WorldWideScience

Sample records for seismic reflection technique

  1. The high resolution shear wave seismic reflection technique

    International Nuclear Information System (INIS)

    Johnson, W.J.; Clark, J.C.

    1991-04-01

    This report presents the state-of-the-art of the high resolution S-wave reflection technique. Published and unpublished literature has been reviewed and discussions have been held with experts. Result is to confirm that the proposed theoretical and practical basis for identifying aquifer systems using both P- and S-wave reflections is sound. Knowledge of S-wave velocity and P-wave velocity is a powerful tool for assessing the fluid characteristics of subsurface layers. Material properties and lateral changes in material properties such as change from clay to sand, can be inferred from careful dual evaluation of P and S-wave records. The high resolution S-wave reflection technique has seen its greatest application to date as part of geotechnical studies for building foundations in the Far East. Information from this type of study has been evaluated and will be incorporated in field studies. In particular, useful information regarding S-wave sources, noise suppression and recording procedures will be incorporated within the field studies. Case histories indicate that the best type of site for demonstrating the power of the high resolution S-wave technique will be in unconsolidated soil without excessive structural complexities. More complex sites can form the basis for subsequent research after the basic principles of the technique can be established under relatively uncomplicated conditions

  2. Feasibility of the Shallow High Resolution Seismic Reflection Technique for Use at the Hanford Site

    International Nuclear Information System (INIS)

    S.M., Narbutovskih.

    1993-01-01

    Data obtained during site characterization should be useful to assess the need for remediation, to evaluate and design effective remedial plans, and to allow long-term monitoring to discern remediation effectiveness. A valuable environmental tool that incorporates this data is a model that describes groundwater and vadose zone flow and transport characteristics. Data on geology and hydrology combined with information on contaminant sources are incorporated into these conceptual models that delineate the relative significance of the various fluid migration pathways. Downstream these same models also support risk assessment, remediation design, and long-term assessment of remediation effectiveness. Consequently, the building of coherent, accurate vadose zone and groundwater models is fundamental to a successful remediation. Among the important requirements for these models is accurate knowledge of flow domain boundaries and soil characteristics. At the Hanford Site, this knowledge is obtained primarily from borehole data, which provides information only at a point. In the high energy flood and fluvial deposits found at the Hanford Site, it can, at times, be difficult to correlate lithologic horizons between boreholes. Where there is no borehole control, our understanding of the geometry of hydrogeologic boundaries and thus of fluid migration paths is limited. Surface geophysical techniques are generally used to provide a measure of geologic control between boreholes. In particular, the seismic reflection method has the potential to provide the greatest resolution of the subsurface hydrogeology between and beyond boreholes

  3. Integration between well logging and seismic reflection techniques for structural a

    Directory of Open Access Journals (Sweden)

    Adel K. Mohamed

    2016-12-01

    Full Text Available Abu El Gharadig basin is located in the northern part of the Western Desert, Egypt. Geophysical investigation in the form of thirty (3D seismic lines and well logging data of five wells have been analyzed in the oil field BED-1 that is located in the northwestern part of Abu El Gharadig basin in the Western Desert of Egypt. The reflection sections have been used to shed more light on the tectonic setting of Late Jurassic–Early Cretaceous rocks. While the well logging data have been analyzed for delineating the petrophysical characteristics of the two main reservoirs, Bahariya and Kharita Formations. The constructed subsurface geologic cross sections, seismic sections, and the isochronous reflection maps indicate that the area is structurally controlled by tectonic trends affecting the current shape of Abu El Gharadig basin. Different types of faults are well represented in the area, particularly normal one. The analysis of the average and interval velocities versus depth has shown their effect by facies changes and/or fluid content. On the other hand, the derived petrophysical parameters of Bahariya and Kharita Formations vary from well to another and they have been affected by the gas effect and/or the presence of organic matter, complex lithology, clay content of dispersed habitat, and the pore volume.

  4. Worldwide Marine Seismic Reflection Profiles

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC maintains a large volume of both Analog and Digital seismic reflection data. Currently only a limited number of lines are available online. Digital data include...

  5. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRIBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    International Nuclear Information System (INIS)

    Michael G. Waddell; William J. Domoracki; Tom J. Temples; Jerome Eyer

    2001-01-01

    The Earth Sciences and Resources Institute, University of South Carolina is conducting a 14 month proof of concept study to determine the location and distribution of subsurface Dense Nonaqueous Phase Liquid (DNAPL) carbon tetrachloride (CCl 4 ) contamination at the 216-Z-9 crib, 200 West area, Department of Energy (DOE) Hanford Site, Washington by use of two-dimensional high resolution seismic reflection surveys and borehole geophysical data. The study makes use of recent advances in seismic reflection amplitude versus offset (AVO) technology to directly detect the presence of subsurface DNAPL. The techniques proposed are a noninvasive means towards site characterization and direct free-phase DNAPL detection. This report covers the results of Task 3 and change of scope of Tasks 4-6. Task 1 contains site evaluation and seismic modeling studies. The site evaluation consists of identifying and collecting preexisting geological and geophysical information regarding subsurface structure and the presence and quantity of DNAPL. The seismic modeling studies were undertaken to determine the likelihood that an AVO response exists and its probable manifestation. Task 2 is the design and acquisition of 2-D seismic reflection data designed to image areas of probable high concentration of DNAPL. Task 3 is the processing and interpretation of the 2-D data. Task 4, 5, and 6 were designing, acquiring, processing, and interpretation of a three dimensional seismic survey (3D) at the Z-9 crib area at 200 west area, Hanford

  6. The seismic reflection inverse problem

    International Nuclear Information System (INIS)

    Symes, W W

    2009-01-01

    The seismic reflection method seeks to extract maps of the Earth's sedimentary crust from transient near-surface recording of echoes, stimulated by explosions or other controlled sound sources positioned near the surface. Reasonably accurate models of seismic energy propagation take the form of hyperbolic systems of partial differential equations, in which the coefficients represent the spatial distribution of various mechanical characteristics of rock (density, stiffness, etc). Thus the fundamental problem of reflection seismology is an inverse problem in partial differential equations: to find the coefficients (or at least some of their properties) of a linear hyperbolic system, given the values of a family of solutions in some part of their domains. The exploration geophysics community has developed various methods for estimating the Earth's structure from seismic data and is also well aware of the inverse point of view. This article reviews mathematical developments in this subject over the last 25 years, to show how the mathematics has both illuminated innovations of practitioners and led to new directions in practice. Two themes naturally emerge: the importance of single scattering dominance and compensation for spectral incompleteness by spatial redundancy. (topical review)

  7. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    Energy Technology Data Exchange (ETDEWEB)

    Michael G. Waddell; William J. Domoracki; Jerome Eyer

    2003-01-01

    The Earth Sciences and Resources Institute, University of South Carolina is conducting a proof of concept study to determine the location and distribution of subsurface DNAPL carbon tetrachloride (CCl{sub 4}) contamination at the 216-Z-9 crib, 200 West area, DOE Hanford Site, Washington by use of two-dimensional high-resolution seismic reflection surveys and borehole geophysical data. The study makes use of recent advances in seismic reflection amplitude versus offset (AVO) technology to directly detect the presence of subsurface DNAPL. The techniques proposed are noninvasive means of site characterization and direct free-phase DNAPL detection. This final report covers the results of Tasks 1, 2, and 3. Task (1) contains site evaluation and seismic modeling studies. The site evaluation consists of identifying and collecting preexisting geological and geophysical information regarding subsurface structure and the presence and quantity of DNAPL. The seismic modeling studies were undertaken to determine the likelihood that an AVO response exists and its probable manifestation. Task (2) is the design and acquisition of 2-D seismic reflection data to image areas of probable high concentration of DNAPL. Task (3) is the processing and interpretation of the 2-D data. During the commission of these tasks four seismic reflection profiles were collected. Subsurface velocity information was obtained by vertical seismic profile surveys in three wells. The interpretation of these data is in two parts. Part one is the construction and interpretation of structural contour maps of the contact between the Hanford Fine unit and the underlying Plio/Pleistocene unit and of the contact between the Plio/Pleistocene unit and the underlying caliche layer. These two contacts were determined to be the most likely surfaces to contain the highest concentration CCl{sub 4}. Part two of the interpretation uses the results of the AVO modeling to locate any seismic amplitude anomalies that might be

  8. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    International Nuclear Information System (INIS)

    Waddell, Michael G.; Domoracki, William J.; Eyer, Jerome

    2003-01-01

    The Earth Sciences and Resources Institute, University of South Carolina is conducting a proof of concept study to determine the location and distribution of subsurface DNAPL carbon tetrachloride (CCl 4 ) contamination at the 216-Z-9 crib, 200 West area, DOE Hanford Site, Washington by use of two-dimensional high-resolution seismic reflection surveys and borehole geophysical data. The study makes use of recent advances in seismic reflection amplitude versus offset (AVO) technology to directly detect the presence of subsurface DNAPL. The techniques proposed are noninvasive means of site characterization and direct free-phase DNAPL detection. This final report covers the results of Tasks 1, 2, and 3. Task (1) contains site evaluation and seismic modeling studies. The site evaluation consists of identifying and collecting preexisting geological and geophysical information regarding subsurface structure and the presence and quantity of DNAPL. The seismic modeling studies were undertaken to determine the likelihood that an AVO response exists and its probable manifestation. Task (2) is the design and acquisition of 2-D seismic reflection data to image areas of probable high concentration of DNAPL. Task (3) is the processing and interpretation of the 2-D data. During the commission of these tasks four seismic reflection profiles were collected. Subsurface velocity information was obtained by vertical seismic profile surveys in three wells. The interpretation of these data is in two parts. Part one is the construction and interpretation of structural contour maps of the contact between the Hanford Fine unit and the underlying Plio/Pleistocene unit and of the contact between the Plio/Pleistocene unit and the underlying caliche layer. These two contacts were determined to be the most likely surfaces to contain the highest concentration CCl 4 . Part two of the interpretation uses the results of the AVO modeling to locate any seismic amplitude anomalies that might be

  9. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRIBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    Energy Technology Data Exchange (ETDEWEB)

    Michael G. Waddell; William J. Domoracki; Tom J. Temples

    2001-12-01

    This annual technical progress report is for part of Task 4 (site evaluation), Task 5 (2D seismic design, acquisition, and processing), and Task 6 (2D seismic reflection, interpretation, and AVO analysis) on DOE contact number DE-AR26-98FT40369. The project had planned one additional deployment to another site other than Savannah River Site (SRS) or DOE Hanford Site. After the SUBCON midyear review in Albuquerque, NM, it was decided that two additional deployments would be performed. The first deployment is to test the feasibility of using non-invasive seismic reflection and AVO analysis as a monitoring tool to assist in determining the effectiveness of Dynamic Underground Stripping (DUS) in removal of DNAPL. The second deployment is to the Department of Defense (DOD) Charleston Naval Weapons Station Solid Waste Management Unit 12 (SWMU-12), Charleston, SC to further test the technique to detect high concentrations of DNAPL. The Charleston Naval Weapons Station SWMU-12 site was selected in consultation with National Energy Technology Laboratory (NETL) and DOD Naval Facilities Engineering Command Southern Division (NAVFAC) personnel. Based upon the review of existing data and due to the shallow target depth, the project team collected three Vertical Seismic Profiles (VSP) and an experimental P-wave seismic reflection line. After preliminary data analysis of the VSP data and the experimental reflection line data, it was decided to proceed with Task 5 and Task 6. Three high resolution P-wave reflection profiles were collected with two objectives; (1) design the reflection survey to image a target depth of 20 feet below land surface to assist in determining the geologic controls on the DNAPL plume geometry, and (2) apply AVO analysis to the seismic data to locate the zone of high concentration of DNAPL. Based upon the results of the data processing and interpretation of the seismic data, the project team was able to map the channel that is controlling the DNAPL plume

  10. Lamont Doherty Seismic Reflection Scanned Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains single channel seismic reflection profiles as provided to NGDC by Lamont Doherty Earh Observatory (LDEO). The profiles were originally...

  11. Existing reflection seismic data re-processing

    International Nuclear Information System (INIS)

    Higashinaka, Motonori; Sano, Yukiko; Kozawa, Takeshi

    2005-08-01

    This document is to report the results of existing seismic data re-processing around Horonobe town, Hokkaido, Japan, which is a part of the Horonobe Underground Research Project. The main purpose of this re-processing is to recognize the subsurface structure of Omagari Fault and fold system around Omagari Fault. The seismic lines for re-processing are TYHR-A3 line and SHRB-2 line, which JAPEX surveyed in 1975. Applying weathering static correction using refraction analysis and noise suppression procedure, we have much enhanced seismic profile. Following information was obtained from seismic re-processing results. TYHR-A3 line: There are strong reflections, dipping to the west. These reflections are corresponding western limb of anticline to the west side of Omagari Fault. SHRB-2 line: There are strong reflections, dipping to the west, at CDP 60-140, while there are reflections, dipping to the east, to the east side of CDP 140. These reflections correspond to the western limb and the eastern limb of the anticline, which is parallel to Omagari FAULT. This seismic re-processing provides some useful information to know the geological structure around Omagari Fault. (author)

  12. Results of the application of seismic-reflection and electromagnetic techniques for near-surface hydrogeologic and environmental investigations at Fort Bragg, North Carolina

    Science.gov (United States)

    Meyer, M.T.; Fine, J.M.

    1997-01-01

    As part of the U.S. Geological Survey's Resource Conservation and Recovery Act, Facilities Investigations at Fort Bragg, North Carolina, selected geophysical techniques were evaluated for their usefulness as assessment tools for determining subsurface geology, delineating the areal extent of potentially contaminated landfill sites, and locating buried objects and debris of potential environmental concern. Two shallow seismic-reflection techniques (compression and shear wave) and two electromagnetic techniques (ground-penetrating radar and terrain conductivity) were evaluated at several sites at the U.S. Army Base. The electromagnetic techniques also were tested for tolerance to cultural noise, such as nearby fences, vehicles, and power lines. For the terrain conductivity tests, two instruments were used--the EM31 and EM34, which have variable depths of exploration. The shallowest reflection event was 70 feet below land surface observed in common-depth point, stacked compression-wave data from 24- and 12-fold shallow-seismic-reflection surveys. Several reflection events consistent with clay-sand interfaces between 70 and 120 feet below land surface, along with basement-saprolite surfaces, were imaged in the 24-fold, common- depth-point stacked data. 12-fold, common-depth-point stacked data set contained considerably more noise than the 24-fold, common-depth-point data, due to reduced shot-to-receiver redundancy. Coherent stacked reflection events were not observed in the 24-fold, common-depth-point stacked shear-wave data because of the partial decoupling of the shear- wave generator from the ground. At one site, ground-penetrating radar effectively delineated a shallow, 2- to 5-foot thick sand unit bounded by thin (less than 1 foot) clay layers. The radar signal was completely attenuated where the overlying and underlying clay units thickened and the sand unit thinned. The pene- tration depth of the radar signal was less than 10 feet below land surface. A slight

  13. Seismic reflection imaging, accounting for primary and multiple reflections

    Science.gov (United States)

    Wapenaar, Kees; van der Neut, Joost; Thorbecke, Jan; Broggini, Filippo; Slob, Evert; Snieder, Roel

    2015-04-01

    Imaging of seismic reflection data is usually based on the assumption that the seismic response consists of primary reflections only. Multiple reflections, i.e. waves that have reflected more than once, are treated as primaries and are imaged at wrong positions. There are two classes of multiple reflections, which we will call surface-related multiples and internal multiples. Surface-related multiples are those multiples that contain at least one reflection at the earth's surface, whereas internal multiples consist of waves that have reflected only at subsurface interfaces. Surface-related multiples are the strongest, but also relatively easy to deal with because the reflecting boundary (the earth's surface) is known. Internal multiples constitute a much more difficult problem for seismic imaging, because the positions and properties of the reflecting interfaces are not known. We are developing reflection imaging methodology which deals with internal multiples. Starting with the Marchenko equation for 1D inverse scattering problems, we derived 3D Marchenko-type equations, which relate reflection data at the surface to Green's functions between virtual sources anywhere in the subsurface and receivers at the surface. Based on these equations, we derived an iterative scheme by which these Green's functions can be retrieved from the reflection data at the surface. This iterative scheme requires an estimate of the direct wave of the Green's functions in a background medium. Note that this is precisely the same information that is also required by standard reflection imaging schemes. However, unlike in standard imaging, our iterative Marchenko scheme retrieves the multiple reflections of the Green's functions from the reflection data at the surface. For this, no knowledge of the positions and properties of the reflecting interfaces is required. Once the full Green's functions are retrieved, reflection imaging can be carried out by which the primaries and multiples are

  14. Near-vertical seismic reflection image using a novel acquisition technique across the Vrancea Zone and Foscani Basin, south-eastern Carpathians (Romania)

    Science.gov (United States)

    Panea, I.; Stephenson, R.; Knapp, C.; Mocanu, V.; Drijkoningen, G.; Matenco, L.; Knapp, J.; Prodehl, K.

    2005-12-01

    The DACIA PLAN (Danube and Carpathian Integrated Action on Process in the Lithosphere and Neotectonics) deep seismic sounding survey was performed in August-September 2001 in south-eastern Romania, at the same time as the regional deep refraction seismic survey VRANCEA 2001. The main goal of the experiment was to obtain new information on the deep structure of the external Carpathians nappes and the architecture of Tertiary/Quaternary basins developed within and adjacent to the seismically-active Vrancea zone, including the Focsani Basin. The seismic reflection line had a WNW-ESE orientation, running from internal East Carpathians units, across the mountainous south-eastern Carpathians, and the foreland Focsani Basin towards the Danube Delta. There were 131 shot points along the profile, with about 1 km spacing, and data were recorded with stand-alone RefTek-125s (also known as "Texans"), supplied by the University Texas at El Paso and the PASSCAL Institute. The entire line was recorded in three deployments, using about 340 receivers in the first deployment and 640 receivers in each of the other two deployments. The resulting deep seismic reflection stacks, processed to 20 s along the entire profile and to 10 s in the eastern Focsani Basin, are presented here. The regional architecture of the latter, interpreted in the context of abundant independent constraint from exploration seismic and subsurface data, is well imaged. Image quality within and beneath the thrust belt is of much poorer quality. Nevertheless, there is good evidence to suggest that a thick (˜10 km) sedimentary basin having the structure of a graben and of indeterminate age underlies the westernmost part of the Focsani Basin, in the depth range 10-25 km. Most of the crustal depth seismicity observed in the Vrancea zone (as opposed to the more intense upper mantle seismicity) appears to be associated with this sedimentary basin. The sedimentary successions within this basin and other horizons

  15. Application of continuous seismic-reflection techniques to delineate paleochannels beneath the Neuse River at US Marine Corps Air Station, Cherry Point, North Carolina

    Science.gov (United States)

    Cardinell, Alex P.

    1999-01-01

    A continuous seismic-reflection profiling survey was conducted by the U.S. Geological Survey on the Neuse River near the Cherry Point Marine Corps Air Station during July 7-24, 1998. Approximately 52 miles of profiling data were collected during the survey from areas northwest of the Air Station to Flanner Beach and southeast to Cherry Point. Positioning of the seismic lines was done by using an integrated navigational system. Data from the survey were used to define and delineate paleochannel alignments under the Neuse River near the Air Station. These data also were correlated with existing surface and borehole geophysical data, including vertical seismic-profiling velocity data collected in 1995. Sediments believed to be Quaternary in age were identified at varying depths on the seismic sections as undifferentiated reflectors and lack the lateral continuity of underlying reflectors believed to represent older sediments of Tertiary age. The sediments of possible Quaternary age thicken to the southeast. Paleochannels of Quaternary age and varying depths were identified beneath the Neuse River estuary. These paleochannels range in width from 870 feet to about 6,900 feet. Two zones of buried paleochannels were identified in the continuous seismic-reflection profiling data. The eastern paleochannel zone includes two large superimposed channel features identified during this study and in re-interpreted 1995 land seismic-reflection data. The second paleochannel zone, located west of the first paleochannel zone, contains several small paleochannels near the central and south shore of the Neuse River estuary between Slocum Creek and Flanner Beach. This second zone of channel features may be continuous with those mapped by the U.S. Geological Survey in 1995 using land seismic-reflection data on the southern end of the Air Station. Most of the channels were mapped at the Quaternary-Tertiary sediment boundary. These channels appear to have been cut into the older sediments

  16. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRIBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    Energy Technology Data Exchange (ETDEWEB)

    Michael G. Waddell; William J. Domoracki; Tom J. Temples

    2001-05-01

    This semi-annual technical progress report is for Task 4 site evaluation, Task 5 seismic reflection design and acquisition, and Task 6 seismic reflection processing and interpretation on DOE contact number DE-AR26-98FT40369. The project had planned one additional deployment to another site other than Savannah River Site (SRS) or DOE Hanford. During this reporting period the project had an ASME peer review. The findings and recommendation of the review panel, as well at the project team response to comments, are in Appendix A. After the SUBCON midyear review in Albuquerque, NM and the peer review it was decided that two additional deployments would be performed. The first deployment is to test the feasibility of using non-invasive seismic reflection and AVO analysis as monitoring to assist in determining the effectiveness of Dynamic Underground Stripping (DUS) in removal of DNAPL. Under the rescope of the project, Task 4 would be performed at the Charleston Navy Weapons Station, Charleston, SC and not at the Dynamic Underground Stripping (DUS) project at SRS. The project team had already completed Task 4 at the M-area seepage basin, only a few hundred yards away from the DUS site. Because the geology is the same, Task 4 was not necessary. However, a Vertical Seismic Profile (VSP) was conducted in one well to calibrate the geology to the seismic data. The first deployment to the DUS Site (Tasks 5 and 6) has been completed. Once the steam has been turned off these tasks will be performed again to compare the results to the pre-steam data. The results from the first deployment to the DUS site indicated a seismic amplitude anomaly at the location and depths of the known high concentrations of DNAPL. The deployment to another site with different geologic conditions was supposed to occur during this reporting period. The first site selected was DOE Paducah, Kentucky. After almost eight months of negotiation, site access was denied requiring the selection of another site

  17. Resolution of Reflection Seismic Data Revisited

    DEFF Research Database (Denmark)

    Hansen, Thomas Mejer; Mosegaard, Klaus; Zunino, Andrea

    The Rayleigh Principle states that the minimum separation between two reflectors that allows them to be visually separated is the separation where the wavelet maxima from the two superimposed reflections combine into one maximum. This happens around Δtres = λb/8, where λb is the predominant...... lower vertical resolution of reflection seismic data. In the following we will revisit think layer model and demonstrate that there is in practice no limit to the vertical resolution using the parameterization of Widess (1973), and that the vertical resolution is limited by the noise in the data...

  18. Seismic reflections associated with submarine gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Andreassen, K

    1996-12-31

    Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural submarine gas hydrates. The presence of these hydrates are commonly inferred from strong bottom simulating reflection (BSR). To investigate the nature of BSR, this work uses seismic studies of hydrate-related BSRs at two different locations, one where gas hydrates are accepted to exist and interpreted to be very extensive (in the Beaufort Sea), the other with good velocity data and downhole logs available (offshore Oregon). To ascertain the presence of free gas under the BSR, prestack offset data must supplement near-vertical incidence seismic data. A tentative model for physical properties of sediments partially saturated with gas hydrate and free gas is presented. This model, together with drilling information and seismic data containing the BSR beneath the Oregon margin and the Beaufort Sea, made it possible to better understand when to apply the amplitude-versus-offset (AVO) method to constrain BSR gas hydrate and gas models. Distribution of natural gas hydrates offshore Norway and Svalbard is discussed and interpreted as reflections from the base of gas hydrate-bearing sediments, overlying sediments containing free gas. Gas hydrates inferred to exist at the Norwegian-Svalbard continental margin correlate well with Cenozoic depocenters, and the associated gas is assumed to be mainly biogenic. Parts of that margin have a high potential for natural gas hydrates of both biogenic and thermogenic origin. 235 refs., 86 figs., 4 tabs.

  19. Seismic reflections associated with submarine gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Andreassen, K.

    1995-12-31

    Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural submarine gas hydrates. The presence of these hydrates are commonly inferred from strong bottom simulating reflection (BSR). To investigate the nature of BSR, this work uses seismic studies of hydrate-related BSRs at two different locations, one where gas hydrates are accepted to exist and interpreted to be very extensive (in the Beaufort Sea), the other with good velocity data and downhole logs available (offshore Oregon). To ascertain the presence of free gas under the BSR, prestack offset data must supplement near-vertical incidence seismic data. A tentative model for physical properties of sediments partially saturated with gas hydrate and free gas is presented. This model, together with drilling information and seismic data containing the BSR beneath the Oregon margin and the Beaufort Sea, made it possible to better understand when to apply the amplitude-versus-offset (AVO) method to constrain BSR gas hydrate and gas models. Distribution of natural gas hydrates offshore Norway and Svalbard is discussed and interpreted as reflections from the base of gas hydrate-bearing sediments, overlying sediments containing free gas. Gas hydrates inferred to exist at the Norwegian-Svalbard continental margin correlate well with Cenozoic depocenters, and the associated gas is assumed to be mainly biogenic. Parts of that margin have a high potential for natural gas hydrates of both biogenic and thermogenic origin. 235 refs., 86 figs., 4 tabs.

  20. Retrieval of reflections from seismic background?noise measurements

    NARCIS (Netherlands)

    Draganov, D.S.; Wapenaar, K.; Mulder, W.; Singer, J.; Verdel, A.

    2007-01-01

    The retrieval of the earth's reflection response from cross?correlations of seismic noise recordings can provide valuable information, which may otherwise not be available due to limited spatial distribution of seismic sources. We cross?correlated ten hours of seismic background?noise data acquired

  1. 2D Seismic Reflection Data across Central Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Valerie; Leetaru, Hannes

    2014-09-30

    In a continuing collaboration with the Midwest Geologic Sequestration Consortium (MGSC) on the Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins project, Schlumberger Carbon Services and WesternGeco acquired two-dimensional (2D) seismic data in the Illinois Basin. This work included the design, acquisition and processing of approximately 125 miles of (2D) seismic reflection surveys running west to east in the central Illinois Basin. Schlumberger Carbon Services and WesternGeco oversaw the management of the field operations (including a pre-shoot planning, mobilization, acquisition and de-mobilization of the field personnel and equipment), procurement of the necessary permits to conduct the survey, post-shoot closure, processing of the raw data, and provided expert consultation as needed in the interpretation of the delivered product. Three 2D seismic lines were acquired across central Illinois during November and December 2010 and January 2011. Traversing the Illinois Basin, this 2D seismic survey was designed to image the stratigraphy of the Cambro-Ordovician sections and also to discern the basement topography. Prior to this survey, there were no regionally extensive 2D seismic data spanning this section of the Illinois Basin. Between the NW side of Morgan County and northwestern border of Douglas County, these seismic lines ran through very rural portions of the state. Starting in Morgan County, Line 101 was the longest at 93 miles in length and ended NE of Decatur, Illinois. Line 501 ran W-E from the Illinois Basin – Decatur Project (IBDP) site to northwestern Douglas County and was 25 miles in length. Line 601 was the shortest and ran N-S past the IBDP site and connected lines 101 and 501. All three lines are correlated to well logs at the IBDP site. Originally processed in 2011, the 2D seismic profiles exhibited a degradation of signal quality below ~400 millisecond (ms) which made

  2. A Seismic Analysis for Reflective Metal Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyuhyung; Kim, Taesoon [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    U.S. NRC (Nuclear Regulatory Commission) GSI- 191 (Generic Safety Issue-191) is concerned about the head-loss of emergency core cooling pumps caused by calcium silicate insulation debris accumulated on a sump screen when a loss of coolant accident (LOCA). In order to cope with the concern, many nuclear plants in U. S. have been replacing calcium silicate insulation in containment building with reflective metal insulation (RMI). In Korea, RMI has been used for only reactor vessels recently constructed, but the RMI was imported. Therefore, we have been developing the domestic design of RMI to supply to nuclear power plants under operation and construction in relation to the GSI-191. This paper covers that the structural integrity of the RMI assembly was evaluated under SSE (safety shutdown earthquake) load. An analysis model was built for the seismic test system of a reflective metal insulation assembly and pre-stress, modal, and spectrum analysis for the model were performed using a commercial structural analysis code, ANSYS. According to the results of the analyses, the buckles fastening the RMIs showed the structural integrity under the required response spectrum containing the safety shutdown earthquake loads applied to main components in containment building. Consequently, since the RMI isn't disassembled under the SSE load, the RMI is judged not to affect safety related components.

  3. A Seismic Analysis for Reflective Metal Insulation

    International Nuclear Information System (INIS)

    Kim, Kyuhyung; Kim, Taesoon

    2016-01-01

    U.S. NRC (Nuclear Regulatory Commission) GSI- 191 (Generic Safety Issue-191) is concerned about the head-loss of emergency core cooling pumps caused by calcium silicate insulation debris accumulated on a sump screen when a loss of coolant accident (LOCA). In order to cope with the concern, many nuclear plants in U. S. have been replacing calcium silicate insulation in containment building with reflective metal insulation (RMI). In Korea, RMI has been used for only reactor vessels recently constructed, but the RMI was imported. Therefore, we have been developing the domestic design of RMI to supply to nuclear power plants under operation and construction in relation to the GSI-191. This paper covers that the structural integrity of the RMI assembly was evaluated under SSE (safety shutdown earthquake) load. An analysis model was built for the seismic test system of a reflective metal insulation assembly and pre-stress, modal, and spectrum analysis for the model were performed using a commercial structural analysis code, ANSYS. According to the results of the analyses, the buckles fastening the RMIs showed the structural integrity under the required response spectrum containing the safety shutdown earthquake loads applied to main components in containment building. Consequently, since the RMI isn't disassembled under the SSE load, the RMI is judged not to affect safety related components

  4. Near-vertical seismic reflection image using a novel acquisition technique across the Vrancea Zone and Foscani Basin, south-eastern Carpathians (Romania).

    NARCIS (Netherlands)

    Panea, I; Stephenson, R.A.; Knapp, C.; Mocanu, V.I.; Drijkoningen, G.; Matenco, L.C.; Knapp, J.; Prodehl, K.

    2005-01-01

    The DACIA PLAN (Danube and Carpathian Integrated Action on Process in the Lithosphere and Neotectonics) deep seismic sounding survey was performed in August-September 2001 in south-eastern Romania, at the same time as the regional deep refraction seismic survey VRANCEA 2001. The main goal of the

  5. Seismic imaging of sandbox experiments – laboratory hardware setup and first reflection seismic sections

    Directory of Open Access Journals (Sweden)

    C. M. Krawczyk

    2013-02-01

    Full Text Available With the study and technical development introduced here, we combine analogue sandbox simulation techniques with seismic physical modelling of sandbox models. For that purpose, we designed and developed a new mini-seismic facility for laboratory use, comprising a seismic tank, a PC-driven control unit, a positioning system, and piezoelectric transducers used here for the first time in an array mode. To assess the possibilities and limits of seismic imaging of small-scale structures in sandbox models, different geometry setups were tested in the first 2-D experiments that also tested the proper functioning of the device and studied the seismo-elastic properties of the granular media used. Simple two-layer models of different materials and layer thicknesses as well as a more complex model comprising channels and shear zones were tested using different acquisition geometries and signal properties. We suggest using well sorted and well rounded grains with little surface roughness (glass beads. Source receiver-offsets less than 14 cm for imaging structures as small as 2.0–1.5 mm size have proven feasible. This is the best compromise between wide beam and high energy output, and is applicable with a consistent waveform. Resolution of the interfaces of layers of granular materials depends on the interface preparation rather than on the material itself. Flat grading of interfaces and powder coverage yields the clearest interface reflections. Finally, sandbox seismic sections provide images of high quality showing constant thickness layers as well as predefined channel structures and indications of the fault traces from shear zones. Since these were artificially introduced in our test models, they can be regarded as zones of disturbance rather than tectonic shear zones characterized by decompaction. The multiple-offset surveying introduced here, improves the quality with respect to S / N ratio and source signature even more; the maximum depth

  6. a Comparative Case Study of Reflection Seismic Imaging Method

    Science.gov (United States)

    Alamooti, M.; Aydin, A.

    2017-12-01

    Seismic imaging is the most common means of gathering information about subsurface structural features. The accuracy of seismic images may be highly variable depending on the complexity of the subsurface and on how seismic data is processed. One of the crucial steps in this process, especially in layered sequences with complicated structure, is the time and/or depth migration of seismic data.The primary purpose of the migration is to increase the spatial resolution of seismic images by repositioning the recorded seismic signal back to its original point of reflection in time/space, which enhances information about complex structure. In this study, our objective is to process a seismic data set (courtesy of the University of South Carolina) to generate an image on which the Magruder fault near Allendale SC can be clearly distinguished and its attitude can be accurately depicted. The data was gathered by common mid-point method with 60 geophones equally spaced along an about 550 m long traverse over a nearly flat ground. The results obtained from the application of different migration algorithms (including finite-difference and Kirchhoff) are compared in time and depth domains to investigate the efficiency of each algorithm in reducing the processing time and improving the accuracy of seismic images in reflecting the correct position of the Magruder fault.

  7. Evolution of a seismic risk assessment technique

    International Nuclear Information System (INIS)

    Wells, J.E.; Cummings, G.E.

    1985-01-01

    To assist the NRC in its licensing evaluation role the Seismic Safety Margins Research Program (SSMRP) was started at LLNL in 1978. Its goal was to develop tools and data bases to evaluate the probability of earthquake caused radioactive releases from commercial nuclear power plants. The methodology was finalized in 1982 and a seismic risk assessment of the Zion Nuclear Power Plant was finished in 1983. Work continues on the study of the LaSalle Boiling Water Reactor. This paper will discuss some of the effects of the assumptions made during development of the systems analysis techniques used in SSMRP in light of the results obtained on studies to date. 5 refs

  8. Seismic Shear Energy Reflection By Radon-Fourier Transform

    Directory of Open Access Journals (Sweden)

    Malik Umairia

    2016-01-01

    Full Text Available Seismic waves split in an anisotropic medium, instead of rotating horizontal component to principal direction, Radon-Fourier is derived to observe the signature of shear wave reflection. Synthetic model with fracture is built and discretized using finite difference scheme for spatial and time domain. Common depth point (CDP with single shot gives traces and automatic gain is preprocessed before Radon Transform (RT, a filtering technique gives radon domain. It makes easier to observe fractures at specific incidence and improves its quality in some way by removing the noise. A comparison of synthetic data and BF-data is performed on the basis of root means square error (RMS values. The RMS error is minimum at the 10th trace in radon domain.

  9. Nucelar reactor seismic safety analysis techniques

    International Nuclear Information System (INIS)

    Cummings, G.E.; Wells, J.E.; Lewis, L.C.

    1979-04-01

    In order to provide insights into the seismic safety requirements for nuclear power plants, a probabilistic based systems model and computational procedure have been developed. This model and computational procedure will be used to identify where data and modeling uncertainties need to be decreased by studying the effect of these uncertainties on the probability of radioactive release and the probability of failure of various structures, systems, and components. From the estimates of failure and release probabilities and their uncertainties the most sensitive steps in the seismic methodologies can be identified. In addition, the procedure will measure the uncertainty due to random occurrences, e.g. seismic event probabilities, material property variability, etc. The paper discusses the elements of this systems model and computational procedure, the event-tree/fault-tree development, and the statistical techniques to be employed

  10. Exploration of lateral discontinuities with shallow seismic reflection

    International Nuclear Information System (INIS)

    Kose, K.; Ecevitoglu, B.

    2007-01-01

    Shallow seismic reflection method is used to for research of mine, fault and stratigraphy and these researches have been result successfully. Survey parameters should be determined with detailed pre-research before data collection. In this study, limestone-fly sch discontinuity experienced at surface and its extension was researched with collected reflection data

  11. Seismic data enhancement with Common Reflection Surface (CRS) stack method

    Energy Technology Data Exchange (ETDEWEB)

    Baykulov, M.; Brink, H.J.; Gajewski, D.; Yoon, Mi-Kyung [Hamburg Univ. (Germany). Inst. fuer Geophysik

    2008-10-23

    We present the results of partial stacking of prestack seismic reflection data based on the kinematic wavefield attributes computed during the automatic CRS stack. The resulting CRS supergathers are more regularised and have better signal to noise ratio compared to original CMP gathers. The improved data can be used in any conventional processing tool instead of the original data, providing enhanced images of better quality. The CRS supergather method is especially suited for low fold seismic reflection data. Application of the new method to synthetic and real low fold data shows a clear improvement of seismograms as well as time and depth-migrated sections. (orig.)

  12. Seismic interferometry : Reconstructing the earth's reflection response

    NARCIS (Netherlands)

    Draganov, D.S.; Wapenaar, C.P.A.; Thorbecke, J.W.

    2006-01-01

    In 1968, Jon Claerbout showed that the reflection response of a 1D acoustic medium can be reconstructed by autocorrelating the transmission response. Since then, several authors have derived relationships for reconstructing Green's functions at the surface, using crosscorrelations of (noise)

  13. Seismic reflection response from cross-correlations of ambient vibrations on non-conventional hidrocarbon reservoir

    Science.gov (United States)

    Huerta, F. V.; Granados, I.; Aguirre, J.; Carrera, R. Á.

    2017-12-01

    Nowadays, in hydrocarbon industry, there is a need to optimize and reduce exploration costs in the different types of reservoirs, motivating the community specialized in the search and development of alternative exploration geophysical methods. This study show the reflection response obtained from a shale gas / oil deposit through the method of seismic interferometry of ambient vibrations in combination with Wavelet analysis and conventional seismic reflection techniques (CMP & NMO). The method is to generate seismic responses from virtual sources through the process of cross-correlation of records of Ambient Seismic Vibrations (ASV), collected in different receivers. The seismic response obtained is interpreted as the response that would be measured in one of the receivers considering a virtual source in the other. The acquisition of ASV records was performed in northern of Mexico through semi-rectangular arrays of multi-component geophones with instrumental response of 10 Hz. The in-line distance between geophones was 40 m while in cross-line was 280 m, the sampling used during the data collection was 2 ms and the total duration of the records was 6 hours. The results show the reflection response of two lines in the in-line direction and two in the cross-line direction for which the continuity of coherent events have been identified and interpreted as reflectors. There is certainty that the events identified correspond to reflections because the time-frequency analysis performed with the Wavelet Transform has allowed to identify the frequency band in which there are body waves. On the other hand, the CMP and NMO techniques have allowed to emphasize and correct the reflection response obtained during the correlation processes in the frequency band of interest. The results of the processing and analysis of ASV records through the seismic interferometry method have allowed us to see interesting results in light of the cross-correlation process in combination with

  14. High resolution reflection seismic mapping of shallow coal seams

    CSIR Research Space (South Africa)

    Mngadi, SB

    2013-10-01

    Full Text Available the extent of the mine workings. Two 94 m profiles (tied to boreholes) were surveyed using a sledgehammer source. Processing was optimized to image the shallow reflections. The refraction seismic models and stacked time sections were compared and integrated...

  15. Seismic reflection survey conducted in Benton County, Washinton

    International Nuclear Information System (INIS)

    Beggs, H.G.; Heineck, R.L.

    1980-01-01

    The massive Columbia River Basalt group that underlies the Hanford Site is being considered as a potential geologic repository for spent nuclear fuel. As part of the effort to ascertain and better understand the physical and geological properties of these basalt flows, a multiphased seismic reflection program has been undertaken. This phase was designed to more thoroughly define geologic features and structural attitudes in an areas in the central part of the Hanford Site. The specific feature of interest is known as the Cold Creek Syncline. This seismic survey, utilized the ''VIBROSEIS'' energy source and multifold common depth point recording. 2 figs

  16. Iterative reflectivity-constrained velocity estimation for seismic imaging

    Science.gov (United States)

    Masaya, Shogo; Verschuur, D. J. Eric

    2018-03-01

    This paper proposes a reflectivity constraint for velocity estimation to optimally solve the inverse problem for active seismic imaging. This constraint is based on the velocity model derived from the definition of reflectivity and acoustic impedance. The constraint does not require any prior information of the subsurface and large extra computational costs, like the calculation of so-called Hessian matrices. We incorporate this constraint into the Joint Migration Inversion algorithm, which simultaneously estimates both the reflectivity and velocity model of the subsurface in an iterative process. Using so-called full wavefield modeling, the misfit between forward modeled and measured data is minimized. Numerical and field data examples are given to demonstrate the validity of our proposed algorithm in case accurate initial models and the low frequency components of observed seismic data are absent.

  17. Seismic reflection imaging with conventional and unconventional sources

    Science.gov (United States)

    Quiros Ugalde, Diego Alonso

    This manuscript reports the results of research using both conventional and unconventional energy sources as well as conventional and unconventional analysis to image crustal structure using reflected seismic waves. The work presented here includes the use of explosions to investigate the Taiwanese lithosphere, the use of 'noise' from railroads to investigate the shallow subsurface of the Rio Grande rift, and the use of microearthquakes to image subsurface structure near an active fault zone within the Appalachian mountains. Chapter 1 uses recordings from the land refraction and wide-angle reflection component of the Taiwan Integrated Geodynamic Research (TAIGER) project. The most prominent reflection feature imaged by these surveys is an anomalously strong reflector found in northeastern Taiwan. The goal of this chapter is to analyze the TAIGER recordings and to place the reflector into a geologic framework that fits with the modern tectonic kinematics of the region. Chapter 2 uses railroad traffic as a source for reflection profiling within the Rio Grande rift. Here the railroad recordings are treated in an analogous way to Vibroseis recordings. These results suggest that railroad noise in general can be a valuable new tool in imaging and characterizing the shallow subsurface in environmental and geotechnical studies. In chapters 3 and 4, earthquakes serve as the seismic imaging source. In these studies the methodology of Vertical Seismic Profiling (VSP) is borrowed from the oil and gas industry to develop reflection images. In chapter 3, a single earthquake is used to probe a small area beneath Waterboro, Maine. In chapter 4, the same method is applied to multiple earthquakes to take advantage of the increased redundancy that results from multiple events illuminating the same structure. The latter study demonstrates how dense arrays can be a powerful new tool for delineating, and monitoring temporal changes of deep structure in areas characterized by significant

  18. Reflection seismic investigations of western Canadian coalfields. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, D.C.; Bertram, M.B.

    1983-03-01

    High resolution reflection seismic studies using a seisgun surface source were undertaken at four sites in Alberta. The objective of the project was to test the feasibility of the seismic method for the exploration and evaluation of coal deposits in a range of environments in western Canada. At Camrose, coherent reflections from a coal zone 70-110 m below the surface were recorde along a 5 km profile. Variations in reflection amplitude and character were interpreted in terms of two main seams. Channel washouts, faults with throws of 5 m or greater, and effects of differential compaction were resolved. Studies at a foothills site showed that good data can be obtained in structurally disturbed areas with mild deformation. At this site, faults with vertical throws of up to 40 m were delineated. In the mountain region, studies indicated that the seismic method is not appropriate in areas with strong deformation. Deep weathering, variable topography and rapid lateral changes in reflector dip were the main reasons for poor data quality. The seisgun is a threshold seismic source which performs well in areas with a shallow water table and a zone of interest within 350 m of the surface. Its effectiveness decreases dramatically if the overburden is both thick and dry. Careful selection of field geometry and recording parameters is critical. In data processing, important aspects are the careful muting of first breaks and evaluation of short and long wavelength weathering statics corrections. A computer program listing for static correction analysis is included. The seismic method is very appropriate for evaluation of Plains and Foothills coal deposits in Alberta. It can provide continuous subsurface coverage between drillholes and therefore reduce the density of drillholes required to delineate a prospective area. 29 refs., 33 figs., 2 tabs.

  19. High-resolution seismic reflection study, Vacherie Dome

    International Nuclear Information System (INIS)

    1984-06-01

    A high-resolution seismic reflection study, consisting of recording, processing, and interpreting four seismic reflection lines, was made at Vacherie Dome, Louisiana. The presumed shape of the dome, as pictured in the geologic area characterization report by Law Engineering Testing Company in 1982, was based largely on interpretation of gravity data, constrained by a few wells and exploration-type seismic profiles. The purpose of the study was to obtain refined profiles of the dome above -914 m (-3000 ft) elevation. Additional study had been recommended by Louisiana State University in 1967 and the Office of Nuclear Waste Isolation in 1981 because the interpreted size of Vacherie Dome was based on limited seismic and gravity data. Forty-eight traces of seismic data were recorded each time shots were made to generate energy. Twelve-fold, common-depth-point data were obtained using geophone stations spaced at 15-m (50-ft) intervals with shots at 30-m (100-ft) intervals. The time-sampling interval used was 1 ms. Processing intended to enhance resolution included iterative static corrections, deconvolution before stacking, and both time- and depth-migration. The locations of the steep dome sides were inferred primarily from terminations of strong reflections (migrated) from strata near the top of the upper and lower Cretaceous sections. This interpretation agrees closely with the presumed shape from the top of the dome to about -610 m (-2000 ft) elevation, but below this on three of the profiles, this interpretation indicates a steeper salt face than the presumed shape. The area reduction at -914 m (-3000 ft) elevation is estimated to be on the order of 20 percent. 10 references, 11 figures, 4 tables

  20. High-resolution seismic reflection surveying with a land streamer

    Science.gov (United States)

    Cengiz Tapırdamaz, Mustafa; Cankurtaranlar, Ali; Ergintav, Semih; Kurt, Levent

    2013-04-01

    In this study, newly designed seismic reflection data acquisition array (land streamer) is utilized to image the shallow subsurface. Our acquisition system consist of 24 geophones screwed on iron plates with 2 m spacing, moving on the surface of the earth which are connected with fire hose. Completely original, 4.5 Kg weight iron plates provides satisfactory coupling. This land-streamer system enables rapid and cost effective acquisition of seismic reflection data due to its operational facilities. First test studies were performed using various seismic sources such as a mini-vibro truck, buffalo-gun and hammer. The final fieldwork was performed on a landslide area which was studied before. Data acquisition was carried out on the line that was previously measured by the seismic survey using 5 m geophone and shot spacing. This line was chosen in order to re-image known reflection patterns obtained from the previous field study. Taking penetration depth into consideration, a six-cartridge buffalo-gun was selected as a seismic source to achieve high vertical resolution. Each shot-point drilled 50 cm for gunshots to obtain high resolution source signature. In order to avoid surface waves, the offset distance between the source and the first channel was chosen to be 50 m and the shot spacing was 2 m. These acquisition parameters provided 12 folds at each CDP points. Spatial sampling interval was 1 m at the surface. The processing steps included standard stages such as gain recovery, editing, frequency filtering, CDP sorting, NMO correction, static correction and stacking. Furthermore, surface consistent residual static corrections were applied recursively to improve image quality. 2D F-K filter application was performed to suppress air and surface waves at relatively deep part of the seismic section. Results show that, this newly designed, high-resolution land seismic data acquisition equipment (land-streamer) can be successfully used to image subsurface. Likewise

  1. Attenuation (1/Q) estimation in reflection seismic records

    International Nuclear Information System (INIS)

    Raji, Wasiu; Rietbrock, Andreas

    2013-01-01

    Despite its numerous potential applications, the lack of a reliable method for determining attenuation (1/Q) in seismic data is an issue when utilizing attenuation for hydrocarbon exploration. In this paper, a new method for measuring attenuation in reflection seismic data is presented. The inversion process involves two key stages: computation of the centroid frequency for the individual signal using a variable window length and fast Fourier transform; and estimation of the difference in the centroid frequency and travel time for paired incident and transmitted signals. The new method introduces a shape factor and a constant which allows several spectral shapes to be used to represent a real seismic signal without altering the mathematical model. Application of the new method to synthetic data shows that it can provide reliable estimates of Q using any of the spectral shapes commonly assumed for real seismic signals. Tested against two published methods of Q measurement, the new method shows less sensitivity to interference from noise and change of frequency bandwidth. The method is also applied to a 3D data set from the Gullfaks field, North Sea, Norway. The trace length is divided into four intervals: AB, BC, CD, and DE. Results show that interval AB has the lowest 1/Q value, and that interval BC has the highest 1/Q value. The values of 1/Q measured in the CDP stack using the new method are consistent with those measured using the classical spectral ratio method. (paper)

  2. Vertical seismic profiling and integration with reflection seismic studies at Laxemar, 2000

    Energy Technology Data Exchange (ETDEWEB)

    Juhlin, C.; Bergman, B. [Uppsala Univ. (Sweden); Cosma, C.; Keskinen, J.; Enescu, N. [Vibrometric Oy, Helsinki (Finland)

    2002-02-01

    Vertical seismic profile (VSP) data were acquired in October 2000 in the 1700 m deep KLX02 borehole, near Laxemar in southeastern Sweden. The objectives of the VSP were to image reflectors in the borehole for correlation with surface seismic and borehole data, study the signal penetration of explosive versus mechanical sources and determine the seismic velocity as a function of depth. Five principal source points were used, one located close to the KLX02 wellhead and 4 others that were offset by about 200 m to 400 m. An explosive source was only used at the wellhead and consisted of 15 grams of dynamite in 90 cm deep shot holes in bedrock. A swept impact seismic source (SIST) was also used at the wellhead, as well as at the other four offset source points. The primary SIST source consisted of a computer controlled mechanical hammer mounted on a tractor. By activating the hammer over a 15 second sweep length, the total energy transferred to the ground is on the same order as that produced by the dynamite. The recorded data are then processed to generate seismic records that are equivalent to a single impact source. A smaller hand held SIST source was also tested at the wellhead. Tests of both the tractor mounted source and dynamite were made at a location offset somewhat from the wellhead at a site containing loose sediments at the surface. Full waveform sonic, resistivity and gamma logs were also acquired in conjunction the VSP survey. A comparison between the explosive and large SIST source shows that comparable energy levels are produced by the two methods. The SIST source appears to be more stable in terms of the energy level, although the frequency content of data are somewhat lower. However, its most significant advantage is the low cost of preparation of the source points and the speed of the acquisition. Numerous reflections are observed on the VSP, as is the case on the surface seismic, implying a complex structure in the vicinity of the KLX02 borehole

  3. Vertical seismic profiling and integration with reflection seismic studies at Laxemar, 2000

    International Nuclear Information System (INIS)

    Juhlin, C.; Bergman, B.; Cosma, C.; Keskinen, J.; Enescu, N.

    2002-02-01

    Vertical seismic profile (VSP) data were acquired in October 2000 in the 1700 m deep KLX02 borehole, near Laxemar in southeastern Sweden. The objectives of the VSP were to image reflectors in the borehole for correlation with surface seismic and borehole data, study the signal penetration of explosive versus mechanical sources and determine the seismic velocity as a function of depth. Five principal source points were used, one located close to the KLX02 wellhead and 4 others that were offset by about 200 m to 400 m. An explosive source was only used at the wellhead and consisted of 15 grams of dynamite in 90 cm deep shot holes in bedrock. A swept impact seismic source (SIST) was also used at the wellhead, as well as at the other four offset source points. The primary SIST source consisted of a computer controlled mechanical hammer mounted on a tractor. By activating the hammer over a 15 second sweep length, the total energy transferred to the ground is on the same order as that produced by the dynamite. The recorded data are then processed to generate seismic records that are equivalent to a single impact source. A smaller hand held SIST source was also tested at the wellhead. Tests of both the tractor mounted source and dynamite were made at a location offset somewhat from the wellhead at a site containing loose sediments at the surface. Full waveform sonic, resistivity and gamma logs were also acquired in conjunction the VSP survey. A comparison between the explosive and large SIST source shows that comparable energy levels are produced by the two methods. The SIST source appears to be more stable in terms of the energy level, although the frequency content of data are somewhat lower. However, its most significant advantage is the low cost of preparation of the source points and the speed of the acquisition. Numerous reflections are observed on the VSP, as is the case on the surface seismic, implying a complex structure in the vicinity of the KLX02 borehole

  4. Reflection seismic imaging of the upper crystalline crust for characterization of potential repository sites: Fine tuning the seismic source

    Energy Technology Data Exchange (ETDEWEB)

    Juhlin, C.; Palm, H.; Bergman, B. [Uppsala Univ. (Sweden). Dept. of Earth Sciences

    2001-09-01

    SKB is currently carrying out studies to determine which seismic techniques, and how, they will be used for investigations prior to and during the building of a high-level nuclear waste repository. Active seismic methods included in these studies are refraction seismics, reflection seismics, and vertical seismic profiling (VSP). The main goal of the active seismic methods is to locate fracture zones in the crystalline bedrock. Plans are to use longer reflection seismic profiles (3.4 km) in the initial stages of the site investigations. The target depth for these seismic profiles is 100-1500 m. Prior to carrying out the seismic surveys over actual candidate waste repository sites it has been necessary to carry out a number of tests to determine the optimum acquisition parameters. This report constitutes a summary of the tests carried out by Uppsala University. In addition, recommended acquisition and processing parameters are presented at the end of the report. A major goal in the testing has been to develop a methodology for acquiring high-resolution reflection seismic data over crystalline rock in as a cost effective manner as possible. Since the seismic source is generally a major cost in any survey, significant attention has been given to reducing the cost of the source. It was agreed upon early in the study that explosives were the best source from a data quality perspective and, therefore, only explosive source methods have been considered in this study. The charge size and shot hole dimension required to image the upper 1-1.5 km of bedrock is dependent upon the conditions at the surface. In this study two types of shot hole drilling methods have been employed depending upon whether the thickness of the loose sediments at the surface is greater or less than 0.5 m. The charge sizes and shot hole dimensions required are: Loose sediment thickness less than 0.5 m: 15 g in 90 cm deep 12 mm wide uncased shot holes. Loose sediment thickness greater than 0.5 m: 75 g

  5. Reassessment of seismic reflection data from the Finnsjoen study site and prospectives for future surveys

    International Nuclear Information System (INIS)

    Cosma, C.; Juhlin, C.

    1994-02-01

    Reprocessing of data from the seismic reflection survey performed at Finnsjoen in 1987 show that reflection seismics is a viable technique for mapping fracture zones in crystalline rock. Application of state of the art processing algorithms clearly image a gently dipping fracture zone located in the depth interval 200-400 m. In addition, several other reflectors were imaged in the reprocessed section, both gently and steeply dipping ones. Correlations with borehole data indicate that the origin of these reflections are also fractures zones. The data acquisition procedures used at the Finnsjoen survey were basically sound and could, with minor modifications, be applied at other sites. The results indicate that both sources and receivers in future surveys should be placed in boreholes a few meter below the ground surface. 30 refs

  6. Seismic Reflectivity of the Crust in the Northern Salton Trough

    Science.gov (United States)

    Bauer, K.; Fuis, G. S.; Goldman, M.; Persaud, P.; Ryberg, T.; Langenheim, V. E.; Scheirer, D. S.; Rymer, M. J.; Hole, J. A.; Stock, J. M.; Catchings, R.

    2015-12-01

    The Salton Trough in southern California is a tectonically active pull-apart basin that was formed by migrating step-overs between strike-slip faults, of which the San Andreas Fault (SAF) and the Imperial Fault are the current, northernmost examples. The Salton Seismic Imaging Project (SSIP) was undertaken to improve our knowledge of fault geometry and seismic velocities within the sedimentary basins and underlying crystalline crust around the SAF. Such data are useful as input for modeling scenarios of strong ground shaking in the surrounding high-population areas. We used pre-stack depth migration of line segments from shot gathers in several seismic profiles that were acquired in the northern part of the SSIP study area (Lines 4 - 7). Our migration approach can be considered as an infinite-frequency approximation of the Fresnel volume pre-stack depth migration method. We use line segments instead of the original waveform data. We demonstrate the method using synthetic data and analyze real data from Lines 4 - 7 to illustrate the relationship between distinct phases in the time domain and their resulting image at depth. We show both normal-moveout reflections from sub-horizontal interfaces and reverse-moveout reflections from steep interfaces, such as faults. Migrated images of dipping faults, such as the SAF and the Pinto Mountain Fault, are presented in this way. The SAF is imaged along Line 4, through the Mecca Hills, as a number of steeply dipping fault segments that collectively form a flower structure, above 5 km depth, that sole into a moderately NE-dipping fault below that depth. The individual migrated reflection packages correlate with mapped surface fault traces in the Mecca Hills. A similar geometry is seen on Line 6, from Palm Springs through Yucca Valley, where fault splays sole or project into a moderately dipping SAF below 10-km depth. We also show and discuss the reflectivity pattern of the middle and lower crust for Lines 4 - 7.

  7. Shallow reflection seismic soundings in bedrock at Lavia

    International Nuclear Information System (INIS)

    Okko, Olli

    1988-03-01

    The well-studied granitic block at Lavia was one of the test sites of a shallow seismic development project. A portable digital seismograph and high frequency geophones were rented fro the field period. A sledge hamme and a drop weight were tested as wave sources. The sounding was carried out on outcropped area in order to record high frequency reflections from known subhorizontal fracture zones as shallow as 30 m. Large amplitude surface waves hide most of the shallow reflections, recognizable only on few traces in the data. The data processing carried out did not reveal the geometry of these reflectors. Events arriving after the ground roll were analyzed in 2-folded CDP-sections. The continuous reflective horizons in them correspond to lithological changes and fracture zones located deeper than 200 m in the bedrock

  8. Seismic reflection survey conducted in Benton and Grant Counties, Washington

    International Nuclear Information System (INIS)

    Durham, T.E.; Beggs, H.G.; Heineck, R.L.

    1979-01-01

    The following report is devoted to a discussion of data acquisition procedures, data processing parameters and interpretation of results for a reflection seismic survey located on the Hanford Site in Benton and Grant Countries, Washington. The Pasco basin was the geologic setting for the survey. The main objectives of the program were to determine the subsurface structural attitudes of the numerous basalt flows known to exist within the basin. The location of areas associated with possible faulting and/or fracturing was also considered of prime concern as these conditions could significantly affect the integrity of the basalt

  9. Experimental technique of neutron reflection

    International Nuclear Information System (INIS)

    Chen Bo; Huang Chaoqiang; Li Xinxi

    2006-12-01

    It is presented that the classifications, structures and components of neutron reflectometer (NR), as well s functions and parameters of each components, detailed characters of NR facility 'PRN-2M'. Based on the practical experiments, the basic experimental techniques, the measurement and the related experimental settings are described, including the choice of experimental conditions, adjustments of polarized neutron beam line, basic experimental technique and approach of measurement. The above can be an instruction for NR experiments and a reference for NR construction. (authors)

  10. Combined analysis of surface reflection imaging and vertical seismic profiling at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Daley, T.M.; Majer, E.L.; Karageorgi, E.

