Using seismic diffractions for assessment of tectonic overprint and fault interpretation

Geophysics ◽  
2019 ◽  
Vol 84 (1) ◽  
pp. IM1-IM9 ◽  
Author(s):  
Sergius Dell ◽  
Andreas Hoelker ◽  
Dirk Gajewski
Keyword(s):  
Coherence Analysis ◽  
Structural Elements ◽  
Fracture Density ◽  
Data Set ◽  
Specular Reflections ◽  
Area Of Interest ◽  
Diffracted Waves ◽  
Geologic Interpretation ◽  
Tectonic Features ◽  
Fault Interpretation

Assessment of the area of interest on tectonic overprint is a key aspect during various geoscientific exploration endeavors. Conventionally, 3D reflection imaging is used because it provides the highest resolution of the subsurface image. Tectonic features, e.g., faults or fractures, are imaged indirectly by means of discontinuities of the specular reflections. Specular reflections, however, are only a part of the backscattering wavefield. Geologic heterogeneities in the subsurface can act as scattering points or scattering edges, which both evoke diffracted waves. Thus, diffracted waves are a direct seismic response from subsurface heterogeneities, which have a size comparable with the prevailing wavelength or a curvature growing locally to infinity. We investigate a dedicated processing of diffracted waves, which allows direct imaging of such heterogeneities. The method is based on separation of reflections from diffractions with subsequent diffraction focusing. We apply a combination of frequency-wavenumber filtering and an adaptive-subtraction engine to isolate diffractions. Once the reflections are removed from a data set, diffracted waves are focused into their apexes yielding an image of scatter points, which can be interpreted as an indicator for the extent of the degree of inhomogeneities or can be used to map structural elements or fracture density. We use a modified coherence analysis as a focusing tool. Diffractions from the scattering points have a different phase response than diffractions from the edges. These differences can be distinguished and further guide the geologic interpretation.

scholarly journals OPTIMIZING RADIOMETRIC PROCESSING AND FEATURE EXTRACTION OF DRONE BASED HYPERSPECTRAL FRAME FORMAT IMAGERY FOR ESTIMATION OF YIELD QUANTITY AND QUALITY OF A GRASS SWARD

2018 ◽  
Vol XLII-3 ◽  
pp. 1305-1310 ◽  
Author(s):  
R. Näsi ◽  
N. Viljanen ◽  
R. Oliveira ◽  
J. Kaivosoja ◽  
O. Niemeläinen ◽  
...  
Keyword(s):  
Feature Extraction ◽  
3D Structure ◽  
Point Clouds ◽  
Estimation Accuracy ◽  
Spectral Features ◽  
Data Set ◽  
Area Of Interest ◽  
Evaluation Task ◽  
Corrected Data ◽  
Grass Sward

Light-weight 2D format hyperspectral imagers operable from unmanned aerial vehicles (UAV) have become common in various remote sensing tasks in recent years. Using these technologies, the area of interest is covered by multiple overlapping hypercubes, in other words multiview hyperspectral photogrammetric imagery, and each object point appears in many, even tens of individual hypercubes. The common practice is to calculate hyperspectral orthomosaics utilizing only the most nadir areas of the images. However, the redundancy of the data gives potential for much more versatile and thorough feature extraction. We investigated various options of extracting spectral features in the grass sward quantity evaluation task. In addition to the various sets of spectral features, we used photogrammetry-based ultra-high density point clouds to extract features describing the canopy 3D structure. Machine learning technique based on the Random Forest algorithm was used to estimate the fresh biomass. Results showed high accuracies for all investigated features sets. The estimation results using multiview data provided approximately 10 % better results than the most nadir orthophotos. The utilization of the photogrammetric 3D features improved estimation accuracy by approximately 40 % compared to approaches where only spectral features were applied. The best estimation RMSE of 239 kg/ha (6.0 %) was obtained with multiview anisotropy corrected data set and the 3D features.

scholarly journals Mosaicking Weather Radar Retrievals from an Operational Heterogeneous Network at C and X Band for Precipitation Monitoring in Italian Central Apennines

2022 ◽  
Vol 14 (2) ◽  
pp. 248
Author(s):  
Stefano Barbieri ◽  
Saverio Di Fabio ◽  
Raffaele Lidori ◽  
Francesco L. Rossi ◽  
Frank S. Marzano ◽  
...  
Keyword(s):  
Atmospheric Precipitation ◽  
Weather Radar ◽  
Geographic Area ◽  
Single Frequency ◽  
Estimation Accuracy ◽  
Central Apennines ◽  
Data Set ◽  
Area Of Interest ◽  
Spatial Coverage ◽  
Network Pattern

