation of seismic refraction data depends on the accurate and reliable identification of the first arrival times. First arrivals can be identified on a graphic or image by conventional picking, but this process... more
The high-quality interpretation of seismic refraction data depends on the accurate and reliable identification of the first arrival times. First arrivals can be identified on a graphic or image by conventional picking, but this process depends on external factors, such as the scale and quality of the imaging data, amplitude ratio, sensitivity of the picking cursor and user experience. Under these considerations, identifying first arrivals in noisy data becomes more complex and unstable. In this study, the Cross-Correlation Technique (CCT), which is widely used in the process of analyzing reflection data, has been used to pick the first arrival times in noisy or noiseless seismic refraction data by a semi-automatic process. The CCT has reduced the dependence on user and decreased incorrect picking caused by environmental noise, displaying characteristics and scaling factors. The CCT has been tested with synthetic models with different noise contents and various field data. The Chi-sq...
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ABSTRACT Accurate picking of dispersion curves is the most critical stage in Multichannel Analysis of Surface Waves (MASW) method. Although there is several acquisition and numerical techniques for the optimal extraction, sometime, this... more
ABSTRACT Accurate picking of dispersion curves is the most critical stage in Multichannel Analysis of Surface Waves (MASW) method. Although there is several acquisition and numerical techniques for the optimal extraction, sometime, this requirement cannot be valid due to interference, which includes different modes, noises, and also lateral inhomogeneity in the near-surface earth. Hence, the interference between the different modes of surface waves can be so serious that neither fundamental, nor higher mode dispersion curve can be extracted with an accurate and a reliable. For this, we calculate surface waveforms, including geometrical and intrinsic dispersion, based on the summation of the particular seismic impulses corresponding to particular frequency-phase velocity curve points for geophone positions from the seismic source. This methodology is demonstrated by using both synthetic and real shot gathers. Synthetic calculations provide us a simple way to check accuracy of dispersion curve picking on a shot gather, which it is the fundamental or higher mode.
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In this study, it is performed an inversion process that combines Cauchy regularization and FX filtering for a stable multi-channel high resolution deconvolution. Applications of the method are made on synthetic and post stack field data.... more
In this study, it is performed an inversion process that combines Cauchy regularization and FX filtering for a stable multi-channel high resolution deconvolution. Applications of the method are made on synthetic and post stack field data. From these applications, it is considered that resolution in the vertical direction and continuity in the lateral direction are more improved by successfully reduction random noise. Results show that the process provides more interpretable seismic sections.
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Aftershock sequences of the magnitude M W =6.4 Bingöl earthquake of 1 May, 2003 (Turkey) are studied to analyze the spatial and temporal variability of seismicity parameters of the b value of the frequency-magnitude distribution and the p... more
Aftershock sequences of the magnitude M W =6.4 Bingöl earthquake of 1 May, 2003 (Turkey) are studied to analyze the spatial and temporal variability of seismicity parameters of the b value of the frequency-magnitude distribution and the p value describing the temporal decay rate of aftershocks. The catalog taken from the KOERI contains 516 events and one month’s time interval.
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Abstract The conventional method to remove swell noise from raw seismic data is band–pass filtering (BPF). It ideally removes whole low frequency band of the spectral content, which results in a total loss of the amplitudes concerning the... more
Abstract The conventional method to remove swell noise from raw seismic data is band–pass filtering (BPF). It ideally removes whole low frequency band of the spectral content, which results in a total loss of the amplitudes concerning the low frequency reflections from deeper reflectors, and hence lower resolution in the deeper reflection events. The procedure described here attenuates swell noise from seismic data while preserving the reflection amplitudes at low frequency band. The proposed Wiener prediction filter (WPF) method is used to estimate the swell noise embedded in the raw marine seismic data and then the estimated noise is subtracted from shots by a trace–by–trace basis. It is observed that the deeper reflections have significantly higher amplitudes and show better trace–by–trace consistency in the final migration sections obtained by the WPF application. The WPF method removes most of the swell noise and may be an alternative filtering technique to the conventional BPF method. It can be used with high resolution marine seismic data which may have weaker reflection amplitudes from deeper reflectors. It also improves the lateral continuity of the events which may be useful for auto–picking tools such as automatic event tracking. We propose that the method can effectively be used to remove any type of coherent noise providing that a suitable noise model can be determined from the data itself.
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Time-dependent amplitude and phase information of stacked seismic data are processed independently using complex trace analysis in order to facilitate interpretation by improving resolution and decreasing random noise. We represent... more
Time-dependent amplitude and phase information of stacked seismic data are processed independently using complex trace analysis in order to facilitate interpretation by improving resolution and decreasing random noise. We represent seismic traces using their envelopes and instantaneous phases obtained by the Hilbert transform. The proposed method reduces the amplitudes of the low-frequency components of the envelope, while preserving the phase information. Several tests are performed in order to investigate the behavior of the present method for resolution improvement and noise suppression. Applications on both 1D and 2D synthetic data show that the method is capable of reducing the amplitudes and temporal widths of the side lobes of the input wavelets, and hence, the spectral bandwidth of the input seismic data is enhanced, resulting in an improvement in the signal-to-noise ratio. The bright-spot anomalies observed on the stacked sections become clearer because the output seismic t...
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High-resolution deconvolution can mathematically be viewed as a regularized inverse problem. Besides, the result of the high-resolution deconvolution is generally accepted as reflectivity series of the layered media. On the other hand,... more
High-resolution deconvolution can mathematically be viewed as a regularized inverse problem. Besides, the result of the high-resolution deconvolution is generally accepted as reflectivity series of the layered media. On the other hand, lateral continuity is frequently poorer than vertical resolution on post-stack seismic section after application of any high-resolution deconvolution. However, because of the ill-posed inherent of the deconvolution problem, the Cauchy norm regularization term, a non-quadratic prior-information is widely used to provide the stability and uniqueness of the problem. But, it does not provide adequate quality of deconvolution if the noise in the data is strong. In this study, a stable and high-resolution deconvolution of post-stack seismic data was accomplished by an iterative inversion algorithm incorporating the Cauchy norm regularization with FX filter weighting. Cauchy norm regularization was utilized to force the solution to a spikiness structure, while the effective random noise reduction was performed by using the FX filter. Applications to synthetic and real post-stack data showed that the resolution in the vertical direction and continuity in the lateral direction are better improved. Thus, we think that this process makes seismic sections obtained especially from thin layered sedimentary basins more interpretable.