    1994-08-01

    This report presents results from surface and borehole seismic profiling performed by the Lawrence Berkeley Laboratory (LBL) on Yucca Mountain. This work was performed as part of the site characterization effort for the potential high-level nuclear waste repository. Their objective was to provide seismic imaging from the near surface (200 to 300 ft. depth) to the repository horizon and below, if possible. Among the issues addressed by this seismic imaging work are location and depth of fracturing and faulting, geologic identification of reflecting horizons, and spatial continuity of reflecting horizons. The authors believe their results are generally positive, with tome specific successes. This was the first attempt at this scale using modem seismic imaging techniques to determine geologic features on Yucca Mountain. The principle purpose of this report is to present the interpretation of the seismic reflection section in a geologic context. Three surface reflection profiles were acquired and processed as part of this study. Because of environmental concerns, all three lines were on preexisting roads. Line 1 crossed the mapped surface trace of the Ghost Dance fault and it was intended to study the dip and depth extent of the fault system. Line 2 was acquired along Drill Hole wash and was intended to help the ESF north ramp design activities. Line 3 was acquired along Yucca Crest and was designed to image geologic horizons which were thought to be less faulted along the ridge. Unfortunately, line 3 proved to have poor data quality, in part because of winds, poor field conditions and limited time. Their processing and interpretation efforts were focused on lines 1 and 2 and their associated VSP studies

  11. Integration of seismic reflection and geologically balanced profiles; Integration reflexionsseismischer und geologisch bilanzierter Profile

    Energy Technology Data Exchange (ETDEWEB)

    Lambrecht, A. [Trappe Erdoel Erdgas Consultant, Isernhagen (Germany)

    1998-12-31

    Geophysics and geology employ different kinds of techniques in order to preserve the underground structure. These techniques are based on different sets of data, i.e. seismic or geological data. A sensible combination of the two techniques should produce a better model of the ground structure. This study attempts to integrate geologically balanced profiles and seismic reflection data. A balanced geological profile can than be compared with seismic reflection data measured in the field. The geological model is then changed into a seismic model of the underground by means of seismic modeling. Synthetic modeling is based on the acquisition of available field data. The synthetic stack section or the synthetic migration image are then compared to the field data. Deviations between the two can be attributed to speed errors and the fact that balances will never give an unequivocal solution but always present a group of solutions. (orig. MSK). [Deutsch] In der Geophysik und der Geologie werden verschiedene Techniken verwendet, um die Untergrundstruktur zu erhalten. Diese Techniken basieren auf verschiedenen Datensaetzen, z.B. seismische und geologische Daten. Eine sinnvolle Kombination der Techniken sollte ein besseres Abbild des Untergrundes liefern. In dieser Studie wird ein Versuch unternommen geologisch bilanzierte Profile und reflexionsseismische Daten zu integrieren. Soll ein bilanziertes geologisches Profil mit im Feld gemessenen reflexionsseismischen Daten verglichen werden, dann wird das geologische Modell mit Hilfe der seismischen Modellierung in ein seismisches Abbild des Untergrundes verwandelt. Dabei wird die synthetische Modellierung entsprechend der Aquisition der vorliegenden Felddaten durchgefuehrt. Die synthetische Stapelsektion oder das synthetische Migrationsimage werden anschliessend mit den Felddaten verglichen. Abweichungen zwischen beobachteten und Felddaten haben ihre Ursachen sowohl in Geschwindigkeitsfehlern, als auch in der Tatsache, dass eine

  12. Reflection seismic studies in the Forsmark area - stage 1

    Energy Technology Data Exchange (ETDEWEB)

    Juhlin, Christopher; Bergman Bjoern; Palm, Hans [Uppsala Univ. (Sweden). Dept. of Earth Sciences

    2002-10-01

    Reflection seismic data were acquired in the Spring of 2002 in the Forsmark area, located about 70 km northeast of Uppsala, Sweden. The Forsmark area has been targeted by SKB as a possible storage site for high level radioactive waste. About 16 km of high resolution seismic data were acquired along five separate profiles varying in length from 2 to 5 km. Non-final source and receiver spacing was 10 m with 100 active channels when recording data from a dynamite source (15-75 g). The profiles were located within a relatively undeformed lens of bedrock that trends in the NW-SE direction. The lens is surrounded by highly deformed rock on all sides. In conjunction with the reflection component of the study, all shots were also recorded on up to eleven 3-component fixed Orion seismographs. These recordings provided long offset data from which a velocity model of the uppermost 400 m of bedrock could be derived. Results from the study show that the bedrock has been well imaged down to depths of at least 3 km. The upper 1000 m of bedrock is much more reflective in the southeastern portion of the lens compared to the northwestern part close to the Forsmark reactors. This is interpreted as the bedrock being more homogeneous in the northwest. However, a major reflective zone (the A1 reflector) is interpreted to dip to the S-SE below this homogeneous bedrock. In the southeastern portion of the lens the orientation of the reflectors is well determined where the profiles cross one another. The general strike of the major reflectors is NE-SW with dips of 20-35 degrees to the southeast.

  13. Surface 3-D reflection seismics - implementation at the Olkiluoto site

    Energy Technology Data Exchange (ETDEWEB)

    Saksa, P.; Lehtimaeki, T.; Heikkinen, E. [Poeyry Environment Oy, Vantaa (Finland)

    2007-03-15

    Posiva Oy takes care of the final disposal of spent nuclear fuel in Finland. In year 2001 Olkiluoto was selected for the site of final disposal. Construction of the underground research facility, ONKALO, is going on at the Olkiluoto site. The aim of this work was to study the possibilities for surface 3-D seismics and to review experiences for design before field work. The physical parameters and geometric properties of the site, as well as efficient survey layout and source arrangements, were considered in this work. Reflection seismics is most used geophysical investigation method in oil exploration and earth studies in sedimentary environment. Recently method has also been applied in crystalline bedrock for ore exploration and nuclear waste disposal site investigations. The advantage of the method is high accuracy combined with large depth of investigation. The principles of seismic 2-D and 3-D soundings are well known and advanced. 3-D sounding is a straightforward expansion of 2-D line based surveying. In investigation of crystalline bedrock, the high frequency wave sources and receivers, their right use in measurements and careful processing procedure (refraction static corrections in particular) are important. Using the site parameters in 2-D numerical modeling, two cases of faulted thin layer at depths of 200, 400 and 600 meters were studied. The first case was a layer with vertical dislocation (a ramp) and the other a layer having limited width of dislocated part. Central frequencies were 100, 200, 400 and 700 Hz. Results indicate that 10 - 20 m dislocation is recognizable, but for depths greater than 600 m, over 20 meters is required. Width of the dislocated part will affect the detectability of vertical displacement. At depths of 200 m and 400 m 10 - 50 m wide parts appear as point-like scatterers, wider areas have more continuity. Dislocations larger than 20 m can be seen. From depth of 600 m over 100 m wide parts are discernible, narrower are visible

  14. Surface 3-D reflection seismics - implementation at the Olkiluoto site

    International Nuclear Information System (INIS)

    Saksa, P.; Lehtimaeki, T.; Heikkinen, E.

    2007-03-01

    Posiva Oy takes care of the final disposal of spent nuclear fuel in Finland. In year 2001 Olkiluoto was selected for the site of final disposal. Construction of the underground research facility, ONKALO, is going on at the Olkiluoto site. The aim of this work was to study the possibilities for surface 3-D seismics and to review experiences for design before field work. The physical parameters and geometric properties of the site, as well as efficient survey layout and source arrangements, were considered in this work. Reflection seismics is most used geophysical investigation method in oil exploration and earth studies in sedimentary environment. Recently method has also been applied in crystalline bedrock for ore exploration and nuclear waste disposal site investigations. The advantage of the method is high accuracy combined with large depth of investigation. The principles of seismic 2-D and 3-D soundings are well known and advanced. 3-D sounding is a straightforward expansion of 2-D line based surveying. In investigation of crystalline bedrock, the high frequency wave sources and receivers, their right use in measurements and careful processing procedure (refraction static corrections in particular) are important. Using the site parameters in 2-D numerical modeling, two cases of faulted thin layer at depths of 200, 400 and 600 meters were studied. The first case was a layer with vertical dislocation (a ramp) and the other a layer having limited width of dislocated part. Central frequencies were 100, 200, 400 and 700 Hz. Results indicate that 10 - 20 m dislocation is recognizable, but for depths greater than 600 m, over 20 meters is required. Width of the dislocated part will affect the detectability of vertical displacement. At depths of 200 m and 400 m 10 - 50 m wide parts appear as point-like scatterers, wider areas have more continuity. Dislocations larger than 20 m can be seen. From depth of 600 m over 100 m wide parts are discernible, narrower are visible

  15. Accelerometer Sensor Specifications to Predict Hydrocarbon Using Passive Seismic Technique

    Directory of Open Access Journals (Sweden)

    M. H. Md Khir

    2016-01-01

    Full Text Available The ambient seismic ground noise has been investigated in several surveys worldwide in the last 10 years to verify the correlation between observed seismic energy anomalies at the surface and the presence of hydrocarbon reserves beneath. This is due to the premise that anomalies provide information about the geology and potential presence of hydrocarbon. However a technology gap manifested in nonoptimal detection of seismic signals of interest is observed. This is due to the fact that available sensors are not designed on the basis of passive seismic signal attributes and mainly in terms of amplitude and bandwidth. This is because of that fact that passive seismic acquisition requires greater instrumentation sensitivity, noise immunity, and bandwidth, with active seismic acquisition, where vibratory or impulsive sources were utilized to receive reflections through geophones. Therefore, in the case of passive seismic acquisition, it is necessary to select the best monitoring equipment for its success or failure. Hence, concerning sensors performance, this paper highlights the technological gap and motivates developing dedicated sensors for optimal solution at lower frequencies. Thus, the improved passive seismic recording helps in oil and gas industry to perform better fracture mapping and identify more appropriate stratigraphy at low frequencies.

  16. An asymptotic model of seismic reflection from a permeable layer

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.; Goloshubin, G.

    2009-10-15

    Analysis of compression wave propagation in a poroelastic medium predicts a peak of reflection from a high-permeability layer in the low-frequency end of the spectrum. An explicit formula expresses the resonant frequency through the elastic moduli of the solid skeleton, the permeability of the reservoir rock, the fluid viscosity and compressibility, and the reservoir thickness. This result is obtained through a low-frequency asymptotic analysis of Biot's model of poroelasticity. A review of the derivation of the main equations from the Hooke's law, momentum and mass balance equations, and Darcy's law suggests an alternative new physical interpretation of some coefficients of the classical poroelasticity. The velocity of wave propagation, the attenuation factor, and the wave number, are expressed in the form of power series with respect to a small dimensionless parameter. The absolute value of this parameter is equal to the product of the kinematic reservoir fluid mobility and the wave frequency. Retaining only the leading terms of the series leads to explicit and relatively simple expressions for the reflection and transmission coefficients for a planar wave crossing an interface between two permeable media, as well as wave reflection from a thin highly-permeable layer (a lens). Practical applications of the obtained asymptotic formulae are seismic modeling, inversion, and at-tribute analysis.

  17. Compressive and Shear Wave Velocity Profiles using Seismic Refraction Technique

    International Nuclear Information System (INIS)

    Aziman, M; Hazreek, Z A M; Azhar, A T S; Haimi, D S

    2016-01-01

    Seismic refraction measurement is one of the geophysics exploration techniques to determine soil profile. Meanwhile, the borehole technique is an established way to identify the changes of soil layer based on number of blows penetrating the soil. Both techniques are commonly adopted for subsurface investigation. The seismic refraction test is a non-destructive and relatively fast assessment compared to borehole technique. The soil velocities of compressive wave and shear wave derived from the seismic refraction measurements can be directly utilised to calculate soil parameters such as soil modulus and Poisson’s ratio. This study investigates the seismic refraction techniques to obtain compressive and shear wave velocity profile. Using the vertical and horizontal geophones as well as vertical and horizontal strike directions of the transient seismic source, the propagation of compressive wave and shear wave can be examined, respectively. The study was conducted at Sejagung Sri Medan. The seismic velocity profile was obtained at a depth of 20 m. The velocity of the shear wave is about half of the velocity of the compression wave. The soil profiles of compressive and shear wave velocities were verified using the borehole data and showed good agreement with the borehole data. (paper)

  18. Seismic margin analysis technique for nuclear power plant structures

    International Nuclear Information System (INIS)

    Seo, Jeong Moon; Choi, In Kil

    2001-04-01

    In general, the Seismic Probabilistic Risk Assessment (SPRA) and the Seismic Margin Assessment(SAM) are used for the evaluation of realistic seismic capacity of nuclear power plant structures. Seismic PRA is a systematic process to evaluate the seismic safety of nuclear power plant. In our country, SPRA has been used to perform the probabilistic safety assessment for the earthquake event. SMA is a simple and cost effective manner to quantify the seismic margin of individual structural elements. This study was performed to improve the reliability of SMA results and to confirm the assessment procedure. To achieve this goal, review for the current status of the techniques and procedures was performed. Two methodologies, CDFM (Conservative Deterministic Failure Margin) sponsored by NRC and FA (Fragility Analysis) sponsored by EPRI, were developed for the seismic margin review of NPP structures. FA method was originally developed for Seismic PRA. CDFM approach is more amenable to use by experienced design engineers including utility staff design engineers. In this study, detailed review on the procedures of CDFM and FA methodology was performed

  19. Multiple attenuation to reflection seismic data using Radon filter and Wave Equation Multiple Rejection (WEMR) method

    Energy Technology Data Exchange (ETDEWEB)

    Erlangga, Mokhammad Puput [Geophysical Engineering, Institut Teknologi Bandung, Ganesha Street no.10 Basic Science B Buliding fl.2-3 Bandung, 40132, West Java Indonesia puput.erlangga@gmail.com (Indonesia)

    2015-04-16

    Separation between signal and noise, incoherent or coherent, is important in seismic data processing. Although we have processed the seismic data, the coherent noise is still mixing with the primary signal. Multiple reflections are a kind of coherent noise. In this research, we processed seismic data to attenuate multiple reflections in the both synthetic and real seismic data of Mentawai. There are several methods to attenuate multiple reflection, one of them is Radon filter method that discriminates between primary reflection and multiple reflection in the τ-p domain based on move out difference between primary reflection and multiple reflection. However, in case where the move out difference is too small, the Radon filter method is not enough to attenuate the multiple reflections. The Radon filter also produces the artifacts on the gathers data. Except the Radon filter method, we also use the Wave Equation Multiple Elimination (WEMR) method to attenuate the long period multiple reflection. The WEMR method can attenuate the long period multiple reflection based on wave equation inversion. Refer to the inversion of wave equation and the magnitude of the seismic wave amplitude that observed on the free surface, we get the water bottom reflectivity which is used to eliminate the multiple reflections. The WEMR method does not depend on the move out difference to attenuate the long period multiple reflection. Therefore, the WEMR method can be applied to the seismic data which has small move out difference as the Mentawai seismic data. The small move out difference on the Mentawai seismic data is caused by the restrictiveness of far offset, which is only 705 meter. We compared the real free multiple stacking data after processing with Radon filter and WEMR process. The conclusion is the WEMR method can more attenuate the long period multiple reflection than the Radon filter method on the real (Mentawai) seismic data.

  20. Regional seismic lines reprocessed using post-stack processing techniques; National Petroleum Reserve, Alaska

    Science.gov (United States)

    Miller, John J.; Agena, W.F.; Lee, M.W.; Zihlman, F.N.; Grow, J.A.; Taylor, D.J.; Killgore, Michele; Oliver, H.L.

    2000-01-01

    This CD-ROM contains stacked, migrated, 2-Dimensional seismic reflection data and associated support information for 22 regional seismic lines (3,470 line-miles) recorded in the National Petroleum Reserve ? Alaska (NPRA) from 1974 through 1981. Together, these lines constitute about one-quarter of the seismic data collected as part of the Federal Government?s program to evaluate the petroleum potential of the Reserve. The regional lines, which form a grid covering the entire NPRA, were created by combining various individual lines recorded in different years using different recording parameters. These data were reprocessed by the USGS using modern, post-stack processing techniques, to create a data set suitable for interpretation on interactive seismic interpretation computer workstations. Reprocessing was done in support of ongoing petroleum resource studies by the USGS Energy Program. The CD-ROM contains the following files: 1) 22 files containing the digital seismic data in standard, SEG-Y format; 2) 1 file containing navigation data for the 22 lines in standard SEG-P1 format; 3) 22 small scale graphic images of each seismic line in Adobe Acrobat? PDF format; 4) a graphic image of the location map, generated from the navigation file, with hyperlinks to the graphic images of the seismic lines; 5) an ASCII text file with cross-reference information for relating the sequential trace numbers on each regional line to the line number and shotpoint number of the original component lines; and 6) an explanation of the processing used to create the final seismic sections (this document). The SEG-Y format seismic files and SEG-P1 format navigation file contain all the information necessary for loading the data onto a seismic interpretation workstation.

  1. Seismic reflection surveys in central Palo Duro basin

    International Nuclear Information System (INIS)

    Acharya, H.; Buller, M.L.; Lewkowicz, J.; Murphy, P.

    1983-01-01

    Seismic reflection surveys have been conducted in the central Palo Duro basin to provide a basis for identifying localities suitable for the emplacement of an underground high level nuclear waste repository. The objectives of this effort were to determine the structure and stratigraphy in the central Palo Duro basin and evaluate the potential for hydrocarbon resources. Of primary interest is the Upper Permian salt section to a depth of about 3000 ft (914 m). Various tests were carried out along a 3 mi (5 km) segment to determine the most appropriate combination of vibrating source and recording parameters. Approximately 130 mi (209 km) of 24-fold CDP stacked data were acquired. The survey lines were tied to test wells in which velocity surveys were conducted. These data were supplemented by about 400 mi (644 km) of available proprietary CDP stacked data. Analysis of these data strongly suggests that central Palo Duro basin has been tectonically stable since Early Permian time. The maximum offset of the basement is about 600 ft (183 m). These basement faults do not appear to affect any strata above. The San Andres Formation and underlying formations can be traced continuously throughout the area surveyed. Available velocity data from various wells in the central Palo Duro basin show few anomalies, confirming the continuity of the reflecting horizons and the tectonic stability of the area. Hydrocarbon potential of the area is presently being evaluated. The preliminary results of this study are in agreement with the stratigraphic correlations among well logs in the Palo Duro basin

  2. Detecting voids in a 0. 6m coal seam, 7m deep, using seismic reflection

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.D.; Steeples, D.W. (University of Kansas, Lawrence, KS (USA). Kansas Geological Survey)

    1991-07-01

    Surface collapse over abandoned subsurface coal mines is a problem in many parts of the world. High-resolution P-wave reflection seismology was successfully used to evaluate the risk of an active sinkhole to a main north-south railroad line in an undermined area of southeastern Kansas, USA. Water-filled cavities responsible for sinkholes in this area are in a 0.6 m thick coal seam, 7 m deep. Dominant reflection frequencies in excess of 200 Hz enabled reflections from the coal seam to be discerned from the direct wave, refractions, air wave, and ground roll on unprocessed field files. Repetitive void sequences within competent coal on three seismic profiles are consistent with the 'room and pillar' mining technique practiced in this area near the turn of the century. The seismic survey showed that the apparent active sinkhole was not the result of reactivated subsidence but probably the results of erosion. 14 refs., 6 figs.

  3. Reflection imaging of the Moon's interior using deep-moonquake seismic interferometry

    NARCIS (Netherlands)

    Nishitsuji, Y.; Rowe, CA; Wapenaar, C.P.A.; Draganov, D.S.

    2016-01-01

    The internal structure of the Moon has been investigated over many years using a variety of seismic methods, such as travel time analysis, receiver functions, and tomography. Here we propose to apply body-wave seismic interferometry to deep moonquakes in order to retrieve zero-offset reflection

  4. Seismic-reflection and ground penetrating radar for environmental site characterization. 1998 annual progress report

    International Nuclear Information System (INIS)

    Plumb, R.; Steeples, D.W.

    1998-01-01

    'The project''s goals are threefold: (1) to examine the complementary site-characterization capabilities of modern, three-component shallow-seismic techniques and ground-penetrating radar (GPR) methods at depths ranging from 2 to 8 m at an existing test site; (2) to demonstrate the usefulness of the two methods when used in concert to characterize, in three-dimensions, the cone of depression of a pumping well, which will serve as a proxy site for fluid-flow at an actual, polluted site; and (3) to use the site as an outdoor mesoscale laboratory to validate existing three-dimensional ground-penetrating radar and seismic-reflection computer models developed at the Univ. of Kansas. To do this, useful seismic and GPR data are being collected along the same line(s) and within the same depth range. The principal investigators selected a site in central Kansas as a primary location and, although the site itself is not environmentally sensitive, the location chosen offers particularly useful attributes for this research and will serve as a proxy site for areas that are contaminated. As part of an effort to evaluate the strengths of each method, the authors will repeat the seismic and GPR surveys on a seasonal basis to establish how the complementary information obtained varies over time. Because the water table fluctuates at this site on a seasonal basis, variations in the two types of data over time also can be observed. Such noninvasive in-situ methods of identifying and characterizing the hydrologic flow regimes at contaminated sites support the prospect of developing effective, cost-conscious cleanup strategies in the near future. As of the end of May 1998, the project is on schedule. The first field work was conducted using both of the geophysical survey methods in October of 1997, and the second field survey employed both methods in March of 1998. One of the stated tasks is to reoccupy the same survey line on a quarterly basis for two years to examine change in both

  5. Multichannel Seismic Reflection Data - SCAR - Antarctic Peninsula 1987-88, SDLS CD-ROM vol 24

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1987-88 in the Antarctic Peninsula, Antarctica, by the Japan National Oil...

  6. Seismic reflection data report: Waste Isolation Pilot Plant (WIPP) site, Southeastern New Mexico

    International Nuclear Information System (INIS)

    Hern, J.L.; Powers, D.W.; Barrows, L.J.

    1978-12-01

    Volume II contains uninterpreted processed lines and shotpoint maps from three seismic reflection surveys conducted from 1976 through 1978 by Sandia Laboratories to support investigations for the Waste Isolation Pilot Plant. Data interpretations will be the subject of subsequent reports

  7. Multichannel Seismic Reflection Data - SCAR - Ross Sea - 1987, SDLS CD-ROM vol 13

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during the 1987 field season in the Ross Sea, Antarctica, by SEVMORGEOLOGIA, RUSSIA. The...

  8. Multichannel Seismic Reflection - SCAR- Antarctic Penn. 1987-88 SDLS CD-ROM vol 27

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1987-88 in the Antarctica Peninsula region, by Petrobras, Brazil. The following...

  9. Multichannel Seismic Reflection - SCAR- Antarctic Penn. 1987-88 SDLS CD-ROM vol 26

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1987-88 in the Antarctica Peninsula region, by Petrobras, Brazil. The following...

  10. Multichannel Seismic Reflection Data - SCAR - Ross Sea - 1980, SDLS, CD-ROM vol 4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data from seven lines recorded during 1980 in the Ross Sea, Antarctica, by the Bundesanstalt fur...

  11. Multichannel Seismic Reflection - SCAR- Prydz Bay 1980 SDLS CD-ROM vol 8

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1980 in the Prydz Bay region, by Australian Geological Survey Organization. The...

  12. Multichannel Seismic Reflection Data - SCAR - Weddell Sea - 1978, SDLS CD-ROM vol 19

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1978 in the Weddell Sea and Queen Maud Land, Antarctica, by the Bundesanstalt fur...

  13. Multichannel Seismic Reflection Data - SCAR - Ross Sea - 1980, SDLS CD-ROM vol 3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data from four lines recorded during 1980 in the Ross Sea, Antarctica, by the Bundesanstalt fur...

  14. Multichannel Seismic Reflection Data, SCAR - Wilkes Land 1982, SDLS, CD-ROM 15

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data from thirteen lines recorded during 1983 off Wilkes Island, Antarctica, by the U.S. Geological...

  15. Multichannel Seismic Reflection Data - SCAR - Prydz Bay - 1984-1985, SDLS CD-ROM vol 21

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1984-85 in the Prydz Bay region, Antarctica, by the Japan National Oil...

  16. Multichannel Seismic Reflection Data - SCAR - Amundsen Sea - 1986-1987, SDLS CD-ROM vol 23

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1986-87 in the Amundsen Sea, Antarctica, by the Japan National Oil Corporation....

  17. Multichannel Seismic Reflection Data - SCAR, Ross Sea - 1982-1983, CD-ROM vol 9

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data from fourteen lines recorded during 1982 in the Ross Sea and Wilkes Island, Antarctica, by the...

  18. Multichannel Seismic Reflection Data - SCAR - Weddell Sea - 1978, SDLS CD-ROM vol 18

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1978 in the Weddell Sea and Queen Maud Land, Antarctica, by the Bundesanstalt fur...

  19. Multichannel Seismic Reflection Data - SCAR - Ross Sea - 1989, SDLS CD-ROM vol 14

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1989 field season in the Ross Sea, Antarctica, by the SEVMORGEOLOGIA, RUSSIS. The...

  20. Multichannel Seismic Reflection Data - SCAR - Ross Sea 1980, SDLS, CD-ROM vol 5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data from eleven lines recorded during 1980 in the Ross Sea, Antarctica, by the Bundesanstalt fur...

  1. Multichannel Seismic Reflection Data - SCAR - Weddell Sea - 1978, SDLS CD-ROM vol 17

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1978 in the Weddell Sea and Queen Maud Land, Antarctica, by the Bundesanstalt fur...

  2. Multichannel Seismic Reflection Data - SCAR - Antarctic Peninsula - 1985, SDLS CD-ROM vol 16

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1985 field season along the north side of the Antarctic-Peninsula by the British...

  3. Multichannel Seismic Reflection Data - SCAR - Ross Sea 1982, SDLS CD-ROM vol 12

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data from seven lines recorded during 1982 in the Ross Sea, Antarctica, by the Institut Francais du...

  4. Multichannel Seismic Reflection Data - SCAR - Wilkes Land, 1983, SDLS CD-ROM vol 10

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data from thirteen lines recorded during 1983 off Wilkes Island, Antarctica, by the Japan National Oil...

  5. Multichannel Seismic Reflection Data - SCAR - Wilkes Land 1982, SDLS CD-ROM vol 11

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data from sixteen lines recorded during 1982 off Wilkes Island, Antarctica, by the Institut Francais du...

  6. Multichannel Seismic Reflection Data - SCAR - Antarctic Peninsula - 1988-1989, SDLS CD-ROM vol 25

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1988-89 in the Antarctic Peninsula, Antarctica, by the Japan National Oil...

  7. Multichannel Seismic Reflection Data - SCAR - Ross Sea 1987-1988, SDLS CD-ROM vol 2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data from six lines recorded during 1988 in the Ross Sea, Antarctica, by the Bundesanstalt fur...

  8. Robust satellite techniques for remote sensing of seismically active areas

    Energy Technology Data Exchange (ETDEWEB)

    Tramutoli, V; Di Bello, G [Potenza Univ., Potenza (Italy). Dipt. di Ingegneria e Fisica dell' Ambiente; Pergola, N; Piscitelli, S [Consiglio Nazionale delle Ricerche, Istituto di Metodologie Avanzate di Analisi Ambientale, Potenza (Italy)

    2001-04-01

    Several satellite techniques have been recently proposed to remotely map seismically active zones and to monitor geophysical phenomena possibly associated with earthquakes. Even if questionable in terms of their effective applicability, all these techniques highlight as the major problem, still to be overcome, the high number of natural factors (independent of any seismic activity) whose variable contributions to the investigated signal can be so high as to completely mask (or simulate) the space-time anomaly possibly associated to the seismic event under study. A robust approach (RAT) has recently been proposed (and successfully applied in the field of the monitoring of the major environmental risks) which, better than other methods, seems suitable for recognising space-time anomalies in the satellite observation field also in the presence of highly variable contributions from atmospheric (transmittance), surface (emissivity and morphology) and observational (time/season, but also solar and satellite zenithal angles) conditions. This work presents the first preliminary results, based on several years of NOA A/AVHRR observations, regarding its extension to satellite monitoring of thermal anomalies possibly associated to seismically active areas of Southern Italy. The main merits of this approach are its robustness against the possibility of false events detection (specially important for this kind of applications) as well as its intrinsic exportability not only to different geographic areas but also to different satellite instrumental packages.

  9. Robust satellite techniques for remote sensing of seismically active areas

    Directory of Open Access Journals (Sweden)

    S. Piscitelli

    2001-06-01

    Full Text Available Several satellite techniques have been recently proposed to remotely map seismically active zones and to monitor geophysical phenomena possibly associated with earthquakes. Even if questionable in terms of their effective applicability, all these techniques highlight as the major problem, still to be overcome, the high number of natural factors (independent of any seismic activity whose variable contributions to the investigated signal can be so high as to completely mask (or simulate the space-time anomaly possibly associated to the seismic event under study. A robust approach (RAT has recently been proposed (and successfully applied in the field of the monitoring of the major environmental risks which, better than other methods, seems suitable for recognising space-time anomalies in the satellite observational field also in the presence of highly variable contributions from atmospheric (transmittance, surface (emissivity and morphology and observational (time/season, but also solar and satellite zenithal angles conditions.This work presents the first preliminary results, based on several years of NOAA/AVHRR observations, regarding its extension to satellite monitoring of thermal anomalies possibly associated to seismically active areas of Southern Italy. The main merits of this approach are its robustness against the possibility of false events detection (specially important for this kind of applications as well as its intrinsic exportability not only to different geographic areas but also to different satellite instrumental packages.

  10. Processing of multichannel seismic reflection data acquired in 2013 for seismic investigations of gas hydrates in the Gulf of Mexico

    Science.gov (United States)

    Miller, John J.; Agena, Warren F.; Haines, Seth; Hart, Patrick E.

    2016-04-13

    As part of a cooperative effort among the U.S. Geological Survey (USGS), the U.S. Department of Energy, and the U.S. Department of the Interior Bureau of Ocean Energy Management, two grids of two-dimensional multichannel seismic reflection data were acquired in the Gulf of Mexico over lease blocks Green Canyon 955 and Walker Ridge 313 between April 18 and May 3, 2013. The purpose of the data acquisition was to fill knowledge gaps in an ongoing study of known gas hydrate accumulations in the area. These data were initially processed onboard the recording ship R/V Pelican for more quality control during the recording. The data were subsequently processed in detail by the U.S. Geological Survey in Denver, Colorado, in two phases. The first phase was to create a “kinematic” dataset that removed extensive noise present in the data but did not preserve relative amplitudes. The second phase was to create a true relative amplitude dataset that included noise removal and “wavelet” deconvolution that preserved the amplitude information. This report describes the processing techniques used to create both datasets.

  11. High Resolution Vertical Seismic Profile from the Chicxulub IODP/ICDP Expedition 364 Borehole: Wave Speeds and Seismic Reflectivity.

    Science.gov (United States)

    Nixon, C.; Kofman, R.; Schmitt, D. R.; Lofi, J.; Gulick, S. P. S.; Christeson, G. L.; Saustrup, S., Sr.; Morgan, J. V.

    2017-12-01

    We acquired a closely-spaced vertical seismic profile (VSP) in the Chicxulub K-Pg Impact Crater drilling program borehole to calibrate the existing surface seismic profiles and provide complementary measurements of in situ seismic wave speeds. Downhole seismic records were obtained at spacings ranging from 1.25 m to 5 m along the borehole from 47.5 m to 1325 mwsf (meters wireline below sea floor) (Fig 1a) using a Sercel SlimwaveTM geophone chain (University of Alberta). The seismic source was a 30/30ci Sercel Mini GI airgun (University of Texas), fired a minimum of 5 times per station. Seismic data processing used a combination of a commercial processing package (Schlumberger's VISTA) and MatlabTM codes. The VSP displays detailed reflectivity (Fig. 1a) with the strongest reflection seen at 600 mwsf (280 ms one-way time), geologically corresponding to the sharp contact between the post-impact sediments and the target peak ring rock, thus confirming the pre-drilling interpretations of the seismic profiles. A two-way time trace extracted from the separated up-going wavefield matches the major reflection both in travel time and character. In the granitic rocks that form the peak ring of the Chicxulub impact crater, we observe P-wave velocities of 4000-4500 m/s which are significantly less than the expected values of granitoids ( 6000 m/s) (Fig. 1b). The VSP measured wave speeds are confirmed against downhole sonic logging and in laboratory velocimetry measurements; these data provide additional evidence that the crustal material displaced by the impact experienced a significant amount of damage. Samples and data provided by IODP. Samples can be requested at http://web.iodp.tamu.edu/sdrm after 19 October 2017. Expedition 364 was jointly funded by ECORD, ICDP, and IODP with contributions and logistical support from the Yucatan State Government and UNAM. The downhole seismic chain and wireline system is funded by grants to DRS from the Canada Foundation for Innovation and

  12. Near-surface 3D reflections seismic survey; Sanjigen senso hanshaho jishin tansa

    Energy Technology Data Exchange (ETDEWEB)

    Nakahigashi, H; Mitsui, H; Nakano, O; Kobayashi, T [DIA Consultants Co. Ltd., Tokyo (Japan)

    1997-05-27

    Faults are being actively investigated across Japan since the Great Hanshin-Awaji Earthquake. Discussed in this report is the application of the 3D near-surface reflection seismic survey in big cities. Data from trenching and drilling is used for the geological interpretation of the surroundings of a fault, and the reflection seismic survey is used to identify the position, etc., of the fault. In this article, when the results obtained from the experimental field are examined, it is found that the conventional 2D imaging reflection survey betrays the limit of its capability when the geological structure is complicated, that the 3D reflection seismic survey, on the contrary, is capable of high-precision imaging and, when augmented by drilling, etc., becomes capable of a more detailed interpretation, and that it also contributes effectively to the improvement of local disaster prevention in big cities. Using as the model the Tachikawa fault that runs near JR Tachikawa Station, embodiment of the 3D reflection seismic survey is reviewed. For the acquisition of data excellent in quality in a 3D reflection seismic survey conducted utilizing the roads in the sector chosen for experiment in the urban area, the shock generating points and receiving points should be positioned by taking into account the parameters in the bin arranging process so that the mid-points will be regularly distributed on the surface. 3 refs., 11 figs., 1 tab.

  13. Application of the surface reflection seismic method to shallow coal exploration in the plains of Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Lyatsky, H.V.; Lawton, D.C. (University of Victoria, Victoria, BC (Canada). Dept. of Physics and Astronomy)

    1988-12-01

    A study was done to make a quantitative interpretation of reflection seismic data from the Highvale-Whitewood shallow coal deposit in central Alberta. Results showed that the data is useful in demonstrating coal thickness and stratigraphy as well as structural formation. Reflection character is affected by nature of the strata surrounding the coal deposit. 22 refs., 1 tab., 23 figs.

  14. Evidence of shallow gas in the Queen Charlotte Basin from waveform tomography of seismic reflection data

    Energy Technology Data Exchange (ETDEWEB)

    Takam Takougang, Eric M.; Calvert, Andrew J. [Simon Fraser University (Canada)], email: eta9@sfu.ca

    2011-07-01

    The Geological Survey of Canada (GSC) collected eight seismic reflection lines in 1988 across the Queen Charlotte sedimentary basin of western Canada, which is the largest tertiary basin on the west coast. This work furthers the study of the upper part of the basin by using quantitative imaging of its structure through application of 2-D waveform tomography to the limited offset seismic reflection data. With the help of waveform tomography, seismic reflection data has allowed the identification of pockmark structures and pipe-like gas chimney in the recovered velocity and attenuation models. Overall, there is an excellent match between field data and predicted data. and a good match between the sonic log and a 1-D velocity function derived from the 2-D velocity model. This shows that specific preconditioning of the data and a good inversion strategy make it possible to use waveform tomography of relatively short offset reflection data for the imaging of shallow geological features.

  15. A workflow for sub-/seismic structure and deformation quantification of 3-D reflection seismic data sets across different scales

    Energy Technology Data Exchange (ETDEWEB)

    Krawczyk, C.M.; Lohr, T.; Oncken, O. [GFZ Potsdam (Germany); Tanner, D.C. [Goettingen Univ. (Germany). GZG; Endres, H. [RWTH Aachen (Germany)]|[TEEC, Isernhagen (Germany); Trappe, H.; Kukla, P. [TEEC, Isernhagen (Germany)

    2007-09-13

    The evolution of a sedimentary basin is mostly affected by deformation. Large-scale, subsurface deformation is typically identified by seismic data, sub-seismic small-scale fractures by well data. Between these two methods, we lack a deeper understanding of how deformation scales. We analysed a 3-D reflection seismic data set in the North German Basin, in order to determine the magnitude and distribution of deformation and its accumulation in space and time. A five-step approach is introduced for quantitative deformation and fracture prediction. An increased resolution of subtle tectonic lineaments is achieved by coherency processing, allowing to unravel the kinematics in the North German Basin from structural interpretation. Extensional events during basin initiation and later inversion are evident. 3-D retrodeformation shows major-strain magnitudes between 0-20% up to 1.3 km away from a fault trace, and variable deviations of associated extensional fractures. Good correlation of FMI data, strain distribution from retro-deformation and from geostatistic tools (see also Trappe et al., this volume) allows the validation of the results and makes the prediction of small-scale faults/fractures possible. The temporal component will be gained in the future by analogue models. The suggested workflow is applicable to reflection seismic surveys and yields in great detail both the tectonic history of a region as well as predictions for hydrocarbon plays or deep groundwater or geothermal reservoirs. (orig.)

  16. Reflection seismic methods applied to locating fracture zones in crystalline rock

    International Nuclear Information System (INIS)

    Juhlin, C.

    1998-01-01

    The reflection seismic method is a potentially powerful tool for identifying and localising fracture zones in crystalline rock if used properly. Borehole sonic logs across fracture zones show that they have reduced P-wave velocities compared to the surrounding intact rock. Diagnostically important S-wave velocity log information across the fracture zones is generally lacking. Generation of synthetic reflection seismic data and subsequent processing of these data show that structures dipping up towards 70 degrees from horizontal can be reliably imaged using surface seismic methods. Two real case studies where seismic reflection methods have been used to image fracture zones in crystalline rock are presented. Two examples using reflection seismic are presented. The first is from the 5354 m deep SG-4 borehole in the Middle Urals, Russia where strong seismic reflectors dipping from 25 to 50 degrees are observed on surface seismic reflection data crossing over the borehole. On vertical seismic profile data acquired in the borehole, the observed P-wave reflectivity is weak from these zones, however, strong converted P to S waves are observed. This can be explained by the source of the reflectors being fracture zones with a high P wave to S wave velocity ratio compared to the surrounding rock resulting in a high dependence on the angle of incidence for the reflection coefficient. A high P wave to S wave velocity ratio (high Poisson's ratio) is to be expected in fluid filled fractured rock. The second case is from Aevroe, SE Sweden, where two 1 km long crossing high resolution seismic reflection lines were acquired in October 1996. An E-W line was shot with 5 m geophone and shotpoint spacing and a N-S one with 10 m geophone and shotpoint spacing. An explosive source with a charge size of 100 grams was used along both lines. The data clearly image three major dipping reflectors in the upper 200 ms (600 m). The dipping ones intersect or project to the surface at/or close to

  17. Seismic stratigraphy, some examples from Indian Ocean, interpretation of reflection data in interactive mode

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.S.

    the sedimentary layers on the basis of density-velocity contrasts. The surfaces may indicate unconformities or conformities. Eventually the method provides image of the sedimentary strata with internal surfaces and basaltic basement and occasionally its... underneath along a profile. Earth scientists will interpret these images in terms of stratigraphy. In simple terminology the seismic stratigraphy can be defined as a viewing of seismic reflection data with a geological approach. Total...

  18. Evaluation of seismic reflection data in the Davis and Lavender Canyons study area, Paradox Basin, Utah

    International Nuclear Information System (INIS)

    Kitcho, C.A.; Wong, I.G.; Turcotte, F.T.

    1986-08-01

    Seismic reflection data purchased from petroleum industry brokers and acquired through group speculative surveys were interpreted for information on the regional subsurface geologic structure and stratigraphy within and surrounding the Davis and Lavender Canyons study area in the Paradox Basin of southeastern Utah. Structures of interest were faults, folds, joints, and collapse structures related to salt dissolution. The seismic reflection data were used to interpret stratigraphy by identifying continuous and discontinuous reflectors on the seismic profiles. Thickening and thinning of strata and possible areas of salt flowage or dissolution could be identified from the seismic data. Identifiable reflectors included the tops of the Precambrian and Mississippian, a distinctive interbed close to the middle of the Pennsylvanian Paradox salt formation (probably the interval between Salt Cycles 10 and 13), and near the top of the Paradox salt. Of the 56 faults identified from the seismic reflection interpretation, 33 trend northwest, west-northwest, or west, and most affect only the deeper part of the stratigraphic section. These faults are part of the deep structural system found throughout the Paradox Basin, including the fold and fault belt in the northeast part of the basin. The faults bound basement Precambrian blocks that experienced minor activity during Mississippian and early Pennsylvanian deposition, and showed major displacement during early Paradox salt deposition as the Paradox Basin subsided. Based on the seismic data, most of these faults appear to have an upward terminus between the top of the Mississippian and the salt interbed reflector

  19. Piedmont seismic reflection study: A program integrated with tectonics to probe the cause of eastern seismicity

    Energy Technology Data Exchange (ETDEWEB)

    Glover, L. III; Coruh, C.; Costain, J.K.; Bollinger, G.A. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences)

    1992-03-01

    A new tectonic model of the Appalachian orogen indicates that one, not two or more, terrane boundaries is present in the Piedmont and Blue Ridge of the central and southern Appalachians. This terrane boundary is the Taconic suture, it has been transported in the allochthonous Blue Ridge/Piedmont crystalline thrust nappe, and it is repeated at the surface by faulting and folding associated with later Paleozoic orogenies. The suture passes through the lower crust and lithosphere somewhere east of Richmond. It is spatially associated with seismicity in the central Virginia seismic zone, but is not conformable with earthquake focal planes and appears to have little causal relation to their localization.

  20. Synergizing Crosswell Seismic and Electromagnetic Techniques for Enhancing Reservoir Characterization

    KAUST Repository

    Katterbauer, Klemens

    2015-11-18

    Increasing complexity of hydrocarbon projects and the request for higher recovery rates have driven the oil-and-gas industry to look for a more-detailed understanding of the subsurface formation to optimize recovery of oil and profitability. Despite the significant successes of geophysical techniques in determining changes within the reservoir, the benefits from individually mapping the information are limited. Although seismic techniques have been the main approach for imaging the subsurface, the weak density contrast between water and oil has made electromagnetic (EM) technology an attractive complement to improve fluid distinction, especially for high-saline water. This crosswell technology assumes greater importance for obtaining higher-resolution images of the interwell regions to more accurately characterize the reservoir and track fluid-front developments. In this study, an ensemble-Kalman-based history-matching framework is proposed for directly incorporating crosswell time-lapse seismic and EM data into the history-matching process. The direct incorporation of the time-lapse seismic and EM data into the history-matching process exploits the complementarity of these data to enhance subsurface characterization, to incorporate interwell information, and to avoid biases that may be incurred from separate inversions of the geophysical data for attributes. An extensive analysis with 2D and realistic 3D reservoirs illustrates the robustness and enhanced forecastability of critical reservoir variables. The 2D reservoir provides a better understanding of the connection between fluid discrimination and enhanced history matches, and the 3D reservoir demonstrates its applicability to a realistic reservoir. History-matching enhancements (in terms of reduction in the history-matching error) when incorporating both seismic and EM data averaged approximately 50% for the 2D case, and approximately 30% for the 3D case, and permeability estimates were approximately 25

  1. Seismic 2D reflection processing and interpretation of shallow refraction data

    International Nuclear Information System (INIS)

    Oehman, I.; Heikkinen, E.; Lehtimaeki, T.

    2006-12-01

    Posiva Oy takes care of the final disposal of spent nuclear fuel in Finland. In year 2001 Olkiluoto was selected for the site of final disposal. Currently construction of the underground research facility, ONKALO, is going on at the Olkiluoto site. The aim of this work was to use two-dimensional reflection seismic processing methods to refraction seismic data collected from the ONKALO area in year 2002, and to locate gently dipping reflectors from the stacked sections. Processing was done using mainly open source software Seismic Unix. After the processing, the most distinct two-dimensional reflectors were picked from seismic sections using visualization environment OpendTect. After picking the features from crossing lines were combined into three-dimensional surfaces. Special attention was given for the detection of possible faults and discontinuities. The surfaces were given coordinates and their orientation was adjusted using a geometric procedure, which corresponds roughly a 3D migration, transferred to 3D presentation utility and compared to available geological information. The advantage of this work is to be able to get three-dimensional reflection seismic results from existing data set at only processing costs. Survey lines are also partly located in ONKALO area where extensive surface seismic surveys may not be possible to perform. The applied processing method was successful in detecting the reflectors. Most significant steps were the refraction and residual statics, and deconvolution. Some distinct reflectors can be seen at times 20-200 ms (vertical depths 50-500 m). The signal gets noisier below 200 ms. Reflectors are best visible as coherent phase between the adjacent traces, but do not raise much above the surrounding noise level. Higher amount of traces to be stacked would emphasis the reflections and their continuity more. Reflectors picked on crossing lines match well to borehole observations (KR4, KR7, KR24 and KR38) of fracture zones, and get

  2. Probabilistic modeling of caprock leakage from seismic reflection data

    DEFF Research Database (Denmark)

    Zunino, Andrea; Hansen, Thomas Mejer; Bergjofd-Kitterød, Ingjerd

    We illustrate a methodology which helps to perform a leakage risk analysis for a CO2 reservoir based on a consistent, probabilistic approach to geophysical and geostatistical inversion. Generally, risk assessments of storage complexes are based on geological models and simulations of CO2 movement...... within the storage complexes. The geological models are built on top of geophysical data such as seismic surveys, geological information and well logs from the reservoir or nearby regions. The risk assessment of CO2 storage requires a careful analysis which accounts for all sources of uncertainty....... However, at present, no well-defined and consistent method for mapping the true uncertainty related to the geophysical data and how that uncertainty affects the overall risk assessment for the potential storage site is available. To properly quantify the uncertainties and to avoid unrealistic...

  3. On development and improvement of evaluation techniques for seismic ground motion

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    Issues regarding evaluation of active fault and ground motion for formulation of design basis ground motion (Ss) were prescribed in 'NSC seismic and tsunami safety reviewing manual' in 2012. Moreover, Nuclear Regulation Authority (NRA) is establishing the new seismic safety guideline. In this theme following four subjects were investigated to resolve the important problems for ground motion evaluation, (1) advanced evaluation of ground motion using fault model and uncertainty; (2) improving evaluation of ground motion using attenuation relation of response spectrum; (3) development of advanced and generic techniques for ground motion observation and observation tool in deep borehole; (4) improving the evaluation of site effect and seismic wave propagation characteristics. In addition as emergency requirements from NRA following two subjects were also investigated; (5) hazard evaluation development on fault displacement; (6) ground motion evaluation at near-by source location. Obtained results will be reflected not only in the domestic guideline established by NRA but in the national safety review and also in the safety standard guidelines of the International Atomic Energy Agency (IAEA) through its Extra-Budgetary Program (EBP), thereby contributing to technical cooperation in global nuclear seismic safety. (author)

  4. Full waveform seismic AVAZ signatures of anisotropic shales by integrated rock physics and the reflectivity method

    Science.gov (United States)

    Liu, Xiwu; Guo, Zhiqi; Han, Xu

    2018-06-01

    A set of parallel vertical fractures embedded in a vertically transverse isotropy (VTI) background leads to orthorhombic anisotropy and corresponding azimuthal seismic responses. We conducted seismic modeling of full waveform amplitude variations versus azimuth (AVAZ) responses of anisotropic shale by integrating a rock physics model and a reflectivity method. The results indicate that the azimuthal variation of P-wave velocity tends to be more complicated for orthorhombic medium compared to the horizontally transverse isotropy (HTI) case, especially at high polar angles. Correspondingly, for the HTI layer in the theoretical model, the short axis of the azimuthal PP amplitudes at the top interface is parallel to the fracture strike, while the long axis at the bottom reflection directs the fracture strike. In contrast, the orthorhombic layer in the theoretical model shows distinct AVAZ responses in terms of PP reflections. Nevertheless, the azimuthal signatures of the R- and T-components of the mode-converted PS reflections show similar AVAZ features for the HTI and orthorhombic layers, which may imply that the PS responses are dominated by fractures. For the application to real data, a seismic-well tie based on upscaled data and a reflectivity method illustrate good agreement between the reference layers and the corresponding reflected events. Finally, the full waveform seismic AVAZ responses of the Longmaxi shale formation are computed for the cases of HTI and orthorhombic anisotropy for comparison. For the two cases, the azimuthal features represent differences mainly in amplitudes, while slightly in the phases of the reflected waveforms. Azimuth variations in the PP reflections from the reference layers show distinct behaviors for the HTI and orthorhombic cases, while the mode-converted PS reflections in terms of the R- and T-components show little differences in azimuthal features. It may suggest that the behaviors of the PS waves are dominated by vertically

  5. Shallow shear-wave reflection seismics in the tsunami struck Krueng Aceh River Basin, Sumatra

    Directory of Open Access Journals (Sweden)

    U. Polom

    2008-01-01

    Full Text Available As part of the project "Management of Georisk" (MANGEONAD of the Federal Institute for Geosciences and Natural Resources (BGR, Hanover, high resolution shallow shear-wave reflection seismics was applied in the Indonesian province Nanggroe Aceh Darussalam, North Sumatra in cooperation with the Government of Indonesia, local counterparts, and the Leibniz Institute for Applied Geosciences, Hanover. The investigations were expected to support classification of earthquake site effects for the reconstruction of buildings and infrastructure as well as for groundwater exploration. The study focussed on the city of Banda Aceh and the surroundings of Aceh Besar. The shear-wave seismic surveys were done parallel to standard geoengineering investigations like cone penetrometer tests to support subsequent site specific statistical calibration. They were also partly supplemented by shallow p-wave seismics for the identification of (a elastic subsurface parameters and (b zones with abundance of groundwater. Evaluation of seismic site effects based on shallow reflection seismics has in fact been found to be a highly useful method in Aceh province. In particular, use of a vibratory seismic source was essential for successful application of shear-wave seismics in the city of Banda Aceh and in areas with compacted ground like on farm tracks in the surroundings, presenting mostly agricultural land use areas. We thus were able to explore the mechanical stiffness of the subsurface down to 100 m depth, occasionally even deeper, with remarkably high resolution. The results were transferred into geotechnical site classification in terms of the International Building Code (IBC, 2003. The seismic images give also insights into the history of the basin sedimentation processes of the Krueng Aceh River delta, which is relevant for the exploration of new areas for construction of safe foundations of buildings and for identification of fresh water aquifers in the tsunami

  6. Variable post-Paleozoic deformation detected by seismic reflection profiling across the northwestern "prong" of New Madrid seismic zone

    Science.gov (United States)

    McBride, J.H.; Pugin, Andre J.M.; Nelson, W.J.; Larson, T.H.; Sargent, S.L.; Devera, J.A.; Denny, F.B.; Woolery, E.W.

    2003-01-01

    High-resolution shallow seismic reflection profiles across the northwesternmost part of the New Madrid seismic zone (NMSZ) and northwestern margin of the Reelfoot rift, near the confluence of the Ohio and Mississippi Rivers in the northern Mississippi embayment, reveal intense structural deformation that apparently took place during the late Paleozoic and/or Mesozoic up to near the end of the Cretaceous Period. The seismic profiles were sited on both sides of the northeast-trending Olmsted fault, defined by varying elevations of the top of Mississippian (locally base of Cretaceous) bedrock. The trend of this fault is close to and parallel with an unusually straight segment of the Ohio River and is approximately on trend with the westernmost of two groups of northeast-aligned epicenters ("prongs") in the NMSZ. Initially suspected on the basis of pre-existing borehole data, the deformation along the fault has been confirmed by four seismic reflection profiles, combined with some new information from drilling. The new data reveal (1) many high-angle normal and reverse faults expressed as narrow grabens and anticlines (suggesting both extensional and compressional regimes) that involved the largest displacements during the late Cretaceous (McNairy); (2) a different style of deformation involving probably more horizontal displacements (i.e., thrusting) that occurred at the end of this phase near the end of McNairy deposition, with some fault offsets of Paleocene and younger units; (3) zones of steeply dipping faults that bound chaotic blocks similar to that observed previously from the nearby Commerce geophysical lineament (CGL); and (4) complex internal deformation stratigraphically restricted to the McNairy, suggestive of major sediment liquefaction or landsliding. Our results thus confirm the prevalence of complex Cretaceous deformations continuing up into Tertiary strata near the northern terminus of the NMSZ. ?? 2003 Elsevier Science B.V. All rights reserved.

  7. New Crustal Thickness for Djibouti, Afar, Using Seismic Techniques

    Science.gov (United States)

    Dugda, Mulugeta; Bililign, Solomon

    2008-10-01

    Crustal thickness and Poisson's ratio for the seismic station ATD in Djibouti, Afar, has been investigated using two seismic techniques (H-κ stacking of receiver functions and a joint inversion of receiver functions and surface wave group velocities). Both techniques give consistent results of crustal thickness 23±1.5 km and Poisson's ratio 0.31±0.02. We also determined a mean P-wave velocity (Vp) of ˜6.2 km/s but ˜6.9-7.0 km/s below a 2 - 5 km thick low velocity layer at the surface. Previous studies of crustal structure for Djibouti reported that the crust is 6 to 11 km thick while our study shows that the crust beneath Djibouti is between 20 and 25 km. This study argues that the crustal thickness values reported for Djibouti for the last 3 decades were not consistent with the reports for the other neighboring region in central and eastern Afar. Our results for ATD in Djibouti, however, are consistent with the reports of crustal thickness in many other parts of central and eastern Afar. We attribute this difference to how the Moho (the crust-mantle discontinuity) is defined (an increase of Vp to 7.4 km/s in this study vs. 6.9 km/s in previous studies).

  8. Low-frequency asymptotic analysis of seismic reflection from afluid-saturated medium

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.B.; Korneev, V.A.; Goloshubin, G.M.; Patzek, T.W.

    2004-04-14

    Reflection of a seismic wave from a plane interface betweentwo elastic media does not depend on the frequency. If one of the mediais poroelastic and fluid-saturated, then the reflection becomesfrequency-dependent. This paper presents a low-frequency asymptoticformula for the reflection of seismic plane p-wave from a fluid-saturatedporous medium. The obtained asymptotic scaling of the frequency-dependentcomponent of the reflection coefficient shows that it is asymptoticallyproportional to the square root of the product of the reservoir fluidmobility and the frequency of the signal. The dependence of this scalingon the dynamic Darcy's law relaxation time is investigated as well.Derivation of the main equations of the theory of poroelasticity from thedynamic filtration theory reveals that this relaxation time isproportional to Biot's tortuosity parameter.

  9. Seismic and electromagnetic interferometry : Retrieval of the earth's reflection response using crosscorrelation

    NARCIS (Netherlands)

    Draganov, D.

    2007-01-01

    One of the goals of exploration geophysics is to obtain an image of the subsurface. In petroleum exploration and near-surface geophysics, this is best achieved using reflected waves. For this, a controlled seismic or electromagnetic source is placed at the surface, activated, and the wavefields that

  10. Structure of the Gabon Margin from integrated seismic reflection and gravity data

    NARCIS (Netherlands)

    Dupre, S.; Cloetingh, S.A.P.L.; Bertotti, G.V.

    2011-01-01

    In the South Gabon Basin, deep multi-channel seismic reflection and gravity modeling analysis have shed light on key features of the structure of the margin. The thinned continental crust beneath the Gabon Margin appears to be composed of two distinct layers, separated by a clear, strong and more or

  11. Theory of reflectivity blurring in seismic depth imaging

    Science.gov (United States)

    Thomson, C. J.; Kitchenside, P. W.; Fletcher, R. P.

    2016-05-01

    A subsurface extended image gather obtained during controlled-source depth imaging yields a blurred kernel of an interface reflection operator. This reflectivity kernel or reflection function is comprised of the interface plane-wave reflection coefficients and so, in principle, the gather contains amplitude versus offset or angle information. We present a modelling theory for extended image gathers that accounts for variable illumination and blurring, under the assumption of a good migration-velocity model. The method involves forward modelling as well as migration or back propagation so as to define a receiver-side blurring function, which contains the effects of the detector array for a given shot. Composition with the modelled incident wave and summation over shots then yields an overall blurring function that relates the reflectivity to the extended image gather obtained from field data. The spatial evolution or instability of blurring functions is a key concept and there is generally not just spatial blurring in the apparent reflectivity, but also slowness or angle blurring. Gridded blurring functions can be estimated with, for example, a reverse-time migration modelling engine. A calibration step is required to account for ad hoc band limitedness in the modelling and the method also exploits blurring-function reciprocity. To demonstrate the concepts, we show numerical examples of various quantities using the well-known SIGSBEE test model and a simple salt-body overburden model, both for 2-D. The moderately strong slowness/angle blurring in the latter model suggests that the effect on amplitude versus offset or angle analysis should be considered in more realistic structures. Although the description and examples are for 2-D, the extension to 3-D is conceptually straightforward. The computational cost of overall blurring functions implies their targeted use for the foreseeable future, for example, in reservoir characterization. The description is for scalar

  12. A robust economic technique for crosswell seismic profiling. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hardage, B.A.; Simmons, J.L. Jr.

    1998-01-01

    The objective of this research program was to investigate a novel way to acquire crosswell tomographic data, that being to use a standard surface-positioned seismic energy source stationed inline with two wells that have downhole receiver arrays. This field technique differs from the traditional way that crosswell tomography is done, which requires that a downhole receiver array be in one well and that a downhole seismic source be in a second well. The purpose of the research effort was to evaluate the relative merits of the potential advantages and pitfalls of surface-source crosswell tomography, which some also refer to as twin-receiver-well crosswell tomography. The principal findings were: (1) surface-source crosswell tomography is a viable technology and can be used in appropriate reservoir conditions, (2) raypath modeling should be done to determine if the targeted interwell space is properly illuminated by surface-generated wavefields before proceeding to collect surface-source tomographic data, (3) crosswell data generated by a surface-based source are subject to a greater range of traveltime errors than are data generated by a downhole source, primarily due to shot statics caused by variable weathered layers, and (4) the accuracy and reliability of the interwell tomogram increase as more independent velocity information (sonic logs, velocity checkshots, vertical seismic profiles, downhole-source crosswell data) is available to constrain the inversion. The surface-source approach to crosswell tomography was evaluated by recording twin-receiver well data at the Texaco Borehole Test Site in Humble, Texas.

  13. Characterization of the Vajont landslide (North-Eastern Italy) by means of reflection and surface wave seismics

    Science.gov (United States)

    Petronio, Lorenzo; Boaga, Jacopo; Cassiani, Giorgio

    2016-05-01

    The mechanisms of the disastrous Vajont rockslide (North-Eastern Italy, October 9, 1963) have been studied in great detail over the past five decades. Nevertheless, the reconstruction of the rockslide dynamics still presents several uncertainties, including those related to the accurate estimation of the actual landslide mass. This work presents the results of a geophysical characterization of the Vajont landslide body in terms of material properties and buried geometry. Both aspects add new information to the existing dataset and will help a better understanding of the rockslide failure mechanisms and dynamics. In addition, some general considerations concerning the intricacies of landslide characterization can be drawn, with due attention to potential pitfalls. The employed techniques are: (i) high resolution P-wave reflection, (ii) high resolution SH-wave reflection, (iii) controlled source surface wave analysis. We adopted as a seismic source a vibrator both for P waves and SH waves, using vertical and horizontal geophones respectively. For the surface wave seismic survey we used a heavy drop-weight source and low frequency receivers. Despite the high noise level caused by the fractured conditions of the large rock body, a common situation in landslide studies, we managed to achieve a satisfying imaging quality of the landslide structure thanks to the large number of active channels, the short receiver interval and the test of appropriate seismic sources. The joint use of different seismic techniques help focus the investigation on the rock mass mechanical properties. Results are in good agreement with the available borehole data, the geological sections and the mechanical properties of the rockmass estimated by other studies. In general the proposed approach is likely to be applicable successfully to similar situations where scattering and other noise sources are a typical bottleneck to geophysical data acquisition on landslide bodies.

  14. Detection of frictional heat in seismic faults by coal reflectance

    Science.gov (United States)

    Kitamura, M.; Mukoyoshi, H.; Fulton, P. M.; Hirose, T.

    2012-12-01

    Quantitative assessment of heat generation along a fault during coseismic faulting is of primary importance in understanding the dynamics of earthquakes. Evidence of substantial frictional heating along a fault is also a reliable indicator determining whether a fault has slipped at high velocity in the past, which is crucial for assessing earthquake and tsunami hazard. The reflectance measurement of vitrinite (one of the primary components of coals) has been considered a possible geothermometer of fault zones, especially in accretionary wedges where vitrinite fragments are common [e.g., Sakaguchi et al., 2011]. Under normal burial conditions, vitrinite reflectance (Ro) increases by irreversible maturation reaction as temperature is elevated and thus sensitively records the maximum temperature to which the vitrinite is subjected. However, the commonly used kinetic models of vitrinite maturation [e.g., Sweeney and Burnham, 1990] may not yield accurate estimates of the peak temperature in a fault zone resulting from fast frictional heating rates [Fulton and Harris, 2012]. Whether or not coal can mature in typical earthquake rise time (e.g., ~10 seconds) remains uncertain. Here we present the results of friction experiments aimed at revealing coal maturation by frictional heat generated at slip velocities representative of natural earthquakes of up to 1.3 m/s. All friction experiments were conducted on a mixture of 90 wt% quartz powder and 10 wt% coal grains for simulated fault gouge at three different velocities of 0.0013 m/s, 0.65 m/s and 1.3 m/s, a constant normal stress of 1.0 MPa and ~15 m displacement under anoxic, dry nitrogen atmosphere at room temperature. We also measured temperature in the gouge zone during faulting by thermocouples. The initial coal fragments consist of vitrinite, inertinite and liptinite. Although liptinite was easy to identify microscopically, it was difficult to discriminate between vitrinite and inertinite grains as their grain size

  15. Fracture detection in crystalline rock using ultrasonic reflection techniques: Volume 1

    International Nuclear Information System (INIS)

    Palmer, S.P.

    1982-11-01

    This research was initiated to investigate using ultrasonic seismic reflection techniques to detect fracture discontinuities in a granitic rock. Initial compressional (P) and shear (SH) wave experiments were performed on a 0.9 x 0.9 x 0.3 meter granite slab in an attempt to detect seismic energy reflected from the opposite face of the slab. It was found that processing techniques such as deconvolution and array synthesis could improve the standout of the reflection event. During the summers of 1979 and 1980 SH reflection experiments were performed at a granite quarry near Knowles, California. The purpose of this study was to use SH reflection methods to detect an in situ fracture located one to three meters behind the quarry face. These SH data were later analyzed using methods similar to those applied in the laboratory. Interpretation of the later-arriving events observed in the SH field data as reflections from a steeply-dipping fracture was inconclusive. 41 refs., 43 figs., 7 tabs

  16. Reflection technique for thermal mapping of semiconductors

    Science.gov (United States)

    Walter, Martin J.