Meteorological radar networks are suited to remotely provide atmospheric precipitation retrieval over a wide geographic area for severe weather monitoring and near-real-time nowcasting. However, blockage due to buildings, hills, and mountains can hamper the potential of an operational weather radar system. The Abruzzo region in central Italy’s Apennines, whose hydro-geological risks are further enhanced by its complex orography, is monitored by a heterogeneous system of three microwave radars at the C and X bands with different features. This work shows a systematic intercomparison of operational radar mosaicking methods, based on bi-dimensional rainfall products and dealing with both C and X bands as well as single- and dual-polarization systems. The considered mosaicking methods can take into account spatial radar-gauge adjustment as well as different spatial combination approaches. A data set of 16 precipitation events during the years 2018–2020 in the central Apennines is collected (with a total number of 32,750 samples) to show the potentials and limitations of the considered operational mosaicking approaches, using a geospatially-interpolated dense network of regional rain gauges as a benchmark. Results show that the radar-network pattern mosaicking, based on the anisotropic radar-gauge adjustment and spatial averaging of composite data, is better than the conventional maximum-value merging approach. The overall analysis confirms that heterogeneous weather radar mosaicking can overcome the issues of single-frequency fixed radars in mountainous areas, guaranteeing a better spatial coverage and a more uniform rainfall estimation accuracy over the area of interest.

scholarly journals Mapping Coastal Ice Cliffs and Icebergs From Altimetry Data (Abstract)

1986 ◽  
Vol 8 ◽  
pp. 208-208
Author(s):  
R.H. Thomas ◽  
H. Jay Zwally
Keyword(s):  
Sea Ice ◽  
Waveform Analysis ◽  
Horizontal Position ◽  
Altimetry Data ◽  
Data Set ◽  
Specular Reflections ◽  
Single Orbit ◽  
Iceberg Calving ◽  
Short Time ◽  
The Antarctic

In a recent paper, Thomas et.al. (1984) showed how the coast of Antarctica could be mapped using satellite altimetry data. As the satellite approached the continent from the ocean, the Seasat altimeter obtained strong reflections from sea ice, even for a short time after passing over the ice front. Measured ranges are actually oblique distances to the nearest portion of sea ice, yielding a false drop in surface elevation. From the sequence of oblique ranges during a single orbit crossing of the ice cliff, the horizontal position of a segment of the ice cliff is mapped. Currently, the entire Seasat data set is being analyzed to map most of the Antarctic coastline north of 72 °S to an accuracy of ± 0.1 to 1 km, which is a major improvement over existing surveys. The altimeter waveforms corresponding to each range measurement are computer analyzed (“retracked”), using procedures that account for the specular reflections from sea ice and the diffuse reflections from firn. Each waveform analysis, along with the corrected range for data obtained in the vicinity of an ice cliff crossing, is verified or recomputed on an interactive computer, which also computes and maps the position of the ice front. The locations of several tabular icebergs have also been mapped with the same procedures, which can ultimately be used to obtain an estimate of iceberg population density in polar waters, initial results include the mapping of the Larsen ice shelf on the eastern side of the Antarctic Peninsula, showing, for example, the protrusion at approximately 68.5 °S. Estimates of errors in the derived horizontal position are obtained from the analysis of data from repeating orbit tracks. Comparison of these results with results from future altimetry missions will reveal changes in the position of coastal ice cliffs, due to ice movement and/or iceberg calving. Systematic measurements over several years would probably distinguish the effects of iceberg calving, which is intermittent, from those of ice movement, which is continuous.

scholarly journals Artificial intelligence in oral and maxillofacial radiology: what is currently possible?

2020 ◽  
pp. 20200375
Author(s):  
Min-Suk Heo ◽  
Jo-Eun Kim ◽  
Jae-Joon Hwang ◽  
Sang-Sun Han ◽  
Jin-Soo Kim ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Open Data ◽  
Data Sets ◽  
Radiographic Images ◽  
Data Set ◽  
Actual Clinical Practice ◽  
Area Of Interest ◽  
The Future ◽  
Treatment Plans ◽  
Image Quality Improvement

Artificial intelligence, which has been actively applied in a broad range of industries in recent years, is an active area of interest for many researchers. Dentistry is no exception to this trend, and the applications of artificial intelligence are particularly promising in the field of oral and maxillofacial (OMF) radiology. Recent researches on artificial intelligence in OMF radiology have mainly used convolutional neural networks, which can perform image classification, detection, segmentation, registration, generation, and refinement. Artificial intelligence systems in this field have been developed for the purposes of radiographic diagnosis, image analysis, forensic dentistry, and image quality improvement. Tremendous amounts of data are needed to achieve good results, and involvement of OMF radiologist is essential for making accurate and consistent data sets, which is a time-consuming task. In order to widely use artificial intelligence in actual clinical practice in the future, there are lots of problems to be solved, such as building up a huge amount of fine-labeled open data set, understanding of the judgment criteria of artificial intelligence, and DICOM hacking threats using artificial intelligence. If solutions to these problems are presented with the development of artificial intelligence, artificial intelligence will develop further in the future and is expected to play an important role in the development of automatic diagnosis systems, the establishment of treatment plans, and the fabrication of treatment tools. OMF radiologists, as professionals who thoroughly understand the characteristics of radiographic images, will play a very important role in the development of artificial intelligence applications in this field.