    1989-06-20

    Semiconductors may be optically tested for their temperatures by illuminating them with tunable monochromatic electromagnetic radiation and observing the light reflected off of them. A transition point will occur when the wavelength of the light corresponds with the actual band gap energy of the semiconductor. At the transition point, the image of the semiconductor will appreciably darken as the light is transmitted through it, rather than being reflected off of it. The wavelength of the light at the transition point corresponds to the actual band gap energy and the actual temperature of the semiconductor.

  17. Improving Vintage Seismic Data Quality through Implementation of Advance Processing Techniques

    Science.gov (United States)

    Latiff, A. H. Abdul; Boon Hong, P. G.; Jamaludin, S. N. F.

    2017-10-01

    It is essential in petroleum exploration to have high resolution subsurface images, both vertically and horizontally, in uncovering new geological and geophysical aspects of our subsurface. The lack of success may have been from the poor imaging quality which led to inaccurate analysis and interpretation. In this work, we re-processed the existing seismic dataset with an emphasis on two objectives. Firstly, to produce a better 3D seismic data quality with full retention of relative amplitudes and significantly reduce seismic and structural uncertainty. Secondly, to facilitate further prospect delineation through enhanced data resolution, fault definitions and events continuity, particularly in syn-rift section and basement cover contacts and in turn, better understand the geology of the subsurface especially in regard to the distribution of the fluvial and channel sands. By adding recent, state-of-the-art broadband processing techniques such as source and receiver de-ghosting, high density velocity analysis and shallow water de-multiple, the final results produced a better overall reflection detail and frequency in specific target zones, particularly in the deeper section.

  18. Reflection imaging of the Moon's interior using deep-moonquake seismic interferometry

    Science.gov (United States)

    Nishitsuji, Yohei; Rowe, C. A.; Wapenaar, Kees; Draganov, Deyan

    2016-04-01

    The internal structure of the Moon has been investigated over many years using a variety of seismic methods, such as travel time analysis, receiver functions, and tomography. Here we propose to apply body-wave seismic interferometry to deep moonquakes in order to retrieve zero-offset reflection responses (and thus images) beneath the Apollo stations on the nearside of the Moon from virtual sources colocated with the stations. This method is called deep-moonquake seismic interferometry (DMSI). Our results show a laterally coherent acoustic boundary around 50 km depth beneath all four Apollo stations. We interpret this boundary as the lunar seismic Moho. This depth agrees with Japan Aerospace Exploration Agency's (JAXA) SELenological and Engineering Explorer (SELENE) result and previous travel time analysis at the Apollo 12/14 sites. The deeper part of the image we obtain from DMSI shows laterally incoherent structures. Such lateral inhomogeneity we interpret as representing a zone characterized by strong scattering and constant apparent seismic velocity at our resolution scale (0.2-2.0 Hz).

  19. Groundwater exploration in a Quaternary sediment body by shear-wave reflection seismics

    Science.gov (United States)

    Pirrung, M.; Polom, U.; Krawczyk, C. M.

    2008-12-01

    The detailed investigation of a shallow aquifer structure is the prerequisite for choosing a proper well location for groundwater exploration drilling for human drinking water supply and subsequent managing of the aquifer system. In the case of shallow aquifers of some 10 m in depth, this task is still a challenge for high-resolution geophysical methods, especially in populated areas. In areas of paved surfaces, shallow shear-wave reflection seismics is advantageous compared to conventional P-wave seismic methods. The sediment body of the Alfbach valley within the Vulkaneifel region in Germany, partly covered by the village Gillenfeld, was estimated to have a maximum thickness of nearly 60 m. It lies on top of a complicated basement structure, constituted by an incorporated lava flow near the basement. For the positioning of new well locations, a combination of a SH-wave land streamer receiver system and a small, wheelbarrow-mounted SH-wave source was used for the seismic investigations. This equipment can be easily applied also in residential areas without notable trouble for the inhabitants. The results of the 2.5D profiling show a clear image of the sediment body down to the bedrock with high resolution. Along a 1 km seismic profile, the sediment thickness varies between 20 to more than 60 m in the centre of the valley. The reflection behaviour from the bedrock surface corroborates the hypothesis of a basement structure with distinct topography, including strong dipping events from the flanks of the valley and strong diffractions from subsurface discontinuities. The reflection seismic imaging leads to an estimation of the former shape of the valley and a reconstruction of the flow conditions at the beginning of the sedimentation process.

  20. Reprocessing and interpretation, seismic reflection data: Hanford Site, Pasco Basin, south central Washington

    International Nuclear Information System (INIS)

    Berkman, E.

    1983-01-01

    The purpose of this project was to reprocess, evaluate, and reinterpret 14 line miles of seismic reflection data acquired at the Hanford Site. Regional and area-specific geology has been reviewed, the data acquisition parameters as they relate to the limitations inherent in the data have been discussed, and the reprocessing procedures have been described in detail along with an evaluation of the original processing. After initial testing, the focus of the reprocessing was placed on resolution of the geologic horizons at and near the top of the basalt. The reprocessed seismic data shows significant improvement over the original processing. The improvement is the result of the integrated processing and interpretation approach where each processing step has been tested in sequence and the intermediate results examined carefully in accordance with the project goals. The interpretation procedure placed strong reliance upon synthetic seismograms and models calculated based upon the physical parameters of the subsurface materials, and upon associated geophysical (reflection, gravity, magnetic) data. The final interpretation of the seismic data is in agreement with the structural contour maps based primarily on borehole information. The seismic interpretation has added important detail concerning areas which should be considered for further study. 60 figs., 1 tab

  1. Crustal structure in the Kiruna area, northern Sweden, based on seismic reflection profiling

    Science.gov (United States)

    Juhojuntti, Niklas; Bergman, Stefan; Olsson, Sverker

    2013-04-01

    Northernmost Sweden is currently one of the most active mining areas in Europe. In order to better understand the regional three-dimensional crustal structure and to support deep ore exploration, we have acquired a 74 km long seismic reflection profile in the Kiruna area. The upper crust in this area is largely composed of various supracrustal units, which are dominated by metabasalts, acidic metavolcanics and clastic metasedimentary rocks, resting on an Archaean metagranitoid complex. All of these units have been intruded by plutonic rocks, and to variable degrees folded, sheared and metamorphosed, during the Svecokarelian orogeny. The profile crosses several steep ductile shear zones, some of which extend for hundreds of kilometres along strike. Many of the lithological contacts and deformation zones are expected to be seismically reflective. The profile is located only a few kilometres from the world's largest underground iron-ore mine in Kiruna, and closer to the profile there are several known ore bodies, some of which are active exploration targets. For the seismic recording we used approximately 350 geophones in split-spread configuration, at a separation of 25 m. The main seismic source was the Vibsist system (an impact source), which normally was employed at every geophone station. We also fired explosive charges (8-16 kg) at a few locations distributed along the profile to image deeper structures, although at very low resolution. Wireless seismometers were placed along and to the side of the profile, mainly in order to achieve better velocity control and to study out-of-the-plane reflections. Some mining blasts in Kiruna were also recorded. The upper crust in the area is quite reflective, most clearly demonstrated by the dynamite shot records. Some of the reflections appear to originate from steeply dipping structures. The dynamite shot records show a set of reflections at 3-4 s twt, corresponding to a depth of roughly 10 km, the explanation for which is

  2. A Comparison of seismic instrument noise coherence analysis techniques

    Science.gov (United States)

    Ringler, A.T.; Hutt, C.R.; Evans, J.R.; Sandoval, L.D.

    2011-01-01

    The self-noise of a seismic instrument is a fundamental characteristic used to evaluate the quality of the instrument. It is important to be able to measure this self-noise robustly, to understand how differences among test configurations affect the tests, and to understand how different processing techniques and isolation methods (from nonseismic sources) can contribute to differences in results. We compare two popular coherence methods used for calculating incoherent noise, which is widely used as an estimate of instrument self-noise (incoherent noise and self-noise are not strictly identical but in observatory practice are approximately equivalent; Holcomb, 1989; Sleeman et al., 2006). Beyond directly comparing these two coherence methods on similar models of seismometers, we compare how small changes in test conditions can contribute to incoherent-noise estimates. These conditions include timing errors, signal-to-noise ratio changes (ratios between background noise and instrument incoherent noise), relative sensor locations, misalignment errors, processing techniques, and different configurations of sensor types.

  3. Uniquely Acquired Vintage Seismic Reflection Data Reveal the Stratigraphic and Tectonic History of the Montana Disturbed Belt, USA

    Science.gov (United States)

    Speece, M. A.; Link, C. A.; Stickney, M.

    2011-12-01

    techniques including linear noise suppression of the air wave and ground roll, refraction statics, and prestack migration. Reprocessing of these data using state-of-the-art seismic reflection processing techniques will provide a detailed picture of the stratigraphy and tectonic framework for this region. Moreover, extended correlations of the Vibroseis records to Moho depths might reveal new insights on crustal thickness and provide a framework for understanding crustal thickening during the Laramide Orogeny as well as later Cenozoic extension.

  4. Seismic reflection profile of the Blake Ridge near sites 994, 995, and 997: Chapter 4

    Science.gov (United States)

    Dillon, William P.; Hutchinson, Deborah R.; Drury, Rebecca M.

    1996-01-01

    Seismic reflection profiles near Sites 994, 995, and 997 were collected with seismic sources that provide maximum resolution with adequate power to image the zone of gas hydrate stability and the region direction beneath it. The overall structure of the sediment drift deposit that constitutes the Blake Ridge consists of southwestward-dipping strata. These strata are approximately conformal to the seafloor on the southwest side of the ridge and are truncated by erosion on the northeast side. A bottom-simulating reflection (BSR) marks the velocity contrast between gas hydrate-bearing sediment and regions containing free gas beneath the zone of gas hydrate stability. The BSR is strong and continuous near the ridge crest but becomes discontinuous on the flanks, where concentration of gas is reduced and dipping strata pass through the level of the base o fgas hydrate stability or the strata are disrupted by faults. Seismic reflection amplitudes appear to be reduced in the region of gas hydrate formation compared to normal amplitudes. A faulted zone ~0.5-0.6 s thick parallels reflections from strata. We infer that this may represent a formerly gas hydrate-bearing zone that was faulted because of a breakdown of hydrate near its phase limit (at the base of the zone). Strong reflections at the top of the faulted zone are caused by free-gas acccumulation at Site 994. Similar strong reflections probably are caused by free-gas accumulations where the top of the faulted zone rises above the BSR, although this would require local free gas within the hydrate-stable zone.

  5. Paleostress Analysis with Reflection Seismic Data: Example from the Songliao Basin, Northeast China

    Science.gov (United States)

    Liu, G.; Persaud, P.; Zhang, Y.

    2017-12-01

    Currently paleostress inversion using fault-slip data is a well established approach. However, the deformation history contained in folds has not yet been fully utilized to determine the paleostress field. By applying a 2D FFT-based algorithm to a structure or isopach map derived from reflection seismic data, we find a new way of exploiting the information preserved in folds to determine the paleostress. Our method requires that the strata have a large areal extent and are well preserved. After pre-processing the maps, we find that in the frequency-wavenumber (F-K) domain, folds with similar strikes are grouped into spectrum belts. Each belt parallels the short axis of the fold group and can therefore indicate the direction of the associated maximum horizontal stress. Some information on the relative chronology of stresses can be deduced by comparing the structure and isopach spectrum maps, e.g., if the structure spectrum map has one more spectrum belt than that of the isopach map (an approximate paleo-structure map of the corresponding stratum), we can conclude that the indicated stress postdated the deposition of the stratum. We selected three Late Cretaceous strata from a 3D seismic survey located in the intracontinental Songliao Basin, northeast China. The Songliao has experienced four episodes of deformation: mantle upwelling, rifting, postrift thermal subsidence and structural inversion (Feng et al., 2009). The selected strata were deposited during the third stage. Three structure and two isopach maps were decomposed in the F-K domain. Spectral analysis of the lower isopach map shows eight paleostress directions. We also identify a ninth paleostress in addition to the previous eight from the structure maps and the upper isopach map. The eight stress directions that exist in both the isopach and structure maps may have been active throughout the time period spanned by the strata. We interpret the ninth paleostress as being active after the deposition of the

  6. Interpretation of seismic reflection data, Central Palo Duro Basin: Technical report

    International Nuclear Information System (INIS)

    1986-11-01

    Seismic reflection data from the Central Palo Duro Basin, Texas, were studied to identify and characterize geologic structure, potential hydrocarbon traps, and anomalies suggesting adverse features such as salt dissolution or diapirism. The data included seismic reflection data, geologic and geophysical data controlled by Stone and Webster Engineering Corporation, and data from the literature. These data comprised approximately 590 line-mi of seismic profiles over approximately 4000 mi 2 , plus well logs from 308 wells. The study addressed the section from shallow reflectors down to basement. Structural contour maps were prepared for the Upper San Andres, Near Top of Glorieta, Wolfcamp, and Precambrian horizons. Isopach maps were prepared for intervals between the Upper and Lower San Andres and between the Upper San Andres and the Wolfcamp. Interpretation indicates southeasterly dips in the northwest part of the mapped area and southwesterly dips in the southwest part. Geologic structures show a generally northwest alignment. Faults at the Precambrian level and geologic structures show a generally northwest alignment. Faulting in the area is largely limited to the Precambrian, but interpretation is uncertain. Evidence of post-Wolfcampian faulting is not recognized. Seismic data delineating the San Andres section indicate a stable section throughout the area. Anomalous reflection events possibly associated with subsurface salt dissolution were seen at the 800- to 1200-ft level in Swisher County. Other anomalies include an overthickened zone northwest of Westway and carbonate buildup in the Wolfcamp and Pennsylvanian in Randall County. Mississippian to Middle Pennsylvanian diastrophism resulting in the Amarillo Uplift and Matador Arch is not manifested structurally in the central Palo Duro Basin. Subsidence or gentle uplift contributed to some structural deformation

  7. Active intra-basin faulting in the Northern Basin of Lake Malawi from seismic reflection data

    Science.gov (United States)

    Shillington, D. J.; Chindandali, P. R. N.; Scholz, C. A.; Ebinger, C. J.; Onyango, E. A.; Peterson, K.; Gaherty, J. B.; Nyblade, A.; Accardo, N. J.; McCartney, T.; Oliva, S. J.; Kamihanda, G.; Ferdinand, R.; Salima, J.; Mruma, A. H.

    2016-12-01

    Many questions remain about the development and evolution of fault systems in weakly extended rifts, including the relative roles of border faults and intra-basin faults, and segmentation at various scales. The northern Lake Malawi (Nyasa) rift in the East African Rift System is an early stage rift exhibiting pronounced tectonic segmentation, which is defined by 100-km-long border faults. The basins also contain a series of intrabasinal faults and associated synrift sediments. The occurrence of the 2009 Karonga Earthquake Sequence on one of these intrabasinal faults indicates that some of them are active. Here we present new multichannel seismic reflection data from the Northern Basin of the Malawi Rift collected in 2015 as a part of the SEGMeNT (Study of Extension and maGmatism in Malawi aNd Tanzania) project. This rift basin is bound on its east side by the west-dipping Livingstone border fault. Over 650 km of seismic reflection profiles were acquired in the Northern Basin using a 500 to 1540 cu in air gun array and a 1200- to 1500-m seismic streamer. Dip lines image a series of north-south oriented west-dipping intra-basin faults and basement reflections up to 5 s twtt near the border fault. Cumulative offsets on intra-basin faults decrease to the west. The largest intra-basin fault has a vertical displacement of >2 s two-way travel time, indicating that it has accommodated significant total extension. Some of these intra-basin faults offset the lake bottom and the youngest sediments by up to 50 s twtt ( 37 m), demonstrating they are still active. The two largest intra-basin faults exhibit the largest offsets of young sediments and also correspond to the area of highest seismicity based on analysis of seismic data from the 89-station SEGMeNT onshore/offshore network (see Peterson et al, this session). Fault patterns in MCS profiles vary along the basin, suggesting a smaller scale of segmentation of faults within the basin; these variations in fault patterns

  8. Formation of diapiric structure in the deformation zone, central Indian Ocean: A model from gravity and seismic reflection data

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.S.; Rao, D.G.; Neprochnov, Y.P.

    Analyses of bathymetry, gravity and seismic reflection data of the diffusive plate boundary in the central Indian Ocean reveal a new kind of deformed structure besides the well-reported structures of long-wavelength anticlinal basement rises...

  9. Multichannel Seismic Reflection Data - SCAR - Queen Maud Land - 1985-1986, SDLS CD-ROM vol 22

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1985-86 in the Queen Maud Land region, Antarctica, by the Japan National Oil...

  10. Faults survey by 3D reflection seismics; Sanjigen hanshaho jishin tansa ni yoru danso chosa

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, T; Ejiri, T; Yamada, N; Narita, N; Aso, H; Takano, H; Matsumura, M [Dia Consultants Company, Tokyo (Japan)

    1996-10-01

    This paper describes fault survey by 3D seismic reflection exploration. Survey has been conducted mainly at flat land area without pavement not in urban area in Japan. Subsurface structure is complicated with intersecting multiple faults. In this area, a lot of geological investigations have been done prior to the seismic reflection exploration. Fairly certain images of faults have been obtained. However, there were still unknown structures. Survey was conducted at an area of 170m{times}280m in the CDP range. Measurements were carried out by using 100 g of dynamite per seismic generation point combined with 40 Hz velocity geophones. Fixed distribution consisting of lattice points of 12{times}12 was adopted as an observation method. In and around the lattice, a great number of explosions were carried out. The CDP stacking method and the method of migration after stacking were used for the data processing. The 3D structures of six horizons and five faults could be interpreted. Interpreted horizons were well agreed with the logging results. 3 figs.

  11. Crustal structure of Shatsky Rise from joint refraction and reflection seismic tomography

    Science.gov (United States)

    Korenaga, J.; Sager, W. W.

    2011-12-01

    Shatsky Rise in the western Pacific is one of a few gigantic oceanic plateaus in the world, with a surface area of ˜ 4.8 ± 105~km2 (about the same size as California). In contrast to other large oceanic plateaus formed during the Cretaceous Quite Period, Shatsky Rise formed during the frequent reversals of magnetic polarity, allowing its tectonic environment to be resolved in detail. It was formed at a rapidly spreading ridge-ridge-ridge triple junction, so the effect of lithospheric lid on magma migration is expected to be minimal, thereby facilitating the petrological interpretation of its seismic structure in terms of parental mantle processes. In the summer of 2010, a seismic refraction survey combined with multichannel seismic profiling was conducted across Shatsky Rise. Twenty eight ocean-bottom seismometers were deployed along two crossing perpendicular lines, and all of the instruments were recovered successfully, yielding a large volume of high-quality wide-angle refraction and reflection data, with the source-receiver distance often exceeding 200~km. In this contribution, we present the P-wave velocity structure of the Shatsky Rise crust, which is constructed by joint refraction and reflection travel time tomography, and also discuss its implications for the origin of Shatsky Rise.

  12. Applicability of reflection seismic measurements in detailed characterization of crystalline bedrock

    International Nuclear Information System (INIS)

    Sireni, S.

    2011-03-01

    Posiva carried out a seismic survey in the access tunnel of the underground research facility ONKALO in 2009. The survey contributes the detailed characterization of the bedrock in the final disposal of spent nuclear fuel. The aim of this work was to examine the geophysical and geological properties of the chosen tunnel intersections to clarify the important characteristics for reflection generation, and evaluate applicability of this survey for characterization of crystalline bedrock. The seismic result consists of 24 projected amplitude images in 12 different angles. The size of an image is 260*300 m. The amount of digitized reflectors is over 100 and all of them could not be included in this work. The study was limited to 14 intersections that were considered important: brittle fault intersections, tunnel-crosscutting fractures, or lithological contacts. Presence of a brittle fault zone or a tunnel-crosscutting fracture limits the suitable bedrock volume for depositing the nuclear fuel canisters, and wide lithological contacts are a common source of reflection. The seismic data was compared to the existing geological, hydrogeological and geophysical data got from the pilot holes and the tunnel. The most important characteristics were fractures: orientation, fillings, and thickness of the fillings, alteration and water leakage. Geophysically interesting was density, seismic velocities and their products: acoustic impedance and synthetic seismograms. Calculated acoustic impedances showed some differences between cases, but they did not indicate the presence of a reflector. The most common cause of reflector was undulating slickensided, highly altered, tunnel-crosscutting fracture that had thick fracture-fillings and water present. Water was included five times in interpreted reflectors. Also few reflectors were connected to varying mineralogy. Few problematic cases occurred, where a geological feature and a reflection did not correlate, and three of the cases with

  13. Crustal evolution of Eocene paleo arc around Ogasawara region obtained by seismic reflection survey

    Science.gov (United States)

    Yamashita, M.; Takahashi, N.; Kodaira, S.; Miura, S.; Ishizuka, O.; Tatsumi, Y.

    2011-12-01

    The Izu-Bonin (Ogasawara)-Mariana (IBM) arc is known to the typical oceanic island arc, and it is the most suitable area to understand the growth process of island arc. The existence of two paleo arc which consists of Oligocene and Eocene paleo age is known in IBM forearc region by geological and geophysical studies. The Ogasawara ridge is also known to locate the initial structure of arc evolution from geologic sampling of research submersible. In this region, IODP drilling site: IBM-2 is proposed in order to understand the temporal and spatial change in arc crust composition from 50 to 40Ma magmatism. Site IBM-2 consists of two offset drilling holes (BON-1, BON-2). BON-1 designed to first encounter forearc basalt and will reach the sheeted dykes. BON-2 will start in boninites and finish in fore arc basalts. The purpose of these drilling is sampling the full volcanic stratigraphy from gabbro to boninite. There is no seismic data around BON-1 and BON-2, therefore it is need to conduct the multi-channel seismic reflection survey. Japan Agency for Marine-Earth Science and Technology carried out multi-channel seismic reflection survey and wide-angle reflection survey using 7,800 cu.in. air gun, 5 km streamer with 444 ch hydrophones and 40 OBSs in March 2011. We obtained two seismic reflection profiles of lines KT06 and KT07 along the paleo arc around Ogasawara ridge. Line KT06 located the north side of Ogasawara ridge. Line KT07 located the trench side of Ogasawara ridge. Lines KT06 is also deployed the OBSs every 5 km interval. Thin sediments are covered with basement in both survey lines. There are some sediment filled in depression topography. The low-frequency reflection from the top of subducting Pacific plate is recognized in line KT06. The continuity of this reflection is not clear due to the complicated bathymetry. The displacement of basement in northern side of Ogasawara ridge is identified along the lineament of bathymetry in Line 06. This structure is

  14. Reflection and tubewave analysis of the seismic data from the Stripa crosshole site

    International Nuclear Information System (INIS)

    Cosma, C.; Baehler, S.; Hammarstroem, M.; Pihl, J.

    1986-12-01

    The data from the crosshole research program (radar, seismics and hydraulics) in the Stripa Phase II Project resulted in the construction of a model. The results from the present study were compared to this model. It was found that the existing data set used for tomographic analysis could only be used to a limited extent, as reflection analysis requires a more dense detector coverage. Nevertheless two reflectors were detected. The positions of the reflectors were compared to the existing crosshole model and proved to correlate well. For the tubewave analysis almost all crosshole seismic data could be used. By comparing the results with previous hydraulic tests, it was found that tubewave sources and hydraulically conductive zones are in concordance. All previously defined zones but one could be detected. (orig./HP)

  15. Monte Carlo reservoir analysis combining seismic reflection data and informed priors

    DEFF Research Database (Denmark)

    Zunino, Andrea; Mosegaard, Klaus; Lange, Katrine

    2015-01-01

    Determination of a petroleum reservoir structure and rock bulk properties relies extensively on inference from reflection seismology. However, classic deterministic methods to invert seismic data for reservoir properties suffer from some limitations, among which are the difficulty of handling...... with the goal to directly infer the rock facies and porosity of a target reservoir zone. We thus combined a rock-physics model with seismic data in a single inversion algorithm. For large data sets, theMcMC method may become computationally impractical, so we relied on multiple-point-based a priori information...... to quantify geologically plausible models. We tested this methodology on a synthetic reservoir model. The solution of the inverse problem was then represented by a collection of facies and porosity reservoir models, which were samples of the posterior distribution. The final product included probability maps...

  16. The tectonics of the area around the Konrad Mine (Salzgitter) based on reflection seismic studies

    International Nuclear Information System (INIS)

    Jaritz, W.

    1986-01-01

    Reflection seismic investigations were carried out to determine the safety of the final disposal of radioactive waste in the Konrad mine. The layer thickness since the Zechstein and the position of the most important geological horizons are described. On the basis of the seismic sections, the Thiede and Vechelde-Broistedt salt structures and the fault systems of the Konrad Graben and Immendorf fault are briefly analysed. The development of the structures in this area is explained by a combination of halokinesis and epirogenic-tectonic processes. The iron-ore deposit is syngenetic with the surrounding salt stocks. This has to be taken into consideration for a reconstruction of the paleogeography and assessment of the deposit. (orig.) [de

  17. Site investigation SFR. Reprocessing of reflection seismic profiles 5b and 8, Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Juhlin, Christopher; Zhang, Fengjiao (Uppsala Univ., Dept. of Earth Sciences (Sweden))

    2010-12-15

    Reflection seismic profiles 5b and 8 in the northern Forsmark area have been reprocessed with the aim of improving the images in the uppermost 500 metres in the SFR area. The main conclusion is that a new reflection (B10) has been identified that may extend below the SFR site. This reflection was not clearly observed in the previous processing. The reflection strikes approximately N25E and dips at about 35 degrees to the southeast. This orientation is similar to the set B group identified earlier /Juhlin and Palm 2005/. Note that the dip of the reflection is uncertain. On shot gathers it appears to dip at a slightly shallower angle while on the stacked sections it appears to dip at a greater angle. This discrepancy is probably due to the crooked nature of the profiles. However, reflections are clearly observed in shot gathers and its presence below SFR is highly probable. Two new reflections were also identified further north along profile 5b (A11 and A12). These dip to the south-southeast, but would be found at a depth of 1-2 km below SFR if they extend to below the site. There are also signs of a 3rd reflection with similar orientation to the set A group identified earlier, A13, but its existence is very speculative. This reflector would intersect the surface within the SFR area. South of the Singoe deformation zone on profile 5b, another new reflection has been found, N1. The orientation of this reflection is speculative since it is not clearly seen on profile 8. It has been modelled as dipping to the north at about 35 degrees and projects to the surface south of the main SFR area. In addition, the orientation of reflection B7 has been revised as has the lateral extent of A1. Most importantly, A1 is now interpreted not to extend to the surface and not cross the Singoe deformation zone

  18. Density-based reflectivity in seismic exploration for coal in Alberta, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, D.C.; Lyatsky, H.V. (University of Calgary, AB (Canada). Dept. of Geology and Geophysics)

    1991-01-01

    At a coal field in central Alberta, Canada, the acoustic reflectivity of shallow coal seams was found to be dominated by the density contrast between coal and host bentonitic sediments. Sonic logs and a check-shot survey showed that the compressional-wave velocity is almost constant through the coal zone and the overlying sediments, and ranges in value between 2000 m/s and 2350 m/s over different parts of the coal field. The average coal density is 1400 kg/m{sup 3}, whereas the density of the sediments is about 2200 kg/m{sup 3}. Results are illustrated using logs from a typical drillhole in the coal field. At this location, the time reflectivity sequence based on both the density and sonic logs is very similar to that obtained when the density log only is used, with a constant velocity assumed through the coal zone. At another drillhole location in the coal field, where reflection seismic data had been acquired, a synthetic seismogram generated from the density log closely matches the stacked seismic section. 6 refs., 4 figs.

  19. Reprocessing of multi-channel seismic-reflection data collected in the Chukchi Sea

    Science.gov (United States)

    Agena, W.F.; Lee, M.W.; Hart, P.E.

    2001-01-01

    Contained on this set of two CD-ROMs are stacked and migrated multi-channel seismic-reflection data for 44 lines recorded in the Chukchi Sea, northern Alaska, by the United States Geological Survey in 1977, 1978, and 1980. All data were reprocessed by the USGS in 2000 using updated methods. The resulting final data have both increased temporal and spatial resolution thus providing improved interpretability. An added benefit of these CD-ROMs is that they are a more stable, long-term archival medium for the data.

  20. Reprocessing of multi-channel seismic-reflection data collected in the Beaufort Sea

    Science.gov (United States)

    Agena, W.F.; Lee, Myung W.; Hart, P.E.

    2000-01-01

    Contained on this set of two CD-ROMs are stacked and migrated multi-channel seismic-reflection data for 65 lines recorded in the Beaufort Sea by the United States Geological Survey in 1977. All data were reprocessed by the USGS using updated processing methods resulting in improved interpretability. Each of the two CD-ROMs contains the following files: 1) 65 files containing the digital seismic data in standard, SEG-Y format; 2) 1 file containing navigation data for the 65 lines in standard SEG-P1 format; 3) an ASCII text file with cross-reference information for relating the sequential trace numbers on each line to cdp numbers and shotpoint numbers; 4) 2 small scale graphic images (stacked and migrated) of a segment of line 722 in Adobe Acrobat (R) PDF format; 5) a graphic image of the location map, generated from the navigation file; 6) PlotSeis, an MS-DOS Application that allows PC users to interactively view the SEG-Y files; 7) a PlotSeis documentation file; and 8) an explanation of the processing used to create the final seismic sections (this document).

  1. Seismic activity prediction using computational intelligence techniques in northern Pakistan

    Science.gov (United States)

    Asim, Khawaja M.; Awais, Muhammad; Martínez-Álvarez, F.; Iqbal, Talat

    2017-10-01

    Earthquake prediction study is carried out for the region of northern Pakistan. The prediction methodology includes interdisciplinary interaction of seismology and computational intelligence. Eight seismic parameters are computed based upon the past earthquakes. Predictive ability of these eight seismic parameters is evaluated in terms of information gain, which leads to the selection of six parameters to be used in prediction. Multiple computationally intelligent models have been developed for earthquake prediction using selected seismic parameters. These models include feed-forward neural network, recurrent neural network, random forest, multi layer perceptron, radial basis neural network, and support vector machine. The performance of every prediction model is evaluated and McNemar's statistical test is applied to observe the statistical significance of computational methodologies. Feed-forward neural network shows statistically significant predictions along with accuracy of 75% and positive predictive value of 78% in context of northern Pakistan.

  2. An application of the baseline correction technique for correcting distorted seismic acceleration time histories

    International Nuclear Information System (INIS)

    Lee, Gyu Mahn; Kim, Jong Wook; Jeoung, Kyeong Hoon; Kim, Tae Wan; Park, Keun Bae; Kim, Keung Koo

    2008-03-01

    Three kinds of baseline correction techniques named as 'Newmark', 'Zero-VD' and 'Newmark and Zero-VD' were introduced to correct the distorted physical characteristics of a seismic time history accelogram. The corrected seismic accelerations and distorted raw acceleration showed an identical response spectra in frequency domains, but showed various time history profiles in velocity and displacement domains. The referred correction techniques were programmed with UNIX-HP Fortran. The verification of the baseline corrected seismic data in terms of frequency response spectrum were performed by ANSYS of a commerical FEM software

  3. Interpretation of shallow crustal structure of the Imperial Valley, California, from seismic reflection profiles

    Energy Technology Data Exchange (ETDEWEB)

    Severson, L.K.

    1987-05-01

    Eight seismic reflection profiles (285 km total length) from the Imperial Valley, California, were provided to CALCRUST for reprocessing and interpretation. Two profiles were located along the western margin of the valley, five profiles were situated along the eastern margin and one traversed the deepest portion of the basin. These data reveal that the central basin contains a wedge of highly faulted sediments that thins to the east. Most of the faulting is strike-slip but there is evidence for block rotations on the scale of 5 to 10 kilometers within the Brawley Seismic Zone. These lines provide insight into the nature of the east and west edges of the Imperial Valley. The basement at the northwestern margin of the valley, to the north of the Superstition Hills, has been normal-faulted and blocks of basement material have ''calved'' into the trough. A blanket of sediments has been deposited on this margin. To the south of the Superstition Hills and Superstition Mountain, the top of the basement is a detachment surface that dips gently into the basin. This margin is also covered by a thick sequence sediments. The basement of the eastern margin consists of metamorphic rocks of the upper plate of the Chocolate Mountain Thrust system underlain by the Orocopia Schist. These rocks dip to the southeast and extend westward to the Sand Hills Fault but do not appear to cross it. Thus, the Sand Hills Fault is interpreted to be the southern extension of the San Andreas Fault. North of the Sand Hills Fault the East Highline Canal seismicity lineament is associated with a strike-slip fault and is probably linked to the Sand Hills Fault. Six geothermal areas crossed by these lines, in agreement with previous studies of geothermal reservoirs, are associated with ''faded'' zones, Bouguer gravity and heat flow maxima, and with higher seismic velocities than surrounding terranes.

  4. Uncertainty analysis of depth predictions from seismic reflection data using Bayesian statistics

    Science.gov (United States)

    Michelioudakis, Dimitrios G.; Hobbs, Richard W.; Caiado, Camila C. S.

    2018-03-01

    Estimating the depths of target horizons from seismic reflection data is an important task in exploration geophysics. To constrain these depths we need a reliable and accurate velocity model. Here, we build an optimum 2D seismic reflection data processing flow focused on pre - stack deghosting filters and velocity model building and apply Bayesian methods, including Gaussian process emulation and Bayesian History Matching (BHM), to estimate the uncertainties of the depths of key horizons near the borehole DSDP-258 located in the Mentelle Basin, south west of Australia, and compare the results with the drilled core from that well. Following this strategy, the tie between the modelled and observed depths from DSDP-258 core was in accordance with the ± 2σ posterior credibility intervals and predictions for depths to key horizons were made for the two new drill sites, adjacent the existing borehole of the area. The probabilistic analysis allowed us to generate multiple realizations of pre-stack depth migrated images, these can be directly used to better constrain interpretation and identify potential risk at drill sites. The method will be applied to constrain the drilling targets for the upcoming International Ocean Discovery Program (IODP), leg 369.

  5. Uncertainty analysis of depth predictions from seismic reflection data using Bayesian statistics

    Science.gov (United States)

    Michelioudakis, Dimitrios G.; Hobbs, Richard W.; Caiado, Camila C. S.

    2018-06-01

    Estimating the depths of target horizons from seismic reflection data is an important task in exploration geophysics. To constrain these depths we need a reliable and accurate velocity model. Here, we build an optimum 2-D seismic reflection data processing flow focused on pre-stack deghosting filters and velocity model building and apply Bayesian methods, including Gaussian process emulation and Bayesian History Matching, to estimate the uncertainties of the depths of key horizons near the Deep Sea Drilling Project (DSDP) borehole 258 (DSDP-258) located in the Mentelle Basin, southwest of Australia, and compare the results with the drilled core from that well. Following this strategy, the tie between the modelled and observed depths from DSDP-258 core was in accordance with the ±2σ posterior credibility intervals and predictions for depths to key horizons were made for the two new drill sites, adjacent to the existing borehole of the area. The probabilistic analysis allowed us to generate multiple realizations of pre-stack depth migrated images, these can be directly used to better constrain interpretation and identify potential risk at drill sites. The method will be applied to constrain the drilling targets for the upcoming International Ocean Discovery Program, leg 369.

  6. Integrated Reflection Seismic Monitoring and Reservoir Modeling for Geologic CO2 Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    John Rogers

    2011-12-31

    The US DOE/NETL CCS MVA program funded a project with Fusion Petroleum Technologies Inc. (now SIGMA) to model the proof of concept of using sparse seismic data in the monitoring of CO{sub 2} injected into saline aquifers. The goal of the project was to develop and demonstrate an active source reflection seismic imaging strategy based on deployment of spatially sparse surface seismic arrays. The primary objective was to test the feasibility of sparse seismic array systems to monitor the CO{sub 2} plume migration injected into deep saline aquifers. The USDOE/RMOTC Teapot Dome (Wyoming) 3D seismic and reservoir data targeting the Crow Mountain formation was used as a realistic proxy to evaluate the feasibility of the proposed methodology. Though the RMOTC field has been well studied, the Crow Mountain as a saline aquifer has not been studied previously as a CO{sub 2} sequestration (storage) candidate reservoir. A full reprocessing of the seismic data from field tapes that included prestack time migration (PSTM) followed by prestack depth migration (PSDM) was performed. A baseline reservoir model was generated from the new imaging results that characterized the faults and horizon surfaces of the Crow Mountain reservoir. The 3D interpretation was integrated with the petrophysical data from available wells and incorporated into a geocellular model. The reservoir structure used in the geocellular model was developed using advanced inversion technologies including Fusion's ThinMAN{trademark} broadband spectral inversion. Seal failure risk was assessed using Fusion's proprietary GEOPRESS{trademark} pore pressure and fracture pressure prediction technology. CO{sub 2} injection was simulated into the Crow Mountain with a commercial reservoir simulator. Approximately 1.2MM tons of CO{sub 2} was simulated to be injected into the Crow Mountain reservoir over 30 years and subsequently let 'soak' in the reservoir for 970 years. The relatively small plume

  7. Reflection seismic studies over the end-glacial Burträsk fault, Skellefteå, Sweden

    Directory of Open Access Journals (Sweden)

    C. Juhlin

    2011-01-01

    Full Text Available Reflection seismic data were acquired along a ca. 22 km long profile over the end-glacial Burträsk fault with a nominal receiver and source spacing of 20 m. A steeply dipping reflection can be correlated to the Burträsk fault, indicating that the fault dips at about 55° to the southeast near the surface. The reflection from the fault is rather poorly imaged, probably due to a lateral offset in the fault of about 1 km at this location and the crookedness of the seismic profile in the vicinity of the fault. A more pronounced steeply dipping reflection is observed about 4 km southeast of the Burträsk fault. Based on its correlation with a topographic low at the surface this reflection is interpreted to originate from a fracture zone. There are no signs of large displacements along this zone as the glacial ice receded, but earthquakes could be associated with it today. Other reflections on the processed seismic section may originate from changes in lithological variations in the supra-crustal rocks or from intrusions of more mafic rock. Constraints on the fault geometry provided by the reflection seismic data will help determine what stresses were required to activate the fault when the major rupture along it occurred ca. 9500 years ago.

  8. Seismarmara experiment: results from reprocessing of selected multi-channel seismic reflection profiles

    Science.gov (United States)

    Cetin, S.; Voogd, B.; Carton, H.; Laigle, M.; Becel, A.; Saatcilar, R.; Singh, S.; Hirn, A.

    2003-04-01

    The North Anatolian Fault (NAF) has been responsible for the earthquakes of Izmit and Duzce in 1999. The occurrence of these earthquakes has drawn scientific attention into the Sea of Marmara since the NAF enters into the Sea of Marmara where the latest Izmit earthquake rupture stopped. The SEISMARMARA-2001 survey is a combined seismic reflection, refraction and earthquake experiment carried out in 2001 in the Marmara Region in Turkey by French-Turkish scientific cooperation. The objectives of this survey were to image the various branches of the NAF and related other fault systems. R/V Le Nadir was equipped with a 4.5 km long streamer with 360 channels and a large airgun source. During Leg 1, a grid of large regional lines encompassing the whole Marmara trough was shot. For part of them a strong 8100 cu.in. source for deepest penetration was used, with a 150 m shot interval giving a 15-fold coverage. Another part was shot for a higher resolution with a 2900 cu. in. array at a 50m or 38 m interval to give a 45 or 60-fold coverage. The latter acquisition parameters were used for Leg 2 that was devoted to a very dense grid of lines in the Cinarcik Basin Reprocessing of the multi-channel seismic data is currently being undertaken in several Institutions using different seismic processing softwares (GeoVecteur, ProMAX, Focus), to take advantage of the diverse acquisitions and cope with their limitations, for instance high fold-order for Leg 2 and strength of signal but loose spatial sampling for the bigger source. The main objectives of the reprocessing of the selected profiles are to do a detailed velocity analysis and stacking after deconvolution, filtering to remove or suppress deep sea bottom multiples and out of plane reflections, and time-migration and depth conversion and thus reveal both the shallow and deeper reflection image of the crust in the Sea of Marmara. We show that choosing an appropriate processing sequence for different sources and acquisition

  9. Quantitative identification and analysis of sub-seismic extensional structure system: technique schemes and processes

    International Nuclear Information System (INIS)

    Chenghua, Ou; Chen, Wei; Ma, Zhonggao

    2015-01-01

    Quantitative characterization of complex sub-seismic extensional structure system that essentially controls petroleum exploitation is difficult to implement in seismic profile interpretation. This research, based on a case study in block M of Myanmar, established a set of quantitative treatment schemes and technique processes for the identification of sub-seismic low-displacement (SSLD) extensional faults or fractures upon structural deformation restoration and geometric inversion. Firstly, the master-subsidiary inheritance relations and configuration of the seismic-scale extensional fault systems are determined by analyzing the structural pattern. Besides, three-dimensional (3D) pattern and characteristics of the seismic-scale extensional structure have been illustrated by a 3D structure model built upon seismic sections. Moreover, according to the dilatancy obtained from structural restoration on the basis of inclined shear method, as well as the fracture-flow index, potential SSLD extensional faults or fractures have been quantitatively identified. Application of the technique processes to the sub-seismic low-displacement extensional structures in block M in Myanmar is instructive to quantitatively interpret those SSLD extensional structure systems in practice. (paper)

  10. Tectonic evolution of the Salton Sea inferred from seismic reflection data

    Science.gov (United States)

    Brothers, D.S.; Driscoll, N.W.; Kent, G.M.; Harding, A.J.; Babcock, J.M.; Baskin, R.L.

    2009-01-01

    Oblique extension across strike-slip faults causes subsidence and leads to the formation of pull-apart basins such as the Salton Sea in southern California. The formation of these basins has generally been studied using laboratory experiments or numerical models. Here we combine seismic reflection data and geological observations from the Salton Sea to understand the evolution of this nascent pull-apart basin. Our data reveal the presence of a northeast-trending hinge zone that separates the sea into northern and southern sub-basins. Differential subsidence (10 mm yr 1) in the southern sub-basin suggests the existence of northwest-dipping basin-bounding faults near the southern shoreline, which may control the spatial distribution of young volcanism. Rotated and truncated strata north of the hinge zone suggest that the onset of extension associated with this pull-apart basin began after 0.5 million years ago. We suggest that slip is partitioned spatially and temporally into vertical and horizontal domains in the Salton Sea. In contrast to previous models based on historical seismicity patterns, the rapid subsidence and fault architecture that we document in the southern part of the sea are consistent with experimental models for pull-apart basins. ?? 2009 Macmillan Publishers Limited.

  11. Multichannel seismic-reflection data collected in 1980 in the eastern Chukchi Sea

    Science.gov (United States)

    Grantz, Arthur; Mann, Dennis M.; May, Steven D.

    1986-01-01

    The U.S. Geological Survey (USGS) collected approximately 2,652 km of 24-channel seismic-reflection data in early September, 1980, over the continental shelf in the eastern Chukchi Sea (Fig. 1). The profiles were collected on the USGS Research Vessel S.P. Lee. The seismic energy source consisted of a tuned array of five airguns with a total volume of 1213 cubic inches of air compressed to approximately 1900 psi. The recording system consisted of a 24-channel, 2400 meter long streamer with a group interval of 100 m, and a GUS (Global Universal Science) model 4200 digital recording instrument. Shots were fired every 50 meters. Navigational control for the survey was provided by a Magnavox integrated navigation system using transit satellites and doppler-sonar augmented by Loran C (Rho-Rho). A 2-millisecond sampling rate was used in the field; the data were later desampled to 4-milliseconds during the demultiplexing process. 8 seconds data length was recorded. Processing was done at the USGS Pacific Marine Geology Multichannel Processing Center in Menlo Park, California, in the sequence: editing-demultiplexing, velocity analysis, CDP stacking, deconvolution-filtering, and plotting on an electrostatic plotter. Plate 1 is a trackline chart showing shotpoint navigation.

  12. Digital single-channel seismic-reflection data from western Santa Monica basin

    Science.gov (United States)

    Normark, William R.; Piper, David J.W.; Sliter, Ray W.; Triezenberg, Peter; Gutmacher, Christina E.

    2006-01-01

    During a collaborative project in 1992, Geological Survey of Canada and United States Geological Survey scientists obtained about 850 line-km of high-quality single-channel boomer and sleeve-gun seismic-reflection profiles across Hueneme, Mugu and Dume submarine fans, Santa Monica Basin, off southern California. The goals of this work were to better understand the processes that lead to the formation of sandy submarine fans and the role of sea-level changes in controlling fan development. This report includes a trackline map of the area surveyed, as well as images of the sleeve-gun profiles and the opportunity to download both images and digital data files (SEG-Y) of all the sleeve-gun profiles.

  13. A low-frequency asymptotic model of seismic reflection from a high-permeability layer

    Energy Technology Data Exchange (ETDEWEB)

    Silin, Dmitriy; Goloshubin, Gennady

    2009-03-01

    Analysis of compression wave propagation through a high-permeability layer in a homogeneous poroelastic medium predicts a peak of reflection in the low-frequency end of the spectrum. An explicit formula expresses the resonant frequency through the elastic moduli of the solid skeleton, the permeability of the reservoir rock, the fluid viscosity and compressibility, and the reservoir thickness. This result is obtained through a low-frequency asymptotic analysis of the Biot's model of poroelasticity. A new physical interpretation of some coefficients of the classical poroelasticity is a result of the derivation of the main equations from the Hooke's law, momentum and mass balance equations, and the Darcy's law. The velocity of wave propagation, the attenuation factor, and the wave number, are expressed in the form of power series with respect to a small dimensionless parameter. The latter is equal to the product of the kinematic reservoir fluid mobility, an imaginary unit, and the frequency of the signal. Retaining only the leading terms of the series leads to explicit and relatively simple expressions for the reflection and transmission coefficients for a planar wave crossing an interface between two permeable media, as well as wave reflection from a thin highly-permeable layer (a lens). The practical implications of the theory developed here are seismic modeling, inversion, and attribute analysis.

  14. Crustal structure of the North Iberian continental margin from seismic refraction/wide-angle reflection profiles

    Science.gov (United States)

    Ruiz, M.; Díaz, J.; Pedreira, D.; Gallart, J.; Pulgar, J. A.

    2017-10-01

    The structure and geodynamics of the southern margin of the Bay of Biscay have been investigated from a set of 11 multichannel seismic reflection profiles, recorded also at wide angle offsets in an onshore-offshore network of 24 OBS/OBH and 46 land sites. This contribution focuses on the analysis of the wide-angle reflection/refraction data along representative profiles. The results document strong lateral variations of the crustal structure along the margin and provide an extensive test of the crustal models previously proposed for the northern part of the Iberian Peninsula. Offshore, the crust has a typical continental structure in the eastern tip of the bay, which disappears smoothly towards the NW to reach crustal thickness close to 10 km at the edge of the studied area ( 45°N, 6°W). The analysis of the velocity-depth profiles, altogether with additional information provided by the multichannel seismic data and magnetic surveys, led to the conclusion that the crust in this part of the bay should be interpreted as transitional from continental to oceanic. Typical oceanic crust has not been imaged in the investigated area. Onshore, the new results are in good agreement with previous results and document the indentation of the Bay of Biscay crust into the Iberian crust, forcing its subduction to the North. The interpreted profiles show that the extent of the southward indentation is not uniform, with an Alpine root less developed in the central and western sector of the Basque-Cantabrian Basin. N-S to NE-SW transfer structures seem to control those variations in the indentation degree.

  15. Virtual source reflection imaging of the Socorro Magma Body, New Mexico, using a dense seismic array

    Science.gov (United States)

    Finlay, T. S.; Worthington, L. L.; Schmandt, B.; Hansen, S. M.; Bilek, S. L.; Aster, R. C.; Ranasinghe, N. R.

    2017-12-01

    The Socorro Magma Body (SMB) is one of the largest known actively inflating continental magmatic intrusions. Previous studies have relied on sparse instrument coverage to determine its spatial extent, depth, and seismic signature, which characterized the body as a thin sill with a surface at 19 km below the Earth's surface. However, over the last two decades, InSAR and magneto-telluric (MT) studies have shed new light on the SMB and invigorated the scientific debate of the spatial distribution and uplift rate of the SMB. We return to seismic imaging of the SMB with the Sevilleta Array, a 12-day deployment of approximately 800 vertical component, 10-Hz geophones north of Socorro, New Mexico above and around the estimated northern half of the SMB. Teleseismic virtual source reflection profiling (TVR) employs the free surface reflection off of a teleseismic P as a virtual source in dense arrays, and has been used successfully to image basin structure and the Moho in multiple tectonic environments. The Sevilleta Array recorded 62 teleseismic events greater than M5. Applying TVR to the data collected by the Sevilleta Array, we present stacks from four events that produced the with high signal-to-noise ratios and simple source-time functions: the February 11, 2015 M6.7 in northern Argentina, the February 19, 2015 M5.4 in Kamchatka, Russia, and the February 21, 2015 M5.1 and February 22, 2015 M5.5 in western Colombia. Preliminary results suggest eastward-dipping reflectors at approximately 5 km depth near the Sierra Ladrones range in the northwestern corner of the array. Further analysis will focus on creating profiles across the area of maximum SMB uplift and constraining basin geometry.

  16. Seismic-Reflection Technology Defines Potential Vertical Bypass in Hydrogeologic Confinement within Tertiary Carbonates of the Southeastern Florida Platform

    Science.gov (United States)

    Cunningham, K. J.; Walker, C.; Westcott, R. L.

    2011-12-01

    Continuous improvements in shallow-focused, high-resolution, marine seismic-reflection technology has provided the opportunity to evaluate geologic structures that breach confining units of the Floridan aquifer system within the southeastern Florida Platform. The Floridan aquifer system is comprised mostly of Tertiary platform carbonates. In southeastern Florida, hydrogeologic confinement is important to sustainable use of the Floridan aquifer system, where the saline lower part is used for injection of wastewater and the brackish upper part is an alternative source of drinking water. Between 2007 and 2011, approximately 275 km of 24- and 48-channel seismic-reflection profiles were acquired in canals of peninsular southeastern Florida, Biscayne Bay, present-day Florida shelf margin, and the deeply submerged Miami Terrace. Vertical to steeply dipping offsets in seismic reflections indicate faults, which range from Eocene to possible early Pliocene age. Most faults are associated with karst collapse structures; however, a few tectonic faults of early Miocene to early Pliocene age are present. The faults may serve as a pathway for vertical groundwater flow across relatively low-permeability carbonate strata that separate zones of regionally extensive high-permeability in the Floridan aquifer system. The faults may collectively produce a regional confinement bypass system. In early 2011, twenty seismic-reflection profiles were acquired near the Key Biscayne submarine sinkhole located on the seafloor of the Miami Terrace. Here the water depth is about 365 m. A steeply dipping (eastward) zone of mostly deteriorated quality of seismic-reflection data underlies the sinkhole. Correlation of coherent seismic reflections within and adjacent to the disturbed zone indicates a series of faults occur within the zone. It is hypothesized that upward movement of groundwater within the zone contributed to development of a hypogenic karst system and the resultant overlying sinkhole

  17. Crustal structure of the southeast Greenland margin from joint refraction and reflection seismic tomography

    Science.gov (United States)

    Korenaga, J.; Holbrook, W. S.; Kent, G. M.; Kelemen, P. B.; Detrick, R. S.; Larsen, H.-C.; Hopper, J. R.; Dahl-Jensen, T.

    2000-09-01

    We present results from a combined multichannel seismic reflection (MCS) and wideangle onshore/offshore seismic experiment conducted in 1996 across the southeast Greenland continental margin. A new seismic tomographic method is developed to jointly invert refraction and reflection travel times for a two-dimensional velocity structure. We employ a hybrid ray-tracing scheme based on the graph method and the local ray-bending refinement to efficiently obtain an accurate forward solution, and we employ smoothing and optional damping constraints to regularize an iterative inversion. We invert 2318 Pg and 2078 PmP travel times to construct a compressional velocity model for the 350-km-long transect, and a long-wavelength structure with strong lateral heterogeneity is recovered, including (1) ˜30-km-thick, undeformed continental crust with a velocity of 6.0 to 7.0 km/s near the landward end, (2) 30- to 15-km-thick igneous crust within a 150-km-wide continent-ocean transition zone, and (3) 15- to 9-km-thick oceanic crust toward the seaward end. The thickness of the igneous upper crust characterized by a high-velocity gradient also varies from 6 km within the transition zone to ˜3 km seaward. The bottom half of the lower crust generally has a velocity higher than 7.0 km/s, reaching a maximum of 7.2 to 7.5 km/s at the Moho. A nonlinear Monte Carlo uncertainty analysis is performed to estimate the a posteriori model variance, showing that most velocity and depth nodes are well determined with one standard deviation of 0.05-0.10 km/s and 0.25-1.5 km, respectively. Despite significant variation in crustal thickness, the mean velocity of the igneous crust, which serves as a proxy for the bulk crustal composition, is surprisingly constant (˜7.0 km/s) along the transect. On the basis of a mantle melting model incorporating the effect of active mantle upwelling, this velocity-thickness relationship is used to constrain the mantle melting process during the breakup of Greenland

  18. Shallow Seismic Reflection Study of Recently Active Fault Scarps, Mina Deflection, Western Nevada

    Science.gov (United States)

    Black, R. A.; Christie, M.; Tsoflias, G. P.; Stockli, D. F.

    2006-12-01

    During the spring and summer of 2006 University of Kansas geophysics students and faculty acquired shallow, high resolution seismic reflection data over actively deforming alluvial fans developing across the Emmigrant Peak (in Fish Lake Valley) and Queen Valley Faults in western Nevada. These normal faults represent a portion of the transition from the right-lateral deformation associated with the Walker Lane/Eastern California Shear Zone to the normal and left-lateral faulting of the Mina Deflection. Data were gathered over areas of recent high resolution geological mapping and limited trenching by KU students. An extensive GPR data grid was also acquired. The GPR results are reported in Christie, et al., 2006. The seismic data gathered in the spring included both walkaway tests and a short CMP test line. These data indicated that a very near-surface P-wave to S-wave conversion was taking place and that very high quality S-wave reflections were probably dominating shot records to over one second in time. CMP lines acquired during the summer utilized a 144 channel networked Geode system, single 28 hz geophones, and a 30.06 downhole rifle source. Receiver spacing was 0.5 m, source spacing 1.0m and CMP bin spacings were 0.25m for all lines. Surveying was performed using an RTK system which was also used to develop a concurrent high resolution DEM. A dip line of over 400m and a strike line over 100m in length were shot across the active fan scarp in Fish Lake Valley. Data processing is still underway. However, preliminary interpretation of common-offset gathers and brute stacks indicates very complex faulting and detailed stratigraphic information to depths of over 125m. Depth of information was actually limited by the 1024ms recording time. Several west-dipping normal faults downstep towards the basin. East-dipping antithetic normal faulting is extensive. Several distinctive stratigraphic packages are bound by the faults and apparent unconformitites. A CMP dip line

  19. Fault analysis in the very shallow seismic reflection method. Part 3. Migration; Gokusenso hanshaho ni okeru danso kaiseki. 3. Migration

    Energy Technology Data Exchange (ETDEWEB)

    Nagumo, S; Muraoka, S; Takahashi, T [OYO Corp., Tokyo (Japan)

    1997-10-22

    Concerning the analysis of data obtained by the seismic reflection method, migration in the very shallow layer is discussed. When the dip angle of the reflection plane involved is disclosed by DMO conversion, the amount of migration (travelling sideways) can be calculated by use of simple geometrical formulas though on the presumption that the sector velocity is constant. Categorized into this technique are such methods as DMO conversion migration, direct dip migration, F-K method, and finite difference method. This means that waveforms are not damaged by migration processing although elongation occurs due to time base conversion. When it is taken into account that waveform distortion is generally grave in the migration related methods widely in use, this feature has to be said valuable in holding information on faults. This is especially advantageous in the very shallow layer because the amount of migration is proportionally larger when the level is deeper and, in addition, migration processing is useful when it is necessary to know more accurately the character of the fault plane. 8 figs.

  20. Imaging near-subsurface subrosion structures and faults using SH-wave reflection seismics

    Science.gov (United States)

    Wadas, Sonja; Polom, Ulrich; Buness, Hermann; Krawczyk, Charlotte

    2016-04-01

    Subrosion is a term for underground leaching of soluble rocks and is a global phenomenon. It involves dissolution of evaporites due to the presence of unsaturated water, fractures and faults. Fractures and faults are pathways for water to circulate and to generate subsurface cavities. Depending on the leached material and the parameters of the generation process, especially the dissolution rate, different kinds of subrosion structures evolve in the subsurface. The two end members are collapse and depression structures. Subrosion is a natural process, but it can be enhanced by anthropogenic factors like manipulation of the aquifer system and groundwater flow and by e.g. extraction of saline water. The formation of sinkholes and depressions are a dangerous geohazard, especially if they occur in urban areas, which often leads to building and infrastructural damage and life-threatening situations. For this reason investigations of the processes that induce subrosion and a detailed analysis of the resulting structures are of importance. To develop a comprehensive model of near-subsurface subrosion structures, reflection seismics is one of the methods used by the Leibniz Institute for Applied Geophysics. The study area is located in the city of Bad Frankenhausen in northern Thuringia, Germany. Most of the geological underground of Thuringia is characterized by Permian deposits. Bad Frankenhausen is situated directly south of the Kyffhäuser mountain range at the Kyffhäuser Southern Margin Fault. This major fault is one of the main pathways for the circulating ground- and meteoric waters that leach the Permian deposits, especially the Leine-, Staßfurt- and Werra Formations. 2014 and 2015 eight shear wave reflection seismic profiles were carried out in the urban area of Bad Frankenhausen and three profiles in the countrified surroundings. Altogether ca. 3.6 km were surveyed using a landstreamer as receiver and an electro-dynamic vibrator as source. The surveys were

  1. OCT structure, COB location and magmatic type of the S Angolan & SE Brazilian margins from integrated quantitative analysis of deep seismic reflection and gravity anomaly data

    Science.gov (United States)

    Cowie, Leanne; Kusznir, Nick; Horn, Brian

    2014-05-01

    Integrated quantitative analysis using deep seismic reflection data and gravity inversion have been applied to the S Angolan and SE Brazilian margins to determine OCT structure, COB location and magmatic type. Knowledge of these margin parameters are of critical importance for understanding rifted continental margin formation processes and in evaluating petroleum systems in deep-water frontier oil and gas exploration. The OCT structure, COB location and magmatic type of the S Angolan and SE Brazilian rifted continental margins are much debated; exhumed and serpentinised mantle have been reported at these margins. Gravity anomaly inversion, incorporating a lithosphere thermal gravity anomaly correction, has been used to determine Moho depth, crustal basement thickness and continental lithosphere thinning. Residual Depth Anomaly (RDA) analysis has been used to investigate OCT bathymetric anomalies with respect to expected oceanic bathymetries and subsidence analysis has been used to determine the distribution of continental lithosphere thinning. These techniques have been validated for profiles Lusigal 12 and ISE-01 on the Iberian margin. In addition a joint inversion technique using deep seismic reflection and gravity anomaly data has been applied to the ION-GXT BS1-575 SE Brazil and ION-GXT CS1-2400 S Angola deep seismic reflection lines. The joint inversion method solves for coincident seismic and gravity Moho in the time domain and calculates the lateral variations in crustal basement densities and velocities along the seismic profiles. Gravity inversion, RDA and subsidence analysis along the ION-GXT BS1-575 profile, which crosses the Sao Paulo Plateau and Florianopolis Ridge of the SE Brazilian margin, predict the COB to be located SE of the Florianopolis Ridge. Integrated quantitative analysis shows no evidence for exhumed mantle on this margin profile. The joint inversion technique predicts oceanic crustal thicknesses of between 7 and 8 km thickness with

  2. Forsmark site investigation. Reflection seismic studies in the Forsmark area, 2004: Stage 2

    Energy Technology Data Exchange (ETDEWEB)

    Juhlin, Christopher; Palm, Hans [Uppsala Univ. (Sweden). Dept. of Earth Sciences

    2005-06-15

    Reflection seismic data were acquired in the Fall of 2004 in the Forsmark area, located about 140 km north of Stockholm, Sweden. The Forsmark area has been targeted by SKB as a possible storage site for spent nuclear fuel. About 25 km of high resolution (nominal source and receiver spacing of maximum 10 m and a minimum of 160 active channels) seismic data were acquired along 10 profiles, varying in length from about 1 km to over 4 km. Three of these profiles are extensions of profiles that were acquired in 2002 (Stage 1). While the 2002 Stage 1 profiles were geared towards acquiring data from within the relatively undeformed lens, the current study focused on acquiring data from the boundaries of the lens. Data acquisition was also concentrated towards the western part of the candidate area. Data were acquired using a combination of the same explosive source as in Stage 1 (1575 g of explosives) and the VIBSIST mechanical source consisting of an industrial hammer mounted on a tractor. Earlier tests in Laxemar had shown that the VIBSIST source gives comparable data to the explosive source and is less expensive. It can also be used in areas where explosives are prohibited, such as close to the nuclear power plant. At present, the source cannot be used in the terrain, therefore an explosive component is still required. About 80% of the 2100 source points were activated using the VIBSIST system. Stacked sections from the new profiles are generally consistent with the Stage 1 results. Reflections from the prominent south dipping A1 reflector can be observed on most profiles, however, it is not clear if it can be traced all the way to the surface. Neither is it clearly observed below the power plant, suggesting its lateral extent is limited to the west. Instead, a gently east dipping reflector (B8) is interpreted below the power plant. Reflections consistent with the A2 reflector are also found on two profiles, but cannot be traced very far to the south, suggesting that

  3. Seismic reflection data imaging and interpretation from Braniewo2014 experiment using additional wide-angle refraction and reflection and well-logs data

    Science.gov (United States)

    Trzeciak, Maciej; Majdański, Mariusz; Białas, Sebastian; Gaczyński, Edward; Maksym, Andrzej

    2015-04-01

    Braniewo2014 reflection and refraction experiment was realized in cooperation between Polish Oil and Gas Company (PGNiG) and the Institute of Geophysics (IGF), Polish Academy of Sciences, near the locality of Braniewo in northern Poland. PGNiG realized a 20-km-long reflection profile, using vibroseis and dynamite shooting; the aim of the reflection survey was to characterise Silurian shale gas reservoir. IGF deployed 59 seismic stations along this profile and registered additional full-spread wide-angle refraction and reflection data, with offsets up to 12 km; maximum offsets from the seismic reflection survey was 3 km. To improve the velocity information two velocity logs from near deep boreholes were used. The main goal of the joint reflection-refraction interpretation was to find relations between velocity field from reflection velocity analysis and refraction tomography, and to build a velocity model which would be consistent for both, reflection and refraction, datasets. In this paper we present imaging results and velocity models from Braniewo2014 experiment and the methodology we used.

  4. Structure and petroleum plays of the St. Lawrence Platform and Appalachians in southern Quebec : insights from interpretation of MRNQ seismic reflection data

    Energy Technology Data Exchange (ETDEWEB)

    Castonguay, S.; Lavoie, D. [Natural Resources Canada, Quebec, PQ (Canada). Geological Survey of Canada, Quebec Division; Dietrich, J. [Natural Resources Canada, Calgary, AB (Canada). Geological Survey of Canada; Laliberte, J.Y. [Ministere des Ressources naturelles et de la Faune du Quebec, Charlesbourg, QC (Canada). Direction generale des hydrocarbures et des biocarburants

    2010-09-15

    This paper presented the results of a study in which 3 regional seismic reflection lines originally acquired in 1978 were reprocessed and reinterpreted using current techniques and methodologies. The profiles cross the Chambly-Fortierville syncline and provide images of the St. Lawrence Platform and the Appalachian foreland thrust belt of southern Quebec, including one that spans the entire width of the southern Quebec Appalachians. Post-stack seismic data processing and time migration were used to improve the quality of the original seismic sections, allowing interpretations that provide new information on subsurface geology, such as the recognition of complex structural patterns in platform and foreland units, the presence of a triangle zone at the structural front, and the geometry of thrust slices of platform units and Appalachian thrust beds, as well as images of the internal Humber Zone, including back-thrust faults and mega thrust wedges. The Saint-Flavien natural gas-field and other potential targets in the St. Lawrence Platform and Appalachian Foreland are imaged in the seismic profiles. The study provided new insights into the structure, geological evolution, and petroleum potential of the St. Lawrence Platform and the Appalachian foreland thrust belt of southern Quebec, including a potential, previously unrecognized Ordovician hydrothermal dolomite play. The new subsurface interpretations give a clearer view of the major structure affecting the Utica Shale, providing new insights into the limits of the unconventional shale gas play in the St. Lawrence Platform. 53 refs., 8 figs.

  5. Architecture and growth history of a Miocene carbonate platform from 3D seismic reflection data; Luconia province, offshore Sarawak, Malaysia

    NARCIS (Netherlands)

    Zampetti, V.; Schlager, W.; van Konijnenburg, J.H; Everts, A.J.

    2004-01-01

    Using 3D seismic reflection data and wireline logs we reconstruct in detail the architecture and growth history of a Miocene carbonate platform in the Luconia province, offshore Sarawak, Malaysia. Platform growth started in the Late Oligocene to Early Miocene, by coalescence of isolated patch reefs.

  6. Crustal-scale pop-up structure in cratonic lithosphere: DOBREdeep seismic reflection study of the Donbas fold belt, Ukraine.

    NARCIS (Netherlands)

    Maystrenko, Yu.; Stovba, S.; Stephenson, R.A.; Bayer, U.; Menyoli, E.; Gajewski, D.; Huebscher, Ch.; Rabbel, W.; Saintot, A.N.; Starostenko, V.I.; Thybo, H.; Tolkunov, A.P.

    2003-01-01

    The DOBRE project investigated the interplay of geologic and geodynamic processes that controlled the evolution of the Donbas fold belt, Ukraine, as an example of an inverted intracratonic rift basin. A deep seismic reflection profile provides an excellent image of the structure of the Donbas fold

  7. Analysis of multi-channel seismic reflection and magnetic data along 13 degrees N latitude across the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, D.G.; Bhattacharya, G.C.; Ramana, M.V.; Subrahmanyam, V.; Ramprasad, T.; Krishna, K.S.; Chaubey, A.K.; Murty, G.P.S.; Srinivas, K.; Desa, M.; Reddy, S.I.; Ashalata, B.; Subrahmanyam, C.; Mital, G.S.; Drolia, R.K.; rai, S.N.; Ghosh, S.K.; Singh, R.N.; Majumdar, M.

    Analysis of the multi-channel seismic reflection, magnetic and bathymetric data collected along a transect, 1110 km long parallel to 13 degrees N lat. across the Bay of Bengal was made. The transect is from the continental shelf off Madras...

  8. Journal Writing as a Teaching Technique to Promote Reflection

    Science.gov (United States)

    Walker, Stacy E

    2006-01-01

    Objective: To introduce the process of journal writing to promote reflection and discuss the techniques and strategies to implement journal writing in an athletic training education curriculum. Background: Journal writing can facilitate reflection and allow students to express feelings regarding their educational experiences. The format of this writing can vary depending on the students' needs and the instructor's goals. Description: Aspects of journal writing assignments are discussed, including different points to take into account before assigning the journals. Lastly, various factors to contemplate are presented when providing feedback to the students regarding their written entries. Clinical Advantages: Journal writing assignments can benefit students by enhancing reflection, facilitating critical thought, expressing feelings, and writing focused arguments. Journal writing can be adapted into a student's clinical course to assist with bridging the gap between classroom and clinical knowledge. In addition, journals can assist athletic training students with exploring different options for handling daily experiences. PMID:16791310

  9. Seismic qualification using digital signal processing/modal testing and finite element techniques

    International Nuclear Information System (INIS)

    Steedman, J.B.; Edelstein, A.

    1983-01-01

    A systematic procedure in which digital signal processing, modal testing and finite element techniques can be used to seismically qualify Class IE equipment for use in nuclear generating stations is presented. A new method was also developed in which measured transmissibility functions and Fourier transformation techniques were combined to compute instrument response spectra. As an illustrative example of the qualification method, the paper follows the qualification of a safety related Class IE Heating, Ventilating, and Air Conditioning (HVAC) Control Panel subjected to both seismic and hydrodynamic loading conditions

  10. From the Atlas to the Rif a Crustal seismic image across Morocco: The SIMA & RIFSEIS control source wide-angle seismic reflection data

    Science.gov (United States)

    Carbonell, Ramon; Ayarza, Puy; Gallart, Josep; Diaz, Jordi; Harnafi, Mimoun; Levander, Alan; Teixell, Antonio

    2014-05-01

    The velocity structure of the crust and the geometry of the Moho across Morocco has been the main target of two recently acquired wide-angle seismic reflection transects. One is the SIMA experiment which provided seismic constraints beneath the Atlas Mountains and the second has been the RIFSEIS experiment which sampled the RIF orogen. Jointly these controlled source wide-angle seismic reflection data results in an almost 700 km, seismic profile going from the the Sahara craton across the High and Middle Atlas and Rif Mountain till the Gibraltar-Arc (Alboran). Current work on the interpretation of the seismic data-set is based on forward modeling, ray-tracing, as well as low fold wide-angle stacking. The data has resulted in a detailed crustal structure and velocity model for the Atlas Mountains and a 700 km transect revealing the irregular topography of the Moho beneath these two mountain orogens. Results indicate that the High Atlas features a moderate crustal thickness and that shortening is resolved at depth through a crustal root where the Saharan crust under-thrusts below the Moroccan crust, defining a lower crust imbrication which locally places the Moho boundary at, approximately, 40 km depth. The P-wave velocity model is characterized, in averaged, by relatively low velocities. These low deep crustal velocities together with other geophysical observables such as: conductivity estimates derived from Mt measurements; moderate Bouguer gravity anomaly; surface exposures of recent alkaline volcanics; lead the interpretation to propose that partial melts are currently emplaced in the deep crustal levels and in the upper mantle. The Moho discontinuity defines a crust which is in average relatively thin beneath the Atlas which is almost a 4000 m high orogenic belt. The resulting model supports existence of mantle upwelling as a possible mechanism that contributes, significantly, to maintain the High Atlas topography.

  11. Detection limit calculations for different total reflection techniques

    International Nuclear Information System (INIS)

    Sanchez, H.J.

    2000-01-01

    In this work, theoretical calculations of detection limits for different total-reflection techniques are presented.. Calculations include grazing incidence (TXRF) and gracing exit (GEXRF) conditions. These calculations are compared with detection limits obtained for conventional x-ray fluorescence (XRF). In order to compute detection limits the Shiraiwa and Fujino's model to calculate x-ray fluorescence intensities was used. This model made certain assumptions and approximations to achieve the calculations, specially in the case of the geometrical conditions of the sample, and the incident and takeoff beams. Nevertheless the calculated data of detection limits for conventional XRF and total-reflection XRF show a good agreement with previous results. The model proposed here allows to analyze the different sources of background and the influence of the excitation geometry, which contribute to the understanding of the physical processes involved in the XRF analysis by total reflection. Finally, a comparison between detection limits in total-reflection analysis at grazing incidence and at grazing exit is carried out. Here a good agreement with the theoretical predictions of the reversibility principle is found, showing that detection limits are similar for both techniques. (author)

  12. Analysis of seismic reflectivity and AVO pattern of BSR using OBS data in the southwestern offshore region of Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, W.B.; Yang, H.R. [Jinwen Univ. of Science and Technology, Hsintien City, Taipei County, Taiwan (China). Dept. of Environment and Property Management; Schnurle, P.; Liu, C.S. [National Taiwan Univ., Taipei, Taiwan (China). Inst. of Oceanography; Lee, C.S. [National Taiwan Ocean Univ., Keelung, Taiwan (China). Inst. of Applied Earth Science; Wang, Y.; Chung, S.H.; Chen, S.C. [Ministry of Economic Affairs, Taiwan (China). Central Geological Survey

    2008-07-01

    Regional multi-channel seismic reflection profiles that were conducted in Taiwan from 2003 to 2006 resulted in the identification of a gas hydrate-related bottom simulating reflector (BSR) in the broad southwestern offshore region of Taiwan. In order to understand the regional distribution of methane hydrate bearing layers and explore concentrated hydrate bearing layers, this paper presented a comprehensive analysis of reflection coefficient and amplitude-versus-offset (AVO) pattern of BSR using ocean bottom seismographs (OBSs) seismic data acquired in the southwestern offshore region of Taiwan. The study focused on the analysis and interpretation of airgun array signals recorded by OBSs during 2004 and 2006. Ten profiles of seismic reflection/refraction with a total length of about 140 km and recorded by 50 recovered OBSs were acquired on the active and passive margins in offshore southwestern Taiwan. Amplitudes of the direct water arrival, the multiple, and the BSR were picked interactively for all the OBS lines. A quantitative representation of reflector strength was provided by calculation of reflection coefficients. In general, the seafloor reflection coefficients for the active and passive margins were estimated as 0.1-0.25. The paper presented the data and analysis as well as the results of the study. It was concluded that the results of calculated reflection coefficient of the BSR in offshore southwest Taiwan suggested that inferred hydrate concentration for the passive margin profiles was relatively higher than that for the active margin profiles. 4 refs.

  13. Fault analysis in the very shallow seismic reflection method; Gokusenso jishin hanshaho ni okeru danso kaiseki. 1

    Energy Technology Data Exchange (ETDEWEB)

    Nagumo, S; Muraoka, S; Kaida, Y; Takahashi, T [OYO Corp., Tokyo (Japan)

    1996-10-01

    To effectively use the very shallow seismic reflection for active fault survey, a method has been investigated by which fault structures can be appropriately reconstructed from the fault information detected in the original records. The first step of reconstructing the fault system from the travel time reflection curve was to grasp an outline of fault structure from the patterns of travel time curve observed in the original record. For the very shallow seismic reflection method, especially, the low velocity layers in a shallow part succeeding from the ground surface made the issue complicated. Then, the travel time reflection curves were calculated in the case of existing several horizontal reflection surfaces in the surface layer. The constant values, mean velocities to the depth at individual reflection surfaces were used for the approximation of velocities. The outline of fault structure was grasped from the observation of original record. Then, the structure was reconstructed from the travel time curves. When the mean velocity in the medium was known, reconstruction of the feature of reflection surfaces from the travel time curves could be determined by simple mapping. When the mean velocity was unknown, it was calculated using the reciprocal travel time from the common reflection surface for individual reflection surfaces. 7 figs.

  14. The seismic analyzer: interpreting and illustrating 2D seismic data.

    Science.gov (United States)

    Patel, Daniel; Giertsen, Christopher; Thurmond, John; Gjelberg, John; Gröller, M Eduard

    2008-01-01

    We present a toolbox for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon reservoirs. We improve the search of seismic structures by precalculating the horizon structures of the seismic data prior to interpretation. We improve the annotation of seismic structures by applying novel illustrative rendering algorithms tailored to seismic data, such as deformed texturing and line and texture transfer functions. The illustrative rendering results in multi-attribute and scale invariant visualizations where features are represented clearly in both highly zoomed in and zoomed out views. Thumbnail views in combination with interactive appearance control allows for a quick overview of the data before detailed interpretation takes place. These techniques help reduce the work of seismic illustrators and interpreters.

  15. Reconstruction of reflectance data using an interpolation technique.

    Science.gov (United States)

    Abed, Farhad Moghareh; Amirshahi, Seyed Hossein; Abed, Mohammad Reza Moghareh

    2009-03-01

    A linear interpolation method is applied for reconstruction of reflectance spectra of Munsell as well as ColorChecker SG color chips from the corresponding colorimetric values under a given set of viewing conditions. Hence, different types of lookup tables (LUTs) have been created to connect the colorimetric and spectrophotometeric data as the source and destination spaces in this approach. To optimize the algorithm, different color spaces and light sources have been used to build different types of LUTs. The effects of applied color datasets as well as employed color spaces are investigated. Results of recovery are evaluated by the mean and the maximum color difference values under other sets of standard light sources. The mean and the maximum values of root mean square (RMS) error between the reconstructed and the actual spectra are also calculated. Since the speed of reflectance reconstruction is a key point in the LUT algorithm, the processing time spent for interpolation of spectral data has also been measured for each model. Finally, the performance of the suggested interpolation technique is compared with that of the common principal component analysis method. According to the results, using the CIEXYZ tristimulus values as a source space shows priority over the CIELAB color space. Besides, the colorimetric position of a desired sample is a key point that indicates the success of the approach. In fact, because of the nature of the interpolation technique, the colorimetric position of the desired samples should be located inside the color gamut of available samples in the dataset. The resultant spectra that have been reconstructed by this technique show considerable improvement in terms of RMS error between the actual and the reconstructed reflectance spectra as well as CIELAB color differences under the other light source in comparison with those obtained from the standard PCA technique.

  16. Combined rock-physical modelling and seismic inversion techniques for characterisation of stacked sandstone reservoir

    NARCIS (Netherlands)

    Justiniano, A.; Jaya, Y.; Diephuis, G.; Veenhof, R.; Pringle, T.

    2015-01-01

    The objective of the study is to characterise the Triassic massive stacked sandstone deposits of the Main Buntsandstein Subgroup at Block Q16 located in the West Netherlands Basin. The characterisation was carried out through combining rock-physics modelling and seismic inversion techniques. The

  17. Full 40 km crustal reflection seismic datasets in several Indonesian basins

    Science.gov (United States)

    Dinkelman, M. G.; Granath, J. W.; Christ, J. M.; Emmet, P. A.; Bird, D. E.

    2010-12-01

    Long offset, deep penetration regional 2D seismic data sets have been acquired since 2002 by GX Technology in a number of regions worldwide (www.iongeo.com/Data_Libraries/Spans/). Typical surveys consist of 10+ lines located to image specific critical aspects of basin structure. Early surveys were processed to 20 km, but more recent ones have extended to 40-45 km from 16 sec records. Pre-stack time migration is followed by pre-stack depth migration using gravity and in some cases magnetic modeling to constrain the velocity structure. We illustrate several cases in the SE Asian and Australasian area. In NatunaSPAN™ two generations of inversion can be distinguished, one involving Paleogene faults with Neogene inversion and one involving strike slip-related uplift in the West Natuna Basin. Crustal structure in the very deep Neogene East Natuna Basin has also been imaged. The JavaSPAN™ program traced Paleogene sediments onto oceanic crust of the Flores Sea, thus equating back arc spreading there to the widespread Eocene extension. It also imaged basement in the Makassar Strait beneath as much as 6 km of Cenozoic sedimentary rocks that accumulated Eocene rift basins (the North and South Makassar basins) on the edge of Sundaland, the core of SE Asia. The basement is seismically layered: a noisy upper crust overlies a prominent 10 km thick transparent zone, the base of which marks another change to slightly noisier reflectivity. Eocene normal faults responsible for the opening of extensional basins root in the top of the transparent layer which may be Moho or a brittle-ductile transition within the extended continental crust. Of particular significance is the first image of thick Precambrian basins comprising the bulk of continental crust under the Arafura Sea in the ArafuraSPAN™ program. Four lines some 1200 km long located between Australia and New Guinea on the Arafura platform image a thin Phanerozoic section overlying a striking Precambrian basement composed of

  18. Techniques to Promote Reflective Practice and Empowered Learning.

    Science.gov (United States)

    Nguyen-Truong, Connie Kim Yen; Davis, Andra; Spencer, Cassius; Rasmor, Melody; Dekker, Lida

    2018-02-01

    Health care environments are fraught with fast-paced critical demands and ethical dilemmas requiring decisive nursing actions. Nurse educators must prepare nursing students to practice skills, behaviors, and attitudes needed to meet the challenges of health care demands. Evidence-based, innovative, multimodal techniques with novice and seasoned nurses were incorporated into a baccalaureate (BSN) completion program (RN to-BSN) to deepen learning, complex skill building, reflective practice, teamwork, and compassion toward the experiences of others. Principles of popular education for engaged teaching-learning were applied. Nursing students experience equitable access to content through co-constructing knowledge with four creative techniques. Four creative techniques include poem reading aloud to facilitate connectedness; mindfulness to cultivate self-awareness; string figure activities to demonstrate indigenous knowledge and teamwork; and cartooning difficult subject matter. Nursing school curricula can promote a milieu for developing organizational skills to manage simultaneous priorities, practice reflectively, and develop empathy and the authenticity that effective nursing requires. [J Nurs Educ. 2018;57(2):115-120.]. Copyright 2018, SLACK Incorporated.

  19. Nondestructive damage detection and evaluation technique for seismically damaged structures

    Science.gov (United States)

    Adachi, Yukio; Unjoh, Shigeki; Kondoh, Masuo; Ohsumi, Michio

    1999-02-01

    The development of quantitative damage detection and evaluation technique, and damage detection technique for invisible damages of structures are required according to the lessons from the 1995 Hyogo-ken Nanbu earthquake. In this study, two quantitative damage sensing techniques for highway bridge structures are proposed. One method is to measure the change of vibration characteristics of the bridge structure. According to the damage detection test for damaged bridge column by shaking table test, this method can successfully detect the vibration characteristic change caused by damage progress due to increment excitations. The other method is to use self-diagnosis intelligent materials. According to the reinforced concrete beam specimen test, the second method can detect the damage by rupture of intelligent sensors, such as optical fiber or carbon fiber reinforced plastic rod.

  20. Origin and Formation of Giant Mounds in Lake Ladoga (Russia) from High-Resolution Seismic Reflection Data

    Science.gov (United States)

    Gromig, R.; Lebas, E.; Krastel, S.; Averes, T.; Wagner, B.; Melles, M.; Fedorov, G.

    2017-12-01

    In the framework of the German-Russian project `PLOT - Paleolimnological Transect' (for an overview of the project see Gromig et al., this meeting), a pilot seismic survey was carried out in Lake Ladoga (Russia) in late summer 2013. In total, 1500 km of seismic reflection profiles have been acquired using a mini-GI gun and a 32-channel seismic streamer. The high-resolution of the seismic data allows us to document in detail the sedimentary processes that occurred in the lake during the preglacial and postglacial history. The seismic stratigraphic architecture of the lake shows, from top to bottom, acoustically well-stratified Holocene muds overlaying rather transparent postglacial varves. These sediment successions are usually bordered by a hard reflector underneath, which may represent coarse-grained sediments or a till. The nature of the material composing the uppermost units have been tied to coring information from core Co1309, which was retrieved during the same survey. Of particular interest, are the single to composite, giant (kilometer-scale) mounds directly overlying the hard reflector. Internal architecture of the mounds reveals a complex formation history, with mound types showing significant structural deformation of different degrees; and other mound types showing a central deformation area, which strongly contrasts with the titled reflections or undisturbed stratification visible at the edges. The deepest seismic unit underlying the mounds is characterized by well-bedded, tilted reflectors in the southeastern part of the lake, while clear synclines are identified in the northwestern part of the lake. An erosional truncation separates the deepest unit from the overlying ones. In the work presented here, we focus on the understanding of the origin and the formation of the giant mounds with respect to the glacial history of Lake Ladoga.

  1. Fuzzy logic and image processing techniques for the interpretation of seismic data

    International Nuclear Information System (INIS)

    Orozco-del-Castillo, M G; Ortiz-Alemán, C; Rodríguez-Castellanos, A; Urrutia-Fucugauchi, J

    2011-01-01

    Since interpretation of seismic data is usually a tedious and repetitive task, the ability to do so automatically or semi-automatically has become an important objective of recent research. We believe that the vagueness and uncertainty in the interpretation process makes fuzzy logic an appropriate tool to deal with seismic data. In this work we developed a semi-automated fuzzy inference system to detect the internal architecture of a mass transport complex (MTC) in seismic images. We propose that the observed characteristics of a MTC can be expressed as fuzzy if-then rules consisting of linguistic values associated with fuzzy membership functions. The constructions of the fuzzy inference system and various image processing techniques are presented. We conclude that this is a well-suited problem for fuzzy logic since the application of the proposed methodology yields a semi-automatically interpreted MTC which closely resembles the MTC from expert manual interpretation

  2. High-resolution 3D seismic reflection imaging across active faults and its impact on seismic hazard estimation in the Tokyo metropolitan area

    Science.gov (United States)

    Ishiyama, Tatsuya; Sato, Hiroshi; Abe, Susumu; Kawasaki, Shinji; Kato, Naoko

    2016-10-01

    We collected and interpreted high-resolution 3D seismic reflection data across a hypothesized fault scarp, along the largest active fault that could generate hazardous earthquakes in the Tokyo metropolitan area. The processed and interpreted 3D seismic cube, linked with nearby borehole stratigraphy, suggests that a monocline that deforms lower Pleistocene units is unconformably overlain by middle Pleistocene conglomerates. Judging from structural patterns and vertical separation on the lower-middle Pleistocene units and the ground surface, the hypothesized scarp was interpreted as a terrace riser rather than as a manifestation of late Pleistocene structural growth resulting from repeated fault activity. Devastating earthquake scenarios had been predicted along the fault in question based on its proximity to the metropolitan area, however our new results lead to a significant decrease in estimated fault length and consequently in the estimated magnitude of future earthquakes associated with reactivation. This suggests a greatly reduced seismic hazard in the Tokyo metropolitan area from earthquakes generated by active intraplate crustal faults.

  3. Research on advancement of technique for assessing ground seismic intensity

    International Nuclear Information System (INIS)

    Tamura, Keiichi; Kaneko, Masahiro; Honda, Riki; Tabuchi, Yoshihiro

    1997-01-01

    In the aseismatic design of nuclear power stations, as the characteristics of earthquake motion inputted in released base surface, the maximum amplitude and the frequency characteristics of earthquake motion, the presumption of earthquake motion using fault model, the time of continuation and the change of amplitude envelope with time are to be examined. In this research, in order to upgrade the earthquake motion used for aseismatic design, the method of evaluating quantitatively the amplifying characteristics of earthquake motion in unfair ground and the technique of setting design earthquake motion that can consider the change of structural state were investigated. The course of the research carried out so far is outlined. As to the amplifying characteristics of earthquake motion in unfair ground, the technique of analysis, the index showing the degree of amplifying of earthquake motion, the index showing the degree of unfairness of ground, the amplifying characteristics of earthquake motion in tray type base, and the evaluation of frequency zone of large degree of amplifying are reported. As to the design earthquake motion taking the plasticizing of structures in consideration, the analysis condition, the equivalent peculiar frequency and the equivalent damping constant and the design earthquake motion taking the plasticizing of structures in consideration are reported. (K.I.)

  4. Determining the metallicity of the solar envelope using seismic inversion techniques

    Science.gov (United States)

    Buldgen, G.; Salmon, S. J. A. J.; Noels, A.; Scuflaire, R.; Dupret, M. A.; Reese, D. R.

    2017-11-01

    The solar metallicity issue is a long-lasting problem of astrophysics, impacting multiple fields and still subject to debate and uncertainties. While spectroscopy has mostly been used to determine the solar heavy elements abundance, helioseismologists attempted providing a seismic determination of the metallicity in the solar convective envelope. However, the puzzle remains since two independent groups provided two radically different values for this crucial astrophysical parameter. We aim at providing an independent seismic measurement of the solar metallicity in the convective envelope. Our main goal is to help provide new information to break the current stalemate amongst seismic determinations of the solar heavy element abundance. We start by presenting the kernels, the inversion technique and the target function of the inversion we have developed. We then test our approach in multiple hare-and-hounds exercises to assess its reliability and accuracy. We then apply our technique to solar data using calibrated solar models and determine an interval of seismic measurements for the solar metallicity. We show that our inversion can indeed be used to estimate the solar metallicity thanks to our hare-and-hounds exercises. However, we also show that further dependencies in the physical ingredients of solar models lead to a low accuracy. Nevertheless, using various physical ingredients for our solar models, we determine metallicity values between 0.008 and 0.014.

  5. Ground magnetic studies along a regional seismic-reflection profile across Bare Mountain, Crater Flat and Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Langenheim, V.E.; Ponce, D.A.

    1995-01-01

    Ground magnetic data were collected along a 26-km-long regional seismic-reflection profile in southwest Nevada that starts in the Amargosa Desert, crosses Bare Mountain, Crater Flat and Yucca Mountain, and ends in Midway Valley. Parallel ground magnetic profiles were also collected about 100 m to either side of the western half of the seismic-reflection line. The magnetic data indicate that the eastern half of Crater Flat is characterized by closely-spaced faulting (1--2 km) in contrast to the western half of Crater Flat. Modeling of the data indicates that the Topopah Spring Tuff is offset about 250 m on the Solitario Canyon fault and about 50 m on the Ghost Dance fault. These estimates of fault offset are consistent with seismic-reflection data and geologic mapping. A broad magnetic high of about 500--600 nT is centered over Crater Flat. Modeling of the magnetic data indicates that the source of this high is not thickening and doming of the Bullfrog Tuff, but more likely lies below the Bullfrog Tuff. Possible source lithologies for this magnetic high include altered argillite of the Eleana Formation, Cretaceous or Tertiary intrusions, and mafic sills

  6. Site Characterization of the Source Physics Experiment Phase II Location Using Seismic Reflection Data

    Science.gov (United States)

    Sexton, E. A.; Snelson, C. M.; Chipman, V.; Emer, D. F.; White, R. L.; Emmitt, R.; Wright, A. A.; Drellack, S.; Huckins-Gang, H.; Mercadante, J.; Floyd, M.; McGowin, C.; Cothrun, C.; Bonal, N.

    2013-12-01

    An objective of the Source Physics Experiment (SPE) is to identify low-yield nuclear explosions from a regional distance. Low-yield nuclear explosions can often be difficult to discriminate among the clutter of natural and man-made explosive events (e.g., earthquakes and mine blasts). The SPE is broken into three phases. Phase I has provided the first of the physics-based data to test the empirical models that have been used to discriminate nuclear events. The Phase I series of tests were placed within a highly fractured granite body. The evolution of the project has led to development of Phase II, to be placed within the opposite end member of geology, an alluvium environment, thereby increasing the database of waveforms to build upon in the discrimination models. Both the granite and alluvium sites have hosted nearby nuclear tests, which provide comparisons for the chemical test data. Phase III of the SPE is yet to be determined. For Phase II of the experiment, characterization of the location is required to develop the geologic/geophysical models for the execution of the experiment. Criteria for the location are alluvium thickness of approximately 170 m and a water table below 170 m; minimal fracturing would be ideal. A P-wave mini-vibroseis survey was conducted at a potential site in alluvium to map out the subsurface geology. The seismic reflection profile consisted of 168 geophone stations, spaced 5 m apart. The mini-vibe was a 7,000-lb peak-force source, starting 57.5 m off the north end of the profile and ending 57.5 m past the southern-most geophone. The length of the profile was 835 m. The source points were placed every 5 m, equally spaced between geophones to reduce clipping. The vibroseis sweep was from 20 Hz down to 180 Hz over 8 seconds, and four sweeps were stacked at each shot location. The shot gathers show high signal-to-noise ratios with clear first arrivals across the entire spread and the suggestion of some shallow reflectors. The data were

  7. Seismic reflection data report: Waste Isolation Pilot Plant (WIPP) site, Southeastern New Mexico

    International Nuclear Information System (INIS)

    Hern, J.L.; Powers, D.W.; Barrows, L.J.

    1978-12-01

    Three seismic reflection (Vibroseis) surveys conducted from 1976 through 1978 by Sandia Laboratories to support investigations for the Waste Isolation Pilot Plant (WIPP) are described. Volume I describes the purpose, field parameters, and data processing parameters. Volume II contains uninterpreted processed lines and shotpoint maps. Data interpretations will be the subject of the subsequent reports. The data collected during these three surveys total 77 line miles; 72 line miles of this are on or very near the WIPP site. The first of the surveys (1976 SAN) covered 25 line miles and was conducted similarly to previous petroleum industry surveys in the area. 1976 SAN supplemented existing petroleum industry data. The two subsequent surveys (1977 X and 1978 Y) used shorter geophone spacings (110'), higher signal frequencies (up to 100 Hz), and higher data sampling rates (2 ms.) to better define the shallow zone (less than 4000') of primary interest. 1977 X contained 47 line miles on or near the WIPP site and over several structural features northwest of the site. 1978 Y contains 5 line miles over a one square mile area near the center of the WIPP site. These data show increasing discrimination of shallow reflectors as data collection parameters were modified. Data tables of recording and processing parameters are included. A fourth Vibroseis survey was conducted at the WIPP site in 1978 by Grant Geophysical Company for Bechtel; the data are not in final form and are not included. Petroleum industry data and an inconclusive weight-drop survey, conducted in 1976, are also not included in this report

  8. 4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes; William E. Harrison

    2007-06-30

    The objective of this research project was to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data in the hopes of observing changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE No.DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 30 months of seismic monitoring, one baseline and eight monitor surveys clearly detected changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators and observed in production data. Attribute analysis was a very useful tool in enhancing changes in seismic character present, but difficult to interpret on time amplitude slices. Lessons learned from and tools/techniques developed during this project will allow high-resolution seismic imaging to be routinely applied to many CO{sub 2} injection programs in a large percentage of shallow carbonate oil fields in the midcontinent.

  9. Re-processing of Shallow and Deep Crustal Reflection Seismic Data along BABEL Line 7, Central Sweden

    OpenAIRE

    Shahrokhi, Hanieh

    2012-01-01

    The BABEL project (Baltic And Bothnian Echoes from the Lithosphere) was a collaboration among British, Danish, Finnish, German and Swedish geoscientists to acquire deep-crustal reflection and wide-angle refraction data in the Baltic Shield and Gulf of Bothnia. In 1989, the collection of 2,268 km of deep marine reflection seismic data was carried out. BABEL line 7, one of several BABEL profiles, is the focus of this study and runs north of the Åland islands, in an E-W direction in the Bothnian...

  10. Seismic architecture of the Chalk Group from onshore reflection data in eastern Denmark

    DEFF Research Database (Denmark)

    Moreau, Julien; Anderskouv, Kresten; Boldreel, Lars Ole

    with the seismic stratigraphy. Several seismic facies are identified in the Chalk Group: the 'transparent' (white chalk), the stratified (marl-chalk alternations), the crudely stratified (flint-rich chalk) and the hummocky (bryozoan mounds). The units notably vary in thickness at a relatively small scale...... of the deformations appear to be restricted to the white chalk, whereas the stratified seismic facies are comparatively less disturbed. The origin of the structures observed in the white chalk can either be associated with the regional stress field or with differential diagenetic evolution between strata inducing...

  11. Near-surface, marine seismic-reflection data defines potential hydrogeologic confinement bypass in a tertiary carbonate aquifer, southeastern Florida

    Science.gov (United States)

    Cunningham, Kevin J.; Walker, Cameron; Westcott, Richard L.

    2012-01-01

    Approximately 210 km of near-surface, high-frequency, marine seismic-reflection data were acquired on the southeastern part of the Florida Platform between 2007 and 2011. Many high-resolution, seismic-reflection profiles, interpretable to a depth of about 730 m, were collected on the shallow-marine shelf of southeastern Florida in water as shallow as 1 m. Landward of the present-day shelf-margin slope, these data image middle Eocene to Pleistocene strata and Paleocene to Pleistocene strata on the Miami Terrace. This high-resolution data set provides an opportunity to evaluate geologic structures that cut across confining units of the Paleocene to Oligocene-age carbonate rocks that form the Floridan aquifer system.Seismic profiles image two structural systems, tectonic faults and karst collapse structures, which breach confining beds in the Floridan aquifer system. Both structural systems may serve as pathways for vertical groundwater flow across relatively low-permeability carbonate strata that separate zones of regionally extensive high-permeability rocks in the Floridan aquifer system. The tectonic faults occur as normal and reverse faults, and collapse-related faults have normal throw. The most common fault occurrence delineated on the reflection profiles is associated with karst collapse structures. These high-frequency seismic data are providing high quality structural analogs to unprecedented depths on the southeastern Florida Platform. The analogs can be used for assessment of confinement of other carbonate aquifers and the sealing potential of deeper carbonate rocks associated with reservoirs around the world.

  12. SH-wave reflection seismic and VSP as tools for the investigation of sinkhole areas in Germany

    Science.gov (United States)

    Wadas, Sonja; Tschache, Saskia; Polom, Ulrich; Buness, Hermann; Krawczyk, Charlotte M.

    2017-04-01

    Sinkholes can lead to damage of buildings and infrastructure and they can cause life-threatening situations, if they occur in urban areas. The process behind this phenomenon is called subrosion. Subrosion is the underground leaching of soluble rocks, e.g. anhydrite and gypsum, due to the contact with ground- and meteoric water. Depending on the leached material, and especially the dissolution rate, different kinds of subrosion structures evolve in the subsurface. The two end members are collapse and depression structures. For a better understanding of the subrosion processes a detailed characterization of the resulting structures is necessary. In Germany sinkholes are a problem in many areas. In northern Germany salt and in central and southern Germany sulfate and carbonate deposits are affected by subrosion. The study areas described here are located in Thuringia in central Germany and the underground is characterized by soluble Permian deposits. The occurrence of 20 to 50 sinkholes is reported per year. Two regions, Bad Frankenhausen and Schmalkalden, are investigated, showing a leaning church tower and a sinkhole of 30 m diameter and 20 m depth, respectively. In Bad Frankenhausen four P-wave and 16 SH-wave reflection seismic profiles were carried out, supplemented by three zero-offset VSPs. In Schmalkalden five SH-wave reflection seismic profiles and one zero-offset VSP were acquired. The 2-D seismic sections, in particular the SH-wave profiles, showed known and unknown near-surface faults in the vicinity of sinkholes and depressions. For imaging the near-surface ( 2,5, probably indicating unstable areas due to subrosion. We conclude, that SH-wave reflection seismic offer an important tool for the imaging and characterization of near-surface subrosion structures and the identification of unstable zones, especially in combination with P-wave reflection seismic and zero-offset VSP with P- and S-waves. Presumably there is a connection between the presence of large

  13. Interpretation of reflection seismics in the area North of Laegeren - Zurich Weinland

    International Nuclear Information System (INIS)

    Naef, H.; Birkhaeuser, P.; Roth, P.

    1995-05-01

    The investigations of potential siting areas for a repository for high-level radioactive waste which are concentrated in the crystalline basement of Northern Switzerland have been expanded since the late 1980s to include suitable sedimentary units. After extensive desk study evaluation, the approximately 100 m thick Opalinus Clay of the Tabular Jura east of the Aare river was chosen as the most promising sedimentary option. In this area not only the Opalinus Clay but also the over- and underlying units are clay-rich, in contrast to the tabular Jura west of the Aare river. In the area North of Laegeren - Zurich Weinland, where the Opalinus Clay is situated in the optimum depth range of 400 to 1000 m below surface, approximately 220 km of new high-resolution seismic profiles were recorded and interpreted together with existing seismic lines. Due to thorough field work and data processing, a very good quality of seismic lines was obtained. This allowed precise mapping of the marker horizons in general and the Opalinus Clay in detail. The goal of this study was to determine and delineate the most important tectonic units as well as to describe the potential host rocks in these units. By way of interactive interpretation of all available seismic lines, borehole data and surface data from the investigation area, depth maps of the most prominent marker horizons have been calculated and geological cross-sections constructed along the new seismic lines. The regional seismic character of the Middle Mesozoic units was modelled using borehole data from Weiach and Herdern. From this model the thickness of the Opalinus Clay along the new seismic lines was determined. The results indicate a relatively constant thickness of 95 to 120 m in the investigation area. (author) figs., tabs., refs

  14. Seismic reflection survey in Omama fan area, Gunma prefecture; Gunma Omama senjochi ni okeru hanshaho jishin tansa

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, K; Kano, N; Yokokura, T; Kiguchi, T; Yokota, T; Matsushima, J [Geological Survey of Japan, Tsukuba (Japan)

    1996-10-01

    Seismic reflection survey was performed for the Medial Tectonic Line, an important geological tectonic line in the Kanto plains, at Kushibiki district, Saitama prefecture in the north-western part of the Kanto plains. It was estimated that movements of the basement were different in the individual sides of the active fault. In this study, the seismic reflection survey was performed at the Omama fan area, Gunma prefecture, which is located at the north-eastern extension of the Kushibiki plateau, to grasp the structure of basement to the depth of about 1.0 s of return travel time, and the upper sediments. Two traverse lines passing Ota city, Kiryu city, and Nitta town were used. Southern part of the traverse line-1 was in the bottom land in the middle of Tone river, and northern part was in the Omama fan area. The ground surface along the traverse line was flat. Hachioji heights are the heights elongating in the NW-SE direction and having relative height of 100 to 200 m against the surrounding plain. Another traverse line-2 was set on the steep slope having relative height more than 100 m. The Brute stack time section of each traverse line was characterized by the gradient reflection surface AA of the traverse line-1. It was suggested that the AA or intermittent parts of reflection surfaces deeper than AA may relate to the tectonic lines in the more ancient geological ages. 2 figs., 1 tab.

  15. OCT structure, COB location and magmatic type of the SE Brazilian & S Angolan margins from integrated quantitative analysis of deep seismic reflection and gravity anomaly data

    Science.gov (United States)

    Cowie, L.; Kusznir, N. J.; Horn, B.

    2013-12-01

    Knowledge of ocean-continent transition (OCT) structure, continent-ocean boundary (COB) location and magmatic type are of critical importance for understanding rifted continental margin formation processes and in evaluating petroleum systems in deep-water frontier oil and gas exploration. The OCT structure, COB location and magmatic type of the SE Brazilian and S Angolan rifted continental margins are much debated; exhumed and serpentinised mantle have been reported at these margins. Integrated quantitative analysis using deep seismic reflection data and gravity inversion have been used to determine OCT structure, COB location and magmatic type for the SE Brazilian and S Angolan margins. Gravity inversion has been used to determine Moho depth, crustal basement thickness and continental lithosphere thinning. Residual Depth Anomaly (RDA) analysis has been used to investigate OCT bathymetric anomalies with respect to expected oceanic bathymetries and subsidence analysis has been used to determine the distribution of continental lithosphere thinning. These techniques have been validated on the Iberian margin for profiles IAM9 and ISE-01. In addition a joint inversion technique using deep seismic reflection and gravity anomaly data has been applied to the ION-GXT BS1-575 SE Brazil and ION-GXT CS1-2400 S Angola. The joint inversion method solves for coincident seismic and gravity Moho in the time domain and calculates the lateral variations in crustal basement densities and velocities along profile. Gravity inversion, RDA and subsidence analysis along the S Angolan ION-GXT CS1-2400 profile has been used to determine OCT structure and COB location. Analysis suggests that exhumed mantle, corresponding to a magma poor margin, is absent beneath the allochthonous salt. The thickness of earliest oceanic crust, derived from gravity and deep seismic reflection data is approximately 7km. The joint inversion predicts crustal basement densities and seismic velocities which are

  16. Geology of the continental margin beneath Santa Monica Bay, Southern California, from seismic-reflection data

    Science.gov (United States)

    Fisher, M.A.; Normark, W.R.; Bohannon, R.G.; Sliter, R.W.; Calvert, A.J.

    2003-01-01

    We interpret seismic-reflection data, which were collected in Santa Monica Bay using a 70-in3 generator-injector air gun, to show the geologic structure of the continental shelf and slope and of the deep-water, Santa Monica and San Pedro Basins. The goal of this research is to investigate the earthquake hazard posed to urban areas by offshore faults. These data reveal that northwest of the Palos Verdes Peninsula, the Palos Verdes Fault neither offsets the seafloor nor cuts through an undeformed sediment apron that postdates the last sea level rise. Other evidence indicates that this fault extends northwest beneath the shelf in the deep subsurface. However, other major faults in the study area, such as the Dume and San Pedro Basin Faults, were active recently, as indicated by an arched seafloor and offset shallow sediment. Rocks under the lower continental slope are deformed to differing degrees on opposite sides of Santa Monica Canyon. Northwest of this canyon, the continental slope is underlain by a little-deformed sediment apron; the main structures that deform this apron are two lower-slope anticlines that extend toward Point Dume and are cored by faults showing reverse or thrust separation. Southeast of Santa Monica Canyon, lower-slope rocks are deformed by a complex arrangement of strike-slip, normal, and reverse faults. The San Pedro Escarpment rises abruptly along the southeast side of Santa Monica Canyon. Reverse faults and folds underpinning this escarpment steepen progressively southeastward. Locally they form flower structures and cut downward into basement rocks. These faults merge downward with the San Pedro Basin fault zone, which is nearly vertical and strike slip. The escarpment and its attendant structures diverge from this strike-slip fault zone and extend for 60 km along the margin, separating the continental shelf from the deep-water basins. The deep-water Santa Monica Basin has large extent but is filled with only a thin (less than 1.5-km

  17. Develop and implement preconditioning techniques to control face ejection rockbursts for safer mining in seismically hazardous areas

    CSIR Research Space (South Africa)

    Toper, AZ

    1998-01-01

    Full Text Available This research report discusses the development of preconditioning techniques to control face bursts, for safer mining in seismically hazardous areas. Preconditioning involves regularly setting off carefully tailored blasts in the fractured rock...

  18. Seismic qualification of nuclear control board by using base isolation technique

    International Nuclear Information System (INIS)

    Koizumi, T.; Tsujiuchi, N.; Fujita, T.

    1987-01-01

    The purpose is to adopt base isolation technique as a new approach for seismic qualification of nuclear control board. Basic concept of base isolation technique is expressed. Two dimensional linear motion mechanism with pre-tensioned coil springs and some dampers are included in the isolation device. Control board is regarded as a lamped mass system with inertia moment. Fundamental movement of this device and control board is calculated as a non-linear response problems. Fundamental analysis and numerical estimation, experimental investigation has been undertaken using an actual size control board. Sufficient agreement was recognized between experimental results and numerical estimation. (orig./HP)

  19. Fault-related-folding structures and reflection seismic sections. Study by seismic modeling and balanced cross section; Danso ga kaizaisuru shukyoku kozo no keitai to jishin tansa danmen. 2. Seismic modeling oyobi balanced cross section ni yoru study

    Energy Technology Data Exchange (ETDEWEB)

    Tamagawa, T; Matsuoka, T [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsukui, R [Japan National Oil Corp., Tokyo (Japan). Technology Research Center

    1997-05-27

    It occasionally happens that there exists a part where reflection near the thrust is not clearly observed in a thrust zone seismic survey cross section. For the effective interpretation of such an occurrence, the use of geological structures as well as the reflected pattern is effective. When the velocity structures for a fold structure having a listric fault caused anticline (unidirectionally inclined with a backlimb, without a forelimb) and for a fault propagation fold are involved, a wrong interpretation may be made since they look alike in reflection wave pattern despite their difference in geological structure. In the concept of balanced cross section, a check is performed, when the stratum after deformation is recovered to the time of deposition, as to whether the geologic stratum area is conserved without excess or shortage. An excess or shortage occurs if there is an error in the model, and this shows that the fault surface or fold structure is not correctly reflected. Positive application of geological knowledge is required in the processing and interpreting of data from a seismic survey. 6 refs., 6 figs.

  20. Geotechnical Seismic Hazard Evaluation At Sellano (Umbria, Italy) Using The GIS Technique

    International Nuclear Information System (INIS)

    Capilleri, P.; Maugeri, M.

    2008-01-01

    A tool that has been widely-used in civil engineering in recent years is the geographic information system (GIS). Geographic Information systems (GIS) are powerful tools for organizing, analyzing, and presenting spatial data. The GIS can be used by geotechnical engineers to aid preliminary assessment through to the final geotechnical design. The aim of this work is to provide some indications for the use of the GIS technique in the field of seismic geotechnical engineering, particularly as regards the problems of seismic hazard zonation maps. The study area is the village of Sellano located in the Umbrian Apennines in central Italy, about 45 km east of Perugia and 120 km north-east of Rome The increasing importance attributed to microzonation derives from the spatial variability of ground motion due to particular local conditions. The use of GIS tools can lead to an early identification of potential barriers to project completion during the design process that may help avoid later costly redesign

  1. Refraction and reflection seismic investigations for geological energy-storage site characterization: Dalby (Tornquist Zone), southwest Sweden

    Science.gov (United States)

    Malehmir, Alireza; Bergman, Bo; Andersson, Benjamin; Sturk, Robert; Johansson, Mattis

    2017-04-01

    Three high-resolution, 5 m shot and receiver spacing using 141-172 receivers, refraction and reflection seismic profiles for the planning of a major underground energy-storage site near the town of Dalby-Lund within the Scania Tornquist suture zone in southwest of Sweden were acquired during August 2015. The site is situated ca. 1 km north of the RFZ (Romeleåsen fault and flexure zone) with a complex geologic and tectonic history. Near vertical dikes are observed from several quarries in the area crosscutting granitic-gneissic-amphibiotic rocks and form clear magnetic lineaments. These dikes likely have also acted as surfaces on which further faulting have occurred. Although a major high-speed and traffic road runs in the middle of the study area, the seismic data show excellent quality particularly for the data along two profiles (profiles 2 and 3) perpendicular to the road, and slightly noisy, due to high wind, for the data along a profile (profile 4) parallel to the road. A bobcat-mounted drop hammer (500 kg) was used to generate the seismic signal. To provide continuity from one side of the road to another, 51 wireless recorders connected to 10 Hz geophones and operating in an autonomous mode were used. GPS times of the source impacts were used to extract the data from the wireless recorders and then merged with the data from the cabled recorders (also 10 Hz geophones). Three shot records per source position were generated and vertically stacked to improve the signal-to-noise ratio. First arrivals are clear in most shot gathers allowing them to be used for traditional refraction seismic data analysis and also for more advanced traveltime tomography. The velocity models obtained through traveltime tomography clearly depict bedrock surface and its undulations and in many places show good correlation with the boreholes recently drilled in the area. At places where bedrock is intersected at greater depths than usual, for example 25 m at one place, depression

  2. Seismic structure from multi-channel seismic reflection and wide-angle data of Transect 0E in the Southern Gulf of California

    Science.gov (United States)

    Paramo, P.; Holbrook, W.; Brown, H.; Lizarralde, D.; Fletcher, J.; Umhoefer, P.; Kent, G.; Harding, A.; Gonzalez, A.; Axen, G.

    2005-12-01

    We present a velocity model from wide-angle data along with coincident prestack depth migration sections from seismic reflection data collected in the southern Gulf of California. Transect 0E runs NE to SW from the hills of Sierra Madre in mainland Mexico near Mazatlan to approximately 115 km into Gulf of California waters. Wide-angle data were recorded by 9 ocean bottom seismometers, deployed by the R/V New Horizon and 10 Reftek seismometers located along onshore extension of the transect. The average spacing for the OBS and Refteks is ~12 km and shots were fired from the R/V Maurice Ewing at 150 m intervals. Transect 0E crosses what it is believed to be extended continental crust and lies in the initial direction of extension characteristic of the proto-gulf. Preliminary results from the velocity model show upper crustal velocities of 6.1-6.3 km/s and lower crustal velocities of 6.7-7.0 km/s along the entire transect. Seismic velocities and crustal thicknesses observed along transect 0E are characteristic of non-volcanic margins.

  3. Northeastern Brazilian margin: Regional tectonic evolution based on integrated analysis of seismic reflection and potential field data and modelling

    Science.gov (United States)

    Blaich, Olav A.; Tsikalas, Filippos; Faleide, Jan Inge

    2008-10-01

    Integration of regional seismic reflection and potential field data along the northeastern Brazilian margin, complemented by crustal-scale gravity modelling, is used to reveal and illustrate onshore-offshore crustal structure correlation, the character of the continent-ocean boundary, and the relationship of crustal structure to regional variation of potential field anomalies. The study reveals distinct along-margin structural and magmatic changes that are spatially related to a number of conjugate Brazil-West Africa transfer systems, governing the margin segmentation and evolution. Several conceptual tectonic models are invoked to explain the structural evolution of the different margin segments in a conjugate margin context. Furthermore, the constructed transects, the observed and modelled Moho relief, and the potential field anomalies indicate that the Recôncavo, Tucano and Jatobá rift system may reflect a polyphase deformation rifting-mode associated with a complex time-dependent thermal structure of the lithosphere. The constructed transects and available seismic reflection profiles, indicate that the northern part of the study area lacks major breakup-related magmatic activity, suggesting a rifted non-volcanic margin affinity. In contrast, the southern part of the study area is characterized by abrupt crustal thinning and evidence for breakup magmatic activity, suggesting that this region evolved, partially, with a rifted volcanic margin affinity and character.

  4. A simple method for migrating narrow aperture, noisy seismic reflection data and application to Project INDEPTH (International Deep Profiling of Tibet and the Himalaya) deep seismic profiles

    Science.gov (United States)

    Alsdorf, Doug

    1997-08-01

    Migration of deep seismic data is often hindered by a narrow recording aperture (line length by record length) and a low signal-to-noise ratio. The severity of typical migration artifacts (e.g., lateral smearing of discontinuous reflections into synforms, "smiles") increases with travel time such that interpreters of deep seismic data have often substituted migrated line drawings for the actual sections. As part of Project INDEPTH (International Deep Profiling of Tibet and the Himalaya), a new migration method was developed to address both the noise and migration issues. The method works in the time-space domain and uses the simple, constant velocity, straight ray path to perform the migration. First, only amplitudes within a given range are retained for migration, thus avoiding high-amplitude noise bursts and low-amplitude background noise. Then, the local dip of a reflection is found by automatically fitting a straight line to the highest amplitudes within a small window (several time samples by several traces) and calculating the dip of the line using a constant velocity. Finally, using this dip, the method migrates a selected amplitude value. The dips, lateral positions, and depths of the migrated events compare very well with output from more conventional algorithms (e.g.,fk-Stolt, finite difference, etc.). The advantages of the new method include fewer artifacts, fast computer run times, low memory use and the ability to migrate long profiles and travel times (e.g., 50 s). The output of the method is a grid of migrated amplitudes (not wavelets) or dip values which is particularly effective for making small figures, such as those needed for publication. The principal disadvantage is the use of a constant migration velocity.

  5. Proterozoic structure, cambrian rifting, and younger faulting as revealed by a regional seismic reflection network in the Southern Illinois Basin

    Science.gov (United States)

    Potter, C.J.; Drahovzal, James A.; Sargent, M.L.; McBride, J.H.

    1997-01-01

    Four high-quality seismic reflection profiles through the southern Illinois Basin, totaling 245 km in length, provide an excellent regional subsurface stratigraphic and structural framework for evaluation of seismic risk, hydrocarbon occurrence, and other regional geologic studies. These data provide extensive subsurface information on the geometry of the intersection of the Cambrian Reelfoot and Rough Creek rifts, on extensive Proterozoic reflection sequences, and on structures (including the Fluorspar Area Fault Complex and Hicks Dome) that underlie a transitional area between the well-defined New Madrid seismic zone (to the southwest) and a more diffuse area of seismicity in the southern Illinois Basin. Our principal interpretations from these data are listed here in order of geologic age, from oldest to youngest: 1. Prominent Proterozoic layering, possibly equivalent to Proterozoic (???1 Ga) Middle Run Formation clastic strata and underlying (1.3-1.5 Ga) volcanic rocks of the East Continent rift basin, has been strongly deformed, probably as part of the Grenville foreland fold and thrust belt. 2. A well-defined angular unconformity is seen in many places between Proterozoic and Cambrian strata; a post-Grenville Proterozoic sequence is also apparent locally, directly beneath the base of the Cambrian. 3. We infer a major reversal in Cambrian rift polarity (accommodation zone) in the Rough Creek Graben in western Kentucky. 4. Seismic facies analysis suggests the presence of basin-floor fan complexes at and near the base of the Cambrian interval and within parts of a Proterozoic post-Grenville sequence in several parts of the Rough Creek Graben. 5. There is an abrupt pinchout of the Mount Simon Sandstone against crystalline basement beneath the Dale Dome (near the Texaco no. 1 Cuppy well, Hamilton County) in southeastern Illinois, and a more gradual Mount Simon pinchout to the southeast. 6. Where crossed by the seismic reflection line in southeast Illinois, some

  6. Recording and processing procedures for multi-channel seismic-reflection data collected in the western Ross Sea, Antarctica

    Science.gov (United States)

    Dadisman, Shawn V.; Ryan, Holly F.; Mann, Dennis M.

    1987-01-01

    During 1984, over 2300 km of multichannel seismic-reflection data were recorded by the U.S. Geological Survey in the western Ross Sea and Iselin Bank regions.  A temporary loss and sinking of the streamer led to increasing the streamer tow depth to 20 m, which resulted in some attenuation of frequencies in the 30-50 Hz range but no significant difference in resolution of the stacked data.  Severe water bottom multiples were encountered and removed by dip-filtering, weighted stacking, and severe post-NMO muting.

  7. Analysis of a piping system under seismic load using incremental hinge technique

    International Nuclear Information System (INIS)

    Ravi Kiran, A.; Agrawal, M.K.; Reddy, G.R.; Singh, R.K.; Vaze, K.K.; Ghosh, A.K.; Kushwaha, H.S.; Ramesh Babu, R.

    2008-01-01

    ASME Boiler and Pressure Vessel Code treats piping system as a series of components but not as an overall structural system. Limit analyses and collapse tests at component level are used to establish stress allowables on seismic stresses. The code does not consider the load redistributions and structural redundancy existing in piping systems that prevent system collapse even when one or more individual components loaded beyond their collapse levels. This necessitates a simple analytical method for evaluation of inelastic seismic response at system level. The present paper presents a simplified analytical procedure for predicting inelastic response of a typical piping system subjected to seismic load. The analytical method known as incremental hinge technique is based on plastic system behavior in which the yielded components are replaced with hinge models when a critical hinge moment is reached. It also takes into account the inelastic response spectrum reduction factors and displacement ductility. The analytical method is used to obtain the inelastic response, location of hinge formation and level of base excitation needed for hinge formation. The predicted hinge locations and hinge ordering is compared with the results of a shake table test conducted on the piping system. (author)

  8. Investigation of sinkhole areas in Germany using 2D shear wave reflection seismics and zero-offset VSP

    Science.gov (United States)

    Tschache, Saskia; Wadas, Sonja; Polom, Ulrich; Krawczyk, Charlotte M.

    2017-04-01

    Sinkholes pose a serious geohazard for humans and infrastructure in populated areas. The Junior Research Group Subrosion within the Leibniz Institute for Applied Geophysics and the joint project SIMULTAN work on the multi-scale investigation of subrosion processes in the subsurface, which cause natural sinkholes. In two case studies in sinkhole areas of Thuringia in Germany, we applied 2D shear wave reflection seismics using SH-waves with the aim to detect suitable parameters for the characterisation of critical zones. This method has the potential to image near-surface collapse and faulting structures in improved resolution compared to P-wave surveys resulting from the shorter wavelength of shear waves. Additionally, the shear wave velocity field derived by NMO velocity analysis is a basis to calculate further physical parameters, as e.g. the dynamic shear modulus. In both investigation areas, vertical seismic profiles (VSP) were acquired by generating P- and SH-waves (6 component VSP) directly next to a borehole equipped with a 3C downhole sensor. They provide shear and compressional wave velocity profiles, which are used to improve the 2D shear wave velocity field from surface seismics, to perform a depth calibration of the seismic image and to calculate the Vp/Vs ratio. The signals in the VSP data are analysed with respect to changes in polarisation and attenuation with depth and/or azimuth. The VSP data reveal low shear wave velocities of 200-300 m/s in rock layers known to be heavily affected by subrosion and confirm the low velocities calculated from the surface seismic data. A discrepancy of the shear wave velocities is observed in other intervals probably due to unsymmetrical travel paths in the surface seismics. In some VSP data dominant conversion of the direct SH-wave to P-wave is observed that is assumed to be caused by an increased presence of cavities. A potential fault distorting the vertical travel paths was detected by abnormal P-wave first

  9. The forearc crustal evolution of Izu-Bonin (Ogasawara) region obtained by seismic reflection and refraction surveys

    Science.gov (United States)

    Yamashita, M.; Kodaira, S.; Takahashi, N.; Tatsumi, Y.; Kaneda, Y.

    2009-12-01

    The Izu-Bonin (Ogasawara)-Mariana (IBM) arc is known to the typical oceanic island arc, and it is the most suitable area to understand the growth process of island arc. By previous seismic survey and deep sea drilling, convex basements are distributed along North-South direction in present forearc region. The convex basements are reported to be formed during Oligocene and Eocene (Taylor, 1992). In IBM forearc region, the middle crust with 6 km/s is recognized by seismic survey using OBSs. In IBM region, four IODP drilling sites are proposed in order to understand comprehensive growth process of arc and continental crust evolution. Two of them are located in forearc region. Japan Agency for Marine-Earth Science and Technology (JAMSTEC) carried out multi-channel seismic reflection survey using 7,800/12,000 cu.in. air gun and 5-6 km streamer with 444/204 ch hydrophones in the IBM region since 2004. We investigate the crustal structure beneath the Izu-Bonin forearc region for contribution of IBM drilling site along five long survey lines, which are across from present volcanic front to forearc basin. Seismic refraction survey is also conducted across forearc region using 84 OBSs every 1 km interval. Shallow crustal structure can be classified four units including basement which compared between previous drilling results and obtained seismic profiles. In IBM forearc region, thick sedimentary basin distribute from east side of volcanic front. Two convex basement peaks are indicated in across profile of forearc region. These peaks are estimated the top of paleoarc (Oligocene and Eocene) by previous ODP drilling. The half graben structure with major displacement is identified from west side of present volcanic front to the top of Oligocene arc. On the other hand, there is no displacement of sediments between the Oligocene arc and Eocene arc. This result shows the same origin of basement between the present volcanic front and Oligocene arc. There is long time difference of

  10. Seismic modeling of fluvial-estuarine deposits in the Athabasca oil sands using ray-tracing techniques, Steepbank River area, northeastern Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Langenberg, C. W.; Hein, F. J. [Alberta Energy and Utilities Board, Edmonton, AB (Canada); Lawton, D.; Cunningham, J. [Calgary Univ., Dept. of Geology and Geophysics, Calgary, AB (Canada)

    2002-03-01

    Seismic reflection characteristics of contrasting channel geometries in a five-section portion of the Steepbank River are modeled using ray-tracing techniques. Outcrop lithofacies associations are used to create a seismic model that can be used as a subsurface analog of other similar oil-sands successions. At least four channel complexes based on stratal bounding surfaces, arrangement of lithofacies, and consistent paleoflow patterns have been identified. The lower part of each channel complex contains trough crossbedded sandstone, exhibiting high porosity and permeability. These sandstones were deposited in channel axes and are the highest grade bitumen deposits in the area. The upper parts of the channels contain significantly lower bitumen saturation values due to common interbedded mudstone. Nearby wells contain cored and logged intervals that are similar to exposed outcrops in the riverbank. Overall modeling results indicate that channel complexes can be imaged seismically, given data of sufficient quality and frequency. Bitumen grade may be predicted in these seismic lines, which has important consequences for bitumen exploration and extraction in the Steepbank River region. 64 refs., 26 figs.