High resolution LST climatology in an urban area using Landsat 8 thermal data

2020 ◽  
Author(s):  
Sorin Cheval ◽  
Alexandru Dumitrescu ◽  
Vlad Amihăesei
Keyword(s):  
Missing Data ◽  
High Resolution ◽  
Urban Area ◽  
Land Surface ◽  
Missing Values ◽  
Urban Climate ◽  
Landsat 8 ◽  
Data Set ◽  
Area Of Interest ◽  
Spatial Coverage

<p>The Landsat 8 satellites retrieve land surface temperature (LST) values at 30-m spatial resolution since 2013, but the urban climate studies frequently use a limited number of images due to the problems related to missing data over the area of interest. This paper proposes a procedure for building a long-term LST data set in an urban area using the high-resolution Landsat 8 imagery. The methodology is demonstrated on 94 images available through 2013-2018 over Bucharest (Romania). The raw images contain between 1.1% and 58.4% missing data. Based on an Empirical Orthogonal Filling (EOF) procedure, the LST missing values were reconstructed by means of the function dineof implemented in sinkr R packages. The output was used for exploring the LST climatology in the area of interest. The gap filling procedure was validated by comparing artificial gaps created in the real data sets. At the best of our knowledge, this is the first study using full spatial coverage high resolution remote sensing data for investigating the urban climate. The validation pursued the comparison between LST and Ta at 3 WMO stations monitoring the climate of Bucharest, and returned strong correlation coefficients (R2 > 0.9). Further research may be envisaged aiming to update the data set with more recent LST information and to combine data from various sources in order to build a more robust urban LST climatology.</p><p>This work was supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CCCDI -<br>UEFISCDI, project number COFUND-SUSCROP-SUSCAP-2, within PNCDI III.</p>

Fault interpretation from high‐resolution seismic data in the northern Negev, Israel

Geophysics ◽  
1991 ◽  
Vol 56 (7) ◽  
pp. 1064-1070 ◽  
Author(s):  
Ilan Bruner ◽  
Eugeny Landa
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Field Data ◽  
Dynamic Properties ◽  
Fault Zones ◽  
Diffracted Waves ◽  
Fault Interpretation ◽  
Low Amplitude ◽  
Seismic Lines ◽  
Sense Reverse

Detection and investigation of fault zones are important tools for tectonic analysis and geological studies. A fault zone inferred on high‐resolution seismic lines has been interpreted using a method of detection of diffracted waves utilizing the main kinematic and dynamic properties of the wavefield. The application of the method to field data from the northern Negev in Israel shows that it provides a good estimate of results and, when used in conjunction with the final stacked data, can give the suspected location of the fault, its sense (reverse or normal), and the amount of “low amplitude” displacement (in an order of the wavelength or even less).

Seismic characterization of a Mississippi Lime resource play in Osage County, Oklahoma, USA

2013 ◽  
Vol 1 (2) ◽  
pp. SB97-SB108 ◽  
Author(s):  
Benjamin L. Dowdell ◽  
J. Tim Kwiatkowski ◽  
Kurt J. Marfurt
Keyword(s):  
Seismic Data ◽  
Seismic Analysis ◽  
High Porosity ◽  
Fracture Density ◽  
Coherent Noise ◽  
High Fracture ◽  
Data Set ◽  
Horizontal Drilling ◽  
Prestack Inversion ◽  
Osage County

With the advent of horizontal drilling and hydraulic fracturing in the Midcontinent, USA, fields once thought to be exhausted are now experiencing renewed exploitation. However, traditional Midcontinent seismic analysis techniques no longer provide satisfactory reservoir characterization for these unconventional plays; new seismic analysis methods are needed to properly characterize these radically innovative play concepts. Time processing and filtering is applied to a raw 3D seismic data set from Osage County, Oklahoma, paying careful attention to velocity analysis, residual statics, and coherent noise filtering. The use of a robust prestack structure-oriented filter and spectral whitening greatly enhances the results. After prestack time migrating the data using a Kirchhoff algorithm, new velocities are picked. A final normal moveout correction is applied using the new velocities, followed by a final prestack structure-oriented filter and spectral whitening. Simultaneous prestack inversion uses the reprocessed and time-migrated seismic data as input, along with a well from within the bounds of the survey. With offsets out to 3048 m and a target depth of approximately 880 m, we can invert for density in addition to P- and S-impedance. Prestack inversion attributes are sensitive to lithology and porosity while surface seismic attributes such as coherence and curvature are sensitive to lateral changes in waveform and structure. We use these attributes in conjunction with interpreted horizontal image logs to identify zones of high porosity and high fracture density.