  11. Shear-wave seismic reflection imaging and impedance inversion for a near-surface point-bar

    Science.gov (United States)

    Benton, N. W.; Morrison, M.; Lorenzo, J. M.; Odom, B.; Clift, P. D.; Olson, E.; Gostic, A.

    2017-12-01

    Imaging and inversion of SH-waves are useful to detect, map, and quantitatively characterize near-surface point-bar strata. We conduct a horizontally-polarized (SH) reflection survey across and along a near-surface (9 - 40 m) downstream point-bar. We invert for shear-impedance profiles and correlate our interpretation to electrical conductivity (EC) logs in adjacent wells to study the internal architecture and lithology of point-bars. We acquire two common-midpoint (CMP) SH-wave seismic reflection lines at False River (Point Coupee Parish, Louisiana). A 104 m long seismic line (L1) is oriented orthogonal (NW - SE) to point-bar strike. A second line (L2) is 48 m long and set parallel to point-bar strike (NE - SW). Two EC wells lie 33 m apart. Both wells are parallel with respect to the L1 survey and offset from it by 15 m. EC log measurements range from 1 - 25 m depth. Interference of Love-waves prevents seismic imaging at depths less than 9 m. The L1 and L2 data sets are inverted for shear-impedance using a model-based band-limited impedance (BLIMP) algorithm that incorporates a low-frequency velocity model. This model is also used for the depthing processing. The L1 cross-section shows coherent dipping reflection events ( 4 - 7º) from 0.15 - 0.35 s (10 - 40 m). The corresponding shear-impedance profile also reveals coherent and dipping impedance contrasts that grow in magnitude with increasing depth. The L2 cross-section shows comparatively less dip ( 1º) as well as sharper and shallower continuity of reflection events (0.1 - 0.28 s TWT or 9 - 25 m). Depth-converted (TVD) seismic amplitudes and impedance values correlate to near-surface point-bar geology via superposition of log data. The first well (W5) shows distinct EC local maxima (+50 - 70 mS/m) at 14.5 and 15.5 m depth that correlate well with the seismic amplitudes and impedance values from both L1 and L2 data sets. The second well (W7) shows comparatively lower local maxima (+40 - 60 mS/m) but at greater

  12. Seismic site-response characterization of high-velocity sites using advanced geophysical techniques: application to the NAGRA-Net

    Science.gov (United States)

    Poggi, V.; Burjanek, J.; Michel, C.; Fäh, D.

    2017-08-01

    The Swiss Seismological Service (SED) has recently finalised the installation of ten new seismological broadband stations in northern Switzerland. The project was led in cooperation with the National Cooperative for the Disposal of Radioactive Waste (Nagra) and Swissnuclear to monitor micro seismicity at potential locations of nuclear-waste repositories. To further improve the quality and usability of the seismic recordings, an extensive characterization of the sites surrounding the installation area was performed following a standardised investigation protocol. State-of-the-art geophysical techniques have been used, including advanced active and passive seismic methods. The results of all analyses converged to the definition of a set of best-representative 1-D velocity profiles for each site, which are the input for the computation of engineering soil proxies (traveltime averaged velocity and quarter-wavelength parameters) and numerical amplification models. Computed site response is then validated through comparison with empirical site amplification, which is currently available for any station connected to the Swiss seismic networks. With the goal of a high-sensitivity network, most of the NAGRA stations have been installed on stiff-soil sites of rather high seismic velocity. Seismic characterization of such sites has always been considered challenging, due to lack of relevant velocity contrast and the large wavelengths required to investigate the frequency range of engineering interest. We describe how ambient vibration techniques can successfully be applied in these particular conditions, providing practical recommendations for best practice in seismic site characterization of high-velocity sites.

  13. The Investigation of Active Tectonism Offshore Cide-Sinop, Southern Black Sea by Seismic Reflection and Bathymetric Data

    Science.gov (United States)

    Alp, Y. I.; Ocakoglu, N.; Kılıc, F.; Ozel, A. O.

    2017-12-01

    The active tectonism offshore Cide-Sinop at the Southern Black Sea shelf area was first time investigated by multi-beam bathymetric and multi-channel seismic reflection data under the Research Project of The Scientific and Technological Research Council of Turkey (TUBİTAK-ÇAYDAG-114Y057). The multi-channel seismic reflection data of about 700 km length were acquired in 1991 by Turkish Petroleum Company (TP). Multibeam bathymetric data were collected between 2002-2008 by the Turkish Navy, Department of Navigation, Hydrography and Oceanography (TN-DNHO). Conventional data processing steps were applied as follows: in-line geometry definition, shot-receiver static correction, editing, shot muting, gain correction, CDP sorting, velocity analysis, NMO correction, muting, stacking, predictive deconvolution, band-pass filtering, finite-difference time migration, and automatic gain correction. Offshore area is represented by a quite smooth and large shelf plain with an approx. 25 km wide and the water depth of about -100 m. The shelf gently deepens and it is limited by the shelf break with average of -120 m contour. The seafloor morphology is charasterised by an erosional surface. Structurally, E-W trending strike-slip faults with generally compression components and reverse/thrust faults have been regionally mapped for the first time. Most of these faults deform all seismic units and reach the seafloor delimiting the morphological highs and submarine plains. Thus, these faults are intepreted as active faults. These results support the idea that the area is under the active compressional tectonic regime

  14. High-resolution seismic-reflection imaging 25 years of change in I-70 sinkhole, Russell County, Kansas

    Science.gov (United States)

    Miller, R.D.; Steeples, D.W.; Lambrecht, J.L.; Croxton, N.

    2006-01-01

    Time-lapse seismic reflection imaging improved our understanding of the consistent, gradual surface subsidence ongoing at two sinkholes in the Gorham Oilfield discovered beneath a stretch of Interstate Highway 70 through Russell and Ellis Counties in Kansas in 1966. With subsidence occurring at a rate of around 10 cm per year since discovery, monitoring has been beneficial to ensure public safety and optimize maintenance. A miniSOSIE reflection survey conducted in 1980 delineated the affected subsurface and successfully predicted development of a third sinkhole at this site. In 2004 and 2005 a high-resolution vibroseis survey was completed to ascertain current conditions of the subsurface, rate and pattern of growth since 1980, and potential for continued growth. With time and improved understanding of the salt dissolution affected subsurface in this area it appears that these features represent little risk to the public from catastrophic failure. However, from an operational perspective the Kansas Department of Transportation should expect continued subsidence, with future increases in surface area likely at a slightly reduced vertical rate. Seismic characteristics appear empirically consistent with gradual earth material compaction/settling. ?? 2005 Society of Exploration Geophysicists.

  15. Seismic-reflection surveys of the Blake Ridge, R/V Cape Hatteras, 1992 and 1995; data acquisition, navigation and processing

    Science.gov (United States)

    Taylor, Michael H.; Dillon, William P.; Anton, Christopher H.; Danforth, William W.

    1999-01-01

    As part of an ongoing study, seismic-reflection profiles were collected over the Blake Ridge in 1992 and 1995, in order to map the volume and distribution of methane hydrate. Faulting and seafloor instabilities appear to be related to methane hydrate processes at the Blake Ridge. Seismic profiles display a prominent collapse structure at the crest, which is inferred to have resulted from the mobilization of sediment that was associated with methane hydrate dissociation.

  16. Seismic reflection and structuring characterization of deep aquifer system in the Dakhla syncline (Cap Bon, North-Eastern Tunisia)

    Science.gov (United States)

    Bellali, Abir; Jarraya Horriche, Faten; Gabtni, Hakim; Bédir, Mourad

    2018-04-01

    The Dakhla syncline is located in the North-Eastern Tunisia. It is bounded by Abd El Rahmene anticline to the North-West, El Haouaria Graben to the North-East, Grombalia Graben to the South-West and the Mediterranean Sea to the East. The main aquifer reservoirs of Dakhla syncline are constituted by stacks of fluvial to deltaic Neogene sequences and carbonates. The interpretation of eight seismic reflection profiles, calibrated by wire line logging data of three oil wells, hydraulic wells and geologic field sections highlighted the impact of tectonics on the structuring geometry of aquifers and their distribution in elevated structures and subsurface depressions. Lithostratigraphic correlations and seismic profiles analysis through the syncline show that the principal aquifers are thickest within the central and northern part of the study area and thinnest to the southern part of the syncline. Seismic sections shows that the fracture/fault pattern in this syncline is mainly concentrated along corridors with a major direction of NW-SE and secondary directions of N-S, E-W and NE-SW with different release. This is proved by the complexity structure of Eastern Tunisia, resulted from the interaction between the African and Eurasiatic plates. Isochron maps of aquifers systems exhibited the structuring of this syncline in sub-surface characterized by important lateral and vertical geometric and thickness variations. Seismic sections L1, L2, L3, L4, L5 and petroleum wells showed an heterogeneous multilayer aquifers of Miocene formed by the arrangement of ten sandstone bodies, separated by impermeable clay packages. Oligo-Miocene deposits correspond to the most great potential aquifers, with respectively an average transmissivity estimated: Somaa aquifer 6.5 10-4 m2/s, Sandstone level aquifer 2.6 10-3 m2/s, Beglia aquifer 1.1 10-3 m2/s, Ain Ghrab aquifer 1.3 10-4 m2/s and Oligocene aquifer 2 10-3 m2/s. The interpretation of spatial variations of seismic units and the

  17. Gas hydrate concentration and characteristics within Hydrate Ridge inferred from multicomponent seismic reflection data

    Science.gov (United States)

    Kumar, Dhananjay; Sen, Mrinal K.; Bangs, Nathan L.

    2007-12-01

    A seismic experiment composed of streamer and ocean bottom seismometer (OBS) surveys was conducted in the summer of 2002 at southern Hydrate Ridge, offshore Oregon, to map the gas hydrate distribution within the hydrate stability zone. Gas hydrate concentrations within the reservoir can be estimated with P wave velocity (Vp); however, we can further constrain gas hydrate concentrations using S wave velocity (Vs), and use Vs through its relationship to Vp (Vp/Vs) to reveal additional details such as gas hydrate form within the matrix (i.e., hydrate cements the grains, becomes part of the matrix frame or floats in pore space). Both Vp and Vs can be derived simultaneously by inverting multicomponent seismic data. In this study, we use OBS data to estimate seismic velocities where both gas hydrate and free gas are present in the shallow sediments. Once Vp and Vs are estimated, they are simultaneously matched with modeled velocities to estimate the gas hydrate concentration. We model Vp using an equation based on a modification of Wood's equation that incorporates an appropriate rock physics model and Vs using an empirical relation. The gas hydrate concentration is estimated to be up to 7% of the rock volume, or 12% of the pore space. However, Vp and Vs do not always fit the model simultaneously. Vp can vary substantially more than Vs. Thus we conclude that a model, in which higher concentrations of hydrate do not affect shear stiffness, is more appropriate. Results suggest gas hydrates form within the pore space of the sediments and become part of the rock framework in our survey area.

  18. Dew point measurement technique utilizing fiber cut reflection

    Science.gov (United States)

    Kostritskii, S. M.; Dikevich, A. A.; Korkishko, Yu. N.; Fedorov, V. A.

    2009-05-01

    The fiber optical dew point hygrometer based on change of reflection coefficient for fiber cut has been developed and examined. We proposed and verified the model of condensation detector functioning principle. Experimental frost point measurements on air with different frost points have been performed.

  19. Structural and Tectonic Map Along the Pacific-North America Plate Boundary in Northern Gulf of California, Sonora Desert and Valle de Mexicali, Mexico, from Seismic Reflection Evidence

    Science.gov (United States)

    Gonzalez-Escobar, M.; Suarez-Vidal, F.; Mendoza-Borunda, R.; Martin Barajas, A.; Pacheco-Romero, M.; Arregui-Estrada, S.; Gallardo-Mata, C.; Sanchez-Garcia, C.; Chanes-Martinez, J.

    2012-12-01

    Between 1978 and 1983, Petróleos Mexicanos (PEMEX) carried on an intense exploration program in the northern Gulf of California, the Sonora Desert and the southern part of the Mexicali Valley. This program was supported by a seismic reflection field operation. The collected seismic data was 2D, with travel time of 6 s recording, in 48 channels, and the source energy was: dynamite, vibroseis and air guns. Since 2007 to present time, the existing seismic data has been re-processing and ire-interpreting as part of a collaboration project between the PEMEX's Subdirección de Exploración (PEMEX) and CICESE. The study area is located along a large portion of the Pacific-North America plate boundary in the northern Gulf of California and the Southern part of the Salton Trough tectonic province (Mexicali Valley). We present the result of the processes reflection seismic lines. Many of the previous reported known faults were identify along with the first time described located within the study region. We identified regions with different degree of tectonic activity. In structural map it can see the location of many of these known active faults and their associated seismic activity, as well as other structures with no associated seismicity. Where some faults are mist placed they were deleted or relocated based on new information. We included historical seismicity for the region. We present six reflection lines that cross the aftershocks zone of the El Mayor-Cucapah earthquake of April 4, 2010 (Mw7.2). The epicenter of this earthquake and most of the aftershocks are located in a region where pervious to this earthquake no major earthquakes are been reported. A major result of this study is to demonstrate that there are many buried faults that increase the seismic hazard.

  20. Seismic reflection data processing in active volcanic areas: an application to Campi Flegrei and Somma Vesuvius offshore (Southern Italy

    Directory of Open Access Journals (Sweden)

    A. Rapolla

    2002-06-01

    Full Text Available The Campanian volcanism develops near the sea. Therefore, the geophysical study of the marine environment is a key to a better understanding of the tectonic evolution and the origin of volcanism in the area. An abundance of high quality seismic data in the marine sector, where little direct information is available, is critical to the study of Campanian volcanism. This paper concerns the reprocessing of a seismic reflection dataset acquired in Naples Bay and processed during 1973. Even though the overall data quality was high for that time, of course their acquisition technological limits have been overcome by the new processing. Our reprocessing aimed at: 1 reduction of random noise in the data; 2 removal of unwanted coherent events; 3 reduction of spatial aliasing by means of trace interpolation on Commod Shot Point (CSP gathering; 4 improvement of resolution of the seismic wavelet with spiking deconvolution algorithms and finally 5 reposition of reflectors in their correct locations in the space-TWT domain by means of dip moveout and post-stack time migration. A comparison between the new and old data shows that the new sections are characterized by a much higher S/N ratio. Diffraction hyperbole has been collapsed. Reverberations, ghosts and multiples have been removed or greatly attenuated, especially between the reflectors of interest, allowing us to follow them with more detail and with greater continuity. Furthermore, data resolution has been boosted by the reprocessing, allowing the interpreter to evaluate reflector position and continuity in greater detail. The reinterpretation phase of such lines, that is already in an advanced stage, will therefore allow us to gain new insights into the structural setting of the bay, with the aim of exploring the connection between tectonics and volcanism.

  1. Reflection seismic characterization of the Grängesberg iron deposit and its mining-induced structures, central Sweden

    Science.gov (United States)

    Place, Joachim; Malehmir, Alireza; Högdahl, Karin; Juhlin, Christopher; Persson Nilsson, Katarina

    2014-05-01

    Reflection seismic investigation has been conducted on the Grängesberg apatite iron deposit where over 150 Mt of iron ore were produced until the mine closed in 1989. The mine infrastructure with shafts and tunnels extend down to ca. 650 m below the surface. Both natural and mine induced fracture and fault systems are today water-filled (some of them extending to the surface). The disputed ore genesis of the apatite-iron ores and its exploration potential due to large remaining quantities once again attracts both scientific and commercial interests. A good understanding of the geometry of mineral deposits and their hostrock structures at depth is essential for optimizing their exploration and exploitation. In addition, deep understanding of the fracture system is vital if mining activity is resumed as these may impact the terrain stability and seismicity, which may put at risk new populated and industrial areas. To address some of these challenging issues related to the past mining and also to obtain information about the depth continuation of the existing deposit, two E-W oriented reflection lines with a total length of 3.5 km were acquired in May 2013 by Uppsala University. A weight drop mounted on an hydraulic bobcat truck (traditionally used for concrete breaking in demolition sector) was used to generate seismic signal. In order to increase the signal-to-noise ratio, several impacts were generated at each shot point and stacked together. The seismic lines intersect at high angle the Grängesberg ore body and open pit, as well as several mining-induced faults. A combination of cabled and wireless receivers placed at every 10 m was used for the data recording. Use of wireless receivers was necessary as deploying cabled sensors was not possible due to city infrastructures, roads and houses. A careful analysis of the data suggested that several field-related issues such as (1) the crooked geometry of the lines (due to the available path and road network), (2

  2. Estimation of Dry Fracture Weakness, Porosity, and Fluid Modulus Using Observable Seismic Reflection Data in a Gas-Bearing Reservoir

    Science.gov (United States)

    Chen, Huaizhen; Zhang, Guangzhi

    2017-05-01

    Fracture detection and fluid identification are important tasks for a fractured reservoir characterization. Our goal is to demonstrate a direct approach to utilize azimuthal seismic data to estimate fluid bulk modulus, porosity, and dry fracture weaknesses, which decreases the uncertainty of fluid identification. Combining Gassmann's (Vier. der Natur. Gesellschaft Zürich 96:1-23, 1951) equations and linear-slip model, we first establish new simplified expressions of stiffness parameters for a gas-bearing saturated fractured rock with low porosity and small fracture density, and then we derive a novel PP-wave reflection coefficient in terms of dry background rock properties (P-wave and S-wave moduli, and density), fracture (dry fracture weaknesses), porosity, and fluid (fluid bulk modulus). A Bayesian Markov chain Monte Carlo nonlinear inversion method is proposed to estimate fluid bulk modulus, porosity, and fracture weaknesses directly from azimuthal seismic data. The inversion method yields reasonable estimates in the case of synthetic data containing a moderate noise and stable results on real data.

  3. Reflection and transmission of seismic waves under initial stress at the earth's core-mantle boundary

    Directory of Open Access Journals (Sweden)

    Sukhendu Dey

    1980-01-01

    Full Text Available In the present paper the influence of the initial stress is shown on the reflection and transmission of P waves at the core-mantle boundary. Taking a particular value of the inherent initial stress, the variations of reflection and transmission coefficients with respect to the angle of emergence are represented by graphs. These graphs when compared with those having no initial stress show that the effect of the initial stress is to produce a reflected P and S waves with numerically higher amplitudes but a transmitted P wave with smaller amplitude. A method is also indicated in this paper to calculate the actual value of the initial stress near the core-mantle boundary by measuring the amplitudes of incident and reflected P waves.

  4. A seismic refraction and wide-angle reflection exploration in 2002 on the Mizuho Plateau, East Antarctica-Outline of observations (JARE-43-

    Directory of Open Access Journals (Sweden)

    Hiroki Miyamachi

    2003-03-01

    Full Text Available A seismic refraction and wide-angle reflection exploration was successfully conducted along a profile crossing the JARE-41 seismic profile on the Mizuho Plateau, in East Antarctica, in the austral summer season of 2001-2002 (JARE-43. One hundred sixty-one seismic stations were temporarily installed along a profile about 151 km long and seven large shots with about 700 kg of dynamite were fired. In addition, one shot with charge size of 20 kg was also arranged along the profile. The obtained seismic records show the clear onsets of the first arrivals at distances of less than 100 km from each large shot. In particular, seismic waves traveling through the ice sheet and dispersed surface waves were clearly observed. Some later reflection phases were also detected. The obtained first travel time data show that the ice sheet is a two-layered structure consisting of an upper layer with a P wave velocity of 2.7-2.9 km/s and a lower layer of 3.7-3.9 km/s. The thickness of the upper layer is estimated to be about 36-45 m. The apparent velocity in the basement rock just beneath the ice sheet is 6.1-6.2 km/s in the central and southern parts of the profile and almost 5.9 km/s in the northern part. This report describes basic outlines of the exploration and the obtained seismic data.

  5. Consecutive collection of new finding and knowledge on science and technology to be reflected to seismic safety assessment for nuclear facilities

    International Nuclear Information System (INIS)

    Tsutsumi, Hideaki; Iijima, Toru

    2013-05-01

    JNES had been collecting and analyzing new finding and knowledge on science and technology to be reflected to seismic safety assessment for nuclear facilities, which was updated so as to develop a system to organize and disseminate such information in response to Nuclear Regulation Authority (NRA)'s policy on new safety regulations requesting enhanced protective measures against extreme natural hazards. The tasks were as follows; (1) collection of new finding and knowledge from seismic safety research of JNES, (2) constructing database of seismic safety research from documents published by committees and including the Great East Japan Earthquake and (3) dissemination of information related to seismic research. As for JFY 2012 activities, collecting and analyzing new finding and knowledge were on three areas such as active fault, seismic source/ground motion and tsunami. 4 theme related with the Great East Japan Earthquake, 7 items not related with the Great East Japan Earthquake and one item on external event were collected and analyzed whether incorporating in seismic safety research important for regulation to increase seismic safety of nuclear facilities, with no such theme confirmed. (T. Tanaka)

  6. Crustal structure beneath discovery bank in the South Scotia Sea from group velocity tomography and seismic reflection data

    International Nuclear Information System (INIS)

    Vuan, A.; Lodolo, E.; Panza, G.F.

    2003-09-01

    Bruce, Discovery, Herdman and Jane Banks, all located along the central-eastern part of the South Scotia Ridge (i.e., the Antarctica-Scotia plate boundary), represent isolated topographic reliefs surrounded by relatively young oceanic crust, whose petrological and structural nature is still the subject of speculations due to the lack of resolving data. In the Scotia Sea and surrounding regions negative anomalies of about 34% are reported in large-scale group velocity tomography maps. The spatial resolution (∼500 km) of these maps does not warrant any reliable interpretation of such anomalies. A recent surface wave tomography in the same area, performed using broad band seismic stations and 300 regional events, shows that in the period range from 15 s to 50 s the central-eastern part of the South Scotia Ridge is characterized by negative anomalies of the group velocities as large as 6. The resolution of our data set (∼300 km) makes it possible to distinguish an area (centered at 61 deg S and 36 deg W) with a crust thicker than 25 km, and a shear wave velocity vs. depth profile similar to that found beneath the northern tip of the Antarctic Peninsula and southern South America. Rayleigh and Love wave dispersion curves are inverted in the period range from 15 s to 80 s to obtain shear wave velocity profiles that suggest a continental nature of Discovery Bank. The continental-type crust of this topographic relief is in agreement with the interpretation of a multi-channel seismic reflection profile acquired across this rise. Peculiar acoustic facies are observed in this profile and are interpreted as thinned and faulted continental plateau. The boundaries of the negative group velocity anomalies are marked by a high seismicity rate. Historical normal faulting earthquakes with magnitude around 7 are localised between the low velocity anomaly region in the eastern South Scotia Ridge and the high velocity anomaly region associated with the surrounding oceanic crust

  7. Assessing the Nature of Crust in the Central Red Sea Using Potential Fields and Seismic Reflection Data

    Science.gov (United States)

    Shi, W.; Mitchell, N. C.; Kalnins, L. M.; A Y, I.

    2017-12-01

    The Red Sea is considered an important example of a rifted continental shield proceeding to a seafloor spreading stage of development, and the transition of crustal types there from stretched continental to oceanic should mark the onset of significant mantle melting. However, whether the crust in the central Red Sea is continental or oceanic has been controversial. To contribute to this debate, we assessed the geometry of the basement from potential fields and seismic reflection data. Prior interpretations of basement in deep seismic reflection profiles were first verified using Werner deconvolution of marine magnetic data. The seismic depths were then used to reconstruct basement depth corrected for evaporite and other sediment loading. We found that the basement deepening with distance is similar to that of oceanic crust near mantle plumes such as the Reykjanes Ridge. In both cases, the data show a 35-80 km wide axial plateau followed by a steep 0.4-1.7 km deepening over 30-50 km distance. It has also been suggested that the variability of free-air anomalies observed in lines parallel to the axis is due to crossing oceanic short-offset fracture zones. We assessed this idea by inverting the gravity anomalies for basement relief. Using densities appropriate for oceanic crust and a modified slab formula, we found values for root-mean square (RMS) relief that are comparable to those of weakly sedimented regions of the Mid-Atlantic Ridge. Forward calculations using 2D modelling revealed that the errors in RMS basement relief caused by the slab approximation are 30%, leaving true RMS basement relief still within the range of values for oceanic crust. While these observations by themselves do not rule out an extremely extended continental crust interpretation, combined with previous analysis of refraction velocities, which are oceanic-like, they are supportive of an oceanic crustal interpretation. Additionally, the RMS values and the cross-axis basement relief both

  8. Seismic reflection results of the GYRE 1997 Cruise at the Bryant Canyon of the Louisiana Gulf Coast

    Science.gov (United States)

    Nealon, Jeffrey W.; Dillon, William P.; Twichell, David

    2000-01-01

    The TexasLouisiana continental slope is one of the few remaining frontiers for hydrocarbon exploration within the US Exclusive Economic Zone.  This area has a complex seafloor morphology and highly discontinuous shallow stratigraphy that are the result of deformation by the highly mobile Louann salt that underlies much of this margin shoreward of the Sigsbee Escarpment.Gas hydrates exist both on the sea floor and at depth throughout the gas hydrate stability zone which extends to several hundred meters beneath the sea floor at greater water depths.  Multibeam bathymetry, GLORIA sidescan sonar imagery, and site-specific studies have identified the presence of faults, mass-wasting deposits, variable sediment types, and gas hydrates exposed on the seafloor.  The expression of these features on the seafloor suggests a tectonically active area.  The distribution of these different processes and their relation to the subsurface stratigraphy and tectonic setting are not well understood, yet an understanding of these issues is essential as exploration extends into this deep-water area.To address the questions of surficial processes and their connection with deeper structures underlying this continental margin, a three-week cruise was conducted by the USGS in April, 1997 aboard the RV GYRE. The study area focussed on Bryant Canyon, a former submarine canyon, through which turbidity currents transported sands from a shelf-edge delta upslope of the study area to the Bryant Fan on the rise seaward of the base of the slope.  The cruise was divided into two parts.  The first part was devoted to collecting seismic-reflection profiles across parts of the canyon system to define the shallow stratigraphy and to determine the presence and distribution of gas hydrates in this area.  Approximately 555 km of single-channel seismic-reflection data were collected during this first part of the cruise.  A track map showing the locations of the profiles, low-resolution images of the

  9. Micro reflectance difference techniques: Optical probes for surface exploration

    Energy Technology Data Exchange (ETDEWEB)

    Lastras-Martinez, L.F.; Del Pozo-Zamudio, O.; Herrera-Jasso, R.; Ulloa-Castillo, N.A.; Balderas-Navarro, R.E.; Ortega-Gallegos, J.; Lastras-Martinez, A. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi, S.L.P. (Mexico)

    2012-06-15

    Micro reflectance difference spectroscopy ({mu}-RDS) is a promising tool for the in-situ and ex-situ characterization of semiconductors surfaces and interfaces. We discuss and compare two different approaches used to measure {mu}-RD spectra. One is based on a charge-coupled device (CCD) camera, while the other uses a laser and a XY translation stage. To show the performance of these systems, we have measured surface optical anisotropies of GaSb(001) sample on which anisotropic strains have been generated by preferential mechanical polishing along [110] and [1 anti 10] directions. The spectrometers are complementary and the selection of one of them depends on the sample to be investigated and on experimental conditions. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Tectonic characteristics and structural styles of a continental rifted basin: Revelation from deep seismic reflection profiles

    Directory of Open Access Journals (Sweden)

    Yuan Li

    2016-09-01

    Full Text Available The Fushan Depression is a half-graben rifted sub-basin located in the southeast of the Beibuwan Basin, South China Sea. The Paleogene Liushagang sequence is the main hydrocarbon-bearing stratigraphic unit in the sub-basin. Using three-dimensional (3-D seismic data and logging data over the sub-basin, we analyzed structural styles and sedimentary characteristics of the Liushagang sequence. Five types of structural styles were defined: ancient horst, traditional slope, flexure slope-break, faulted slope-break and multiple-stage faults slope, and interpretations for positions, background and development formations of each structural style were discussed. Structural framework across the sub-basin reveals that the most remarkable tectonic setting is represented by the central transfer zone (CTZ which divides the sub-basin into two independent depressions, and two kinds of sequence architectures are summarized: (i the western multi-stage faults slope; (ii the eastern flexure slope break belt. Combined with regional stress field of the Fushan Depression, we got plane combinations of the faults, and finally built up plan distribution maps of structural system for main sequence. Also, we discussed the controlling factors mainly focused on subsidence history and background tectonic activities such as volcanic activity and earthquakes. The analysis of structural styles and tectonic evolution provides strong theoretical support for future prospecting in the Fushan sub-basin and other similar rifted basins of the Beibuwan Basin in South China Sea.

  11. Tectonic Inversion Along the Algerian and Ligurian Margins: On the Insight Provided By Latest Seismic Processing Techniques Applied to Recent and Vintage 2D Offshore Multichannel Seismic Data

    Science.gov (United States)

    Schenini, L.; Beslier, M. O.; Sage, F.; Badji, R.; Galibert, P. Y.; Lepretre, A.; Dessa, J. X.; Aidi, C.; Watremez, L.

    2014-12-01

    Recent studies on the Algerian and the North-Ligurian margins in the Western Mediterranean have evidenced inversion-related superficial structures, such as folds and asymmetric sedimentary perched basins whose geometry hints at deep compressive structures dipping towards the continent. Deep seismic imaging of these margins is difficult due to steep slope and superficial multiples, and, in the Mediterranean context, to the highly diffractive Messinian evaporitic series in the basin. During the Algerian-French SPIRAL survey (2009, R/V Atalante), 2D marine multi-channel seismic (MCS) reflection data were collected along the Algerian Margin using a 4.5 km, 360 channel digital streamer and a 3040 cu. in. air-gun array. An advanced processing workflow has been laid out using Geocluster CGG software, which includes noise attenuation, 2D SRME multiple attenuation, surface consistent deconvolution, Kirchhoff pre-stack time migration. This processing produces satisfactory seismic images of the whole sedimentary cover, and of southward dipping reflectors in the acoustic basement along the central part of the margin offshore Great Kabylia, that are interpreted as inversion-related blind thrusts as part of flat-ramp systems. We applied this successful processing workflow to old 2D marine MCS data acquired on the North-Ligurian Margin (Malis survey, 1995, R/V Le Nadir), using a 2.5 km, 96 channel streamer and a 1140 cu. in. air-gun array. Particular attention was paid to multiple attenuation in adapting our workflow. The resulting reprocessed seismic images, interpreted with a coincident velocity model obtained by wide-angle data tomography, provide (1) enhanced imaging of the sedimentary cover down to the top of the acoustic basement, including the base of the Messinian evaporites and the sub-salt Miocene series, which appear to be tectonized as far as in the mid-basin, and (2) new evidence of deep crustal structures in the margin which the initial processing had failed to

  12. Imaging Fracture Networks Using Angled Crosshole Seismic Logging and Change Detection Techniques

    Science.gov (United States)

    Knox, H. A.; Grubelich, M. C.; Preston, L. A.; Knox, J. M.; King, D. K.

    2015-12-01

    We present results from a SubTER funded series of cross borehole geophysical imaging efforts designed to characterize fracture zones generated with an alternative stimulation method, which is being developed for Enhanced Geothermal Systems (EGS). One important characteristic of this stimulation method is that each detonation will produce multiple fractures without damaging the wellbore. To date, we have collected six full data sets with ~30k source-receiver pairs each for the purposes of high-resolution cross borehole seismic tomographic imaging. The first set of data serves as the baseline measurement (i.e. un-stimulated), three sets evaluate material changes after fracture emplacement and/or enhancement, and two sets are used for evaluation of pick error and seismic velocity changes attributable to changing environmental factors (i.e. saturation due to rain/snowfall in the shallow subsurface). Each of the six datasets has been evaluated for data quality and first arrivals have been picked on nearly 200k waveforms in the target area. Each set of data is then inverted using a Vidale-Hole finite-difference 3-D eikonal solver in two ways: 1) allowing for iterative ray tracing and 2) with fixed ray paths determined from the test performed before the fracture stimulation of interest. Utilizing these two methods allows us to compare and contrast the results from two commonly used change detection techniques. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  13. 3D Seismic Reflection Amplitude and Instantaneous Frequency Attributes in Mapping Thin Hydrocarbon Reservoir Lithofacies: Morrison NE Field and Morrison Field, Clark County, KS

    Science.gov (United States)

    Raef, Abdelmoneam; Totten, Matthew; Vohs, Andrew; Linares, Aria

    2017-12-01

    Thin hydrocarbon reservoir facies pose resolution challenges and waveform-signature opportunities in seismic reservoir characterization and prospect identification. In this study, we present a case study, where instantaneous frequency variation in response to a thin hydrocarbon pay zone is analyzed and integrated with other independent information to explain drilling results and optimize future drilling decisions. In Morrison NE Field, some wells with poor economics have resulted from well-placement incognizant of reservoir heterogeneities. The study area in Clark County, Kanas, USA, has been covered by a surface 3D seismic reflection survey in 2010. The target horizon is the Viola limestone, which continues to produce from 7 of the 12 wells drilled within the survey area. Seismic attributes extraction and analyses were conducted with emphasis on instantaneous attributes and amplitude anomalies to better understand and predict reservoir heterogeneities and their control on hydrocarbon entrapment settings. We have identified a higher instantaneous frequency, lower amplitude seismic facies that is in good agreement with distinct lithofacies that exhibit better (higher porosity) reservoir properties, as inferred from well-log analysis and petrographic inspection of well cuttings. This study presents a pre-drilling, data-driven approach of identifying sub-resolution reservoir seismic facies in a carbonate formation. This workflow will assist in placing new development wells in other locations within the area. Our low amplitude high instantaneous frequency seismic reservoir facies have been corroborated by findings based on well logs, petrographic analysis data, and drilling results.

  14. Geological affinity of reflecting boundaries in the intermediate structural stage of the Chu Sarysuyskiy depression based on results of vertical seismic profilling

    Energy Technology Data Exchange (ETDEWEB)

    Davydov, N.G.; Kiselevskiy, Yu.N.

    1983-01-01

    A computer (EVM) and an ASOI-VSP-SK program complex are used to analyze data from seismic exploration and acoustical logging with interval by interval calculation of the velocity every four meters. Vertical seismic profilling (VSP) results are used to identify all the upper layers as reference layers. The basic reference level, the third, which corresponds to the floor of the carbonate middle to upper Visean series, is not sustained due to the thin layered state of the terrigeneous section. Based on data from vertical seismic profilling, the reflected wave method (MOV) and the common depth point method (MOGT), the reference 3-a and 6-a levels are identified. Deep reflections of the seventh, 7-a and Rf, approximately confined to the roof and floor of the lower Paleozoic deposits and the upper part of the upper reef series, are noted in the series of the Caledonian cap of the Prebaykal massifs based on vertical seismic profilling. Collector levels are noted on the basis of the frequency of the wave spectra and from the absorption coefficient in the Testas structure and in other low amplitude structures. The insufficiency of the depth capability of the common depth point method and the poor knowledge level of seismic exploration of the section of the lower Paleozoa and the upper Proterozoa of the Chu Sarysuyskiy depresion are noted.

  15. The Geologic History of Lake of the Woods, Minnesota, Reconstructed Using Seismic-Reflection Imaging and Sediment Core Analysis

    Science.gov (United States)

    Hougardy, Devin D.

    The history of glacial Lake Agassiz is complex and has intrigued researchers for over a century. Over the course of its ˜5,000 year existence, the size, shape, and location of Lake Agassiz changed dramatically depending on the location of the southern margin of the Laurentide Ice Sheet (LIS), the location and elevation of outflow channels, and differential isostatic rebound. Some of the best-preserved sequences of Lake Agassiz sediments are found in remnant lake basins where erosional processes are less pronounced than in adjacent higher-elevation regions. Lake of the Woods (LOTW), Minnesota, is among the largest of the Lake Agassiz remnant lakes and is an ideal location for Lake Agassiz sediment accumulation. High-resolution seismic-reflection (CHIRP) data collected from the southern basin of LOTW reveal up to 28 m of stratified lacustrine sediment deposited on top of glacial diamicton and bedrock. Five seismic units (SU A-E) were identified and described based on their reflection character, reflection configuration, and external geometries. Three prominent erosional unconformities (UNCF 1-3) underlie the upper three seismic units and indicate that deposition at LOTW was interrupted by a series of relatively large fluctuations in lake level. The lowermost unconformity (UNCF-1) truncates uniformly draped reflections within SU-B at the margins of the basin, where as much as four meters of sediment were eroded. The drop in lake level is interpreted to be contemporaneous with the onset of the low-stand Moorhead phase of Lake Agassiz identified from subaerial deposits in the Red River Valley, Rainy River basin, and Lake Winnipeg. A rise in lake level, indicated by onlapping reflections within SU-C onto UNCF-1, shifted the wave base outwards and as much as 11 m of sediment were deposited (SU-C) in the middle of the basin before a second drop, and subsequent rise, in lake level resulted in the formation of UNCF-2. Reflections in the lower part of SU-D onlap onto UNCF-2

  16. Tectonic history in the Fort Worth Basin, north Texas, derived from well-log integration with multiple 3D seismic reflection surveys: implications for paleo and present-day seismicity in the basin

    Science.gov (United States)

    Magnani, M. B.; Hornbach, M. J.

    2016-12-01

    Oil and gas exploration and production in the Fort Worth Basin (FWB) in north Texas have accelerated in the last 10 years due to the success of unconventional gas production. Here, hydraulic fracturing wastewater is disposed via re-injection into deep wells that penetrate Ordovician carbonate formations. The rise in wastewater injection has coincided with a marked rise in earthquake rates, suggesting a causal relationship between industry practices and seismicity. Most studies addressing this relationship in intraplate regions like the FWB focus on current seismicity, which provides an a-posteriori assessment of the processes involved. 3D seismic reflection data contribute complementary information on the existence, distribution, orientation and long-term deformation history of faults that can potentially become reactivated by the injection process. Here we present new insights into the tectonic evolution of faults in the FWB using multiple 3D seismic reflection surveys in the basin, west of the Dallas Fort-Worth Metroplex, where high-volume wastewater injection wells have increased most significantly in number in the past few years. The datasets image with remarkable clarity the 3,300 m-thick sedimentary rocks of the basin, from the crystalline basement to the Cretaceous cover, with particular detail of the Paleozoic section. The data, interpreted using coincident and nearby wells to correlate seismic reflections with stratigraphic markers, allow us to identify faults, extract their orientation, length and displacements at several geologic time intervals, and therefore, reconstruct the long-term deformation history. Throughout the basin, the data show that all seismically detectable faults were active during the Mississippian and Pennsylvanian, but that displacement amounts drop below data resolution ( 7 m) in the post-Pennsylvanian deposits. These results indicate that faults have been inactive for at least the past 300 Ma, until the recent 2008 surge in

  17. Seismic velocity structure and spatial distribution of reflection intensity off the Boso Peninsula, Central Japan, revealed by an ocean bottom seismographic experiment

    Science.gov (United States)

    Kono, Akihiro; Sato, Toshinori; Shinohara, Masanao; Mochizuki, Kimihiro; Yamada, Tomoaki; Uehira, Kenji; Shinbo, Takashi; Machida, Yuuya; Hino, Ryota; Azuma, Ryosuke

    2016-04-01

    Off the Boso Peninsula, central Japan, where the Sagami Trough is in the south and the Japan Trench is in the east, there is a triple junction where the Pacific plate (PAC), the Philippine Sea plate (PHS) and the Honshu island arc (HIA) meet each other. In this region, the PAC subducts beneath the PHS and the HIA, and the PHS subducts beneath the HIA. Due to the subduction of 2 oceanic plates, numerous seismic events took place in the past. In order to understand these events, it is important to image structure of these plates. Hence, many researchers attempted to reveal the substructure from natural earthquakes and seismic experiments. Because most of the seismometers are placed inland area and the regular seismicity off Boso is inactive, it is difficult to reveal the precise substructure off Boso area using only natural earthquakes. Although several marine seismic experiments using active sources were conducted, vast area remains unclear off Boso Peninsula. In order to improve the situation, a marine seismic experiment, using airgun as an active source, was conducted from 30th July to 4th of August, 2009. The survey line has 216 km length and 20 Ocean Bottom Seismometers (OBSs) were placed on it. We estimated 2-D P-wave velocity structure from the airgun data using the PMDM (Progressive Model Development Method; Sato and Kenett, 2000) and the FAST (First Arrival Seismic Tomography ; Zelt and Barton, 1998). Furthermore, we identified the probable reflection phases from the data and estimated the location of reflectors using Travel time mapping method (Fujie et al. 2006). We found some reflection phases from the data, and the reflectors are located near the region where P-wave velocity is 5.0 km/s. We interpret that the reflectors indicate the plate boundary between the PHS and the HIA. The variation of the intensity of reflection along the upper surface of PHS seems to be consistent with the result from previous reflection seismic experiment conducted by Kimura et

  18. Structural characteristics around the frontal thrust along the Nankai Trough revealed by bathymetric and seismic reflection survey

    Science.gov (United States)

    Yamashita, M.; Nakanishi, A.; Moore, G. F.; Kodaira, S.; Nakamura, Y.; Miura, S.; Kaneda, Y.

    2016-12-01

    Great earthquakes with tsunamis with recurrence intervals of 100-200 years have occurred along the Nankai Trough near central Japan where the Shikoku Basin is subducting with thick sediments on the Philippine Sea plate. To predict the exact height of the tsunami on the coast region generated by these large ruptures, it is important to estimate the vertical deformation that occurs on the seaward end of the rupture area. Recent drilling results have also yielded evidence not only of splay faults that generate tsunamigenic rupture, but also new evidence of tsunamigenic rupture along the frontal thrust at the trench axis in the Nankai Trough. In order to understand the deformation around the frontal thrust at the trench axis, we conducted a dense high-resolution seismic reflection survey with 10-20 km spacing over 1500 km of line length during 2013 and 2014. Clear seismic reflection images of frontal thrusts in the accretionary prism and subducting Shikoku Basin, image deformation along the trench axis between off Muroto Cape and off Ashizuri Cape. The cumulative displacement along the frontal thrust and second thrust are measured from picked distinct reflectors in depth-converted profiles. The average value of cumulative displacement of the frontal thrust is more than 100 m within 2 km depth beneath the seafloor. The location of highest displacement of 300 m displacement agree with the seaward end of slip distribution of the 1946 Nankai event calculated by numerical simulations. We also evaluate the seaward structure for understanding the future rupture distribution. The protothrust zone (PTZ) consisting of many incipient thrusts is identifiable in the portion of trough-fill sediments seaward of the frontal thrust. In order to emphasize the characteristics of frontal thrust and PTZ, we construct the detailed relief image for focusing on the lineated slope of the PTZ at the trough axis. Although our surveys covered a part of Nankai seismogenic zone, it is important to

  19. Preliminary Interpretations of Multi-Channel Seismic Reflection and Magnetic Data on North Anatolian Fault (NAF) in the Eastern Marmara Region, Turkey

    Science.gov (United States)

    Gözde Okut Toksoy, Nigar; Kurt, Hülya; İşseven, Turgay

    2017-04-01

    The North Anatolian Fault (NAF) is 1600 km long, right lateral strike-slip fault nearly E-W elongated between Karlıova in the east and Saros Gulf in the west. NAF splays into two major strands near the west of Bolu city as Northern and Southern strands. Northern strand passes Sapanca Lake and extends towards west and reaches Marmara Sea through the Gulf of Izmit. The area has high seismicity; 1999 Kocaeli (Mw=7.4) and 1999 Düzce (Mw=7.2) earthquakes caused approximately 150 km long surface rupture between the Gulf of Izmit and Bolu. The rupture has four distinct fault segments as Gölcük, Sapanca, Sakarya, and Karadere from west to east. In this study multi-channel seismic and magnetic data are collected for the first time on the Sapanca Segment to investigate the surficial and deeper geometry of the NAF. Previously, the NAF in the eastern Marmara region is investigated using by paleo-seismological data from trenches on the surface rupture of fault or the geomorphological data (Lettis et al., 2000; Dikbaş and Akyüz, 2010) which have shallower depth targets. Crustal structure and seismic velocities for Central Anatolia and eastern Marmara regions are obtained from deeper targeted refraction data (Gürbüz et al., 1992). However, their velocity models do not have the spatial resolution to determine details of the fault zone structure. Multi-channel seismic and magnetic data in this study were acquired on two N-S directed profiles crossing NAF perpendicularly near Kartepe on the western part of the Sapanca Lake in October 2016. The receiver interval is 5 m, shot interval is 5-10 m, and the total length of the profiles are approximately 1400 m. Buffalo Gun is used as a seismic source for deeper penetration. Conventional seismic reflection processing steps are applied to the data. These are geometry definition, editing, filtering, static correction, velocity analysis and deconvolution, stacking and migration. Echos seismic software package in Geophysical Department

  20. Implications of seismic reflection and potential field geophysical data on the structural framework of the Yucca Mountain--Crater Flat region, Nevada

    International Nuclear Information System (INIS)

    Brocher, T.M.; Langenheim, V.E.; Hunter, W.C.

    1998-01-01

    Seismic reflection and gravity profiles collected across Yucca Mountain, Nevada, together with geologic data, provide evidence against proposed active detachment faults at shallow depth along the pre-Tertiary-Tertiary contact beneath this potential repository for high-level nuclear waste. The new geophysical data show that the inferred pre-Tertiary-Tertiary contact is offset by moderate-to-high-angle faults beneath Crater Flat and Yucca Mountain, and thus this shallow surface cannot represent an active detachment surface. The reflection lines reveal that the Amargosa Desert rift zone is an asymmetric half-graben having a maximum depth of about 4 km and a width of about 25 km. The east-dipping Bare Mountain fault that bounds this graben to the west can be traced by seismic reflection data to a depth of at least 3.5 km and possibly as deep as 6 km, with a constant dip of 64 degree ± 5 degree. Along the profile the transition from east- to west-dipping faults occurs at or just west of the Solitario Canyon fault, which bounds the western side of Yucca Mountain. The interaction at depth of these east- and west-dipping faults, having up to hundreds of meters offset, is not imaged by the seismic reflection profile. Understanding potential seismic hazards at Yucca Mountain requires knowledge of the subsurface geometry of the faults near Yucca Mountain, since earthquakes generally nucleate and release the greatest amount of their seismic energy at depth. The geophysical data indicate that many fault planes near the potential nuclear waste facility dip toward Yucca Mountain, including the Bare Mountain range-front fault and several west-dipping faults east of Yucca Mountain. Thus, earthquake ruptures along these faults would lie closer to Yucca Mountain than is often estimated from their surface locations and could therefore be more damaging

  1. Development of rational design technique for frame steel structure combining seismic resistance and economic performance

    International Nuclear Information System (INIS)

    Kato, Motoki; Morishita, Kunihiro; Shimono, Masaki; Chuman, Yasuharu; Okafuji, Takashi; Monaka, Toshiaki

    2015-01-01

    Anti-seismic designs have been applied to plant support steel frames for years. Today, a rational structure that further improves seismic resistance and ensures economic performance is required in response to an increase of seismic load on the assumption of predicted future massive earthquakes. For satisfying this requirement, a steel frame design method that combines a steel frame weight minimizing method, which enables economic design through simultaneous minimization of multiple steel frame materials, and a seismic response control design technology that improves seismic resistance has been established. Its application in the design of real structures has been promoted. This paper gives an overview of this design technology and presents design examples to which this design technology is applied. (author)

  2. Archive of digital chirp seismic reflection data collected during USGS cruise 05SCC01 offshore of Port Fourchon and Timbalier Bay, Louisiana, August 2005

    Science.gov (United States)

    Harrison, Arnell S.; Dadisman, Shawn V.; Flocks, James G.; Wiese, Dana S.; Calderon, Karynna

    2007-01-01

    In August of 2005, the U.S. Geological Survey conducted geophysical surveys offshore of Port Fourchon and Timbalier Bay, Louisiana, and in nearby waterbodies. This report serves as an archive of unprocessed digital chirp seismic reflection data, trackline maps, navigation files, GIS information, Field Activity Collection System (FACS) logs, observer's logbook, and formal FGDC metadata. Filtered and gained digital images of the seismic profiles are also provided. The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG-Y format (Barry and others, 1975) and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU). Example SU processing scripts and USGS software for viewing the SEG-Y files (Zihlman, 1992) are also provided.

  3. Aspects of the Quaternary evolution of the Southern Kattegat and the central North Sea based on interpretation of 2D and 3D marine reflection seismic profiles

    DEFF Research Database (Denmark)

    Bendixen, Carina

    In this PhD study interpretation of 2D shallow seismic data in the Kattegat region (Pinger, Sparker and Innomar parametric sub-bottom profiler), 3D conventional seismic data in the central North Sea, combined with sediment core interpretation and radiocarbon dating has been carried out in order...... to outline the geological development of the southwestern part of the Kattegat region, from the Late Weichselian to Early Holocene and to investigate the potential of using 3D seismic in Quaternary geology. Within the study area of the Kattegat region Late Weichselian (Lateglacial - LG) sediments...... are widespread and seen as semi-transparent reflections. The LG deposits drape the surface of the underlying till and were deposited during a period of relative high sea level (highstand system tract). The following postglacial (PG - Holocene) sediments represent a full depositional sequence including lowstand...

  4. Seismic reflection and vibracoring studies of the continental shelf offshore central and western Long Island, New York

    Science.gov (United States)

    Kelly, W.M.; Albanese, J.R.; Coch, N.K.; Harsch, A.A.

    1999-01-01

    The ridge-and-swale topography on the continental shelf south of Fire Island, New York, is characterized by northeast-trending linear shoals that are shore attached and shore oblique on the inner shelf and isolated and shore parallel on the middle shelf. High-resolution seismic reflection profiles show that the ridges and swales occur independent of, and are not controlled by, the presence of internal structures (for example, filled tidal inlet channels, paleobarrier strata) or underlying structure (for example, high-relief Cretaceous unconformity). Grab samples of surficial sediments on the shelf south of Fire Island average 98% sand. Locally, benthic fauna increase silt and clay content through fecal pellet production or increase the content of gravel-size material by contribution of their fragmented shell remains. Surficial sand on the ridges is unimodal at 0.33 mm (medium sand, about 50 mesh), and surficial sand in troughs is bimodal at 0.33 mm and 0.15 mm (fine sand, about 100 mesh). In addition to seismic studies, 26 vibracores were recovered from the continental shelf in state and federal waters from south of Rockaway and Long Beaches, Long Island, New York. Stratigraphic and sedimentological data gleaned from these cores were used to outline the geologic framework in the study area. A variety of sedimentary features were noted in the cores, including burrow-mottled sections of sand in a finer silty-sand, rhythmic lamination of sand and silty-sand that reflect cyclic changes in sediment transport, layers of shell hash and shells that probably represent tempestites, and changes from dark color to light color in the sediments that probably represent changes in the oxidation-reduction conditions in the area with time. The stratigraphic units identified are an upper, generally oxidized, nearshore facies, an underlying fine- to medium-sand and silty-clay unit considered to be an estuarine facies, and a lower, coarse-grained deeply oxidized, cross-laminated pre

  5. Modelling of seismic reflection data for underground gas storage in the Pečarovci and Dankovci structures - Mura Depression

    Directory of Open Access Journals (Sweden)

    Andrej Gosar

    1995-12-01

    Full Text Available Two antiform structures in the Mura Depression were selected as the most promising in Slovenia for the construction of an underground gas storage facility in an aquifer. Seventeen reflection lines with a total length of 157km were recorded, and three boreholes were drilled. Structural models corresponding to two different horizons (the pre-Tertiary basement and the Badenian-Sarmatianboundary were constructed using the Sierra Mimic program. Evaluation of different velocity data (velocity analysis, sonic log, the down-hole method, and laboratory measurements on cores was carried out in order to perform correct timeto-depth conversion and to estabUsh lateral velocity variations. The porous rock in Pečarovci structure is 70m thick layer of dolomite, occurring at a depth of 1900m, whereas layers of marl, several hundred meter thick, represent the impermeable cap-rock. Due to faults, the Dankovci structure, at a depth of 1200m,where the reservoir rocks consist of thin layers of conglomerate and sandstone,was proved to be less reliable. ID synthetic seismograms were used to correlatethe geological and seismic data at the borehole locations, especially at intervals with thin layers. The raytracing method on 2D models (the Sierra Quik packagewas applied to confirm lateral continuity of some horizons and to improve the interpretation of faults which are the critical factor for gas storage.

  6. FINOSEIS: A new approach to offshore-building foundation soil analysis using high resolution reflection seismic and Scholte-wave dispersion analysis

    Science.gov (United States)

    Wilken, Dennis; Wölz, Susanne; Müller, Christof; Rabbel, Wolfgang

    2009-05-01

    As part of the FINOSEIS project we present the development of new seismic acquisition and inversion concepts for offshore-building foundation soil analysis. FINOSEIS is a subproject of the FINO3 project, which is aimed at the construction of an offshore research platform based in 28 m water depth, hosting eight research projects dealing with offshore wind energy topics. Our investigations focus on the determination of seismic parameters and structural information of the building plot of FINO3. We infer the shear-wave velocity structure by exploiting the dispersive properties of Scholte-waves and use high resolution 2.5D reflection seismic acquisition to determine seismic stratigraphy in three dimensions. Our work is motivated regarding possible hazards to offshore foundations such as wind parks and the FINO3 platform itself, e.g. permanent mechanical load by wind- and wave-forces possibly leading to an impairment of the soil. We conducted a pre-investigation of the site of the future platform in order to help finding a suitable foundation soil by improving common site investigation methods. In May 2006 we did a survey covering an area of 2 km square employing high resolution 2.5D reflection seismic. Along three 2 km airgun profiles Scholte-waves were recorded with Ocean-Bottom-Seismometers. Spectral analysis of these led to pseudo-2D shear-wave velocity models along the profiles. The reflection seismic area is characterized by glacial stratigraphy and diffractions documented within the penetration range of 30 m. With respect to the topography of the identified horizons as well as to the distribution of diffracting objects, a suitable foundation area for the platform was suggested. The results of the Scholte-wave experiment provide valuable information for further inversion models as well as for the dimensioning of further measurements. We also implemented an inversion strategy using the particle swarm optimization method. The inverted layers of shear-wave velocity

  7. Nuclear power plants seismic review programme in Spain

    International Nuclear Information System (INIS)

    Sanchez Cabanero, J.G.; Jimenez Juan, A.

    1995-01-01

    This presentation deals with seismic design and seismic reevaluation of Spanish operating nuclear power plants. The Spanish NPPs owners Probabilistic seismic hazard study requires an independent and deep review of methodology, modelling techniques, data management and method of eliciting in order to make decision on its acceptability. It reflects the opinion of only one expert tem and it would be necessary to involve more expert opinions to consider the uncertainties. It is proposed to evaluate the probabilistic seismic hazard study and the seismic categorisation

  8. 3D shape measurement of automotive glass by using a fringe reflection technique

    Science.gov (United States)

    Skydan, O. A.; Lalor, M. J.; Burton, D. R.

    2007-01-01

    In automotive and glass making industries, there is a need for accurately measuring the 3D shapes of reflective surfaces to speed up and ensure product development and manufacturing quality by using non-contact techniques. This paper describes a technique for the measurement of non-full-field reflective surfaces of automotive glass by using a fringe reflection technique. Physical properties of the measurement surfaces do not allow us to apply optical geometries used in existing techniques for surface measurement based upon direct fringe pattern illumination. However, this property of surface reflectivity can be used to implement similar ideas from existing techniques in a new improved method. In other words, the reflective surface can be used as a mirror to reflect illuminated fringe patterns onto a screen behind. It has been found that in the case of implementing the reflective fringe technique, the phase-shift distribution depends not only on the height of the object but also on the slope at each measurement point. This requires the solving of differential equations to find the surface slope and height distributions in the x and y directions and development of the additional height reconstruction algorithms. The main focus has been made on developing a mathematical model of the optical sub-system and discussing ways for its practical implementation including calibration procedures. A number of implemented image processing algorithms for system calibration and data analysis are discussed and two experimental results are given for automotive glass surfaces with different shapes and defects. The proposed technique showed the ability to provide accurate non-destructive measurement of 3D shapes of the reflective automotive glass surfaces and can be used as a key element for a glass shape quality control system on-line or in a laboratory environment.

  9. Reflective Journaling as a Flipped Classroom Technique to Increase Reading and Participation With Social Work Students.

    Science.gov (United States)

    Sage, Melanie; Sele, Patti

    Students in undergraduate social work practice courses come to the class with varying levels of educational, life, and practice experience. Students require an introduction to the material through textbook reading before they are able to engage in critical discussions, yet reading adherence varies widely among students. This research explores the use of reflective journals as a Flipped Classroom technique to increase reflective thinking and reading adherence. This study surveys 27 students in two practice courses about the use of weekly reflective journaling as a flipped classroom assignment. Findings support that reflective reading journals increase student preparation and engagement, but require more work for students and instructors. Implications are discussed.

  10. Modelling of ground penetrating radar data in stratified media using the reflectivity technique

    International Nuclear Information System (INIS)

    Sena, Armando R; Sen, Mrinal K; Stoffa, Paul L

    2008-01-01

    Horizontally layered media are often encountered in shallow exploration geophysics. Ground penetrating radar (GPR) data in these environments can be modelled by techniques that are more efficient than finite difference (FD) or finite element (FE) schemes because the lateral homogeneity of the media allows us to reduce the dependence on the horizontal spatial variables through Fourier transforms on these coordinates. We adapt and implement the invariant embedding or reflectivity technique used to model elastic waves in layered media to model GPR data. The results obtained with the reflectivity and FDTD modelling techniques are in excellent agreement and the effects of the air–soil interface on the radiation pattern are correctly taken into account by the reflectivity technique. Comparison with real wide-angle GPR data shows that the reflectivity technique can satisfactorily reproduce the real GPR data. These results and the computationally efficient characteristics of the reflectivity technique (compared to FD or FE) demonstrate its usefulness in interpretation and possible model-based inversion schemes of GPR data in stratified media

  11. Application on technique of joint time-frequency analysis of seismic signal's first arrival estimation

    International Nuclear Information System (INIS)

    Xu Chaoyang; Liu Junmin; Fan Yanfang; Ji Guohua

    2008-01-01

    Joint time-frequency analysis is conducted to construct one joint density function of time and frequency. It can open out one signal's frequency components and their evolvements. It is the new evolvement of Fourier analysis. In this paper, according to the characteristic of seismic signal's noise, one estimation method of seismic signal's first arrival based on triple correlation of joint time-frequency spectrum is introduced, and the results of experiment and conclusion are presented. (authors)

  12. Initiation and evolution of the Oligo-Miocene rift basins of southwestern Europe: Contribution of deep seismic reflection profiling

    Science.gov (United States)

    Bois, C.

    1993-11-01

    Southwestern European Oligo-Miocene rift basins have recently been investigated by deep seismic reflection profiling. The study of these data, together with other geophysical and geological data, shows that the rifts, which run from the Rhinegraben to the western Mediterranean, do not form a single clearcut system. The N-trending rifts (Rhinegraben, Bresse and Limagne) were developed on a cold and rigid lithosphere affected by the Alpine collision. The NE-trending rifts (southeastern France, Gulf of Lions and Valencia Trough) were formed slightly later in a backarc basin associated with an active segment of the European-Iberian plate that was heated, affected by widespread calcalkaline volcanism and probably weakened. All the southwestern European rifts and basins together may, however, be related to a common heritage represented by the boundary between the European-Iberian and African-Apulian plates that was created in the Jurassic with the initiation of the Tethys Ocean. The present features of the southwestern European Oligo-Miocène rift basins may be explained by a combination of three geodynamic mechanisms: mechanical stretching of the lithosphere, active mantle uplifting, and subordinate lithospheric flexuring. All the rifts were probably initiated by passive stretching. A systematic discrepancy between stretching derived from fault analysis and attenuation of the crust has been observed in all the rifts. This suggests that these rifts were subsequently reworked by one or several active mantle upwelling events associated with late shoulder uplift, asthenosphere upwelling and anomalous P-wave velocities in the lowermost crust and the uppermost mantle. Crustal attenuation may have been achieved by mantle intrusion, metamorphism of the deep crust and/or its delamination. Some of the rifts were affected by lithospheric flexuring. Combinations, in various proportions, of a small number of geodynamic mechanisms probably controlled many basins in the world. This

  13. The determination of acoustic reflection coefficients by using cepstral techniques, II: Extensions of the technique and considerations of accuracy

    Science.gov (United States)

    Bolton, J. S.; Gold, E.

    1986-10-01

    In a companion paper the cepstral technique for the measurement of reflection coefficients was described. In particular the concepts of extraction noise and extraction delay were introduced. They are considered further here, and, in addition, a means of extending the cepstral technique to accommodate surfaces having lengthy impulse responses is described. The character of extraction noise, a cepstral component which interferes with reflection measurements, is largely determined by the spectrum of the signal radiated from the source loudspeaker. Here the origin and effects of extraction noise are discussed and it is shown that inverse filtering techniques may be used to reduce extraction noise without making impractical demands of the electrical test signal or the source loudspeaker. The extraction delay, a factor which is introduced when removing the reflector impulse response from the power cepstrum, has previously been estimated by a cross-correlation technique. Here the importance of estimating the extraction delay accurately is emphasized by showing the effect of small spurious delays on the calculation of the normal impedance of a reflecting surface. The effects are shown to accord with theory, and it was found that the real part of the estimated surface normal impedance is very nearly maximized when the spurious delay is eliminated; this has suggested a new way of determining the extraction delay itself. Finally, the basic cepstral technique is suited only to the measurement of surfaces whose impulse responses are shorter than τ, the delay between the arrival of the direct and specularly reflected components at the measurement position. Here it is shown that this restriction can be eliminated, by using a process known as cepstral inversion, when the direct cepstrum has a duration less than τ and cepstral aliasing is insignificant. It is also possible to use this technique to deconvolve a signal from an echo sequence in the time domain, an operation

  14. The discrete Kalman filtering approach for seismic signals deconvolution

    International Nuclear Information System (INIS)

    Kurniadi, Rizal; Nurhandoko, Bagus Endar B.

    2012-01-01

    Seismic signals are a convolution of reflectivity and seismic wavelet. One of the most important stages in seismic data processing is deconvolution process; the process of deconvolution is inverse filters based on Wiener filter theory. This theory is limited by certain modelling assumptions, which may not always valid. The discrete form of the Kalman filter is then used to generate an estimate of the reflectivity function. The main advantage of Kalman filtering is capability of technique to handling continually time varying models and has high resolution capabilities. In this work, we use discrete Kalman filter that it was combined with primitive deconvolution. Filtering process works on reflectivity function, hence the work flow of filtering is started with primitive deconvolution using inverse of wavelet. The seismic signals then are obtained by convoluting of filtered reflectivity function with energy waveform which is referred to as the seismic wavelet. The higher frequency of wavelet gives smaller wave length, the graphs of these results are presented.

  15. Subsurface investigation on Quarter 27 of May 15th city, Cairo, Egypt using electrical resistivity tomography and shallow seismic refraction techniques

    Directory of Open Access Journals (Sweden)

    Sultan Awad Sultan Araffa

    2014-12-01

    Full Text Available Geophysical tools such as electrical resistivity tomography (ERT and shallow seismic (both P-wave seismic refraction and Multi-channel Analysis of Surface Waves (MASW are interesting techniques for delineating the subsurface configurations as stratigraphy, structural elements, caves and water saturated zones. The ERT technique is used to delineate the contamination, to detect the buried objects, and to quantify some aquifer properties. Eight 2-D (two dimensional electrical resistivity sections were measured using two different configurations (dipole–dipole and Wenner. The spread length is of 96 m and the electrodes spacing are 2, 4 and 6 m, respectively to reach a depth ranging from 13 to 17 m. The results indicate that, the subsurface section is divided into main three geo-electrical units, the first is fractured marl and limestone which exhibits high resistivity values ranging from 40 to 300 ohm m. The second unit is corresponding to marl of moderate resistivity values and the third unit, which is the deeper unit, exhibits very low resistivity values corresponding to clayey marl. The fourth layer is marly clay with water. The presence of clay causes the most geotechnical problems. Fourteen shallow seismic sections (both for P-wave and MASW were carried out using spread of 94 m and geophone spacing of 2 m for each P-wave section. The results demonstrate that the deduced subsurface section consists of four layers, the first layer exhibits very low P-wave velocity ranging from 280 to 420 m/s, the second layer reveals P-wave velocity ranging from 400 to 1200 m/s, the third layer has P-wave velocity ranging from 970 to 2000 m/s and the fourth layer exhibits high velocity ranging from 1900 to 3600 m/s. The ERT and shallow seismic results, reflect the presence of two parallel faults passing through Quarter 27 and trending NW-SE.

  16. Seismic texture classification. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Vinther, R.

    1997-12-31

    The seismic texture classification method, is a seismic attribute that can both recognize the general reflectivity styles and locate variations from these. The seismic texture classification performs a statistic analysis for the seismic section (or volume) aiming at describing the reflectivity. Based on a set of reference reflectivities the seismic textures are classified. The result of the seismic texture classification is a display of seismic texture categories showing both the styles of reflectivity from the reference set and interpolations and extrapolations from these. The display is interpreted as statistical variations in the seismic data. The seismic texture classification is applied to seismic sections and volumes from the Danish North Sea representing both horizontal stratifications and salt diapers. The attribute succeeded in recognizing both general structure of successions and variations from these. Also, the seismic texture classification is not only able to display variations in prospective areas (1-7 sec. TWT) but can also be applied to deep seismic sections. The seismic texture classification is tested on a deep reflection seismic section (13-18 sec. TWT) from the Baltic Sea. Applied to this section the seismic texture classification succeeded in locating the Moho, which could not be located using conventional interpretation tools. The seismic texture classification is a seismic attribute which can display general reflectivity styles and deviations from these and enhance variations not found by conventional interpretation tools. (LN)

  17. "Attitude is a little thing that makes a big difference": reflection techniques for addiction psychiatry training.

    Science.gov (United States)

    Ballon, Bruce C; Skinner, Wayne

    2008-01-01

    The authors aim to incorporate educational reflection techniques in an addiction psychiatry postgraduate core rotation in order to increase critical self-awareness of attitudes, values, and beliefs related to working with people with substance use and other addictive disorders. Reflection discussion times, reflection journaling, and mandatory end-of-rotation reflection papers were embedded into a core addiction psychiatry postgraduate training block. Qualitative analysis of 28 reflection papers was performed to determine key factors and constructs that impacted on the development of attitudes and professionalism. A number of constructs emerged that demonstrated the attitudes, beliefs, stereotypes, and stigmas students have regarding addictive disorders. Some constructs also highlighted that students felt much more comfortable dealing with addictive disorders after the training and would treat individuals with these conditions in a more effective manner. Reflection techniques were endorsed as extremely valuable by students, especially in the development of professional attitudes that will help clinicians effectively engage and provide appropriate care for individuals suffering from addictive disorders. The authors suggest that reflective practices be used more extensively in psychiatric training in order to build and establish reflexive self-awareness as a core professional competence essential to work effectively in clinical practice, especially in the most demanding contexts.

  18. Technique and the scheme of engineering-seismometric supervision over seismic events on large dams

    Energy Technology Data Exchange (ETDEWEB)

    Karapetyan, S.; Babayan, T.; Mkrtchyan, G. [National Academy of Sciences of the Republic of Armenia (Armenia). Inst. of Geophysics and Engineering Seismology

    2004-07-01

    A network of engineering-seismometric monitoring stations have been installed at the Tavshout dam in a seismically active region of Armenia. The 37 meter high embankment dam consists of gravel-pebbles with a core of sandy clay. Recent earthquakes have presented a direct hazard for the dam and its water reservoir. In order to determine the degree of seismic hazard and prevention, it is necessary to study the interaction between the ground and the foundation of the dam. The seismometers were fixed at three points both on the foundation and the ground to obtain information on the whole route of seismic waves and to define the geology based amplification factors using empirical equations. The system of engineering-seismometric observations included a network of seismometric instruments, communications and a recording complex. 4 refs., 14 figs.

  19. Pick- and waveform-based techniques for real-time detection of induced seismicity

    Science.gov (United States)

    Grigoli, Francesco; Scarabello, Luca; Böse, Maren; Weber, Bernd; Wiemer, Stefan; Clinton, John F.

    2018-05-01

    The monitoring of induced seismicity is a common operation in many industrial activities, such as conventional and non-conventional hydrocarbon production or mining and geothermal energy exploitation, to cite a few. During such operations, we generally collect very large and strongly noise-contaminated data sets that require robust and automated analysis procedures. Induced seismicity data sets are often characterized by sequences of multiple events with short interevent times or overlapping events; in these cases, pick-based location methods may struggle to correctly assign picks to phases and events, and errors can lead to missed detections and/or reduced location resolution and incorrect magnitudes, which can have significant consequences if real-time seismicity information are used for risk assessment frameworks. To overcome these issues, different waveform-based methods for the detection and location of microseismicity have been proposed. The main advantages of waveform-based methods is that they appear to perform better and can simultaneously detect and locate seismic events providing high-quality locations in a single step, while the main disadvantage is that they are computationally expensive. Although these methods have been applied to different induced seismicity data sets, an extensive comparison with sophisticated pick-based detection methods is still missing. In this work, we introduce our improved waveform-based detector and we compare its performance with two pick-based detectors implemented within the SeiscomP3 software suite. We test the performance of these three approaches with both synthetic and real data sets related to the induced seismicity sequence at the deep geothermal project in the vicinity of the city of St. Gallen, Switzerland.

  20. General discrimination technique to determine between earthquake and nuclear test with seismic data

    International Nuclear Information System (INIS)

    Bashillah Baharuddin; Alawiah Musa; Roslan Mohd Ali

    2007-01-01

    The Comprehensive Nuclear-Test-Ban Treaty (CTBT) was developed to ban of any nuclear weapon test explosion moreover will restrict the development and qualitative improvement of nuclear weapons and end the development of advanced new types of these weapons. The Treaty provides for a comprehensive global verification regime, which includes an International Monitoring System (IMS). The IMS comprises a network of 321 monitoring stations and 16 radionuclide laboratories that monitor the Earth for evidence of nuclear explosions, which cover underground, underwater and atmosphere environments. Presently, Malaysia receives seismic, infrasound, hydroacoustic and radionuclide data from the International Data Centre (IDC) of the CTBT. In order to maximise the use of the data for the purposes of the CTBT, the Malaysian Nuclear Agency is developing capability to analyse the data in order to detect nuclear weapon test, with an initial focus on the seismic data. Through the CTBT IMS, seismic data is constantly being obtained to monitor and detect nuclear explosions. However, in the process, other natural and man-made activities that generate seismic waves, especially earthquakes and large man-made explosions, are also detectable through the IMS, and need to be differentiated and discriminated before any nuclear explosions can be identified. The detection capability by using seismological methods was proven through simulated explosion tests at selected nuclear weapon test sites. This is supported by data previously collected from a total of 2089 nuclear weapon tests that have been carried out globally, out of which 1567 were underground, 514 in the atmosphere, including outer space, and 8 underwater. The discrimination of seismic data to detect nuclear explosions from natural earthquake and explosions can be undertaken through the identification of the epicentre location, hypocentre depth, magnitude and short-period discrimination of the seismic events. (Author)

  1. Interlobate esker architecture and related hydrogeological features derived from a combination of high-resolution reflection seismics and refraction tomography, Virttaankangas, southwest Finland

    Science.gov (United States)

    Maries, Georgiana; Ahokangas, Elina; Mäkinen, Joni; Pasanen, Antti; Malehmir, Alireza

    2017-05-01

    A novel high-resolution (2-4 m source and receiver spacing) reflection and refraction seismic survey was carried out for aquifer characterization and to confirm the existing depositional model of the interlobate esker of Virttaankangas, which is part of the Säkylänharju-Virttaankangas glaciofluvial esker-chain complex in southwest Finland. The interlobate esker complex hosting the managed aquifer recharge (MAR) plant is the source of the entire water supply for the city of Turku and its surrounding municipalities. An accurate delineation of the aquifer is therefore critical for long-term MAR planning and sustainable use of the esker resources. Moreover, an additional target was to resolve the poorly known stratigraphy of the 70-100-m-thick glacial deposits overlying a zone of fractured bedrock. Bedrock surface as well as fracture zones were confirmed through combined reflection seismic and refraction tomography results and further validated against existing borehole information. The high-resolution seismic data proved successful in accurately delineating the esker cores and revealing complex stratigraphy from fan lobes to kettle holes, providing valuable information for potential new pumping wells. This study illustrates the potential of geophysical methods for fast and cost-effective esker studies, in particular the digital-based landstreamer and its combination with geophone-based wireless recorders, where the cover sediments are reasonably thick.

  2. Detailed structure of the top of the melt body beneath the East Pacific Rise at 9°40'N from waveform inversion of seismic reflection data

    Science.gov (United States)

    Collier, J. S.; Singh, S. C.

    1997-01-01

    We have applied waveform inversion to multichannel seismic reflection data collected at the East Pacific Rise at 9°40'N in order to determine the precise velocity structure of the magma body causing the axial magma chamber reflection. Our analysis supports the idea of a molten sill as previously suggested from forward modeling of seismic data from this location. Our inverted solution has a 30-m-thick sill with a P wave seismic velocity of 2.6 km s-1. Although not well constrained by the data we believe that the S wave velocity in the sill is not significantly different from 0.0 km s-1. The low P- and S wave velocities in the sill imply that it contains less than 30% crystals. The molten sill is underlain by a velocity gradient in which the P wave velocity increases from 2.6 to 3.5 km s-1 over a vertical distance of 50-m. The shape of our velocity-depth profile implies that accretion of material to the roof of the sill is minor compared to accretion to the floor. The underlying velocity gradient zone may represent crystal settling under gravity. We suggest that only material from the 30-m-thick layer can erupt.

  3. Density determination of langmuir-blodgett monolayer films using x-ray reflectivity technique

    International Nuclear Information System (INIS)

    Damar Yoga Kusuma

    2015-01-01

    Monolayer deposition by Langmuir-Blodgett technique produces monolayer films that are uniform with controllable thickness down to nanometer scale. To evaluate the quality of the monolayer deposition, X-ray reflectivity technique are employed to monitor the monolayers density. Langmuir-Blodgett monolayer with good coverage and uniformity results in film density close to its macroscopic film counterpart whereas films with presence of air gaps shows lower density compared to its macroscopic film counterpart. (author)

  4. Evidences of intraplate deformation in the West Madeira Abyssal Plain (eastern North Atlantic) from seismic reflection and multibeam swath bathymetry data

    Science.gov (United States)

    Roque, C.; Simões, M.; Lourenço, N.; Pinto de Abreu, M.

    2009-04-01

    The West Madeira Abyssal Plain is located in the eastern North Atlantic off Madeira Islands, forming part of the Canary Basin and reaching a mean water depth of 5300 m. This region is also located within Africa plate at about 500 km southwards from the Açores-Gibraltar plate boundary, and for that reason lacks seismic activity. Although this region being located in an intraplate setting, the presence of faulted sediments was reported in several works published during the eighties of last century following a study conducted in late 1970s to evaluate the feasibility of disposal of high-level radioactive wastes in the ocean. According these works, the Madeira Abyssal Plain sediments are cut by many normal growth faults and this deformation is a result of compaction and dewatering of the sediments. Evidences of tectonic deformation of oceanic sediments in intraplate settings are uncommon, but folded sediments and reverse faults extending into the basement, were recognized in the equatorial Indian Ocean and in the West African continental margin. Recently, during 2006 multi-channel seismic reflection and multibeam swath bathymetry surveys were carried out in the West Madeira Abyssal Plain by EMEPC in order to prepare the Portuguese proposal for the extension of the continental shelf. The seismic lines were acquired onboard R/V Akademik Shatskiy using a source of 5720 cu in bolt gun array, cable length of 7950 m and shot interval of 50.00 m. The multibeam swath bathymetry was acquired onboard NRP Gago Coutinho, and allowed a high resolution mapping of the main geomorphological features. The multichannel seismic lines, oriented WNW-ESE, image the Madeira island lower slope located at about 4000 m water depth and the almost flat abyssal plain at about 5300 m water depth. These seismic lines show a thick sedimentary succession that reaches a maximum thickness of about 1.5 sec twt in the deepest parts of the West Madeira Abyssal Plain, overlying an irregular diffractive

  5. Integration of 2D and 3D reflection seismic data with deep boreholes in the Kevitsa Ni-Cu-PGE deposit, northern Finland

    Science.gov (United States)

    Koivisto, Emilia; Malehmir, Alireza; Voipio, Teemu; Wijns, Chris

    2013-04-01

    Kevitsa is a large disseminated sulphide Ni-Cu-PGE deposit hosted by the Kevitsa mafic-ultramafic intrusion in northern Finland and dated as about 2.06 Ga old. The Geological Survey of Finland first discovered the Kevitsa deposit in 1987. Open pit mining by Kevitsa Mining Oy/First Quantum Minerals Ltd. commenced in June 2012. The final pit depth is planned to be 550-600 m. The estimated ore reserves of the Kevitsa intrusion are about 240 million tones (using a nickel cut-off grade of 0.1%). The expected life-of-mine is 20-30 years. More than 400 hundred holes have been drilled in the Kevitsa area, but most are concentrated close to the known deposit and do not provide a comprehensive understanding of the extent of the intrusion. The basal contact of the intrusion is penetrated by only about 30 drill holes, most of which are shallow. A better knowledge of the geometry of the intrusion would provide a framework for near-mine and deep exploration in the area. An exact knowledge on the basal contact of the intrusion would also provide an exploration target for the contact-type mineralization that is often more massive and richer in Ni-Cu. In December 2007, a series of 2D reflection seismic profiles was acquired in the Kevitsa area. It consisted of four connected survey lines between 6 and 11 km long. In 2010, the initial positive results of the 2D seismic survey led Kevitsa Mining Oy/First Quantum Minerals Ltd. to initiate a 3D reflection seismic survey. The 3D seismic survey is limited to the closer vicinity of the known deposit, while the 2D seismic survey was designed to provide a more regional view of the Kevitsa intrusive complex. The main aims of the 2D and 3D seismic surveys were to delineate the shape and extent of the ore-bearing Kevitsa intrusion and the geometry of some of the host rock and surrounding units, and extract information about the larger-scale structures and structures important for mine-planning purposes. The 2D and 3D seismic data were used to

  6. Manuel Rocha Medal recipient - A relative moment tensor inversion technique applied to seismicity induced by mining

    CSIR Research Space (South Africa)

    Linzer, LM

    2005-04-01

    Full Text Available The primary objective of this study was to develop a robust MTI method to estimate the moment tensors of clusters of seismic events recorded in the underground environment. To achieve this, three 'hybrid' MTI methods were developed by the author...

  7. The crustal characteristics at syn- and/or post-rifting in eastern Shikoku basin by seismic reflection survey

    Science.gov (United States)

    Yamashita, M.; Takahashi, N.; Kodaira, S.; Takizawa, K.; No, T.; Miura, S.; Kaneda, Y.

    2008-12-01

    Imaging of the arc-backarc transition zone is important in relation to the backarc opening process. Shikoku Basin locates between the Kyushu-Palau Ridge and the Izu-Ogasawara Arc, which is an important area to reveal the opening evolution of the backarc basins as a part of the growth process of the Philippine Sea. The Shikoku Basin was in the backarc rifting and spreading stage during about 30-15 Ma (e.g. Okino et al., 1994). High P-wave velocity lower crust is identified in arc-backarc transition zone by refraction survey using OBSs (Takahashi et al., 2007). Japan Agency for Marine-Earth Science and Technology (JAMSTEC) carried out multi-channel seismic reflection (MCS) survey using 12,000 cu.in. air gun and 5 km streamer with 204 ch hydrophones in the Izu-Ogasawara region since 2004. We extracted and mapped the crustal characteristics from poststack and prestack depth migrated profiles. According to obtained profiles, the deformation structure with share component is recognized in arc-backarc transition zone, which located eastern side of Shikoku Basin from Zenisu Ridge to about 500 km south. The maximum width of this deformation zone is about 100 km. The relative displacement of horizon is little; however, it is strongly deformed from upper crust beneath seafloor. This deformation zone indicates the post- rifting activity in east side of Shikoku Basin. On the other hand, some knolls are indicated along the en- echelon arrangement from Izu-Ogasawara arc. Ishizuka et al. (2003) reported post-rifting volcanism with Miocene age in en-echelon arrangement. A part of these knolls are estimated to penetrate at syn-rifting and/or post-rifting stage in backarc opening. By comparing the both side of arc-backarc transition zone, we elucidate syn- and post-rifting effect in Shikoku Basin. We also carried out high density MCS surveys in Shikoku Basin in order to IODP proposal site for reconstruction of magmatic processes since Oligocene in rear arc. In this survey, we use new

  8. Study of the Ouarzazate basin structure by seismic reflection: hydrogeological implications; Etude de la structure du bassin d'Ouarzazate par sismique reflexion: Implications hydrogeologiques

    Energy Technology Data Exchange (ETDEWEB)

    Boummane, Kh.; Jaffal, M.; Kchikach, A.

    2009-07-01

    A large number of seismic reflection lines have been carried out in the Ouarzazate basin by the oil industry. The present study is concerned with the interpretation of a part of these data in order to characterize the structure of the Eocene aquifer system. The reflector corresponding to the base of this system, made up of sandstone and limestone, was first identified then digitized on each time-migrated seismic section. An isochrone map of this reflector was realized. The analysis of this map shows that the area under study is subdivided into two structurally contrasted domains. The first, the northern one, is intensively deformed; while the second, the southern one, is slightly folded. The results of this study provide a better understanding of the deep geological structure of the Ouarzazate basin. This allows us to better comprehend the functioning of the Eocene aquifer system, and to rationalize the future potential underground water exploration in the Ouarzazate basin. (Author) 16 refs.

  9. The behavior of moisture content in Durian after harvesting by neutron reflection and transmission techniques

    International Nuclear Information System (INIS)

    Chimoye, T.; Fuangfoong, M.

    1998-01-01

    The study aimed at development of a neutron reflection and transmission technique to determine moisture content in Durian fruit as a function of time after harvesting. A system of a 3 mCi Am-Be neutron source with a BF 3 detector as a neutron probe was developed. The results obtained were validated using weighting method

  10. Using 3D Reflection Seismics for Deep Platinum Mine Planning and Risk Mitigation: A Case Study from the Bushveld Complex, South Africa

    Science.gov (United States)

    Scheiber-Enslin, S. E.; Manzi, M. S.; Webb, S. J.

    2017-12-01

    Loss-of-ground in mining is a common problem. Using the integration of high resolution aeromagnetic and 3D reflection seismic data to delineate the causative geological features allows for more efficient mine planning and risk reduction. High resolution data from Impala Platinum mine in the western Bushveld Complex are used to image potholes, iron-rich ultramafic pegmatoids (IRUPs), faults, dykes and diapirs that may impact the economic horizons (UG2). Imaging of these structures was previously limited to outcrop, both on surface and underground, as well as 2D seismic data. These high resolution seismic data are able to resolve faults with throws as small as 10 m. A diapir is imaged in the southwest of the study area with a diameter of approximately 6 km. The diapir has a depth extend of around 4 km below the UG2 horizon and displaces the horizon by 350 m. It has been suggested that topographic highs in the Transvaal Supergroup basement initiate the formation of these diapirs as new magma is injected into the chamber. The origin of the diapir within the layered basement rocks, and disruption of layering within the complex is visible on the seismic section. In the north of the study area a large region of slumping or several merged potholes is identified that is up to 2.5 km in length, with up to 700 m of vertical displacement. Ductile deformation that formed the potholes is imaged on the seismic section, with the UG2 cutting down into the footwall. However, brittle deformation of the UG2 is also imaged with faulting at the edges of the regions of slumping. The edges of these slump regions are also characterised by the emplacement of iron-rich ultramafic pegmatoids (IRUPs), which show up as regions of diffuse reflectivity on the seismic data and magnetic highs. The proximity of these faults and IRUPs to the edges of the slump structure brings in to question whether they contribute to pothole formation. The diapir and slump structure displaces the economic UG2

  11. A Sparse Bayesian Imaging Technique for Efficient Recovery of Reservoir Channels With Time-Lapse Seismic Measurements

    KAUST Repository

    Sana, Furrukh

    2016-06-01

    Subsurface reservoir flow channels are characterized by high-permeability values and serve as preferred pathways for fluid propagation. Accurate estimation of their geophysical structures is thus of great importance for the oil industry. The ensemble Kalman filter (EnKF) is a widely used statistical technique for estimating subsurface reservoir model parameters. However, accurate reconstruction of the subsurface geological features with the EnKF is challenging because of the limited measurements available from the wells and the smoothing effects imposed by the \\\\ell _{2} -norm nature of its update step. A new EnKF scheme based on sparse domain representation was introduced by Sana et al. (2015) to incorporate useful prior structural information in the estimation process for efficient recovery of subsurface channels. In this paper, we extend this work in two ways: 1) investigate the effects of incorporating time-lapse seismic data on the channel reconstruction; and 2) explore a Bayesian sparse reconstruction algorithm with the potential ability to reduce the computational requirements. Numerical results suggest that the performance of the new sparse Bayesian based EnKF scheme is enhanced with the availability of seismic measurements, leading to further improvement in the recovery of flow channels structures. The sparse Bayesian approach further provides a computationally efficient framework for enforcing a sparse solution, especially with the possibility of using high sparsity rates through the inclusion of seismic data.

  12. A Sparse Bayesian Imaging Technique for Efficient Recovery of Reservoir Channels With Time-Lapse Seismic Measurements

    KAUST Repository

    Sana, Furrukh; Ravanelli, Fabio; Al-Naffouri, Tareq Y.; Hoteit, Ibrahim

    2016-01-01

    Subsurface reservoir flow channels are characterized by high-permeability values and serve as preferred pathways for fluid propagation. Accurate estimation of their geophysical structures is thus of great importance for the oil industry. The ensemble Kalman filter (EnKF) is a widely used statistical technique for estimating subsurface reservoir model parameters. However, accurate reconstruction of the subsurface geological features with the EnKF is challenging because of the limited measurements available from the wells and the smoothing effects imposed by the \\ell _{2} -norm nature of its update step. A new EnKF scheme based on sparse domain representation was introduced by Sana et al. (2015) to incorporate useful prior structural information in the estimation process for efficient recovery of subsurface channels. In this paper, we extend this work in two ways: 1) investigate the effects of incorporating time-lapse seismic data on the channel reconstruction; and 2) explore a Bayesian sparse reconstruction algorithm with the potential ability to reduce the computational requirements. Numerical results suggest that the performance of the new sparse Bayesian based EnKF scheme is enhanced with the availability of seismic measurements, leading to further improvement in the recovery of flow channels structures. The sparse Bayesian approach further provides a computationally efficient framework for enforcing a sparse solution, especially with the possibility of using high sparsity rates through the inclusion of seismic data.

  13. The Seismic Analyzer: Interpreting and Illustrating 2D Seismic Data

    OpenAIRE

    Patel, Daniel; Giertsen, Christopher; Thurmond, John; Gjelberg, John; Gröller, Eduard

    2008-01-01

    We present a toolbox for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon reservoirs. We improve the search of seismic structures by precalculating the horizon structures of the seismic data prior to interpretation. We improve the annotation of seismic structures by applying novel illustrative rendering algorithms tailored to seism...

  14. On the accuracy of Rüger's approximation for reflection coefficients in HTI media: implications for the determination of fracture density and orientation from seismic AVAZ data

    International Nuclear Information System (INIS)

    Ali, Aamir; Jakobsen, Morten

    2011-01-01

    We have investigated the accuracy of Rüger's approximation for PP reflection coefficients in HTI media (relative to an exact generalization of Zoeppritz to anisotropy derived by Schoenberg and Protazio) within the context of seismic fracture characterization. We consider the inverse problem of seismic amplitude-versus-angle and azimuth (AVAZ) inversion with respect to fracture density and azimuthal fracture orientation, as well as the forward problem of calculating PP reflection coefficients for different contrasts and anisotropy levels. The T-matrix approach was used to relate the contrast and anisotropy level to the parameters of the fractures (in the case of a single set of vertical fractures). We have found that Rüger's approximation can be used to recover the true fracture density with small uncertainty if, and only if, the fracture density and contrast are significantly smaller than the values that are believed to occur in many practically interesting cases of fractured (carbonate) reservoirs. In one example involving a minimal contrast and a fracture density in the range 0.05–0.1, Rüger's approximation performed satisfactorily for inversion, although the forward modelling results were not very accurate at high incident angles. But for fracture densities larger than 0.1 (which we believe may well occur in real cases), Rüger's approximation did not perform satisfactorily for forward or inverse modelling. However, it appears that Rüger's approximation can always be used to obtain estimates of the azimuthal fracture orientation with small uncertainty, even when the contrast and anisotropy levels are extremely large. In order to illustrate the significance of our findings within the context of seismic fracture characterization, we analysed a set of synthetic seismic AVAZ data associated with a fault facies model where the fracture density decreases exponentially with distance from the fault core, and a set of real seismic AVAZ data involving offset

  15. Gas hydrates:estimation of the gas potential, from reflection seismic data in the continental shelf of Uruguay

    International Nuclear Information System (INIS)

    De Santa Ana, H.; Ucha, N.; Gutierrez, L.; Veroslavsky, G.

    2004-01-01

    The uruguayan continental shelf shows geophysical indicators of gas hydrates in the Oriental del Plata, Pelotas and Punta del Este basin. The aim of this work is to present the potential presence of gas at the continental shelf in Uruguay and to evaluate the possibility of exploration of unconventional hydrocarbon plays. Analysis of the seismic surface based on regional and stratgigraphic information that proceeded from previous hydrocarbon exploration in the area have been used to estimatge resources of gas hydrates. Gas hydrates accumulation was mapped using characteristic reflectors and amplitude anomalies of seismic lines (BSR). Its quantity was estimated on this basis in about 86 TCF.

  16. Archive of Digital Boomer Seismic Reflection Data Collected During USGS Field Activity 96LCA04 in Lakes Mabel and Starr, Central Florida, August 1996

    Science.gov (United States)

    Harrison, Arnell S.; Dadisman, Shawn V.; Swancar, Amy; Tihansky, Ann B.; Flocks, James G.; Wiese, Dana S.

    2008-01-01

    In August of 1996, the U.S. Geological Survey conducted geophysical surveys of Lakes Mabel and Starr, central Florida, as part of the Central Highlands Lakes project, which is part of a larger USGS Lakes and Coastal Aquifers (LCA) study. This report serves as an archive of unprocessed digital boomer seismic reflection data, trackline maps, navigation files, Geographic Information System (GIS) files, observer's logbook; and formal Federal Geographic Data Committee (FGDC) metadata. Filtered and gained (a relative increase in signal amplitude) digital images of the seismic profiles are also provided. Refer to the Acronyms page for expansions of acronyms and abbreviations used in this report. For detailed information about the hydrologic setting of Lake Starr and the interpretation of some of these seismic reflection data, see Swancar and others (2000) at http://fl.water.usgs.gov/publications/Abstracts/wri00_4030_swancar.html. The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG-Y format (Barry and others, 1975) and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU). Example SU processing scripts and USGS software for viewing the SEG-Y files (Zihlman, 1992) are also provided. The USGS Florida Integrated Science Center (FISC) - St. Petersburg assigns a unique identifier to each cruise or field activity. For example, 96LCA04 tells us the data were collected in 1996 for the Lakes and Coastal Aquifers (LCA) study and the data were collected during the fourth field activity for that project in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the field activity ID. The boomer plate is an acoustic energy source that consists of capacitors charged to a high voltage and discharged through a transducer in the water. The transducer is towed on a sled floating on the water surface and when

  17. A three-microphone acoustic reflection technique using transmitted acoustic waves in the airway.

    Science.gov (United States)

    Fujimoto, Yuki; Huang, Jyongsu; Fukunaga, Toshiharu; Kato, Ryo; Higashino, Mari; Shinomiya, Shohei; Kitadate, Shoko; Takahara, Yutaka; Yamaya, Atsuyo; Saito, Masatoshi; Kobayashi, Makoto; Kojima, Koji; Oikawa, Taku; Nakagawa, Ken; Tsuchihara, Katsuma; Iguchi, Masaharu; Takahashi, Masakatsu; Mizuno, Shiro; Osanai, Kazuhiro; Toga, Hirohisa

    2013-10-15

    The acoustic reflection technique noninvasively measures airway cross-sectional area vs. distance functions and uses a wave tube with a constant cross-sectional area to separate incidental and reflected waves introduced into the mouth or nostril. The accuracy of estimated cross-sectional areas gets worse in the deeper distances due to the nature of marching algorithms, i.e., errors of the estimated areas in the closer distances accumulate to those in the further distances. Here we present a new technique of acoustic reflection from measuring transmitted acoustic waves in the airway with three microphones and without employing a wave tube. Using miniaturized microphones mounted on a catheter, we estimated reflection coefficients among the microphones and separated incidental and reflected waves. A model study showed that the estimated cross-sectional area vs. distance function was coincident with the conventional two-microphone method, and it did not change with altered cross-sectional areas at the microphone position, although the estimated cross-sectional areas are relative values to that at the microphone position. The pharyngeal cross-sectional areas including retropalatal and retroglossal regions and the closing site during sleep was visualized in patients with obstructive sleep apnea. The method can be applicable to larger or smaller bronchi to evaluate the airspace and function in these localized airways.

  18. Improved techniques in data analysis and interpretation of potential fields: examples of application in volcanic and seismically active areas

    Directory of Open Access Journals (Sweden)

    G. Florio

    2002-06-01

    Full Text Available Geopotential data may be interpreted by many different techniques, depending on the nature of the mathematical equations correlating specific unknown ground parameters to the measured data set. The investigation based on the study of the gravity and magnetic anomaly fields represents one of the most important geophysical approaches in the earth sciences. It has now evolved aimed both at improving of known methods and testing other new and reliable techniques. This paper outlines a general framework for several applications of recent techniques in the study of the potential methods for the earth sciences. Most of them are here described and significant case histories are shown to illustrate their reliability on active seismic and volcanic areas.

  19. Study of fault configuration related mysteries through multi seismic attribute analysis technique in Zamzama gas field area, southern Indus Basin, Pakistan

    Directory of Open Access Journals (Sweden)

    Shabeer Ahmed Abbasi

    2016-03-01

    Full Text Available Seismic attribute analysis approach has been applied for the interpretation and identification of fault geometry of Zamzama Gas Field. Zamzama gas field area, which lies in the vicinity of Kirthar fold and thrust belt, Southern Indus Basin of Pakistan. The Zamzama fault and its related structure have been predicted by applying the Average Energy Attribute, Instantaneous Frequency Attribute, relative Acoustic Impedance Attribute and Chaotic Reflection Attribute on the seismic line GHPK98A.34. The results have been confirmed by applying the spectral decomposition attribute on the same seismic line that reveal the geometric configuration of Zamzama structure. The fault is reverse and started from 0 s and ended at the depth of 2.5 s on the vertical seismic section. Hanging wall moves up along the fault plane under the action of eastward oriented stress, which formed a large north–south oriented and eastward verging thrusted anticline.

  20. Construction and use of an optical semi-automatic titrator employing the technique of reflectance photometry

    International Nuclear Information System (INIS)

    Hwang, Hoon

    2001-01-01

    An optical semi-automatic titrator was constructed employing the technique of the reflectance spectrometry and was tested for the determination of the end points of the acid-base, precipitation, and EDTA titrations. And since the current optical semi-automatic titrator built on the principle of the reflectance spectrometry could be successfully used even for the determination of the end of the end point in the precipitation titration where the solid particles are formed during the titration process, it was found to be feasible that a completely automated optical titrator would be designed and built based on the current findings

  1. Use of an ultrasonic reflectance technique to examine bubble size changes in dough

    Science.gov (United States)

    Strybulevych, A.; Leroy, V.; Shum, A. L.; Koksel, H. F.; Scanlon, M. G.; Page, J. H.

    2012-12-01

    Bread quality largely depends on the manner in which bubbles are created and manipulated in the dough during processing. We have developed an ultrasonic reflectance technique to monitor bubbles in dough, even at high volume fractions, where near the bubble resonances it is difficult to make measurements using transmission techniques. A broadband transducer centred at 3.5 MHz in a normal incidence wave reflection set-up is used to measure longitudinal velocity and attenuation from acoustic impedance measurements. The technique is illustrated by examining changes in bubbles in dough due to two very different physical effects. In dough made without yeast, a peak in attenuation due to bubble resonance is observed at approximately 2 MHz. This peak diminishes rapidly and shifts to lower frequencies, indicative of Ostwald ripening of bubbles within the dough. The second effect involves the growth of bubble sizes due to gas generated by yeast during fermentation. This process is experimentally challenging to investigate with ultrasound because of very high attenuation. The reflectance technique allows the changes of the velocity and attenuation during fermentation to be measured as a function of frequency and time, indicating bubble growth effects that can be monitored even at high volume fractions of bubbles.

  2. Use of an ultrasonic reflectance technique to examine bubble size changes in dough

    International Nuclear Information System (INIS)

    Strybulevych, A; Leroy, V; Page, J H; Shum, A L; Koksel, H F; Scanlon, M G

    2012-01-01

    Bread quality largely depends on the manner in which bubbles are created and manipulated in the dough during processing. We have developed an ultrasonic reflectance technique to monitor bubbles in dough, even at high volume fractions, where near the bubble resonances it is difficult to make measurements using transmission techniques. A broadband transducer centred at 3.5 MHz in a normal incidence wave reflection set-up is used to measure longitudinal velocity and attenuation from acoustic impedance measurements. The technique is illustrated by examining changes in bubbles in dough due to two very different physical effects. In dough made without yeast, a peak in attenuation due to bubble resonance is observed at approximately 2 MHz. This peak diminishes rapidly and shifts to lower frequencies, indicative of Ostwald ripening of bubbles within the dough. The second effect involves the growth of bubble sizes due to gas generated by yeast during fermentation. This process is experimentally challenging to investigate with ultrasound because of very high attenuation. The reflectance technique allows the changes of the velocity and attenuation during fermentation to be measured as a function of frequency and time, indicating bubble growth effects that can be monitored even at high volume fractions of bubbles.

  3. ENDORSING REFLECTIVE TECHNIQUES TO PROLIFERATE STUDENTS’ INTERACTIONS AND UTTERANCES IN A DISCUSSION FORUM

    Directory of Open Access Journals (Sweden)

    Marwito Wihadi

    2012-12-01

    Full Text Available High Intermediate-2 students’ brief responses in a discussion forum cause a long-expected discussion last in a couple of minutes in mixed-ability classes, depicting a minority of students are overtly dominant, while others are precisely passive. What yields discussions endure immaturely stems from both unclear roles of participants and their inadequate techniques to expand both interactions and spoken discourse. Therefore, Teacher-researcher assigned each participant in a discussion group of three to put reflection into practice, referring to the self-selected and discussed topics. The data were gained through non-participant observations, in which the teacher-researcher observed and recorded a singled-out group. A sample recording was, subsequently, transcribed and analyzed regarding with the number of exchanges in a five-minute discussion intake and the number of content words that students generated. It was found that employing reflective techniques, students were able to keep a particular topic being discussed at full. As a result, the number of content words multiplied. These findings resulted classroom teachers in insightful use of reflective techniques as one of the ways to proliferate students’ benefits in a discussion forum. Adequately practiced, students would be able to employ the techniques preponderantly, multiplying interactions among discussion members.

  4. Hydrogeological study of the Triassic series in the JeffaraDahar region (Southern part of Tunisia): Contribution of well logs data and seismic reflection

    Energy Technology Data Exchange (ETDEWEB)

    Ben Lasmar, R.; Guellala, R.; Zouhri, L.; Sarsar Naouali, B.; Garrach, M.; Inoubli, M.H.

    2016-07-01

    The present study concentrates on the interpretation of well logs and seismic reflection data in the JeffaraDahar region (Southeast part of Tunisia) for a better characterization of the Triassic aquifer, a potential target of water supply. Lithological columns and their corresponding well logs reveal that Sidi Stout, Kirchaou and Touareg. sandstones as well as Mekraneb and Rehach dolomites are the main reservoirs of the Triassic aquifer. Well log analysis highlights many permeable and fractured layers that could play an important role in the groundwater circulation. The interpreted seismic sections and the resulting isochrone maps show a tectonic influence on the Triassic aquifer geometry in the Jeffara-Dahar region. The normal faulting of E-W and NW-SE accidents created an aquifer compartmentalized by raised and tilted blocks. Seismic cross-sections reveal that this structure controls the depth of permeable formations and the circulation of groundwater. These results will be useful for rationalising the future hydrogeological research that will be undertaken in the Jeffara-Dahar area. (Author)

  5. Pattern recognition techniques and neo-deterministic seismic hazard: Time dependent scenarios for North-Eastern Italy

    International Nuclear Information System (INIS)

    Peresan, A.; Vaccari, F.; Panza, G.F.; Zuccolo, E.; Gorshkov, A.

    2009-05-01

    An integrated neo-deterministic approach to seismic hazard assessment has been developed that combines different pattern recognition techniques, designed for the space-time identification of strong earthquakes, with algorithms for the realistic modeling of seismic ground motion. The integrated approach allows for a time dependent definition of the seismic input, through the routine updating of earthquake predictions. The scenarios of expected ground motion, associated with the alarmed areas, are defined by means of full waveform modeling. A set of neo-deterministic scenarios of ground motion is defined at regional and local scale, thus providing a prioritization tool for timely prevention and mitigation actions. Constraints about the space and time of occurrence of the impending strong earthquakes are provided by three formally defined and globally tested algorithms, which have been developed according to a pattern recognition scheme. Two algorithms, namely CN and M8, are routinely used for intermediate-term middle-range earthquake predictions, while a third algorithm allows for the identification of the areas prone to large events. These independent procedures have been combined to better constrain the alarmed area. The pattern recognition of earthquake-prone areas does not belong to the family of earthquake prediction algorithms since it does not provide any information about the time of occurrence of the expected earthquakes. Nevertheless, it can be considered as the term-less zero-approximation, which restrains the alerted areas (e.g. defined by CN or M8) to the more precise location of large events. Italy is the only region of moderate seismic activity where the two different prediction algorithms CN and M8S (i.e. a spatially stabilized variant of M8) are applied simultaneously and a real-time test of predictions, for earthquakes with magnitude larger than 5.4, is ongoing since 2003. The application of the CN to the Adriatic region (s.l.), which is relevant

  6. Evidence of Enhanced Subrosion in a Fault Zone and Characterization of Hazard Zones with Elastic Parameters derived from SH-wave reflection Seismics and VSP

    Science.gov (United States)

    Wadas, S. H.; Tanner, D. C.; Tschache, S.; Polom, U.; Krawczyk, C. M.

    2017-12-01

    Subrosion, the dissolution of soluble rocks, e.g., sulfate, salt, or carbonate, requires unsaturated water and fluid pathways that enable the water to flow through the subsurface and generate cavities. Over time, different structures can occur that depend on, e.g., rock solubility, flow rate, and overburden type. The two main structures are sinkholes and depressions. To analyze the link between faults, groundwater flow, and soluble rocks, and to determine parameters that are useful to characterize hazard zones, several shear-wave (SH) reflection seismic profiles were surveyed in Thuringia in Germany, where Permian sulfate rocks and salt subcrop close to the surface. From the analysis of the seismic sections we conclude that areas affected by tectonic deformation phases are prone to enhanced subrosion. The deformation of fault blocks leads to the generation of a damage zone with a dense fracture network. This increases the rock permeability and thus serves as a fluid pathway for, e.g., artesian-confined groundwater. The more complex the fault geometry and the more interaction between faults, the more fractures are generated, e.g., in a strike slip-fault zone. The faults also act as barriers for horizontal groundwater flow perpendicular to the fault surfaces and as conduits for groundwater flow along the fault strike. In addition, seismic velocity anomalies and attenuation of seismic waves are observed. Low velocities high attenuation may indicate areas affected by subrosion. Other parameters that characterize the underground stability are the shear modulus and the Vp/Vs ratio. The data revealed zones of low shear modulus high Vp/Vs ratio >2.5, which probably indicate unstable areas due to subrosion. Structural analysis of S-wave seismics is a valuable tool to detect near-surface faults in order to determine whether or not an area is prone to subrosion. The recognition of even small fault blocks can help to better understand the hydrodynamic groundwater conditions

  7. An evaluation of directional analysis techniques for multidirectional, partially reflected waves .1. numerical investigations

    DEFF Research Database (Denmark)

    Ilic, C; Chadwick, A; Helm-Petersen, Jacob

    2000-01-01

    , non-phased locked methods are more appropriate. In this paper, the accuracy of two non-phased locked methods of directional analysis, the maximum likelihood method (MLM) and the Bayesian directional method (BDM) have been quantitatively evaluated using numerical simulations for the case...... of multidirectional waves with partial reflections. It is shown that the results are influenced by the ratio of distance from the reflector (L) to the length of the time series (S) used in the spectral analysis. Both methods are found to be capable of determining the incident and reflective wave fields when US > 0......Recent studies of advanced directional analysis techniques have mainly centred on incident wave fields. In the study of coastal structures, however, partially reflective wave fields are commonly present. In the near structure field, phase locked methods can be successfully applied. In the far field...

  8. Orbital- to Sub-Orbital-Scale Cyclicity in Seismic Reflections and Sediment Character in Early to Middle Pleistocene Mudstone, Santa Barbara Basin, California

    Science.gov (United States)

    Peterson, C. D.; Behl, R. J.; Nicholson, C.; Lisiecki, L. E.; Sorlien, C. C.

    2009-12-01

    High-resolution seismic reflection records and well logs from the Santa Barbara Channel suggest that large parts of the Pleistocene succession records climate variability on orbital to sub-orbital scales with remarkable sensitivity, much like the well-studied sediments of the last glacial cycle (ODP Site 893). Spectral analysis of seismic reflection data and gamma ray logs from stratigraphically similar Pleistocene sections finds similar cyclic character and shifts through the section. This correlation suggests that acoustic impedance and physical properties of sediment are linked by basin-scale, likely climatically-driven, oscillations in lithologic composition and fabric during deposition, and that seismic profiling can provide a method for remote identification and correlation of orbital- and sub-orbital-scale sedimentary cyclicity. Where it crops out along the northern shelf of the central Santa Barbara Channel, the early to middle Pleistocene succession (~1.8-1.2 Ma) is a bathyal hemipelagic mudstone with remarkably rhythmic planar bedding, finely laminated fabric, and well-preserved foraminifera, none of which have been significantly altered, or obscured by post-depositional diagenesis or tectonic deformation. Unlike the coarser, turbiditic successions in the central Ventura and Los Angeles basins, this sequence has the potential to record Quaternary global climate change at high resolution. Seismic reflection data (towed chirp) collected on the R/V Melville 2008 Cruise (MV08) penetrate 10's of meters below seafloor into a ~1 km-long sequence of south-dipping seismic reflectors. Sampling parallel to the seafloor permits acquisition of consistent signal amplitude for similar reflectors without spreading loss. Based on established age ranges for this section, sedimentation rates may range from 0.4 to 1.4 meters/kyr, therefore suggesting that the most powerful cycles are orbital- to sub-orbital-scale. Discrete sets of cycles with high power show an abrupt shift

  9. Acquisition and preliminary analysis of multi-channel seismic reflection data, acquired during the oceanographic cruises of the TOMO-ETNA experiment

    Directory of Open Access Journals (Sweden)

    Marco Firetto Carlino

    2016-09-01

    Full Text Available The TOMO-ETNA experiment was performed in the framework of the FP7 “MED-SUV” (MEDiterranean SUpersite Volcanoes in order to gain a detailed geological and structural model of the continental and oceanic crust concerning Etna and Aeolian Islands volcanoes (Sicily, Italy, by means of active and passive seismic exploration methodologies. Among all data collected, some 1410 km of marine multi-channel seismic (MCS reflection profiles were acquired in the Ionian and Tyrrhenian Seas during two of the three oceanographic cruises of the TOMO-ETNA experiment, in July and November 2014, with the aim of shading light to deep, intermediate and shallow stratigraphy and crustal structure of the two above mentioned areas. The MCS sections, targeted to deep exploration, were acquired during the oceanographic cruise on board the R/V “Sarmiento de Gamboa”, using an active seismic source of 16 air-guns, for a total volume of 4340 cu. in., and a 3000 m long, 240-channels digital streamer as receiving system. High-resolution seismic profiles were instead collected through the R/V “Aegaeo”, using two smaller air-guns (overall 270 cu. in. volume and a 96 channels, 300 m long digital streamer. This paper provides a detailed description of the acquisition parameters and main processing steps adopted for the MCS data. Some processed lines are shown and preliminarily interpreted, to highlight the overall good quality and the high potential of the MCS sections collected during the TOMO-ETNA experiment.

  10. Improving Image Matching by Reducing Surface Reflections Using Polarising Filter Techniques

    Science.gov (United States)

    Conen, N.; Hastedt, H.; Kahmen, O.; Luhmann, T.

    2018-05-01

    In dense stereo matching applications surface reflections may lead to incorrect measurements and blunders in the resulting point cloud. To overcome the problem of disturbing reflexions polarising filters can be mounted on the camera lens and light source. Reflections in the images can be suppressed by crossing the polarising direction of the filters leading to homogeneous illuminated images and better matching results. However, the filter may influence the camera's orientation parameters as well as the measuring accuracy. To quantify these effects, a calibration and an accuracy analysis is conducted within a spatial test arrangement according to the German guideline VDI/VDE 2634.1 (2002) using a DSLR with and without polarising filter. In a second test, the interior orientation is analysed in more detail. The results do not show significant changes of the measuring accuracy in object space and only very small changes of the interior orientation (Δc ≤ 4 μm) with the polarising filter in use. Since in medical applications many tiny reflections are present and impede robust surface measurements, a prototypic trinocular endoscope is equipped with polarising technique. The interior and relative orientation is determined and analysed. The advantage of the polarising technique for medical image matching is shown in an experiment with a moistened pig kidney. The accuracy and completeness of the resulting point cloud can be improved clearly when using polarising filters. Furthermore, an accuracy analysis using a laser triangulation system is performed and the special reflection properties of metallic surfaces are presented.

  11. Reflections

    Directory of Open Access Journals (Sweden)

    Joanne Embree

    2001-01-01

    Full Text Available Ideally, editorials are written one to two months before publication in the Journal. It was my turn to write this one. I had planned to write the first draft the evening after my clinic on Tuesday, September 11. It didn't get done that night or during the next week. Somehow, the topic that I had originally chosen just didn't seem that important anymore as I, along my friends and colleagues, reflected on the changes that the events of that day were likely to have on our lives.

  12. Visualization of volumetric seismic data

    Science.gov (United States)

    Spickermann, Dela; Böttinger, Michael; Ashfaq Ahmed, Khawar; Gajewski, Dirk

    2015-04-01

    Mostly driven by demands of high quality subsurface imaging, highly specialized tools and methods have been developed to support the processing, visualization and interpretation of seismic data. 3D seismic data acquisition and 4D time-lapse seismic monitoring are well-established techniques in academia and industry, producing large amounts of data to be processed, visualized and interpreted. In this context, interactive 3D visualization methods proved to be valuable for the analysis of 3D seismic data cubes - especially for sedimentary environments with continuous horizons. In crystalline and hard rock environments, where hydraulic stimulation techniques may be applied to produce geothermal energy, interpretation of the seismic data is a more challenging problem. Instead of continuous reflection horizons, the imaging targets are often steep dipping faults, causing a lot of diffractions. Without further preprocessing these geological structures are often hidden behind the noise in the data. In this PICO presentation we will present a workflow consisting of data processing steps, which enhance the signal-to-noise ratio, followed by a visualization step based on the use the commercially available general purpose 3D visualization system Avizo. Specifically, we have used Avizo Earth, an extension to Avizo, which supports the import of seismic data in SEG-Y format and offers easy access to state-of-the-art 3D visualization methods at interactive frame rates, even for large seismic data cubes. In seismic interpretation using visualization, interactivity is a key requirement for understanding complex 3D structures. In order to enable an easy communication of the insights gained during the interactive visualization process, animations of the visualized data were created which support the spatial understanding of the data.

  13. Comparison of mouse mammary gland imaging techniques and applications: Reflectance confocal microscopy, GFP Imaging, and ultrasound

    International Nuclear Information System (INIS)

    Tilli, Maddalena T; Parrish, Angela R; Cotarla, Ion; Jones, Laundette P; Johnson, Michael D; Furth, Priscilla A

    2008-01-01

    Genetically engineered mouse models of mammary gland cancer enable the in vivo study of molecular mechanisms and signaling during development and cancer pathophysiology. However, traditional whole mount and histological imaging modalities are only applicable to non-viable tissue. We evaluated three techniques that can be quickly applied to living tissue for imaging normal and cancerous mammary gland: reflectance confocal microscopy, green fluorescent protein imaging, and ultrasound imaging. In the current study, reflectance confocal imaging offered the highest resolution and was used to optically section mammary ductal structures in the whole mammary gland. Glands remained viable in mammary gland whole organ culture when 1% acetic acid was used as a contrast agent. Our application of using green fluorescent protein expressing transgenic mice in our study allowed for whole mammary gland ductal structures imaging and enabled straightforward serial imaging of mammary gland ducts in whole organ culture to visualize the growth and differentiation process. Ultrasound imaging showed the lowest resolution. However, ultrasound was able to detect mammary preneoplastic lesions 0.2 mm in size and was used to follow cancer growth with serial imaging in living mice. In conclusion, each technique enabled serial imaging of living mammary tissue and visualization of growth and development, quickly and with minimal tissue preparation. The use of the higher resolution reflectance confocal and green fluorescent protein imaging techniques and lower resolution ultrasound were complementary

  14. Seismic characterization of geothermal reservoirs by application of the common-reflection-surface stack method and attribute analysis

    OpenAIRE

    Marcin Pussak

    2015-01-01

    An important contribution of geosciences to the renewable energy production portfolio is the exploration and utilization of geothermal resources. For the development of a geothermal project at great depths a detailed geological and geophysical exploration program is required in the first phase. With the help of active seismic methods high-resolution images of the geothermal reservoir can be delivered. This allows potential transport routes for fluids to be identified as well as regions with h...

  15. Application of Musical Information Retrieval (MIR Techniques to Seismic Facies Classification. Examples in Hydrocarbon Exploration

    Directory of Open Access Journals (Sweden)

    Paolo Dell’Aversana

    2016-12-01

    Full Text Available In this paper, we introduce a novel approach for automatic pattern recognition and classification of geophysical data based on digital music technology. We import and apply in the geophysical domain the same approaches commonly used for Musical Information Retrieval (MIR. After accurate conversion from geophysical formats (example: SEG-Y to musical formats (example: Musical Instrument Digital Interface, or briefly MIDI, we extract musical features from the converted data. These can be single-valued attributes, such as pitch and sound intensity, or multi-valued attributes, such as pitch histograms, melodic, harmonic and rhythmic paths. Using a real data set, we show that these musical features can be diagnostic for seismic facies classification in a complex exploration area. They can be complementary with respect to “conventional” seismic attributes. Using a supervised machine learning approach based on the k-Nearest Neighbors algorithm and on Automatic Neural Networks, we classify three gas-bearing channels. The good performance of our classification approach is confirmed by borehole data available in the same area.

  16. Frontier seismic geologic techniques and the exploration of the Miocene reefs in offshore Palawan, Philippines

    Science.gov (United States)

    Biswas, Buddhadeb

    An 88 km grid of Seislog sections (synthetic sonic log traces) was used to supplement the conventional seismic interpretation to assess the hydrocarbon potential of Lower Miocene reefs of offshore Palawan, Philippines. The porosity distribution in the zone of interest as well as the oil-water contact in and around the Tara and Libro patch reefs were mapped. The structural mapping was also fine tuned, including mapping of faults with small displacements. The paradox of pooling of hydrocarbons is evident in the maximum fill in the front line of traps near the shelf-slope break that are in the lowest structural position. Progressively dwindling amounts of fill in the structurally higher updip basin positions are interpreted to be due to the migration of hydrocarbons from the hydrocarbon kitchen in the Palawan Trough. The front line of traps had the benefit of maximum fill, the traps at the rear only of residual fill that spilled past the frontal traps. Three play types corresponding to the front line of traps, the rear line of traps and the most remote line of traps have been identified. Frontal reefs are considered to have the highest hydrocarbon potential. Diminishing hydrocarbon potential is inferred for closures in the updip direction. A thorough screening of all available seismic control for mapping all the patch reefs that might compensate for their dimensions by their numbers as well as for detecting possible pinnacle reefs in the downdip basin position has been suggested.

  17. Improved seismic risk estimation for Bucharest, based on multiple hazard scenarios, analytical methods and new techniques

    Science.gov (United States)

    Toma-Danila, Dragos; Florinela Manea, Elena; Ortanza Cioflan, Carmen

    2014-05-01

    Bucharest, capital of Romania (with 1678000 inhabitants in 2011), is one of the most exposed big cities in Europe to seismic damage. The major earthquakes affecting the city have their origin in the Vrancea region. The Vrancea intermediate-depth source generates, statistically, 2-3 shocks with moment magnitude >7.0 per century. Although the focal distance is greater than 170 km, the historical records (from the 1838, 1894, 1908, 1940 and 1977 events) reveal severe effects in the Bucharest area, e.g. intensities IX (MSK) for the case of 1940 event. During the 1977 earthquake, 1420 people were killed and 33 large buildings collapsed. The nowadays building stock is vulnerable both due to construction (material, age) and soil conditions (high amplification, generated within the weak consolidated Quaternary deposits, their thickness is varying 250-500m throughout the city). A number of 373 old buildings, out of 2563, evaluated by experts are more likely to experience severe damage/collapse in the next major earthquake. The total number of residential buildings, in 2011, was 113900. In order to guide the mitigation measures, different studies tried to estimate the seismic risk of Bucharest, in terms of buildings, population or economic damage probability. Unfortunately, most of them were based on incomplete sets of data, whether regarding the hazard or the building stock in detail. However, during the DACEA Project, the National Institute for Earth Physics, together with the Technical University of Civil Engineering Bucharest and NORSAR Institute managed to compile a database for buildings in southern Romania (according to the 1999 census), with 48 associated capacity and fragility curves. Until now, the developed real-time estimation system was not implemented for Bucharest. This paper presents more than an adaptation of this system to Bucharest; first, we analyze the previous seismic risk studies, from a SWOT perspective. This reveals that most of the studies don't use

  18. Fault analysis in the very shallow seismic reflection method. 2; Gokusenso hanshaho ni okeru danso kaiseki. 2

    Energy Technology Data Exchange (ETDEWEB)

    Nagumo, S; Muraoka, S; Takahashi, T [Oyo Corp., Tokyo (Japan)

    1997-05-27

    Fault analysis is required in addition to the ordinary process of structural analysis (CDP stacking) for the examination of discontinuity in the reflection horizon in question. The fault shape restoration principle is that the reflection point of a reflection wave observed at a certain receiving point is on an ellipse with the shock point and receiving point at its focal points and that the sum of the distances between the reflection point and the focal points is equal to the reflection wave propagation time. The DMO velocity is worked out by calculation using the positive travel time and inverse travel time from the common reflection surface. When the reflection surface is inclined by {theta}, the average interval velocity/cos{theta} is called the DMO velocity. When the reflection surface inclination and the average interval velocities are determined separately in this way, the position of the reflection point may be worked out, and this enables the calculation of the amount of migration (lateral movement). The reflection wave lineups carried by the original record are picked up one by one, and the average interval velocities are treated very prudently. After such a basic DMO conversion treatment, the actualities of the fault are described fairly correctly. 3 figs.

  19. Method for inverting reflection trace data from 3-D and 4-D seismic surveys and identifying subsurface fluid and pathways in and among hydrocarbon reservoirs based on impedance models

    Science.gov (United States)

    He, W.; Anderson, R.N.

    1998-08-25

    A method is disclosed for inverting 3-D seismic reflection data obtained from seismic surveys to derive impedance models for a subsurface region, and for inversion of multiple 3-D seismic surveys (i.e., 4-D seismic surveys) of the same subsurface volume, separated in time to allow for dynamic fluid migration, such that small scale structure and regions of fluid and dynamic fluid flow within the subsurface volume being studied can be identified. The method allows for the mapping and quantification of available hydrocarbons within a reservoir and is thus useful for hydrocarbon prospecting and reservoir management. An iterative seismic inversion scheme constrained by actual well log data which uses a time/depth dependent seismic source function is employed to derive impedance models from 3-D and 4-D seismic datasets. The impedance values can be region grown to better isolate the low impedance hydrocarbon bearing regions. Impedance data derived from multiple 3-D seismic surveys of the same volume can be compared to identify regions of dynamic evolution and bypassed pay. Effective Oil Saturation or net oil thickness can also be derived from the impedance data and used for quantitative assessment of prospective drilling targets and reservoir management. 20 figs.