Corporate strategies for technology acquisition: evidence from patent transactions

2017 ◽  
Vol 55 (6) ◽  
pp. 1163-1181 ◽  
Author(s):  
Federico Caviggioli ◽  
Antonio De Marco ◽  
Giuseppe Scellato ◽  
Elisa Ughetto
Keyword(s):  
Firm Level ◽  
Data Set ◽  
Content Type ◽  
Technology Acquisition ◽  
Corporate Strategies ◽  
Area Of Interest ◽  
Core Technology ◽  
Acquisition Strategies ◽  
The Us ◽  
Ip Management

Purpose The purpose of this paper is to examine, for a sample of ten corporations in three industries (i.e. automotive suppliers, semiconductors, and computer networks), the different strategies that firms undertake when acquiring patent-protected technologies. In particular, the authors analyze and compare two alternative channels for patent acquisition: markets for technology (MFT) and merger and acquisition (M&A) processes. Design/methodology/approach The authors implement two types of analyses, at both patent and firm level. First, the authors perform an econometric analysis to evaluate whether acquired patented technologies differ in their patent bibliographic characteristics with respect to patent-protected technologies that have been developed internally by the examined firms. The authors then investigate the presence of differences in the characteristics of transacted patents acquired in the MFT or by means of M&A activities. Second, the authors take a firm-level perspective and examine the technology acquisition strategies adopted by selected companies to identify the presence of common patterns, industry-driven specificities and firm peculiarities. Findings The authors find that acquired patented technologies are, on average, more complex, of higher technical merit and the corresponding patents show a higher legal robustness. Econometric results reveal the presence of differences between M&A and MFT patents: the latter seem to protect less complex, and thus easier to trade, inventions. The analysis of the patterns of patent acquisitions at the firm level shows the presence of different strategies for the external sourcing of patented technologies, based on whether acquired patents protect core or non-core technology areas of the analyzed firms. Such patterns are discussed in the light of the different streams of the literature on intellectual property (IP) management. Originality/value This paper makes use of a new and comprehensive data set of the US patent transactions that took place between 2002 and 2010. The authors added detailed data on the evolution of the corporate trees of analyzed firms. The paper contributes to the literature on technology acquisitions and MFT by examining the different channels for patented technology acquisitions. The issue represents an emerging area of interest in the field of IP management.

Diffraction imaging by focusing‐defocusing: An outlook on seismic superresolution

Geophysics ◽  
2004 ◽  
Vol 69 (6) ◽  
pp. 1478-1490 ◽  
Author(s):  
V. Khaidukov ◽  
E. Landa ◽  
T. J. Moser
Keyword(s):  
Image Resolution ◽  
Correct Identification ◽  
Structural Elements ◽  
Large Area ◽  
Specular Reflections ◽  
Full Wave ◽  
Geological Discontinuities ◽  
Diffraction Imaging ◽  
And Migration ◽  
Traditional Image

Diffractions always need more advertising. It is true that conventional seismic processing and migration are usually successful in using specular reflections to estimate subsurface velocities and reconstruct the geometry and strength of continuous and pronounced reflectors. However, correct identification of geological discontinuities, such as faults, pinch‐outs, and small‐size scattering objects, is one of the main objectives of seismic interpretation. The seismic response from these structural elements is encoded in diffractions, and diffractions are essentially lost during the conventional processing/migration sequence. Hence, we advocate a diffraction‐based, data‐oriented approach to enhance image resolution—as opposed to the traditional image‐oriented techniques, which operate on the image after processing and migration. Even more: it can be shown that, at least in principle, processing of diffractions can lead to superresolution and the recovery of details smaller than the seismic wavelength. The so‐called reflection stack is capable of effectively separating diffracted and reflected energy on a prestack shot gather by focusing the reflection to a point while the diffraction remains unfocused over a large area. Muting the reflection focus and defocusing the residual wavefield result in a shot gather that contains mostly diffractions. Diffraction imaging applies the classical (isotropic) diffraction stack to these diffraction shot gathers. This focusing‐muting‐defocusing approach can successfully image faults, small‐size scattering objects, and diffracting edges. It can be implemented both in model‐independent and model‐dependent contexts. The resulting diffraction images can greatly assist the interpreter when used as a standard supplement to full‐wave images.

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