  20. Two types of SDR recognised in pre-stack velocity analysis of ultra-long-offset seismic reflection data in the South Atlantic

    Science.gov (United States)

    Collier, J.; McDermott, C.; Lonergan, L.; McDermott, K.; Bellingham, P.

    2017-12-01

    Our understanding of continental breakup at volcanic margins has lagged behind that of non-volcanic margins in recent years. This is largely due to seismic imaging problems caused by the presence of thick packages of Seaward-Dipping Reflectors (SDRs) in the continent-ocean transition zone. These packages consist of interbedded tholeiitic lava flows, volcanic tuffs and terrestrial sediment that results in scattering, peg-leg multiples and defocusing of seismic energy. Here we analyse three ultra-long-offset (10.2 km), wide-bandwidth (5-100 Hz) seismic reflection profiles acquired by ION-GXT offshore South America during 2009-12 to gain new insights into the velocity structure of the SDRs and hence pattern of magmatism during continental breakup. We observe two seismic velocity patterns within the SDRs. The most landward packages show high velocity anomaly "bulls-eyes" of up to 1 km s-1. These highs occur where the stacked section shows them to thicken at the down-dip end of individual packages that are bounded by faults. All lines show 5-6 velocity highs spaced approximately 10 km apart. We interpret the velocity bulls-eyes as depleted mafic or ultramafic bodies that fed the sub-aerial tholeiitic lava flows during continental stretching. Similar relationships have been observed in outcrop onshore but have not been previously demonstrated in seismic data. The bulls-eye packages pass laterally into SDR packages that show no velocity highs. These packages are not associated with faulting and become more extensive going north towards the impact point of the Tristan da Cunha hotspot. This second type of SDR coincides with linear magnetic anomalies. We interpret these SDRs as the products of sub-aerial oceanic spreading similar to those seen on Iceland and described in the classic "Hinz model" and marine geophysical literature. Our work demonstrates that these SDRs are preceded by ones generated during an earlier phase of mechanical thinning of the continental crust. The

  1. Locating seismicity on the Arctic plate boundary using multiple-event techniques and empirical signal processing

    Science.gov (United States)

    Gibbons, S. J.; Harris, D. B.; Dahl-Jensen, T.; Kværna, T.; Larsen, T. B.; Paulsen, B.; Voss, P. H.

    2017-12-01

    The oceanic boundary separating the Eurasian and North American plates between 70° and 84° north hosts large earthquakes which are well recorded teleseismically, and many more seismic events at far lower magnitudes that are well recorded only at regional distances. Existing seismic bulletins have considerable spread and bias resulting from limited station coverage and deficiencies in the velocity models applied. This is particularly acute for the lower magnitude events which may only be constrained by a small number of Pn and Sn arrivals. Over the past two decades there has been a significant improvement in the seismic network in the Arctic: a difficult region to instrument due to the harsh climate, a sparsity of accessible sites (particularly at significant distances from the sea), and the expense and difficult logistics of deploying and maintaining stations. New deployments and upgrades to stations on Greenland, Svalbard, Jan Mayen, Hopen, and Bjørnøya have resulted in a sparse but stable regional seismic network which results in events down to magnitudes below 3 generating high-quality Pn and Sn signals on multiple stations. A catalogue of several hundred events in the region since 1998 has been generated using many new phase readings on stations on both sides of the spreading ridge in addition to teleseismic P phases. A Bayesian multiple event relocation has resulted in a significant reduction in the spread of hypocentre estimates for both large and small events. Whereas single event location algorithms minimize vectors of time residuals on an event-by-event basis, the Bayesloc program finds a joint probability distribution of origins, hypocentres, and corrections to traveltime predictions for large numbers of events. The solutions obtained favour those event hypotheses resulting in time residuals which are most consistent over a given source region. The relocations have been performed with different 1-D velocity models applicable to the Arctic region and

  2. Inverting travel times with a triplication. [spline fitting technique applied to lunar seismic data reduction

    Science.gov (United States)

    Jarosch, H. S.

    1982-01-01

    A method based on the use of constrained spline fits is used to overcome the difficulties arising when body-wave data in the form of T-delta are reduced to the tau-p form in the presence of cusps. In comparison with unconstrained spline fits, the method proposed here tends to produce much smoother models which lie approximately in the middle of the bounds produced by the extremal method. The method is noniterative and, therefore, computationally efficient. The method is applied to the lunar seismic data, where at least one triplication is presumed to occur in the P-wave travel-time curve. It is shown, however, that because of an insufficient number of data points for events close to the antipode of the center of the lunar network, the present analysis is not accurate enough to resolve the problem of a possible lunar core.

  3. Mechanical and chemical processes affecting the chalk during burial, insights from combined reflection seismics, well data and field work

    DEFF Research Database (Denmark)

    Moreau, Julien; Boussaha, Myriam; Thibault, Nicolas Rudolph

    2014-01-01

    and cores analyses, respectively.However, few sites allow to combine all the different scale of observation for chalk diagenesis. Onshore and offshore high resolution seismics, two fully cored >350 m wells with wireline logging tools and very high quality exposures from a coastal cliff and a quarry form...... works have been performed with astronomical calibration based on stable isotope stratigraphy, wireline logs as well as several palaeontological proxies and detailed sedimentological analysis. Since a couple of decades, a specific kind of fractures has been described in the Chalk of Denmark, the so...

  4. Discrimination techniques employing both reflective and thermal multispectral signals. [for remote sensor technology

    Science.gov (United States)

    Malila, W. A.; Crane, R. B.; Richardson, W.

    1973-01-01

    Recent improvements in remote sensor technology carry implications for data processing. Multispectral line scanners now exist that can collect data simultaneously and in registration in multiple channels at both reflective and thermal (emissive) wavelengths. Progress in dealing with two resultant recognition processing problems is discussed: (1) More channels mean higher processing costs; to combat these costs, a new and faster procedure for selecting subsets of channels has been developed. (2) Differences between thermal and reflective characteristics influence recognition processing; to illustrate the magnitude of these differences, some explanatory calculations are presented. Also introduced, is a different way to process multispectral scanner data, namely, radiation balance mapping and related procedures. Techniques and potentials are discussed and examples presented.

  5. Robust satellite techniques (RST for the thermal monitoring of earthquake prone areas: the case of Umbria-Marche October, 1997 seismic events

    Directory of Open Access Journals (Sweden)

    V. Tramutoli

    2008-06-01

    Full Text Available Several authors claim a space-time correlation between increases in Earth’s emitted Thermal Infra-Red (TIR radiation and earthquake occurrence. The main problems of such studies regard data analysis and interpretation, which are often done without a validation/confutation control. In this context, a robust data analysis technique (RST, i.e. Robust Satellite Techniques is proposed which permits a statistically based definition of TIR «anomaly » and uses a validation/confutation approach. This technique was already applied to satellite TIR surveys in seismic regions for about twenty earthquakes that occurred in the world. In this work RST is applied for the first time to a time sequence of seismic events. Nine years of Meteosat TIR observations have been analyzed to characterize the unperturbed TIR signal behaviour at specific observation times and locations. The main seismic events of the October 1997 Umbria-Marche sequence have been considered for validation, and relatively unperturbed periods (no earthquakes with Mb ? 4 were taken for confutation purposes. Positive time-space persistent TIR anomalies were observed during seismic periods, generally overlapping the principal tectonic lineaments of the region and sometimes focusing on the vicinity of the epicentre. No similar (in terms of relative intensity and space-time persistence TIR anomalies were detected during seismically unperturbed periods.

  6. IMPROVING IMAGE MATCHING BY REDUCING SURFACE REFLECTIONS USING POLARISING FILTER TECHNIQUES

    Directory of Open Access Journals (Sweden)

    N. Conen

    2018-05-01

    Full Text Available In dense stereo matching applications surface reflections may lead to incorrect measurements and blunders in the resulting point cloud. To overcome the problem of disturbing reflexions polarising filters can be mounted on the camera lens and light source. Reflections in the images can be suppressed by crossing the polarising direction of the filters leading to homogeneous illuminated images and better matching results. However, the filter may influence the camera’s orientation parameters as well as the measuring accuracy. To quantify these effects, a calibration and an accuracy analysis is conducted within a spatial test arrangement according to the German guideline VDI/VDE 2634.1 (2002 using a DSLR with and without polarising filter. In a second test, the interior orientation is analysed in more detail. The results do not show significant changes of the measuring accuracy in object space and only very small changes of the interior orientation (Δc ≤ 4 μm with the polarising filter in use. Since in medical applications many tiny reflections are present and impede robust surface measurements, a prototypic trinocular endoscope is equipped with polarising technique. The interior and relative orientation is determined and analysed. The advantage of the polarising technique for medical image matching is shown in an experiment with a moistened pig kidney. The accuracy and completeness of the resulting point cloud can be improved clearly when using polarising filters. Furthermore, an accuracy analysis using a laser triangulation system is performed and the special reflection properties of metallic surfaces are presented.

  7. Development of an ultrasonic shear reflection technique to monitor the crystallization of cocoa butter.

    Science.gov (United States)

    Rigolle, Annelien; Foubert, Imogen; Hettler, Jan; Verboven, Erik; Demuynck, Ruth; Van Den Abeele, Koen

    2015-09-01

    The quasi-isothermal crystallization process of cocoa butter was monitored by an ultrasonic shear reflection technique utilizing a custom-built experimental set-up in a temperature controlled environment. To facilitate the interpretation of the measurement results, the propagation of shear waves was first theoretically studied in different configurations of gas, liquid or solid layers with varying thickness for the case of normal incidence, yielding theoretical equations of the shear wave reflection coefficient (swRC) for different layering conditions. The typical experimentally observed pattern of the swRC during quasi-isothermal cocoa butter crystallization was subsequently linked to the theoretical equations. The remarkable oscillatory damped response in the swRC as function of the crystallization time could be explained by constructive and destructive interference of a first reflection at the boundary between a plexiglass delay line and the crystallized cocoa butter and a second reflection occurring at the interface between crystallized and liquid substance. This hypothesis was supported by the excitation frequency dependence of the oscillations. The quality of the fit of the theoretical model to the experimental results was very good and also the reproducibility between different independent measurements was acceptable. Finally, measurements at different temperatures (18°C and 20°C) suggested that the technique was able to detect differences in crystallization behavior, as measurements at 18°C displayed faster oscillations compared to measurements at 20°C. Moreover, this was also confirmed by the theoretical model, as a higher value of the crystallization rate parameter K, exhibited more rapid oscillations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Archive of digital boomer seismic reflection data collected offshore east-central Florida during USGS cruise 00FGS01, July 14-22, 2000

    Science.gov (United States)

    Subino, Janice A.; Dadisman, Shawn V.; Wiese, Dana S.; Calderon, Karynna; Phelps, Daniel C.

    2009-01-01

    In July of 2000, the U.S. Geological Survey (USGS), in cooperation with the Florida Geological Survey (FGS), conducted a geophysical survey of the Atlantic Ocean offshore Florida's east coast from Brevard County to northern Martin County. This report serves as an archive of unprocessed digital boomer seismic reflection data, trackline maps, navigation files, Geographic Information System (GIS) information, digital and handwritten Field Activity Collection System (FACS) logs, and Federal Geographic Data Committee (FGDC) metadata. A filtered and gained (a relative increase in signal amplitude) digital image of each seismic profile is also provided. Refer to the Acronyms page for expansions of all acronyms and abbreviations used in this report. The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG-Y format (Barry and others, 1975) and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU) (Cohen and Stockwell, 2005). Example SU processing scripts and USGS Software for viewing the SEG-Y files (Zihlman, 1992) are also provided. The USGS St. Petersburg Coastal and Marine Science Center assigns a unique identifier to each cruise or field activity. For example, 00FGS01 tells us the data were collected in 2000 for cooperative work with the Florida Geological Survey (FGS) and the data were collected during the first field activity for that study in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the field activity ID. The boomer plate is an acoustic energy source that consists of capacitors charged to a high voltage and discharged through a transducer in the water. The transducer is towed on a sled floating on the water surface and when discharged, emits a short acoustic pulse, or shot, which propagates through the water, sediment column, or rock beneath. The acoustic energy is reflected

  9. Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment

    Science.gov (United States)

    Ayarza, P.; Carbonell, R.; Teixell, A.; Palomeras, I.; Martí, D.; Kchikach, A.; Harnafi, M.; Levander, A.; Gallart, J.; Arboleya, M. L.; Alcalde, J.; Fernández, M.; Charroud, M.; Amrhar, M.

    2014-05-01

    The crustal structure and topography of the Moho boundary beneath the Atlas Mountains of Morocco has been constrained by a controlled source, wide-angle seismic reflection transect: the SIMA experiment. This paper presents the first results of this project, consisting of an almost 700 km long, high-resolution seismic profile acquired from the Sahara craton across the High and the Middle Atlas and the Rif Mountains. The interpretation of this seismic data set is based on forward modeling by raytracing, and has resulted in a detailed crustal structure and velocity model for the Atlas Mountains. Results indicate that the High Atlas features a moderate crustal thickness, with the Moho located at a minimum depth of 35 km to the S and at around 31 km to the N, in the Middle Atlas. Upper crustal shortening is resolved at depth through a crustal root where the Saharan crust underthrusts the northern Moroccan crust. This feature defines a lower crust imbrication that, locally, places the Moho boundary at ˜40-41 km depth in the northern part of the High Atlas. The P-wave velocity model is characterized by relatively low velocities, mostly in the lower crust and upper mantle, when compared to other active orogens and continental regions. These low deep crustal velocities together with other geophysical observables such as conductivity estimates derived from MT measurements, moderate Bouguer gravity anomaly, high heat flow, and surface exposures of recent alkaline volcanism lead to a model where partial melts are currently emplaced at deep crustal levels and in the upper mantle. The resulting model supports the existence of a mantle upwelling as mechanism that would contribute significantly to sustain the High Atlas topography. However, the detailed Moho geometry deduced in this work should lead to a revision of the exact geometry and position of this mantle feature and will require new modeling efforts.

  10. Crustal structure variations along the NW-African continental margin: A comparison of new and existing models from wide-angle and reflection seismic data

    Science.gov (United States)

    Klingelhoefer, Frauke; Biari, Youssef; Sahabi, Mohamed; Aslanian, Daniel; Schnabel, Michael; Matias, Luis; Benabdellouahed, Massinissa; Funck, Thomas; Gutscher, Marc-André; Reichert, Christian; Austin, James A.

    2016-04-01

    Deep seismic data represent a key to understand the geometry and mechanism of continental rifting. The passive continental margin of NW-Africa is one of the oldest on earth, formed during the Upper Triassic-Lower Liassic rifting of the central Atlantic Ocean over 200 Ma. We present new and existing wide-angle and reflection seismic data from four study regions along the margin located in the south offshore DAKHLA, on the central continental margin offshore Safi, in the northern Moroccan salt basin, and in the Gulf of Cadiz. The thickness of unthinned continental crust decreases from 36 km in the North to about 27 km in the South. Crustal thinning takes place over a region of 150 km in the north and only 70 km in the south. The North Moroccan Basin is underlain by highly thinned continental crust of only 6-8 km thickness. The ocean-continent transition zone shows a variable width between 40 and 70 km and is characterized by seismic velocities in between those of typical oceanic and thinned continental crust. The neighbouring oceanic crust is characterized by a thickness of 7-8 km along the complete margin. Relatively high velocities of up to 7.5 km/s have been imaged between magnetic anomalies S1 and M25, and are probably related to changes in the spreading velocities at the time of the Kimmeridgian/Tithonian plate reorganization. Volcanic activity seems to be mostly confined to the region next to the Canary Islands, and is thus not related to the initial opening of the ocean, which was associated to only weak volcanism. Comparison with the conjugate margin off Nova Scotia shows comparable continental crustal structures, but 2-3 km thinner oceanic crust on the American side than on the African margin.

  11. Subsea ice-bearing permafrost on the U.S. Beaufort Margin: 1. Minimum seaward extent defined from multichannel seismic reflection data

    Science.gov (United States)

    Brothers, Laura; Herman, Bruce M.; Hart, Patrick E.; Ruppel, Carolyn D.

    2016-01-01

    Subsea ice-bearing permafrost (IBPF) and associated gas hydrate in the Arctic have been subject to a warming climate and saline intrusion since the last transgression at the end of the Pleistocene. The consequent degradation of IBPF is potentially associated with significant degassing of dissociating gas hydrate deposits. Previous studies interpreted the distribution of subsea permafrost on the U.S. Beaufort continental shelf based on geographically sparse data sets and modeling of expected thermal history. The most cited work projects subsea permafrost to the shelf edge (∼100 m isobath). This study uses a compilation of stacking velocity analyses from ∼100,000 line-km of industry-collected multichannel seismic reflection data acquired over 57,000 km2 of the U.S. Beaufort shelf to delineate continuous subsea IBPF. Gridded average velocities of the uppermost 750 ms two-way travel time range from 1475 to 3110 m s−1. The monotonic, cross-shore pattern in velocity distribution suggests that the seaward extent of continuous IBPF is within 37 km of the modern shoreline at water depths < 25 m. These interpretations corroborate recent Beaufort seismic refraction studies and provide the best, margin-scale evidence that continuous subsea IBPF does not currently extend to the northern limits of the continental shelf.

  12. Structure across the northeastern margin of Flemish Cap, offshore Newfoundland from Erable multichannel seismic reflection profiles: evidence for a transtensional rifting environment

    Science.gov (United States)

    Welford, J. Kim; Hall, Jeremy; Sibuet, Jean-Claude; Srivastava, Shiri P.

    2010-11-01

    We present the results from processing and interpreting nine multichannel seismic reflection lines collected during the 1992 Erable experiment over the northeastern margin of Flemish Cap offshore Newfoundland. These lines, combined into five cross-sections, provide increased seismic coverage over this lightly probed section of the margin and reveal tectonically significant along-strike variations in the degree and compartmentalization of crustal thinning. Similar to the southeastern margins of Flemish Cap and the Grand Banks, a transitional zone of exhumed serpentinized mantle is interpreted between thinned continental and oceanic crust. The 25 km wide transitional zone bears similarities to the 120 km wide transitional zone interpreted as exhumed serpentinized mantle on the conjugate Irish Atlantic margin but the significant width difference is suggestive of an asymmetric conjugate pair. A 40-50 km wide zone of inferred strike-slip shearing is interpreted and observed to extend along most of the northeastern margin of Flemish Cap. Individual shear zones (SZs) may represent extensions of SZs and normal faults within the Orphan Basin providing further evidence for the rotation and displacement of Flemish Cap out of Orphan Basin. The asymmetry between the Flemish Cap and Irish conjugate pairs is likely due in large part to the rotation and displacement of Flemish Cap which resulted in the Flemish Cap margin displaying features of both a strike-slip margin and an extensional margin.

  13. Seismic Studies

    Energy Technology Data Exchange (ETDEWEB)

    R. Quittmeyer

    2006-09-25

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground

  14. Seismic Studies

    International Nuclear Information System (INIS)

    R. Quittmeyer

    2006-01-01

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground motion at

  15. Seismic explosion sources on an ice cap

    DEFF Research Database (Denmark)

    Shulgin, Alexey; Thybo, Hans

    2015-01-01

    crustal model can be modelled. A crucial challenge for applying the technique is to control the sources. Here, we present data that describe the efficiency of explosive sources in the ice cover. Analysis of the data shows, that the ice cap traps a significant amount of energy, which is observed......Controlled source seismic investigation of crustal structure below ice covers is an emerging technique. We have recently conducted an explosive refraction/wide-angle reflection seismic experiment on the ice cap in east-central Greenland. The data-quality is high for all shot points and a full...

  16. New High-Resolution Multibeam Mapping and Seismic Reflection Imaging of Mudflows on the Mississippi River Delta Front

    Science.gov (United States)

    Chaytor, J. D.; Baldwin, W. E.; Danforth, W. W.; Bentley, S. J.; Miner, M. D.; Damour, M.

    2017-12-01

    Mudflows (channelized and unconfined debris flows) on the Mississippi River Delta Front (MRDF) are a recognized hazard to oil and gas infrastructure in the shallow Gulf of Mexico. Preconditioning of the seafloor for failure results from high sedimentation rates coupled with slope over-steepening, under-consolidation, and abundant biogenic gas production. Cyclical loading of the seafloor by waves from passing major storms appears to be a primary trigger, but the role of smaller (more frequent) storms and background oceanographic processes are largely unconstrained. A pilot high-resolution seafloor mapping and seismic imaging study was carried out across portions of the MRDF aboard the R/V Point Sur from May 19-26, 2017, as part of a multi-agency/university effort to characterize mudflow hazards in the area. The primary objective of the cruise was to assess the suitability of seafloor mapping and shallow sub-surface imaging tools in the challenging environmental conditions found across delta fronts (e.g., variably-distributed water column stratification and wide-spread biogenic gas in the shallow sub-surface). More than 600 km of multibeam bathymetry/backscatter/water column data, 425 km of towed chirp data, and > 500 km of multi-channel seismic data (boomer/mini-sparker sources, 32-channel streamer) were collected. Varied mudflow (gully, lobe), pro-delta morphologies, and structural features, some of which have been surveyed more than once, were imaged in selected survey areas from Pass a Loutre to Southwest Pass. The present location of the SS Virginia, which has been moving with one of the mudflow lobes since it was sunk in 1942, was determined and found to be 60 m SW of its 2006 position, suggesting movement not linked to hurricane-induced wave triggering of mudflows. Preliminary versions these data were used to identify sediment sampling sites visited on a cruise in early June 2017 led by scientists from LSU and other university/agency partners.

  17. [Study on predicting sugar content and valid acidity of apples by near infrared diffuse reflectance technique].

    Science.gov (United States)

    Liu, Yan-de; Ying, Yi-bin; Fu, Xia-ping

    2005-11-01

    The nondestructive method for quantifying sugar content (SC) and available acid (VA) of intact apples using diffuse near infrared reflectance and optical fiber sensing techniques were explored in the present research. The standard sample sets and prediction models were established by partial least squares analysis (PLS). A total of 120 Shandong Fuji apples were tested in the wave number of 12,500 - 4000 cm(-1) using Fourier transform near infrared spectroscopy. The results of the research indicated that the nondestructive quantification of SC and VA, gave a high correlation coefficient 0.970 and 0.906, a low root mean square error of prediction (RMSEP) 0.272 and 0.056 2, a low root mean square error of calibration (RMSEC) 0.261 and 0.0677, and a small difference between RMSEP and RMSEC 0.011 a nd 0.0115. It was suggested that the diffuse nearinfrared reflectance technique be feasible for nondestructive determination of apple sugar content in the wave number range of 10,341 - 5461 cm(-1) and for available acid in the wave number range of 10,341 - 3818 cm(-1).

  18. Three-dimensional seismic survey planning based on the newest data acquisition design technique; Saishin no data shutoku design ni motozuku sanjigen jishin tansa keikaku

    Energy Technology Data Exchange (ETDEWEB)

    Minehara, M; Nakagami, K; Tanaka, H [Japan National Oil Corp., Tokyo (Japan). Technology Research Center

    1996-10-01

    Theory of parameter setting for data acquisition is arranged, mainly as to the seismic generating and receiving geometry. This paper also introduces an example of survey planning for three-dimensional land seismic exploration in progress. For the design of data acquisition, fundamental parameters are firstly determined on the basis of the characteristics of reflection records at a given district, and then, the layout of survey is determined. In this study, information through modeling based on the existing interpretation of geologic structures is also utilized, to reflect them for survey specifications. Land three-dimensional seismic survey was designed. Ground surface of the surveyed area consists of rice fields and hilly regions. The target was a nose-shaped structure in the depth about 2,500 m underground. A survey area of 4km{times}5km was set. Records in the shallow layers could not obtained when near offset was not ensured. Quality control of this distribution was important for grasping the shallow structure required. In this survey, the seismic generating point could be ensured more certainly than initially expected, which resulted in the sufficient security of near offset. 2 refs., 2 figs.

  19. Crustal structure variations along the NW-African continental margin: a comparison of new and existing models from wide angle and reflection seismic data

    Science.gov (United States)

    Biari, Y.; Klingelhoefer, F.; Sahabi, M.; Aslanian, D.; Philippe, S.; Louden, K. E.; Berglar, K.; Moulin, M.; Mehdi, K.; Graindorge, D.; Evain, M.; Benabellouahed, M.; Reichert, C. J.

    2014-12-01

    Deep seismic data represent a key to understand the geometry and mechanism of continental rifting. The passive continental margin of NW-Africa is one of the oldest on earth, formed during the Upper Triassic-Lower Liassic rifting of the central Atlantic Ocean over 200 Ma. We present new and existing wide-angle and reflection seismic data from three study regions along the margin located in the North Moroccan salt basin, on the central continental margin offshore Safi and in the south, offshore Dakhla. In each of the study areas several combined wide-angle and reflection seismic profiles perpendicular and parallel to the margin have been acquired and forward modelled using comparable methods. The thickness of unthinned continental crust decreases from 36 km in the North to about 27 km in the South. In the North Moroccan Basin continental crust thins from originally 36 km to about 8 km in a 150 km wide zone. The basin itself is underlain by highly thinned continental crust. Offshore safi thinning of the continental crust is confined to a 130 km wide zone with no neighboring sedimentary basin underlain by continental crust. In both areas the zone of crustal thinning is characterised by the presence of large blocks and abundant salt diapirs. In the south crustal thinning is more rapid in a zone of 90 km and asymmetric with the upper crust thinning more closely to the continent than the lower crust, probably due to depth-dependent stretching and the presence of the precambrian Reguibat Ridge on land. Oceanic crust is characterised by a thickness of 7-8 km along the complete margin. Relatively high velocities of up to 7.5 km/s have been imaged between magnetic anomalies S1 and M25, and are probably related to changes in the spreading velocities at the time of the Kimmeridgian/Tithonian plate reorganisation. Volcanic activity seems to be confined to the region next to the Canary Islands, and is thus not related to the initial opening of the oceanic, which was related to no

  20. The effect of deformation after backarc spreading between the rear arc and current volcanic front in Shikoku Basin obtained by seismic reflection survey

    Science.gov (United States)

    Yamashita, M.; Takahashi, N.; Nakanishi, A.; Kodaira, S.; Tamura, Y.

    2012-12-01

    Detailed crustal structure information of a back-arc basin must be obtained to elucidate the mechanism of its opening. Especially, the Shikoku Basin, which occupies the northern part of the Philippine Sea Plate between the Kyushu-Palau Ridge and the Izu-Bonin (Ogasawara) Arc, is an important area to understand the evolution of the back-arc basins as a part of the growth process of the Philippine Sea. Especially, the crustal structure oft the east side of Shikoku Basin is complicated by colliding to the Izu Peninsula Japan Agency for Marine-Earth Science and Technology has been carried out many multi-channel seismic reflection surveys since 2004 in Izu-Bonin region. Kodaira et al. (2008) reported the results of a refraction seismic survey along a north-south profile within paleoarc in the rear arc (i.e., the Nishi-shichito ridge) about 150 km west of current volcanic front. According to their results, the variation relationship of crustal thickness between the rear arc and volcanic front is suggested the evidence of rifting from current volcanic arc. There is the en-echelon arrangement is located in the eastern side of Shikoku Basin from current arc to rear arc, and it is known to activate after ceased spreading at 15 Ma (Okino et al., 1994) of Shikoku Basin by geologic sampling of Ishizuka et al. (2003). Our MCS results are also recognized the recent lateral fault zone is located in east side of Shikoku Basin. We carried out high density grid multi-channel seismic reflection (MCS) survey using tuned airgun in order to obtain the relationship between the lateral faults and en-echelon arrangement in KR08-04 cruise. We identified the deformation of sediments in Shikoku Basin after activity of Kanbun seamount at 8 Ma in MCS profile. It is estimated to activate a part of the eastern side of Shikoku Basin after construction of en-echelon arrangement and termination of Shikoku Basin spreading. Based on analyses of magnetic and gravity anomalies, Yamazaki and Yuasa (1998

  1. Using typing techniques in a specific outbreak: the ethical reflection of public health professionals.

    Science.gov (United States)

    Rump, B; Cornelis, C; Woonink, F; VAN Steenbergen, J; Verweij, M; Hulscher, M

    2017-05-01

    Typing techniques are laboratory methods used in outbreak management to investigate the degree to which microbes found within an outbreak are related. Knowledge about relational patterns between microbes benefits outbreak management, but inevitably also tells us something about the relational patterns of the people hosting them. Since the technique is often used without explicit consent of all individuals involved, this may raise ethical questions. The aim of this study was to unravel the complex ethical deliberation of professionals over the use of such techniques. We organised group discussions (n = 3) with Dutch outbreak managers (n = 23). The topic list was based on previously identified ethical issues and discussions were analysed for recurrent themes. We found that outbreak managers first and foremost reflect on the balance of individual harm with public health benefit. This key question was approached by way of discussing four more specific ethical themes: (1) justification of governmental intervention, (2) responsibility to prevent infections, (3) scientific uncertainty and (4) legal consequences. The themes found in this study, rephrased into accessible questions, represent the shared ethical understanding of professionals and can help to articulate the ethical dimensions of using molecular science in response to infectious disease outbreaks.

  2. Modeling seismic wave propagation across the European plate: structural models and numerical techniques, state-of-the-art and prospects

    Science.gov (United States)

    Morelli, Andrea; Danecek, Peter; Molinari, Irene; Postpischl, Luca; Schivardi, Renata; Serretti, Paola; Tondi, Maria Rosaria

    2010-05-01

    Together with the building and maintenance of observational and data banking infrastructures - i.e. an integrated organization of coordinated sensor networks, in conjunction with connected data banks and efficient data retrieval tools - a strategic vision for bolstering the future development of geophysics in Europe should also address the essential issue of improving our current ability to model coherently the propagation of seismic waves across the European plate. This impacts on fundamental matters, such as correctly locating earthquakes, imaging detailed earthquake source properties, modeling ground shaking, inferring geodynamic processes. To this extent, we both need detailed imaging of shallow and deep earth structure, and accurate modeling of seismic waves by numerical methods. Our current abilities appear somewhat limited, but emerging technologies may enable soon a significant leap towards better accuracy and reliability. To contribute to this debate, we present here the state-of-the-art of knowledge of earth structure and numerical wave modeling in the European plate, as the result of a comprehensive study towards the definition of a continental-scale reference model. Our model includes a description of crustal structure (EPcrust) merging information deriving from previous studies - large-scale compilations, seismic prospection, receiver functions, inversion of surface wave dispersion measurements and Green functions from noise correlation. We use a simple description of crustal structure, with laterally-varying sediment and cristalline layers thickness, density, and seismic parameters. This a priori crustal model improves the overall fit to observed Bouguer anomaly maps over CRUST2.0. The new crustal model is then used as a constraint in the inversion for mantle shear wave speed, based on fitting Love and Rayleigh surface wave dispersion. The new mantle model sensibly improves over global S models in the imaging of shallow asthenospheric (slow) anomalies

  3. Technical evaluation of seismic qualification of safety-related equipment

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yang Hui; Park, Heong Gee; Park, Yeong Seok [Univ. of Incheon, Incheon (Korea, Republic of)

    1994-04-15

    This study is purposed to evaluate the technical acceptability of the procedures and techniques of seismic qualifications which were performed for the YGN 3 and 4 safety-related equipment.This study is also targeted to suggest a systematized technical procedure guide for the effective performance and review of the seismic qualification, which reflects the most up-to-date licensing requirements and state-of the-art.

  4. Path integration guided with a quality map for shape reconstruction in the fringe reflection technique

    Science.gov (United States)

    Jing, Xiaoli; Cheng, Haobo; Wen, Yongfu

    2018-04-01

    A new local integration algorithm called quality map path integration (QMPI) is reported for shape reconstruction in the fringe reflection technique. A quality map is proposed to evaluate the quality of gradient data locally, and functions as a guideline for the integrated path. The presented method can be employed in wavefront estimation from its slopes over the general shaped surface with slope noise equivalent to that in practical measurements. Moreover, QMPI is much better at handling the slope data with local noise, which may be caused by the irregular shapes of the surface under test. The performance of QMPI is discussed by simulations and experiment. It is shown that QMPI not only improves the accuracy of local integration, but can also be easily implemented with no iteration compared to Southwell zonal reconstruction (SZR). From an engineering point-of-view, the proposed method may also provide an efficient and stable approach for different shapes with high-precise demand.

  5. Application of the photomodulated reflectance technique to the monitoring of metal layers

    Energy Technology Data Exchange (ETDEWEB)

    Dobos, Gabor; Lenk, Sandor; Ujhelyi, Ferenc; Szita, Zsofia; Kocsanyi, Laszlo [Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111 Budapest (Hungary); Somogyi, Andras [Semilab Corporation, Prielle Kornelia ut 2, 1117 Budapest (Hungary)

    2011-09-15

    Photomodulated reflectance (PMR) measurement techniques are currently used for the monitoring of ultra-shallow junctions. This paper discusses the possibility of applying them to the characterisation of metal layers. A finite element method based computer model has been created to study the dependence of the PMR signal on different sample parameters. We present the results of these simulations and show that the method can be used to establish the thickness of a metal layer (if the material is known) and it can also provide information about the metal/semiconductor interface. This information might be used to characterise the barrier seed layer beneath the metal, by a non-contact and non-destructive way. Simulation results are also supported by actual measurements on test samples. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Assessment of serum selenium levels in 2-month-old sucking calves using total reflection technique

    International Nuclear Information System (INIS)

    Bernardini, D.; Testoni, S.; Buoso, M.C.; Ceccato, D.; Moschini, G.; Valdes, M.; Torboli, A.

    2000-01-01

    The assessment of selenium status of livestock is an important aspect of production medicine as evidence for the influence of low Se levels on disease resistance in ruminants is reviewed with emphasis on susceptibility to various pathologies (such as infections, exudative diathesis, pneumonia, pancreatic degeneration). Additional evidence suggests that Se deficiency may cause muscular dystrophy in calves, while, severe deficiency has been associated with cardiomyopathy and even death. Serum Se content is a good indicator of the short term Se status and reflects the recent dietary intake of the element. Since serum Se content is a good indicator of the short term status of the element and reflects the its recent dietary intake, the present work is aimed to determine Se concentration in serum from a group of 2 months old sucking calves suspected to be severely deficient. We used the TX 2000 X-ray spectrometer manufactured by Ital Structures. The energy resolution (FWHM) of the Si(Li) detector was 137 eV for Mn Kα. Among nuclear techniques the TXRF method is the best suitable for trace element analysis in liquid or dissolved samples and can deal much easier with elemental investigation. Physical basis of used analytical method, experimental set up and the sample preparation procedure are described. The concentration data obtained are presented and discussed. (author)

  7. Using bathymetry and reflective seismic profiles to tests a suspected link between melt flux and cumulative fault heave at mid-ocean ridges

    Science.gov (United States)

    Haughton, G.; Murton, B. J.; Le Bas, T.; Henstock, T.

    2017-12-01

    The interplay between magma supply and spreading rate is believed to play a major role in determining large scale seafloor morphology. Here we use bathymetry to test this relationship in areas with similar spreading rates and differing magma supplies. By using open source bathymetry data we have developed a repeatable, automated method for categorising seafloor cumulative fault heave and then attempt to identify the controlling variables. We measure the total apparent fault heave along axis and off-axis at 29°N and 60°N on the Mid-Atlantic Ridge then compare this to proxies for deformation and magma supply. Two approaches are adopted for identifying faults: one using bathymetry and the other spreading-parallel seismic reflection data. The first re-examines the orthogonally spreading Broken Spur segment (26°N) spreading at 23 mm yr-1 (full rate). The other examines the Reykjanes Ridge (60°N) spreading obliquely at 21 mm yr-1 (full rate), which may be influenced by the Icelandic hotspot. Each have contrasting residual depth and structure, with the former being typical of slow spreading ridges, with marked axial valleys, whereas the latter is more typical of fast spreading ridge morphology, with smooth axial rise. We find that high total heave (indicating high tectonic spreading) on the Broken Spur segment does not correlate with high mantle Bouguer anomalies (indicating thin crust and low melt flux). From this we hypothesise that total heave on the large scale at the Broken Spur segment is not controlled by crustal thickness or melt supply. At the Raykjanes Ridge, V-shaped ridges have thicker crust (measured seismically) which converge south of Iceland. These are thought to reflect transient (every 4-6 Myrs) pulses of hot mantle radiating away from the Iceland plume. We find ridge-symmetrical variation in fault heave but with a lower frequency (6-8 Myrs) and longer wavelength (3-7 Myrs) than the V-shaped ridges. Our analysis shows that plume pulses do not

  8. Seismic testing

    International Nuclear Information System (INIS)

    Sollogoub, Pierre

    2001-01-01

    This lecture deals with: qualification methods for seismic testing; objectives of seismic testing; seismic testing standards including examples; main content of standard; testing means; and some important elements of seismic testing

  9. Poisson's ratio model derived from P- and S-wave reflection seismic data at the CO2CRC Otway Project pilot site, Australia

    Science.gov (United States)

    Beilecke, Thies; Krawczyk, Charlotte M.; Tanner, David C.; Ziesch, Jennifer; Research Group Protect

    2014-05-01

    Compressional wave (P-wave) reflection seismic field measurements are a standard tool for subsurface exploration. 2-D seismic measurements are often used for overview measurements, but also as near-surface supplement to fill gaps that often exist in 3-D seismic data sets. Such supplementing 2-D measurements are typically simple with respect to field layout. This is an opportunity for the use of shear waves (S-waves). Within the last years, S-waves have become more and more important. One reason is that P- and S-waves are differently sensitive to fluids and pore fill so that the additional S-wave information can be used to enhance lithological studies. Another reason is that S-waves have the advantage of higher spatial resolution. Within the same signal bandwidth they typically have about half the wavelength of P-waves. In near-surface unconsolidated sediments they can even enhance the structural resolution by one order of magnitude. We make use of these capabilities within the PROTECT project. In addition to already existing 2-D P-wave data, we carried out a near surface 2-D S-wave field survey at the CO2CRC Otway Project pilot site, close to Warrnambool, Australia in November 2013. The combined analysis of P-wave and S-wave data is used to construct a Poisson's Ratio 2-D model down to roughly 600 m depth. The Poisson's ratio values along a 1 km long profile at the site are surprisingly high, ranging from 0.47 in the carbonate-dominated near surface to 0.4 at depth. In the literature, average lab measurements of 0.22 for unfissured carbonates and 0.37 for fissured examples have been reported. The high values that we found may indicate areas of rather unconsolidated or fractured material, or enhanced fluid contents, and will be subject of further studies. This work is integrated in a larger workflow towards prediction of CO2 leakage and monitoring strategies for subsurface storage in general. Acknowledgement: This work was sponsored in part by the Australian

  10. Tectonic History and Deep Structure of the Demerara Plateau from Combined Wide-Angle and Reflection Seismic Data and Plate Kinematic Reconstructions

    Science.gov (United States)

    Klingelhoefer, F.; Museur, T.; Roest, W. R.; Graindorge, D.; Chauvet, F.; Loncke, L.; Basile, C.; Poetisi, E.; Deverchere, J.; Lebrun, J. F.; Perrot, J.; Heuret, A.

    2017-12-01

    Many transform margins have associated intermediate depth marginal plateaus, which are commonly located between two oceanic basins. The Demerara plateau is located offshore Surinam and French Guiana. Plate kinematic reconstructions show that the plateau is located between the central and equatorial Atlantic in a position conjugate to the Guinean Plateau. In the fall of 2016, the MARGATS cruise acquired geophysical data along the 400 km wide Demerara plateau. The main objective of the cruise was to image the deep structure of the Demerara plateau and to study its tectonic history. A set of 4 combined wide-angle and reflection seismic profiles was acquired along the plateau, using 80 ocean-bottom seismometers, a 3 km long seismic streamer and a 8000 cu inch tuned airgun array. Forward modelling of the wide-angle seismic data on a profile, located in the eastern part of the plateau and oriented in a NE-SW direction, images the crustal structure of the plateau, the transition zone and the neighbouring crust of oceanic origin, up to a depth of 40 km. The plateau itself is characterised by a crust of 30 km thickness, subdivided into three distinct layers. However, the velocities and velocity gradients do not fit typical continental crust, with a lower crustal layer showing untypically high velocities and an upper layer having a steep velocity gradient. From this model we propose that the lowermost layer is probably formed from volcanic underplated material and that the upper crustal layer likely consists of the corresponding extrusive volcanic material, forming thick seaward-dipping reflector sequences on the plateau. A basement high is imaged at the foot of the slope and forms the ocean-continent transition zone. Further oceanward, a 5-6 km thick crust is imaged with velocities and velocity gradients corresponding to a thin oceanic crust. A compilation of magnetic data from the MARGATS and 3 previous cruises shows a high amplitude magnetic anomaly along the northern

  11. Structural and stratigraphic constraints on tsunamigenic rupture along the frontal Sunda megathrust from MegaTera bathymetric and seismic reflection data

    Science.gov (United States)

    Bradley, K. E.; Qin, Y.; Villanueva-Robles, F.; Hananto, N.; Leclerc, F.; Singh, S. C.; Tapponnier, P.; Sieh, K.; Wei, S.; Carton, H. D.; Permana, H.; Avianto, P.; Nugroho, A. B.

    2017-12-01

    The joint EOS/IPG/LIPI 2015 MegaTera expedition collected high-resolution seismic reflection profiles and bathymetric data across the Sunda trench, updip of the Mw7.7, 2010 Mentawai tsunami-earthquake rupture patch. These data reveal rapid lateral variations in both the stratigraphic level of the frontal Sunda megathrust and the vergence of frontal ramp faults. The stratigraphic depth of the megathrust at the deformation front correlates with ramp-thrust vergence and with changes in the basal friction angle inferred by critical-taper wedge theory. Where ramp thrusts verge uniformly seaward and have an average dip of 30°, the megathrust decollement resides atop a high-amplitude reflector that marks the inferred top of pelagic sediments. Where ramp thrusts are bi-vergent (similar throw on both landward- and seaward-vergent faults) and have an average dip of 42°, the decollement is higher, within the incoming clastic sequence, above a seismically transparent unit inferred to represent distal fan muds. Where ramp thrusts are uniformly landward vergent, the decollement sits directly on top of the oceanic crust that forms the bathymetrically prominent, subducting Investigator Ridge. The two, separate regions of large tsunamigenic ground-surface uplift during the 2010 tsunami earthquake that have been inferred from joint inversions of seismic, GPS, and tsunami data (e.g. Yue et al., 2014; Satake et al., 2013) correspond to the areas of frontal bi-vergence in the MegaTera data. We propose that enhanced surface uplift and tsunamigenesis during this event occurred when rupture propagated onto areas where the decollement sits directly above the basal muds of the incoming clastic sequence. Thus we hypothesize that frontal bi-vergence may mark areas of enhanced tsunami hazard posed by small magnitude, shallow megathrust ruptures that propagate to the trench. [Yue, H. et al., 2014, Rupture process of the…, JGR 119 doi:10.1002/2014JB011082; Satake, K. et al., 2013, Tsunami

  12. Seismic Refraction & Wide-angle Reflection Experiment on the Northern Margin of North China Craton -Data Acquisition and Preliminary Processing Result

    Science.gov (United States)

    Li, W.; Gao, R.; Keller, G. R.; Hou, H.; Li, Q.; Cox, C. M.; Chang, J. C.; Zhang, J.; Guan, Y.

    2010-12-01

    The evolution history of Central Asian Orogen Belt (CAOB) is still the main tectonic problems in northeastern Asia. The Siberia Craton (NC), North China Craton (NCC) and several blocks collided, and the resulting tectonic collage formed as the Paleo-Asian Ocean disappeared. Concerning the northern margin of North China Craton, many different geological questions remain unanswered, such as: the intracontinental orogenic process in the Yanshan orogen and the nature and location of the suture between the southern NC and the northern NCC. In Dec 2009, a 400 km long seismic refraction and wide-angle reflection profile was completed jointly by Institute of Geology, CAGS and University of Oklahoma. The survey line extended from the west end of the Yanshan orogen, across a granitoid belt to the Solonker suture zone. The recording of seismic waves from 8 explosions (500~1500 kg each) was conducted in four deployments of 300 Reftek125 (Texan) seismic recorders, with an average spacing of 1 km. For the calculations, we used the Rayinvr, Vmed and Zplot programs for ray tracing, model modification and phase picking. The initial result show that: 1)the depth of low velocity sediment cover ranges from 0.6 to 2.7 km (velocity: 2.8~5.6 km/s); 2)the depth of basement is 5.6~10 km (the depth of basement under the granitoid belt deepens to 10 km and velocity increases to 6.2 km/s); 3)the upper crust extends to a depth of 15.5~21 km and has the P-wave velocities between 5.6 and 6.4 km/s; 4)the thickness of the lower crust ranges from 22~28 km(velocity: 6.4~6.9 km/s); and 5)the depth of Moho varies from 39.5 km under the granitoid belt to 49 km under the Yanshan orogen. Based on these results, we can preliminarily deduce that: 1) the concave depression of the Moho observed represents the root of the Yanshan orogen, and it may prove that the orogen is dominated by thick-skinned tectonics; 2) the shape of velocity variations under the granitoid belt is suggestive of a magma conduit. It

  13. Virtual-stereo fringe reflection technique for specular free-form surface testing

    Science.gov (United States)

    Ma, Suodong; Li, Bo

    2016-11-01

    Due to their excellent ability to improve the performance of optical systems, free-form optics have attracted extensive interest in many fields, e.g. optical design of astronomical telescopes, laser beam expanders, spectral imagers, etc. However, compared with traditional simple ones, testing for such kind of optics is usually more complex and difficult which has been being a big barrier for the manufacture and the application of these optics. Fortunately, owing to the rapid development of electronic devices and computer vision technology, fringe reflection technique (FRT) with advantages of simple system structure, high measurement accuracy and large dynamic range is becoming a powerful tool for specular free-form surface testing. In order to obtain absolute surface shape distributions of test objects, two or more cameras are often required in the conventional FRT which makes the system structure more complex and the measurement cost much higher. Furthermore, high precision synchronization between each camera is also a troublesome issue. To overcome the aforementioned drawback, a virtual-stereo FRT for specular free-form surface testing is put forward in this paper. It is able to achieve absolute profiles with the help of only one single biprism and a camera meanwhile avoiding the problems of stereo FRT based on binocular or multi-ocular cameras. Preliminary experimental results demonstrate the feasibility of the proposed technique.

  14. Study on rapid valid acidity evaluation of apple by fiber optic diffuse reflectance technique

    Science.gov (United States)

    Liu, Yande; Ying, Yibin; Fu, Xiaping; Jiang, Xuesong

    2004-03-01

    Some issues related to nondestructive evaluation of valid acidity in intact apples by means of Fourier transform near infrared (FTNIR) (800-2631nm) method were addressed. A relationship was established between the diffuse reflectance spectra recorded with a bifurcated optic fiber and the valid acidity. The data were analyzed by multivariate calibration analysis such as partial least squares (PLS) analysis and principal component regression (PCR) technique. A total of 120 Fuji apples were tested and 80 of them were used to form a calibration data set. The influence of data preprocessing and different spectra treatments were also investigated. Models based on smoothing spectra were slightly worse than models based on derivative spectra and the best result was obtained when the segment length was 5 and the gap size was 10. Depending on data preprocessing and multivariate calibration technique, the best prediction model had a correlation efficient (0.871), a low RMSEP (0.0677), a low RMSEC (0.056) and a small difference between RMSEP and RMSEC by PLS analysis. The results point out the feasibility of FTNIR spectral analysis to predict the fruit valid acidity non-destructively. The ratio of data standard deviation to the root mean square error of prediction (SDR) is better to be less than 3 in calibration models, however, the results cannot meet the demand of actual application. Therefore, further study is required for better calibration and prediction.

  15. Field test investigation of high sensitivity fiber optic seismic geophone

    Science.gov (United States)

    Wang, Meng; Min, Li; Zhang, Xiaolei; Zhang, Faxiang; Sun, Zhihui; Li, Shujuan; Wang, Chang; Zhao, Zhong; Hao, Guanghu

    2017-10-01

    Seismic reflection, whose measured signal is the artificial seismic waves ,is the most effective method and widely used in the geophysical prospecting. And this method can be used for exploration of oil, gas and coal. When a seismic wave travelling through the Earth encounters an interface between two materials with different acoustic impedances, some of the wave energy will reflect off the interface and some will refract through the interface. At its most basic, the seismic reflection technique consists of generating seismic waves and measuring the time taken for the waves to travel from the source, reflect off an interface and be detected by an array of geophones at the surface. Compared to traditional geophones such as electric, magnetic, mechanical and gas geophone, optical fiber geophones have many advantages. Optical fiber geophones can achieve sensing and signal transmission simultaneously. With the development of fiber grating sensor technology, fiber bragg grating (FBG) is being applied in seismic exploration and draws more and more attention to its advantage of anti-electromagnetic interference, high sensitivity and insensitivity to meteorological conditions. In this paper, we designed a high sensitivity geophone and tested its sensitivity, based on the theory of FBG sensing. The frequency response range is from 10 Hz to 100 Hz and the acceleration of the fiber optic seismic geophone is over 1000pm/g. sixteen-element fiber optic seismic geophone array system is presented and the field test is performed in Shengli oilfield of China. The field test shows that: (1) the fiber optic seismic geophone has a higher sensitivity than the traditional geophone between 1-100 Hz;(2) The low frequency reflection wave continuity of fiber Bragg grating geophone is better.

  16. Archive of Digital Boomer and CHIRP Seismic Reflection Data Collected During USGS Field Activity 08LCA03 in Lake Panasoffkee, Florida, May 2008

    Science.gov (United States)

    Harrison, Arnell S.; Dadisman, Shawn V.; McBride, W. Scott; Flocks, James G.; Wiese, Dana S.

    2009-01-01

    In May of 2008, the U.S. Geological Survey (USGS) conducted geophysical surveys in Lake Panasoffkee, located in central Florida, as part of the USGS Lakes and Coastal Aquifers (LCA) study. This report serves as an archive of unprocessed digital boomer and Compressed High Intensity Radar Pulse (CHIRP)* seismic reflection data, trackline maps, navigation files, Field Activity Collection System (FACS) logs, Geographic Information System (GIS) files, and formal Federal Geographic Data Committee (FGDC) metadata. Filtered and gained (a relative increase in signal amplitude) digital images of the seismic profiles and geospatially corrected interactive profiles are also provided. Refer to the Acronyms page for expansions of acronyms and abbreviations used in this report. *Due to poor data acquisition conditions associated with the lake bottom sediments, only two CHIRP tracklines were collected during this field activity. The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG-Y format (Barry and others, 1975) and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU). Example SU processing scripts and USGS software for viewing the SEG-Y files (Zihlman, 1992) are provided. The USGS Florida Integrated Science Center (FISC) - St. Petersburg assigns a unique identifier to each cruise or field activity. For example, 08LCA03 tells us the data were collected in 2008 for the Lakes and Coastal Aquifers (LCA) study and the data were collected during the third field activity for that study in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the field activity ID. The naming convention used for each seismic line is as follows: yye##a, where 'yy' are the last two digits of the year in which the data were collected, 'e' is a 1-letter abbreviation for the equipment type (for example, b for boomer and c

  17. Indication to distinguish the burst region of coal gas from seismic data

    Energy Technology Data Exchange (ETDEWEB)

    Jian-yuan Cheng; Hong-wei Tang; Lin Xu; Yan-fang Li [China Coal Research Institute, Xi' an (China). Xi' an Research Institute

    2009-09-15

    The velocity of an over-burst coal seam is about 1/3 compared to a normal coal seam based on laboratory test results. This can be considered as a basis to confirm the area of coal and gas burst by seismic exploration technique. Similarly, the simulation result of the theoretical seismic model shows that there is obvious distinction between over-burst coal and normal coal based on the coal reflection's travel-time, energy and frequency. The results from the actual seismic data acquired in the coal and gas over-burst cases is consistent with that of the laboratory and seismic modeling; that is, in the coal and gas burst region, seismic reflection travel time is delayed, seismic amplitude is weakened and seismic frequency is reduced. Therefore, it can be concluded that seismic exploration technique is promising for use in distinguishing coal and gas over-burst regions based on the variation of seismic reflection travel time, amplitude and frequency. 7 refs., 6 figs.

  18. Stochastic velocity inversion of seismic reflection/refraction traveltime data for rift structure of the southwest Barents Sea

    DEFF Research Database (Denmark)

    Clark, Stephen A.; Faleide, Jan Inge; Hauser, Juerg

    2013-01-01

    reflection profiles. We utilize layer-based raytracing in a Markov Chain Monte Carlo (MCMC) inversion to determine a probabilistic velocity model constraining the sedimentary rocks, crystalline crust, and uppermost mantle in a complex tectonic regime. The profile images a wide range of crustal types and ages...... with the amount of overlap derived from published plate reconstructions. Local β factors approach 3, where Bjørnøya Basin reaches a depth of more than 13 km. Volcanics, carbonates, salt, diagenesis and metamorphism make deep sedimentary basin fill difficult to distinguish from original, pre-rift crystalline crust...

  19. Investigation of karst collapse based on 3-D seismic technique and DDA method at Xieqiao coal mine, China

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Jian-Ping; Chen, Zhong-Hui [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083 (China); Institute of Rock Mechanical and Fractals, China University of Mining and Technology, Beijing 100083 (China); Peng, Su-Ping; Li, Yong-Jun [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083 (China); Xie, He-Ping [Institute of Rock Mechanical and Fractals, China University of Mining and Technology, Beijing 100083 (China)

    2009-06-01

    Karst collapse is a serious geological problem in most of the coal mines in the north of China, but recently it has been found in the south as well. The present study is aimed at investigating subsidence mechanism and deformation field of a karst collapse column at Xieqiao, in the south of China. A method of three-dimensional (3-D) seismic technique has been successful in exploring the spatial morphology of the karst collapse at Xieqiao, and the discontinuous deformation analysis (DDA) method is used to calculate the deformation field and analyze the subsidence mechanism. The results indicated that DDA could approximately simulate and back analyze the subsidence process and strata deformation fields. The subsidence processes of the collapse column depend on the sizes of the karst caves. With the continuous expansion of the karst caves, a semi-elliptic stress field, local separation strata and fracture zone will be formed around the karst cave. Moreover, they will gradually expand upwards along the vertical direction. The paper also indicates that the subsidence failure stage may trigger a sudden collapse of the karst column because of the sudden energy release. Also, it will make a great impact on the vicinity working face so as to cause a rock burst. The effects of the friction angle of rock strata on the subsidence mechanism were reported firstly based on DDA. (author)

  20. Building Quakes: Detection of Weld Fractures in Buildings using High-Frequency Seismic Techniques

    Science.gov (United States)

    Heckman, V.; Kohler, M. D.; Heaton, T. H.

    2009-12-01

    Catastrophic fracture of welded beam-column connections in buildings was observed in the Northridge and Kobe earthquakes. Despite the structural importance of such connections, it can be difficult to locate damage in structural members underneath superficial building features. We have developed a novel technique to locate fracturing welds in buildings in real time using high-frequency information from seismograms. Numerical and experimental methods were used to investigate an approach for detecting the brittle fracture of welds of beam-column connections in instrumented steel moment-frame buildings through the use of time-reversed Green’s functions and wave propagation reciprocity. The approach makes use of a prerecorded catalogue of Green’s functions for an instrumented building to detect high-frequency failure events in the building during a later earthquake by screening continuous data for the presence of one or more of the events. This was explored experimentally by comparing structural responses of a small-scale laboratory structure under a variety of loading conditions. Experimentation was conducted on a polyvinyl chloride frame model structure with data recorded at a sample rate of 2000 Hz using piezoelectric accelerometers and a 24-bit digitizer. Green’s functions were obtained by applying impulsive force loads at various locations along the structure with a rubber-tipped force transducer hammer. We performed a blind test using cross-correlation techniques to determine if it was possible to use the catalogue of Green’s functions to pinpoint the absolute times and locations of subsequent, induced failure events in the structure. A finite-element method was used to simulate the response of the model structure to various source mechanisms in order to determine the types of elastic waves that were produced as well as to obtain a general understanding of the structural response to localized loading and fracture.

  1. Seismic reflection survey of the Uemachi fault in Osaka Prefecture; Osaka Uemachi danso no hanshaho danseiha tansa

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Y [Geological Survey of Japan, Tsukuba (Japan); Yoshizawa, M; Hirooka, S [Nikko Exploration and Development Co. Ltd., Tokyo (Japan); Yokota, H; Ito, S [Hanshin Consultant Co., Osaka (Japan); Hayashi, K; Aizawa, H

    1997-05-27

    Reflection survey is conducted using three traverse lines in Sakai City for confirming the presence of a southward stretch of the Uemachi fault underground along the western periphery of the Uemachi terrace, Osaka, and for elucidating its connection to the Sakamoto fault distributed near Izumi. Another reflection survey is conducted in the bed of Kanzaki river, Osaka, for the confirmation of its connection to the Nembutsuji-zan fault in Senri hillock. It is estimated on the basis of boring data that there exists another flexural structure approximately 3km south of the flexural structure whose presence is confirmed by the Sakai second traverse line. Accordingly, possibilities are high that the southward stretch of the Uemachi fault connects to the Sakamoto fault. The confirmation by the Kanzaki river traverse line of the flexural structure again confirms the continuity between the Uemachi fault and Nembutsuji-zan fault. The above-said findings enable an inference that the three faults of Nembutsuji-zan, Uemachi, and Sakamoto constitute a chain of active faults. Furthermore, there exists an active fault to the south of the Sakamoto fault, which zigzags to the south on the right-hand side as far as the south of the Kumeda pond. Accordingly, the Uemachi fault system as a whole spans approximately 43km from the northern end of the Nembutsuji-zan fault as far as the south of the Kumeda pond. 5 refs., 6 figs.

  2. Biomimetic approaches to create anti-reflection glass surfaces for solar cells using self-organizing techniques

    International Nuclear Information System (INIS)

    Achtelik, J.; Sievers, W.; Lindner, J.K.N.

    2013-01-01

    Highlights: ► Nanostructured glass surfaces with theoretically near-to-zero reflectivity in the UVNIR region. ► Simple fabrication process using self-organization during reactive ion etching proposed. ► Prediction of optical reflectivity from AFM measured surface morphology. -- Abstract: Aiming to diminish the reflection losses of glass covered light harvesting devices, the optical reflectivity of nanostructured glass surfaces is studied theoretically and experimentally. The work is inspired by the nanoscale roughness of insect eyes, which is tried to be replicated on a technical glass surface. To this end, the reflectivity of glass surfaces with topographies represented by linear, parabolic and Fermi-shaped glass/air fill factor profiles is calculated for normal incidence. It is shown that using the latter ones, an almost complete suppression of reflections can be achieved. A simple, self-organization technique to create such Fermi-shaped filling factor profiles in glass experimentally is also presented

  3. Biomimetic approaches to create anti-reflection glass surfaces for solar cells using self-organizing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Achtelik, J.; Sievers, W. [University of Paderborn, Department of Physics, 33098 Paderborn (Germany); Center of Optoelectronics and Photonics Paderborn CeOPP, 33098 Paderborn (Germany); Lindner, J.K.N., E-mail: lindner@physik.uni-paderborn.de [University of Paderborn, Department of Physics, 33098 Paderborn (Germany); Center of Optoelectronics and Photonics Paderborn CeOPP, 33098 Paderborn (Germany)

    2013-05-15

    Highlights: ► Nanostructured glass surfaces with theoretically near-to-zero reflectivity in the UVNIR region. ► Simple fabrication process using self-organization during reactive ion etching proposed. ► Prediction of optical reflectivity from AFM measured surface morphology. -- Abstract: Aiming to diminish the reflection losses of glass covered light harvesting devices, the optical reflectivity of nanostructured glass surfaces is studied theoretically and experimentally. The work is inspired by the nanoscale roughness of insect eyes, which is tried to be replicated on a technical glass surface. To this end, the reflectivity of glass surfaces with topographies represented by linear, parabolic and Fermi-shaped glass/air fill factor profiles is calculated for normal incidence. It is shown that using the latter ones, an almost complete suppression of reflections can be achieved. A simple, self-organization technique to create such Fermi-shaped filling factor profiles in glass experimentally is also presented.

  4. A review on reflective remote sensing and data assimilation techniques for enhanced agroecosystem modeling

    Science.gov (United States)

    Dorigo, W. A.; Zurita-Milla, R.; de Wit, A. J. W.; Brazile, J.; Singh, R.; Schaepman, M. E.

    2007-05-01

    During the last 50 years, the management of agroecosystems has been undergoing major changes to meet the growing demand for food, timber, fibre and fuel. As a result of this intensified use, the ecological status of many agroecosystems has been severely deteriorated. Modeling the behavior of agroecosystems is, therefore, of great help since it allows the definition of management strategies that maximize (crop) production while minimizing the environmental impacts. Remote sensing can support such modeling by offering information on the spatial and temporal variation of important canopy state variables which would be very difficult to obtain otherwise. In this paper, we present an overview of different methods that can be used to derive biophysical and biochemical canopy state variables from optical remote sensing data in the VNIR-SWIR regions. The overview is based on an extensive literature review where both statistical-empirical and physically based methods are discussed. Subsequently, the prevailing techniques of assimilating remote sensing data into agroecosystem models are outlined. The increasing complexity of data assimilation methods and of models describing agroecosystem functioning has significantly increased computational demands. For this reason, we include a short section on the potential of parallel processing to deal with the complex and computationally intensive algorithms described in the preceding sections. The studied literature reveals that many valuable techniques have been developed both for the retrieval of canopy state variables from reflective remote sensing data as for assimilating the retrieved variables in agroecosystem models. However, for agroecosystem modeling and remote sensing data assimilation to be commonly employed on a global operational basis, emphasis will have to be put on bridging the mismatch between data availability and accuracy on one hand, and model and user requirements on the other. This could be achieved by

  5. Linearized inversion frameworks toward high-resolution seismic imaging

    KAUST Repository

    Aldawood, Ali

    2016-09-01

    Seismic exploration utilizes controlled sources, which emit seismic waves that propagate through the earth subsurface and get reflected off subsurface interfaces and scatterers. The reflected and scattered waves are recorded by recording stations installed along the earth surface or down boreholes. Seismic imaging is a powerful tool to map these reflected and scattered energy back to their subsurface scattering or reflection points. Seismic imaging is conventionally based on the single-scattering assumption, where only energy that bounces once off a subsurface scatterer and recorded by a receiver is projected back to its subsurface position. The internally multiply scattered seismic energy is considered as unwanted noise and is usually suppressed or removed from the recorded data. Conventional seismic imaging techniques yield subsurface images that suffer from low spatial resolution, migration artifacts, and acquisition fingerprint due to the limited acquisition aperture, number of sources and receivers, and bandwidth of the source wavelet. Hydrocarbon traps are becoming more challenging and considerable reserves are trapped in stratigraphic and pinch-out traps, which require highly resolved seismic images to delineate them. This thesis focuses on developing and implementing new advanced cost-effective seismic imaging techniques aiming at enhancing the resolution of the migrated images by exploiting the sparseness of the subsurface reflectivity distribution and utilizing the multiples that are usually neglected when imaging seismic data. I first formulate the seismic imaging problem as a Basis pursuit denoise problem, which I solve using an L1-minimization algorithm to obtain the sparsest migrated image corresponding to the recorded data. Imaging multiples may illuminate subsurface zones, which are not easily illuminated by conventional seismic imaging using primary reflections only. I then develop an L2-norm (i.e. least-squares) inversion technique to image

  6. New insights into structural and stratigraphic aspects of central Northern Switzerland from the Nagra 2D reflection seismic campaign 2011/12

    International Nuclear Information System (INIS)

    Meier, B.

    2015-01-01

    In this article, some findings resulting from the interpretation of reprocessed and newly acquired 2D seismic data in the central Northern Switzerland are presented. The seismic examples illustrate the relationship between basement and cover-tectonics and offer a closer look at seismic-stratigraphic characteristics which can be observed in the Middle Jurassic sequence. The new 2D seismic data have closed an important data gaps between the Nagra siting regions 'Jura Ost' and Nördlich Lägern' proposed for radioactive waste disposal and allow clarification of the general structural framework and internal composition of the Permo-Carboniferous Through. Furthermore, the kinematic relationships between the basement and cover structures can be studied and the newly acquired seismic data have allowed detailed depositional structures and seismic facies changes within the Mid-Upper Dogger sequence to be recognized, particularly east and west of the lower Aare valley. (author)

  7. Controls of late Palaeozoic and Mesozoic extension in the British Isles: evidence from seismic reflection data in the Central North Sea

    Science.gov (United States)

    Smith, K.; Cameron, T. D. J.

    2009-04-01

    Controls of late Palaeozoic and Mesozoic extension in the British Isles: evidence from seismic reflection data in the Central North Sea. Kevin Smith (1) and Don Cameron (2) (1) British Geological Survey, Murchison House, West Mains Road, Edinburgh, EH9 3LA. (ksm@bgs.ac.uk). (2) British Geological Survey, 376 Gilmerton Road, Edinburgh, EH17 7QS. In the area of the British Isles during the late Devonian and early Carboniferous, the oblique convergence of Laurentia and Gondwana imposed a torque on the adjoining terranes of Baltica and Avalonia. Their resulting clockwise rotation was accommodated by widely distributed N-S extension in the intervening zones previously formed by Caledonian and Acadian convergence. South of Laurentia and Baltica, late Palaeozoic extension was focused (1) at terrane margins, (2) in areas of limited Caledonian-Acadian plutonism, and (3) in places where the western (Iapetus) and eastern (Tornquist) convergence zones intersect at a high angle. One of these latter areas lies in Central England immediately north of the Midland Microcraton (part of Eastern Avalonia), where thermal subsidence associated with early Carboniferous extension gave rise to the late Carboniferous Pennine Basin. Interpretation of an extensive set of 3D and 2D long-offset seismic reflection data suggests that a similar area of enhanced extension at a fold belt intersection lies to north of the Mid North Sea High in the middle of the Central North Sea. Variscan uplift and inversion of the late Palaeozoic basins began to predominate in mid-Carboniferous times as final amalgamation of all the different terranes to form Pangaea curtailed the initial episode of extension and thermal subsidence. This change in the tectonic regime was associated with the onset of tholeiitic volcanism within the convergence zones, and was followed by localised extension during the earliest Permian. Evidence obtained from seismic interpretation of the deep structure of the UK sector of the Central

  8. A calibration method for fringe reflection technique based on the analytical phase-slope description

    Science.gov (United States)

    Wu, Yuxiang; Yue, Huimin; Pan, Zhipeng; Liu, Yong

    2018-05-01

    The fringe reflection technique (FRT) has been one of the most popular methods to measure the shape of specular surface these years. The existing system calibration methods of FRT usually contain two parts, which are camera calibration and geometric calibration. In geometric calibration, the liquid crystal display (LCD) screen position calibration is one of the most difficult steps among all the calibration procedures, and its accuracy is affected by the factors such as the imaging aberration, the plane mirror flatness, and LCD screen pixel size accuracy. In this paper, based on the deduction of FRT analytical phase-slope description, we present a novel calibration method with no requirement to calibrate the position of LCD screen. On the other hand, the system can be arbitrarily arranged, and the imaging system can either be telecentric or non-telecentric. In our experiment of measuring the 5000mm radius sphere mirror, the proposed calibration method achieves 2.5 times smaller measurement error than the geometric calibration method. In the wafer surface measuring experiment, the measurement result with the proposed calibration method is closer to the interferometer result than the geometric calibration method.

  9. Integrating seismic-reflection and sequence-stratigraphic methods to characterize the hydrogeology of the Floridan aquifer system in southeast Florida

    Science.gov (United States)

    Cunningham, Kevin J.

    2013-01-01

    The Floridan aquifer system (FAS) is receiving increased attention as a result of regulatory restrictions on water-supply withdrawals and treated wastewater management practices. The South Florida Water Management District’s Regional Water Availability Rule, adopted in 2007, restricts urban withdrawals from the shallower Biscayne aquifer to pre-April 2006 levels throughout southeast Florida. Legislation adopted by the State of Florida requires elimination of ocean outfalls of treated wastewater by 2025. These restrictions have necessitated the use of the more deeply buried FAS as an alternate water resource to meet projected water-supply shortfalls, and as a repository for the disposal of wastewater via Class I deep injection wells and injection of reclaimed water. Some resource managers in Broward County have expressed concern regarding the viability of the FAS as an alternative water supply due to a lack of technical data and information regarding its long-term sustainability. Sustainable development and management of the FAS for water supply is uncertain because of the potential risk posed by structural geologic anomalies (faults, fractures, and karst collapse structures) and knowledge gaps in the stratigraphy of the system. The integration of seismic-reflection and borehole data into an improved geologic and hydrogeologic framework will provide a better understanding of the structural and stratigraphic features that influence groundwater flow and contaminant transport.

  10. Supra-salt normal fault growth during the rise and fall of a diapir: Perspectives from 3D seismic reflection data, Norwegian North Sea

    Science.gov (United States)

    Tvedt, Anette B. M.; Rotevatn, Atle; Jackson, Christopher A.-L.

    2016-10-01

    Normal faulting and the deep subsurface flow of salt are key processes controlling the structural development of many salt-bearing sedimentary basins. However, our detailed understanding of the spatial and temporal relationship between normal faulting and salt movement is poor due to a lack of natural examples constraining their geometric and kinematic relationship in three-dimensions. To improve our understanding of these processes, we here use 3D seismic reflection and borehole data from the Egersund Basin, offshore Norway, to determine the structure and growth of a normal fault array formed during the birth, growth and decay of an array of salt structures. We show that the fault array and salt structures developed in response to: (i) Late Triassic-to-Middle Jurassic extension, which involved thick-skinned, sub-salt and thin-skinned supra-salt faulting with the latter driving reactive diapirism; (ii) Early Cretaceous extensional collapse of the walls; and (iii) Jurassic-to-Neogene, active and passive diapirism, which was at least partly coeval with and occurred along-strike from areas of reactive diapirism and wall collapse. Our study supports physical model predictions, showcasing a three-dimensional example of how protracted, multiphase salt diapirism can influence the structure and growth of normal fault arrays.

  11. Geological Constraints on the Evolution of the Angolan Margin Based on Reflection and Refraction Seismic Data (ZaïAngo project)

    Science.gov (United States)

    Moulin, M.; Aslanian, D.; Olivet, J.; Contrucci, I.; Matias, L.; Geli, L.; Klingelhoefer, F.; Nouze, H.; Rabineau, M.; Labails, C.; Rehault, J.; Unternehr, P.

    2005-05-01

    Deep penetration multi-channel reflection and OBS wide-angle seismic data from the Congo-Angola margin were collected in 2000 during the ZaiAngo cruise (Ifremer and Total). These data help constrain the deep structure of the non-volcanic continental margin, the geometry of the pre-salt sediment layers and the geometry of the Aptian salt layer. Dating the deposition of the salt relative to the chronology of the margin formation is an issue of fundamental importance for reconstructing the evolution of the margin and for the understanding of the crustal thinning processes. The data show that the crust thins abruptly, from a 30 - 40km thickness to less than 10km, over a lateral distance of less than 50km. The transitional domain is a 180km wide basin with a thickness lower than 7 km. The pre-salt sediment layering within this basin is parallel to the base of the salt and hardly affected by tectonic deformation. In addition, the presence of a continuous salt cover, from the continental platform down to the presumed oceanic boundary, provides indications on the conditions of salt deposition that constrain the geometry of the margin at that time. These crucial observations imply shallow deposition environments during the rifting and suggest that vertical motions prevailed - compared to horizontal motions - during the formation of the basin.

  12. Geological constraints on the evolution of the Angolan margin based on reflection and refraction seismic data (ZaïAngo project)

    Science.gov (United States)

    Moulin, Maryline; Aslanian, Daniel; Olivet, Jean-Louis; Contrucci, Isabelle; Matias, Luis; Géli, Louis; Klingelhoefer, Frauke; Nouzé, Hervé; Réhault, Jean-Pierre; Unternehr, Patrick

    2005-09-01

    Deep penetration multichannel reflection and Ocean Bottom Seismometer wide-angle seismic data from the Congo-Angola margin were collected in 2000 during the ZaïAngo cruise. These data help constrain the deep structure of the continental margin, the geometry of the pre-salt sediment layers and the geometry of the Aptian salt layer. Dating the deposition of the salt relative to the chronology of the margin formation is an issue of fundamental importance for reconstructing the evolution of the margin and for the understanding of the crustal thinning processes. The data show that the crust thins abruptly, from a 30-40 km thickness to less than 10 km, over a lateral distance of less than 50 km. The transitional domain is a 180-km-wide basin. The pre-salt sediment layering within this basin is parallel to the base of the salt and hardly affected by tectonic deformation. In addition, the presence of a continuous salt cover, from the continental platform down to the presumed oceanic boundary, provides indications on the conditions of salt deposition that constrain the geometry of the margin at that time. These crucial observations imply shallow deposition environments during the rifting and suggest that vertical motions prevailed-compared to horizontal motions-during the formation of the basin.

  13. The Tunisian Jurassic aquifer in the North African Sahara aquifer system: information derived from two-dimensional seismic reflection and well logs

    Science.gov (United States)

    Ben Lasmar, Rafika; Guellala, Rihab; Garrach, Mohamed; Mahroug, Ali; Sarsar Naouali, Benen; Inoubli, Mohamed Hédi

    2017-12-01

    Southern Tunisia is an arid area where socio-economic activities are dependent on groundwater resources. The presented study aims to better characterize the Jurassic aquifer based on geological and geophysical data, with a view to develop a rational exploitation program. Well logs are used to precisely determine the position and composition of the known Jurassic aquifer layers and to identify others able to produce good quality water. The logs show that limestones, sandstones and dolomites of the Krachoua, Techout and Foum Tataouine formations are the main Jurassic aquifers. Sixty-eight seismic-reflection sections are integrated within this study. The interpolation between the interpreted sections leads to the construction of isochronous isopach maps and geoseismic sections, and their analysis finds that compressive and extensive tectonic deformations have influenced the Jurassic aquifer geometry. The Hercynian orogeny phase manifestation is remarkable in that there are several stratigraphic gaps in the Jurassic sequence. The E-W, NW-SE, and NNW-SSE accidents, reactivated in normal faults since the Permian to Lower Cretaceous epochs, have generated the structures found in the Jurassic series, such as subsided and raised blocks. Their syn-sedimentary activity has controlled the thickness and facies of these series. The Cretaceous, Tortonian and Post-Villafranchian compressions are responsible for the Jurassic-deposits folding in some localities. The highlighted tectonic and sedimentary events have an important impact on the Jurassic aquifer function by favoring the Jurassic aquifer interconnections and their connections with the Triassic and Cretaceous permeable series.

  14. Thickness of the oligo-neogene sedimentary cover in the Central Depression, northern Chile (Pampa del Tamarugal, 20°45'-21°30'S), based on seismic reflection

    Science.gov (United States)

    Garcia, M.; Simicic, Y.; Contreras Reyes, E.; Charrier, R.

    2013-12-01

    The estimation of the Pampa de Tamarugal oligo-neogene sedimentary cover thickness from seismic interpretation is crucial for scientific and applied subjects, such as placing aquifers traps and Mesozoic-Paleogene basement top location for mining exploration drilling. The Chilean National Petroleum Company (ENAP) has explored hydrocarbon resources in the area, raising several reflection seismic lines and drilling some wells. Previous studies used the paper seismic data by determining the cover geometry and defining the basement-cover boundary. We have obtained directly SGY digital files, which allow a better definition and modeling of stratigraphy and cover thickness. This thickness was estimated by the travel time in the seismic reflection lines and the value of the p-wave propagation velocity (0.91 to 1.97 km/s for cover). The last value was obtained by density measurements of field samples, which resulted from 1,895 to 2,065 g/cm3. In the central-south part of the Pampa del Tamarugal, immediately south of Cerro Challacollo, the west-east-oriented 99_7 seismic line shows a 'basement high' whose top is at 100 m from the surface. The basement was uplift by a north-trend west-verging reverse fault and separates two sub-basins of 9.5 km and 13.8 km wide, and maximum cover thicknesses of 600 and 850 m, west and east respectively. To the north of Cerro Challacollo, the subparallel 99_6 line shows a similar geometry, and increasing the depth of the basement high top up to 350 m in the central part of the section. For seismic lines south of Cerro Challacollo, the basement high disappears and the cover thickness increases. To improve the accuracy of the cover thickness estimations, we will test directly measurements of p-wave propagation velocity in field samples of basement and cover (instead of approximations from the density measurements).

  15. Qualitative and quantitative comparison of geostatistical techniques of porosity prediction from the seismic and logging data: a case study from the Blackfoot Field, Alberta, Canada

    Science.gov (United States)

    Maurya, S. P.; Singh, K. H.; Singh, N. P.

    2018-05-01

    In present study, three recently developed geostatistical methods, single attribute analysis, multi-attribute analysis and probabilistic neural network algorithm have been used to predict porosity in inter well region for Blackfoot field, Alberta, Canada, an offshore oil field. These techniques make use of seismic attributes, generated by model based inversion and colored inversion techniques. The principle objective of the study is to find the suitable combination of seismic inversion and geostatistical techniques to predict porosity and identification of prospective zones in 3D seismic volume. The porosity estimated from these geostatistical approaches is corroborated with the well log porosity. The results suggest that all the three implemented geostatistical methods are efficient and reliable to predict the porosity but the multi-attribute and probabilistic neural network analysis provide more accurate and high resolution porosity sections. A low impedance (6000-8000 m/s g/cc) and high porosity (> 15%) zone is interpreted from inverted impedance and porosity sections respectively between 1060 and 1075 ms time interval and is characterized as reservoir. The qualitative and quantitative results demonstrate that of all the employed geostatistical methods, the probabilistic neural network along with model based inversion is the most efficient method for predicting porosity in inter well region.

  16. Seismic modelling of shallow coalfields

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, D.C. (University of Calgary, Calgary, Alberta (Canada). Dept. of Geology and Geophysics.)

    1987-01-01

    This study was undertaken in order to determine whether reflection seismic surveys can be used to map stratigraphic and structural detail of shallow Plains-type coal deposits. Two coalfields in central Alberta were used to examine and determine optimum acquisition parameters for reflection seismic surveys in such settings. The study was based on 1-D and 2-D numerical seismic modelling using sonic and density well logs to formulate a layered earth model. Additional objectives were to interpret the reflection seismic data in terms of geologic features in the study area, and to investigate the relationship between vertical resolution and field acquisition geometry. 27 refs., 41 figs.

  17. Reflection curves—new computation and rendering techniques

    Directory of Open Access Journals (Sweden)

    Dan-Eugen Ulmet

    2004-05-01

    Full Text Available Reflection curves on surfaces are important tools for free-form surface interrogation. They are essential for industrial 3D CAD/CAM systems and for rendering purposes. In this note, new approaches regarding the computation and rendering of reflection curves on surfaces are introduced. These approaches are designed to take the advantage of the graphics libraries of recent releases of commercial systems such as the OpenInventor toolkit (developed by Silicon Graphics or Matlab (developed by The Math Works. A new relation between reflection curves and contour curves is derived; this theoretical result is used for a straightforward Matlab implementation of reflection curves. A new type of reflection curves is also generated using the OpenInventor texture and environment mapping implementations. This allows the computation, rendering, and animation of reflection curves at interactive rates, which makes it particularly useful for industrial applications.

  18. Seismic reflection-based evidence of a transfer zone between the Wagner and Consag basins: implications for defining the structural geometry of the northern Gulf of California

    Science.gov (United States)

    González-Escobar, Mario; Suárez-Vidal, Francisco; Hernández-Pérez, José Antonio; Martín-Barajas, Arturo

    2010-12-01

    This study examines the structural characteristics of the northern Gulf of California by processing and interpreting ca. 415 km of two-dimensional multi-channel seismic reflection lines (data property of Petróleos Mexicanos PEMEX) collected in the vicinity of the border between the Wagner and Consag basins. The two basins appear to be a link between the Delfín Superior Basin to the south, and the Cerro Prieto Basin to the north in the Mexicali-Imperial Valley along the Pacific-North America plate boundary. The seismic data are consistent with existing knowledge of four main structures (master faults) in the region, i.e., the Percebo, Santa María, Consag Sur, and Wagner Sur faults. The Wagner and Consag basins are delimited to the east by the Wagner Sur Fault, and to the west by the Consag Sur Fault. The Percebo Fault borders the western margin of the modern Wagner Basin depocenter, and is oriented N10°W, dipping (on average) ˜40° to the northeast. The trace of the Santa María Fault located in the Wagner Basin strikes N19°W, dipping ˜40° to the west. The Consag Sur Fault is oriented N14°W, and dips ˜42° to the east over a distance of 21 km. To the east of the study area, the Wagner Sur Fault almost parallels the Consag Sur Fault over a distance of ˜86 km, and is oriented N10°W with an average dip of 59° to the east. Moreover, the data provide new evidence that the Wagner Fault is discontinuous between the two basins, and that its structure is more complex than previously reported. A structural high separates the northern Consag Basin from the southern Wagner Basin, comprising several secondary faults oriented NE oblique to the main faults of N-S direction. These could represent a zone of accommodation, or transfer zone, where extension could be transferred from the Wagner to the Consag Basin, or vice versa. This area shows no acoustic basement and/or intrusive body, which is consistent with existing gravimetric and magnetic data for the region.

  19. Structural and geological analysis of the northern Pescadero basin: preliminary results based on the analysis of 2D multichannel seismic reflection profiles

    Science.gov (United States)

    Spelz, R. M.; Ramirez-Zerpa, N. A.; Gonzalez-Fernandez, A.; Yarbuh, I.; Contreras, J.

    2017-12-01

    The Pacific-North America plate boundary along the Gulf of California is characterized by an array of right-stepping, right-lateral, transform faults connecting a series of pull-apart basins distributed along the gulf axis. Altogether, these structures accommodate an oblique-divergent component of deformation characterizing the modern tectonic regime along the gulf. The northern Pescadero complex, in the southern Gulf of California, is one of the deepest and probably least studied transtensional fault-termination basins in the gulf. The complex is bounded to the north and south by Atl and Farallon transform faults, respectively, and consists of two asymmetric, rhomboidal-shaped, basins with a series of intrabasinal high-angle normal faults and ramps connecting their depocenters. In this study we present preliminary results derived from the processing and analysis of 400 km of seismic reflection profiles, collected in 2006 onboard the R/V Francisco de Ulloa in northern Pescadero, providing new insights into the geology and internal structure of the basin. Northern Pescadero is a deep and narrow basin characterized by a maximum sedimentary infill of 1 km, and depths to the basin floor exceeding 3500 m. Deformation is chiefly accommodated by an array of self-parallel half-graben structures that appear to grow towards the northern flank of the basin. Faults-scarps located farther from the deformation axis appear to be more degraded, suggesting a progressively younger age of the half-grabens near the basin's depocenter. Another important feature revealed in the seismic images is the lack of sediments on top of the crystalline basement that floors the narrow central portion of the basin. In this area the reflectors at the basin's floor show a pronounced increase in amplitude and coherence, indicating the emplacement of magmatic extrusions. Likewise, in those areas with the greater sediment infill, the occurrence of high-amplitude reflectors, located 150 m below the

  20. tomo3d: a new 3-D joint refraction and reflection travel-time tomography code for active-source seismic data

    Science.gov (United States)

    Meléndez, A.; Korenaga, J.; Sallares, V.; Ranero, C. R.

    2012-12-01

    We present the development state of tomo3d, a code for three-dimensional refraction and reflection travel-time tomography of wide-angle seismic data based on the previous two-dimensional version of the code, tomo2d. The core of both forward and inverse problems is inherited from the 2-D version. The ray tracing is performed by a hybrid method combining the graph and bending methods. The graph method finds an ordered array of discrete model nodes, which satisfies Fermat's principle, that is, whose corresponding travel time is a global minimum within the space of discrete nodal connections. The bending method is then applied to produce a more accurate ray path by using the nodes as support points for an interpolation with beta-splines. Travel time tomography is formulated as an iterative linearized inversion, and each step is solved using an LSQR algorithm. In order to avoid the singularity of the sensitivity kernel and to reduce the instability of inversion, regularization parameters are introduced in the inversion in the form of smoothing and damping constraints. Velocity models are built as 3-D meshes, and velocity values at intermediate locations are obtained by trilinear interpolation within the corresponding pseudo-cubic cell. Meshes are sheared to account for topographic relief. A floating reflector is represented by a 2-D grid, and depths at intermediate locations are calculated by bilinear interpolation within the corresponding square cell. The trade-off between the resolution of the final model and the associated computational cost is controlled by the relation between the selected forward star for the graph method (i.e. the number of nodes that each node considers as its neighbors) and the refinement of the velocity mesh. Including reflected phases is advantageous because it provides a better coverage and allows us to define the geometry of those geological interfaces with velocity contrasts sharp enough to be observed on record sections. The code also

  1. Modeling, Analysis, and Preservation Techniques for Historic Reinforced Concrete Structures in Seismic Prone Regions Case Study: Augusta Airship Hangar, Sicily

    International Nuclear Information System (INIS)

    Cronin, Kelly; Whyte, Catherine; Reiner, Tom

    2008-01-01

    Throughout the world there are hundreds of historic monuments and structures considered to be invaluable and irreplaceable. They are symbols of cultural identity and a means of educating people about history. Preservation of historic monuments and structures is therefore an important part of safeguarding these cultural heritage sites so that they retain their value for future generations.This report discusses a procedure for the investigation of seismic hazards in existing buildings and possible steps that can be taken to avoid damage caused by these hazards. The Augusta Airship Hangar located in Sicily, will be used as a case study however the topics addressed in this paper can be applied to other structures of historic value around the world.First state-of-the-art scanning procedures were used to create scale digital models that were imported into a structural analysis program. Within this program dynamic analyses were performed on the model based on actual ground motions taken close to the site. This data was used to determine the period and mode shapes of the structure. Then a nonlinear analysis, including a static pushover analysis, was implemented on a two-dimensional model of the structural frame. From this analysis the failure mechanisms of the structure were revealed with relation to an allowable roof displacement. The structural integrity of the structure was evaluated based on pre-defined performance goals. Finally multiple suggestions were made how the Augusta Airship Hangar might be repaired and strengthened so that this structure will not be destroyed should an earthquake occur.The results of our study show that historic structures, despite their age, can still be strong and ductile. Also there are a multitude of effective preservation and retrofit techniques that can be used to strengthen these historic structures, should an earthquake occur. Through this study, the Augusta Airship Hangar has proven to be not only a historic symbol for Sicily but

  2. Using the IGCRA (individual, group, classroom reflective action technique to enhance teaching and learning in large accountancy classes

    Directory of Open Access Journals (Sweden)

    Cristina Poyatos

    2011-02-01

    Full Text Available First year accounting has generally been perceived as one of the more challenging first year business courses for university students. Various Classroom Assessment Techniques (CATs have been proposed to attempt to enrich and enhance student learning, with these studies generally positioning students as learners alone. This paper uses an educational case study approach and examines the implementation of the IGCRA (individual, group, classroom reflective action technique, a Classroom Assessment Technique, on first year accounting students’ learning performance. Building on theoretical frameworks in the areas of cognitive learning, social development, and dialogical learning, the technique uses reports to promote reflection on both learning and teaching. IGCRA was found to promote feedback on the effectiveness of student, as well as teacher satisfaction. Moreover, the results indicated formative feedback can assist to improve the learning and learning environment for a large group of first year accounting students. Clear guidelines for its implementation are provided in the paper.

  3. Recent Vs. Historical Seismicity Analysis For Banat Seismic Region (Western Part Of Romania)

    OpenAIRE

    Oros Eugen; Diaconescu Mihai

    2015-01-01

    The present day seismic activity from a region reflects the active tectonics and can confirm the seismic potential of the seismogenic sources as they are modelled using the historical seismicity. This paper makes a comparative analysis of the last decade seismicity recorded in the Banat Seismic Region (western part of Romania) and the historical seismicity of the region (Mw≥4.0). Four significant earthquake sequences have been recently localized in the region, three of them nearby the city of...

  4. Cavity ring-down technique for measurement of reflectivity of high ...

    Indian Academy of Sciences (India)

    Laser & Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085,. India. *Corresponding author. E-mail: gsridhar@barc.gov.in. Abstract. A simple, accurate and reliable method for measuring the reflectivity of laser- ... Keywords. Cavity ring-down method; reflectivity measurement; optical resonator.

  5. Seismic analysis and testing of nuclear power plants

    International Nuclear Information System (INIS)

    1979-01-01

    The following subjects are discussed in this guide: General Recommendations for seismic classification, loading combinations and allowable limits; seismic analysis methods; implications for seismic design; seismic testing and qualification; seismic instrumentation; modelling techniques; material property characterization; seismic response of soil deposits and earth structures; liquefaction and ground failure; slope stability; sloshing effects in water pools; qualification testing by means of the transport vehicle

  6. Crustal investigations of the earthquake-prone Vrancea region in Romania - Part 2: Novel deep seismic reflection experiment in the southeastern Carpathian belt and its foreland basin - survey target, design, and first results

    Science.gov (United States)

    Mocanu, V. I.; Stephenson, R. A.; Diaconescu, C. C.; Knapp, J. H.; Matenco, L.; Dinu, C.; Harder, S.; Prodehl, C.; Hauser, F.; Raileanu, V.; Cloetingh, S. A.; Leever, K.

    2001-12-01

    Seismic studies of the outer Carpathian Orogen and its foreland (Focsani Basin) in the vicinity of the Vrancea Zone and Danube Delta (Romania) forms one component of a new multidisciplinary initiative of ISES (Netherlands Centre for Integrated Solid Earth Sciences) called DACIA PLAN ("Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics"). The study area, at the margin of the European craton, constitutes one of the most active seismic zones in Europe, yet has remained a geological and geodynamic enigma within the Alpine-Himalayan orogenic system. Intermediate depth (50-220 km) mantle earthquakes of significant magnitude occur in a geographically restricted area in the south-east Carpathians bend. The adjacent, foreland Focsani Basin appears to exhibit recent extensional deformation in what is otherwise understood to be a zone of convergence. The deep seismic reflection component of DACIA PLAN comprises a ~140-km near-vertical profile across the Vrancea Zone and Focsani Basin. Data acquisition took place in August-September 2001, as part of the integrated refraction/reflection seismic field programme "Vrancea-2001" co-ordinated at Karlsruhe University (cf. Abstract, Part 1), utilising 640 independently deployed recorders provided by UTEP and IRIS/PASSCAL ("Texans"). Station spacing was every 100-m with shots every 1-km. These data are to be integrated with industry seismic as well as planned new medium-high resolution seismic reflection profiling across key neotectonically active structures in the Focsani Basin. Particular goals of DACIA PLAN include: (1) the architecture of the Tertiary/Quaternary basins developed within and adjacent to this zone, including the foreland Focsani Basin; (2) the presence and geometry of structural detachment(s) in relation with foreland basin development, including constraints for balanced cross-sections and geodynamic modelling of basin origin and evolution; (3) the relationship between crustal

  7. Application of Reflectance Transformation Imaging Technique to Improve Automated Edge Detection in a Fossilized Oyster Reef

    Science.gov (United States)

    Djuricic, Ana; Puttonen, Eetu; Harzhauser, Mathias; Dorninger, Peter; Székely, Balázs; Mandic, Oleg; Nothegger, Clemens; Molnár, Gábor; Pfeifer, Norbert

    2016-04-01

    The world's largest fossilized oyster reef is located in Stetten, Lower Austria excavated during field campaigns of the Natural History Museum Vienna between 2005 and 2008. It is studied in paleontology to learn about change in climate from past events. In order to support this study, a laser scanning and photogrammetric campaign was organized in 2014 for 3D documentation of the large and complex site. The 3D point clouds and high resolution images from this field campaign are visualized by photogrammetric methods in form of digital surface models (DSM, 1 mm resolution) and orthophoto (0.5 mm resolution) to help paleontological interpretation of data. Due to size of the reef, automated analysis techniques are needed to interpret all digital data obtained from the field. One of the key components in successful automation is detection of oyster shell edges. We have tested Reflectance Transformation Imaging (RTI) to visualize the reef data sets for end-users through a cultural heritage viewing interface (RTIViewer). The implementation includes a Lambert shading method to visualize DSMs derived from terrestrial laser scanning using scientific software OPALS. In contrast to shaded RTI no devices consisting of a hardware system with LED lights, or a body to rotate the light source around the object are needed. The gray value for a given shaded pixel is related to the angle between light source and the normal at that position. Brighter values correspond to the slope surfaces facing the light source. Increasing of zenith angle results in internal shading all over the reef surface. In total, oyster reef surface contains 81 DSMs with 3 m x 2 m each. Their surface was illuminated by moving the virtual sun every 30 degrees (12 azimuth angles from 20-350) and every 20 degrees (4 zenith angles from 20-80). This technique provides paleontologists an interactive approach to virtually inspect the oyster reef, and to interpret the shell surface by changing the light source direction

  8. Integration of seismic-reflection and well data to assess the potential impact of stratigraphic and structural features on sustainable water supply from the Floridan aquifer system, Broward County, Florida

    Science.gov (United States)

    Cunningham, Kevin J.

    2014-01-01

    The U.S. Geological Survey and Broward County water managers commenced a 3.5-year cooperative study in July 2012 to refine the geologic and hydrogeologic framework of the Floridan aquifer system (FAS) in Broward County. A lack of advanced stratigraphic knowledge of the physical system and structural geologic anomalies (faults and fractures originating from tectonics and karst-collapse structures) within the FAS pose a risk to the sustainable management of the resource. The principal objective of the study is to better define the regional stratigraphic and structural setting of the FAS in Broward County. The objective will be achieved through the acquisition, processing, and interpretation of new seismic-reflection data along several canals in Broward County. The interpretation includes integration of the new seismic-reflection data with existing seismic-reflection profiles along Hillsboro Canal in Broward County and within northeast Miami-Dade County, as well as with data from nearby FAS wellbores. The scope of the study includes mapping the geologic, hydrogeologic, and seismic-reflection framework of the FAS, and identifying stratigraphic and structural characteristics that could either facilitate or preclude the sustainable use of the FAS as an alternate water supply or a treated effluent repository. In addition, the investigation offers an opportunity to: (1) improve existing groundwater flow models, (2) enhance the understanding of the sensitivity of the groundwater system to well-field development and upconing of saline fluids, and (3) support site selection for future FAS projects, such as Class I wells that would inject treated effluent into the deep Boulder Zone.

  9. Effects of Reflective Inquiry Instructional Technique on Students' Academic Achievement and Ability Level in Electronic Work Trade in Technical Colleges

    Science.gov (United States)

    Ogbuanya, T. C.; Owodunni, A. S.

    2015-01-01

    This study was designed to determine the effect of reflective inquiry instructional technique on achievement of students in Technical Colleges. The study adopted a pre-test, post-test, non-equivalent control group, quasi-experimental research design which involved groups of students in their intact class assigned to experimental group and control…

  10. Determination of lead in clay enameled by X-ray fluorescence technique in Total reflection and by Scanning Electron Microscopy

    International Nuclear Information System (INIS)

    Zarazua O, G.; Carapia M, L.

    2000-01-01

    This work has the objective of determining lead free in the glazed commercial stewing pans using the X-ray fluorescence technique in Total reflection (FRX) and the observation and semiquantitative determination of lead by Analytical Scanning Electron Microscopy (ASEM). (Author)

  11. Analysis of ancient-river systems by 3D seismic time-slice technique: A case study in northeast Malay Basin, offshore Terengganu, Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Sulaiman, Noorzamzarina; Hamzah, Umar; Samsudin, Abdul Rahim [Geology Programme, School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2014-09-03

    Fluvial sandstones constitute one of the major clastic petroleum reservoir types in many sedimentary basins around the world. This study is based on the analysis of high-resolution, shallow (seabed to 500 m depth) 3D seismic data which generated three-dimensional (3D) time slices that provide exceptional imaging of the geometry, dimension and temporal and spatial distribution of fluvial channels. The study area is in the northeast of Malay Basin about 280 km to the east of Terengganu offshore. The Malay Basin comprises a thick (> 8 km), rift to post-rift Oligo-Miocene to Pliocene basin-fill. The youngest (Miocene to Pliocene), post-rift succession is dominated by a thick (1–5 km), cyclic succession of coastal plain and coastal deposits, which accumulated in a humid-tropical climatic setting. This study focuses on the Pleistocene to Recent (500 m thick) succession, which comprises a range of seismic facies analysis of the two-dimensional (2D) seismic sections, mainly reflecting changes in fluvial channel style and river architecture. The succession has been divided into four seismic units (Unit S1-S4), bounded by basin-wide strata surfaces. Two types of boundaries have been identified: 1) a boundary that is defined by a regionally-extensive erosion surface at the base of a prominent incised valley (S3 and S4); 2) a sequence boundary that is defined by more weakly-incised, straight and low-sinuosity channels which is interpreted as low-stand alluvial bypass channel systems (S1 and S2). Each unit displays a predictable vertical change of the channel pattern and scale, with wide low-sinuosity channels at the base passing gradationally upwards into narrow high-sinuosity channels at the top. The wide variation in channel style and size is interpreted to be controlled mainly by the sea-level fluctuations on the widely flat Sunda land Platform.

  12. Analysis of ancient-river systems by 3D seismic time-slice technique: A case study in northeast Malay Basin, offshore Terengganu, Malaysia

    Science.gov (United States)

    Sulaiman, Noorzamzarina; Hamzah, Umar; Samsudin, Abdul Rahim

    2014-09-01

    Fluvial sandstones constitute one of the major clastic petroleum reservoir types in many sedimentary basins around the world. This study is based on the analysis of high-resolution, shallow (seabed to 500 m depth) 3D seismic data which generated three-dimensional (3D) time slices that provide exceptional imaging of the geometry, dimension and temporal and spatial distribution of fluvial channels. The study area is in the northeast of Malay Basin about 280 km to the east of Terengganu offshore. The Malay Basin comprises a thick (> 8 km), rift to post-rift Oligo-Miocene to Pliocene basin-fill. The youngest (Miocene to Pliocene), post-rift succession is dominated by a thick (1-5 km), cyclic succession of coastal plain and coastal deposits, which accumulated in a humid-tropical climatic setting. This study focuses on the Pleistocene to Recent (500 m thick) succession, which comprises a range of seismic facies analysis of the two-dimensional (2D) seismic sections, mainly reflecting changes in fluvial channel style and river architecture. The succession has been divided into four seismic units (Unit S1-S4), bounded by basin-wide strata surfaces. Two types of boundaries have been identified: 1) a boundary that is defined by a regionally-extensive erosion surface at the base of a prominent incised valley (S3 and S4); 2) a sequence boundary that is defined by more weakly-incised, straight and low-sinuosity channels which is interpreted as low-stand alluvial bypass channel systems (S1 and S2). Each unit displays a predictable vertical change of the channel pattern and scale, with wide low-sinuosity channels at the base passing gradationally upwards into narrow high-sinuosity channels at the top. The wide variation in channel style and size is interpreted to be controlled mainly by the sea-level fluctuations on the widely flat Sunda land Platform.

  13. Analysis of ancient-river systems by 3D seismic time-slice technique: A case study in northeast Malay Basin, offshore Terengganu, Malaysia

    International Nuclear Information System (INIS)

    Sulaiman, Noorzamzarina; Hamzah, Umar; Samsudin, Abdul Rahim

    2014-01-01

    Fluvial sandstones constitute one of the major clastic petroleum reservoir types in many sedimentary basins around the world. This study is based on the analysis of high-resolution, shallow (seabed to 500 m depth) 3D seismic data which generated three-dimensional (3D) time slices that provide exceptional imaging of the geometry, dimension and temporal and spatial distribution of fluvial channels. The study area is in the northeast of Malay Basin about 280 km to the east of Terengganu offshore. The Malay Basin comprises a thick (> 8 km), rift to post-rift Oligo-Miocene to Pliocene basin-fill. The youngest (Miocene to Pliocene), post-rift succession is dominated by a thick (1–5 km), cyclic succession of coastal plain and coastal deposits, which accumulated in a humid-tropical climatic setting. This study focuses on the Pleistocene to Recent (500 m thick) succession, which comprises a range of seismic facies analysis of the two-dimensional (2D) seismic sections, mainly reflecting changes in fluvial channel style and river architecture. The succession has been divided into four seismic units (Unit S1-S4), bounded by basin-wide strata surfaces. Two types of boundaries have been identified: 1) a boundary that is defined by a regionally-extensive erosion surface at the base of a prominent incised valley (S3 and S4); 2) a sequence boundary that is defined by more weakly-incised, straight and low-sinuosity channels which is interpreted as low-stand alluvial bypass channel systems (S1 and S2). Each unit displays a predictable vertical change of the channel pattern and scale, with wide low-sinuosity channels at the base passing gradationally upwards into narrow high-sinuosity channels at the top. The wide variation in channel style and size is interpreted to be controlled mainly by the sea-level fluctuations on the widely flat Sunda land Platform

  14. Effects of irregular basement structure on the geometry and emplacement of frontal thrusts and duplexes in the Quebec Appalachians: Interpretations from well and seismic reflection data

    Science.gov (United States)

    Konstantinovskaya, E.; Malo, M.; Badina, F.

    2014-12-01

    Irregular basement geometry may affect thrust propagation in foreland fold-thrust belts creating a perturbation in structural continuity of hydrocarbon fields. Here we investigate how the irregular pattern of normal faults, along with the presence of uplifts and transverse faults in the Grenvillian basement has influenced the geometry and emplacement of frontal thrusts and duplexes in the parautochthonous domain of the southern Quebec Appalachians during the middle-late Ordovician Taconian orogeny. Integration of data from surface geology, wells, and 2D and 3D seismic reflection surveys into a regional-scale structural model is used to reconstruct the 3D geometry and emplacement history of one- and two-horse duplexes in the Joly-Saint-Flavien gas storage area. The normal hinterland to foreland sequence of thrusting in this area is complicated by the differential emplacement of tectonic slices along strike of the orogenic front, starting in the SW and developing subsequently to the NE within each structural level. The shortening related to duplex emplacement decreases laterally over the distance of 20 km from - 49% in the SW (Joly area) to - 31% in the NE (Saint-Flavien area). Duplex emplacement resulted from the differential forward propagation, deflexion and vertical-axis rotation of the roof thrust (Logan's Line), which, in turn, has been induced by the presence of frontal uplift and transverse faults in the basement. The structural-lithological analysis of tectonic slices and restoration of their initial location allows us to consider the lower slice of the Joly duplex as a structural trap comparable to the fractured reservoir in lower Ordovician dolomites of the Saint-Flavien duplex.

  15. Thick deltaic sedimentation and detachment faulting delay the onset of continental rupture in the Northern Gulf of California: Analysis of seismic reflection profiles

    Science.gov (United States)

    Martin, A.; González-Escobar, M.; Fletcher, J. M.; Pacheco, M.; Oskin, M. E.; Dorsey, R. J.

    2013-12-01

    The transition from distributed continental extension to the rupture of continental lithosphere is imaged in the northern Gulf of California across the obliquely conjugate Tiburón-Upper Delfín basin segment. Structural mapping on a 5-20 km grid of seismic reflection lines of Petroleos Mexicanos (PEMEX) demonstrates that ~1000% extension is accommodated on a series of NNE-striking listric-normal faults that merge at depth into a detachment fault. The detachment juxtaposes a late-Neogene marine sequence over thinned continental crust and contains an intrabasinal divide due to footwall uplift. Two northwest striking, dextral-oblique faults bound both ends of the detachment and shear the continental crust parallel to the tectonic transport. A regional unconformity in the upper 0.5 seconds (TWTT) and crest erosion of rollover anticlines above the detachment indicates inversion and footwall uplift during the lithospheric rupture in the Upper Delfin and Lower Delfin basins. The maximum length of new crust in both Delfin basins is less than 40 km based on the lack of an acoustic basement and the absence of a lower sedimentary sequence beneath a wedge shaped upper sequence that reaches >5 km in thickness. A fundamental difference exists between the Tiburón-Delfin segment and the Guaymas segment to the south in terms of presence of low angle normal faults and amount of new oceanic lithosphere, which we attribute to thermal insulation, diffuse upper-plate extension, and slip on low angle normal faults engendered by a thick sedimentary lid.

  16. Advanced analysis techniques for X-ray reflectivities. Theory and application

    International Nuclear Information System (INIS)

    Zimmermann, Klaus Martin

    2005-01-01

    The first part of this thesis adresses the phase problem in X-ray reflectivity. The analytical properties of the reflection coefficient imply that the phase is completely determined by the Hilbert transform of the logarithm of the modulus and the zeros in the upper half complex plane (UHP). To account in addition for interfacial roughness, a new formula for the Hilbert-phase is derived.In the following, the conditions for which the reflection coefficient has zeros in the UHP is discussed and the existing sufficient condition is extended to rough multi-layer systems. Procedures for locating these zeros are developed. The second part of this thesis introduces a new iterative inversion method for X-ray reflectivity. It expands the profile in a set of eigenfunctions, which are discrete approximations of the eigenfunction of the classical reconstruction problem of a compact supported function from its partially known Fourier-transform. In this work, piecewise constant functions, polygons and second-order B-splines are used to expand the density profile. The eigenvalue problems for the calculation of the above mentioned approximations are stated and solved. The formalism for the calculation of the reflection coefficient for these profiles is developed in dynamical and single-scattering theory. In the experimental part of this work iterative inverse schemes are applied to the analysis of X-ray reflectivity. Different sample systems are investigated: For two titanium-carbon samples tiny details at the Ti/C interface such as the formation of a thin TiC layer can be observed.The density profiles obtained from the reflectivities taken from nickel-carbon samples show the formation of SiC inside the Si sub strate. Finally, the new inversion scheme is applied to a series of reflectivities from a 700 AaSiGe film on a substrate.

  17. Advanced analysis techniques for X-ray reflectivities. Theory and application

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Klaus Martin

    2005-07-01

    The first part of this thesis adresses the phase problem in X-ray reflectivity. The analytical properties of the reflection coefficient imply that the phase is completely determined by the Hilbert transform of the logarithm of the modulus and the zeros in the upper half complex plane (UHP). To account in addition for interfacial roughness, a new formula for the Hilbert-phase is derived.In the following, the conditions for which the reflection coefficient has zeros in the UHP is discussed and the existing sufficient condition is extended to rough multi-layer systems. Procedures for locating these zeros are developed. The second part of this thesis introduces a new iterative inversion method for X-ray reflectivity. It expands the profile in a set of eigenfunctions, which are discrete approximations of the eigenfunction of the classical reconstruction problem of a compact supported function from its partially known Fourier-transform. In this work, piecewise constant functions, polygons and second-order B-splines are used to expand the density profile. The eigenvalue problems for the calculation of the above mentioned approximations are stated and solved. The formalism for the calculation of the reflection coefficient for these profiles is developed in dynamical and single-scattering theory. In the experimental part of this work iterative inverse schemes are applied to the analysis of X-ray reflectivity. Different sample systems are investigated: For two titanium-carbon samples tiny details at the Ti/C interface such as the formation of a thin TiC layer can be observed.The density profiles obtained from the reflectivities taken from nickel-carbon samples show the formation of SiC inside the Si sub strate. Finally, the new inversion scheme is applied to a series of reflectivities from a 700 AaSiGe film on a substrate.

  18. Detection capability of the IMS seismic network based on ambient seismic noise measurements

    Science.gov (United States)

    Gaebler, Peter J.; Ceranna, Lars

    2016-04-01

    All nuclear explosions - on the Earth's surface, underground, underwater or in the atmosphere - are banned by the Comprehensive Nuclear-Test-Ban Treaty (CTBT). As part of this treaty, a verification regime was put into place to detect, locate and characterize nuclear explosion testings at any time, by anyone and everywhere on the Earth. The International Monitoring System (IMS) plays a key role in the verification regime of the CTBT. Out of the different monitoring techniques used in the IMS, the seismic waveform approach is the most effective technology for monitoring nuclear underground testing and to identify and characterize potential nuclear events. This study introduces a method of seismic threshold monitoring to assess an upper magnitude limit of a potential seismic event in a certain given geographical region. The method is based on ambient seismic background noise measurements at the individual IMS seismic stations as well as on global distance correction terms for body wave magnitudes, which are calculated using the seismic reflectivity method. From our investigations we conclude that a global detection threshold of around mb 4.0 can be achieved using only stations from the primary seismic network, a clear latitudinal dependence for the detection threshold can be observed between northern and southern hemisphere. Including the seismic stations being part of the auxiliary seismic IMS network results in a slight improvement of global detection capability. However, including wave arrivals from distances greater than 120 degrees, mainly PKP-wave arrivals, leads to a significant improvement in average global detection capability. In special this leads to an improvement of the detection threshold on the southern hemisphere. We further investigate the dependence of the detection capability on spatial (latitude and longitude) and temporal (time) parameters, as well as on parameters such as source type and percentage of operational IMS stations.

  19. Seismic site-response characterization of high-velocity sites using advanced geophysical techniques: application to the NAGRA-Net

    Czech Academy of Sciences Publication Activity Database

    Poggi, V.; Burjánek, Jan; Michel, C.; Fäh, D.

    2017-01-01

    Roč. 210, č. 2 (2017), s. 645-659 ISSN 0956-540X Institutional support: RVO:67985530 Keywords : joint inversion * earthquake ground motions * seismic noise * site effects Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 2.414, year: 2016

  20. Seismic reflection and refraction methods

    Digital Repository Service at National Institute of Oceanography (India)

    Chaubey, A.K.

    or shear modulus and λ is the Lame’s constant. P-waves are also known as compressional wave, longitudinal wave, push-pull wave, pressure wave, dilatational wave, rarefaction wave and irrotational wave. Transverse or S-waves - S-waves are sometimes...

  1. Geometry and controls on the development of igneous sill-related forced folds: 2D seismic reflection case study from offshore Southern Australia

    Science.gov (United States)

    Jackson, Christopher; Schofield, Nick; Magee, Craig; Golenkov, Bogdan

    2017-04-01

    Emplacement of magma in the shallow subsurface can result in the development of dome-shaped folds at the Earth's surface. These so-called 'forced folds' have been described in the field and in subsurface datasets, although the exact geometry of the folds and the nature of their relationship to underlying sills remains unclear and, in some cases, controversial. As a result, the utility of these features in tracking the subsurface movement of magma, and predicting the potential size and location of potentially hazardous volcanic eruptions, is uncertain. Here we use high-quality, 2D seismic reflection and borehole data from the Ceduna sub-basin, offshore southern Australia to describe the structure and infer the evolution of igneous sill-related forced folds in the Bight Basin Igneous Complex (BBIC). We mapped 33 igneous sills, which were emplaced 200-1500 m below the palaeo-seabed in an Upper Cretaceous, coal-bearing, predominantly coastal-plain succession. The intrusions, which are expressed as packages of high-amplitude reflections, are 32-250 m thick and 7-19 km in diameter. They are overlain by dome-shaped folds, which are up to 17 km wide and display up to 210 m of relief. The edges of these folds coincide with the margins of the underlying sills and the folds display the greatest relief where the underlying sills are thickest; the folds are therefore interpreted as forced folds that formed in response to emplacement of magma in the shallow subsurface. The folds are onlapped by Lutetian (middle Eocene) strata, indicating they formed and the intrusions were emplaced during the latest Ypresian (c. 48 Ma). We demonstrate that fold amplitude is typically less than sill thickness even for sills with very large diameter-to-depth ratios, suggesting that pure elastic bending (forced folding) of the overburden is not the only process accommodating magma emplacement, and that supra-sill compaction may be important even at relatively shallow depths. Based on the

  2. Reflective discourse techniques: From in-class discussions to out-of-classroom problem solving

    Science.gov (United States)

    Wampler, Wendi; Demaree, Dedra; Gilbert, Dennis

    2013-01-01

    Instructors often give prompts that encourage students to articulate their beliefs and conceptions, as well as encourage students to understand the thoughts of their peers. This reflective discourse is used in a calculus-based introductory physics class at Lane Community College, where the instructor explicitly has discourse goals integrated into his course structure. We investigate whether students utilize this discourse when solving problems outside of the classroom context. We interviewed groups of students after the end of spring term, 2012. The students were asked to solve open-ended problems, with analysis focused on whether students applied this reflective discourse. Students were asked a series of follow-up questions to reflect upon their experiences in the course.

  3. Application of 3D seismic techniques to evaluate ore resources in the West Wits Line goldfield and portions of the West Rand goldfield, South Africa

    CSIR Research Space (South Africa)

    Manzi, MSD

    2012-09-01

    Full Text Available goldfield, derived from the depth-converted PSTM seismic section. Geochronological data and geology after Dan- kert and Hein (2010). WC164 Manzi et al. Downloaded 09 Sep 2012 to 41.132.206.56. Redistribution subject to SEG license or copyright; see Terms... Kirchhoff time migration to 1994 Leeudoorn data im- proved imaging of the VCR, faults, and stratigraphy when com- pared to the older poststack finite difference depth migration technique originally applied to the same data (Figures 3a?3d) Although PSTM...

  4. Effectiveness of a commonly-used technique for experimentally reducing plumage UV reflectance

    NARCIS (Netherlands)

    Korsten, P.; Limbourg, T.; Lessells, C.M.; Komdeur, J.

    2007-01-01

    Ultraviolet (UV) plumage is thought to be sexually selected through intra-sexual competition, female choice and differential allocation. Experimental manipulations of plumage UV reflectance are essential to demonstrate that mate choice or intra-sexual competition are causally related to UV

  5. Effectiveness of a commonly-used technique for experimentally reducing plumage UV reflectance

    NARCIS (Netherlands)

    Korsten, Peter; Limbourg, Tobias; Lessells, Catherine M.; Komdeur, Jan

    Ultraviolet (UV) plumage is thought to be sexually selected through intra-sexual competition, female choice and differential allocation. Experimental manipulations of plumage UV reflectance are essential to demonstrate that mate choice or intra-sexual competition are causally related to UV

  6. Seismic Moment and Recurrence using Luminescence Dating Techniques: Characterizing brittle fault zone materials suitable for luminescence dating

    Science.gov (United States)

    Tsakalos, E.; Lin, A.; Bassiakos, Y.; Kazantzaki, M.; Filippaki, E.

    2017-12-01

    During a seismic-geodynamic process, frictional heating and pressure are generated on sediments fragments resulting in deformation and alteration of minerals contained in them. The luminescence signal enclosed in minerals crystal lattice can be affected and even zeroed during such an event. This has been breakthrough in geochronological studies as it could be utilized as a chronometer for the previous seismic activity of a tectonically active area. Although the employment of luminescence dating has in some cases been successfully described, a comprehensive study outlining and defining protocols for routine luminescence dating applied to neotectonic studies has not been forthcoming. This study is the experimental investigation, recording and parameterization of the effects of tectonic phenomena on minerals luminescence signal and the development of detailed protocols for the standardization of the luminescence methodology for directly dating deformed geological formations, so that the long-term temporal behaviour of seismically active faults could be reasonably understood and modeled. This will be achieved by: a) identifying and proposing brittle fault zone materials suitable for luminescence dating using petrological, mineralogical and chemical analyses and b) investigating the "zeroing" potential of the luminescence signal of minerals contained in fault zone materials by employing experimental simulations of tectonic processes in the laboratory, combined with luminescence measurements on samples collected from real fault zones. For this to be achieved, a number of samples collected from four faults of four different geographical regions will be used. This preliminary-first step of the study presents the microstructural, and mineralogical analyses for the characterization of brittle fault zone materials that contain suitable minerals for luminescence dating (e.g., quartz and feldspar). The results showed that the collected samples are seismically deformed fault

  7. Experiment for deep seismic reflections in Hidaka, Hokkaido. Comparison between Vibroseis and explosive data; Hidaka chiiki ni okeru shinbu hanno data no shutoku jikken. Vibroseis to dynamite no hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, N; Ikawa, T [Japex Jeoscience Institute, Tokyo (Japan); Ito, T; Tsumura, N; Shinohara, M; Ikawa, T. Ikawa, H.; Asano, Y; Tanaka, Y; Miyazono, N [Chiba University, Chiba (Japan); Arita, K; Moriya, T; Otsuka, K; Omura, T [Hokkaido University, Sapporo (Japan); Kimura, M [Osaka Prefectural University, Osaka (Japan); Hirata, N [The University of Tokyo, Tokyo (Japan); Okuike, S

    1997-05-27

    This is a prompt report. These days the importance of acquiring knowledge about the structure from the lower crust down to the upper mantle is often discussed with reference taken to Hyogo-ken Nanbu Earthquake. The Hidaka collision belt where the lower crust is exposed on the surface is a rare phenomenon in the world and has been the subject of seismic survey. As a part of the survey, experiments are conducted by the use of vibrations produced by Vibroseis and dynamite sources. Every one of the shot records (20-second record) from the two types of vibration sources contains a clear echo in the vicinity of 16 seconds supposedly from a level deeper than 40 kilometers, not to mention reflections from shallow levels. Although some studies have to be conducted before the reflecting geological boundary (possibly the upper mantle) of the echo near the 16-second point can be identified, yet this is probably the reflection from the deepest level ever obtained in the seismic reflection survey conducted in Japan`s land area. It is proved by this experiment that vibration from a vibrator can reach as far as that from explosion if the vibrator specifications are rightly chosen. 4 refs., 3 figs.

  8. The Application of Borehole Seismic Techniques in Mine Development at the Millennium Uranium Deposit, Northern Saskatchewan, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Wood, G.; O’Dowd, C., E-mail: garnet_wood@cameco.com [Cameco Corporation, Saskatoon, Saskatchewan (Canada); Cosma, C.; Enescu, N. [Vibrometric Canada Ltd., Toronto, Ontario (Canada)

    2014-05-15

    The Millennium uranium deposit is located within the Athabasca Basin of northern Saskatchewan, Canada. The deposit is situated in metasedimentary rocks, is controlled by multiple sub-vertical faults, and crossfaults and is overlain by over 500 m of intensely altered, porous Manitou Falls group sandstones. The rock quality directly surrounding the deposit is greatly reduced because of alteration and post-Athabasca sandstone structures, which provide conduits for the migration of basinal and meteoric fluids. This leads to significant risk for mine development and shaft sinking, because of the increased potential for water inflow into mine workings. To mitigate the risk involved with mining in such complex geology several projects were proposed as part of a pre-feasibility study. Of these, seismic methods were identified as the best tool to potentially identify alteration and structurally compromised zones. Subsequently, a comprehensive surface and borehole seismic program was completed in an attempt to delineate these engineering hazards and to provide assurance of success of the shaft sinking and mine development. This was the first time a seismic program of this scale was undertaken for geotechnical studies during mine development in the Athabasca Basin. (author)

  9. Implant Monitoring Measurements On Ultra Shallow Implants Before And After Anneal Using Photomodulated Reflection And Junction Photovoltage Measurement Techniques

    Science.gov (United States)

    Tallian, M.; Pap, A.; Mocsar, K.; Somogyi, A.; Nadudvari, Gy.; Kosztka, D.; Pavelka, T.

    2011-01-01

    Ultra shallow junctions are becoming widely used in the micro- and nanoelectronic devices, and novel measurement methods are needed to monitor the manufacturing processes. Photomodulated Reflection measurements before anneal and Junction Photovoltage-based sheet resistance measurements after anneal are non-contact, nondestructive techniques suitable for characterizing both the implantation and the annealing process. Tests verify that these methods are consistent with each other and by using them together, defects originating in the implantation and anneal steps can be separated.

  10. Application of the Total Reflection X-ray Fluorescence technique to trace elements determination in tobacco

    International Nuclear Information System (INIS)

    Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

    2008-01-01

    Many studies have identified an important number of toxic elements along with organic carcinogen molecules and radioactive isotopes in tobacco. In this work we have analyzed by Total Reflection X-Ray Fluorescence 9 brands of cigarettes being manufactured and distributed in the Mexican market. Two National Institute of Standards and Technology standards and a blank were equally treated at the same time. Results show the presence of some toxic elements such as Pb and Ni. These results are compared with available data for some foreign brands, while their implications for health are discussed. It can be confirmed that the Total Reflection X-Ray Fluorescence method provides precise (reproducible) and accuracy (trueness) data for 15 elements concentration in tobacco samples

  11. Application of the Total Reflection X-ray Fluorescence technique to trace elements determination in tobacco

    Science.gov (United States)

    Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

    2008-12-01

    Many studies have identified an important number of toxic elements along with organic carcinogen molecules and radioactive isotopes in tobacco. In this work we have analyzed by Total Reflection X-Ray Fluorescence 9 brands of cigarettes being manufactured and distributed in the Mexican market. Two National Institute of Standards and Technology standards and a blank were equally treated at the same time. Results show the presence of some toxic elements such as Pb and Ni. These results are compared with available data for some foreign brands, while their implications for health are discussed. It can be confirmed that the Total Reflection X-Ray Fluorescence method provides precise (reproducible) and accuracy (trueness) data for 15 elements concentration in tobacco samples.

  12. Determination of hydrogen content of Jatropha biodiesel oil using neutron reflection technique

    International Nuclear Information System (INIS)

    Okunade, I. O.; Jonah, S. A.; Omede, M.

    2014-01-01

    Biofuel is an environmental-friendly alternative to fossil fuel and holds immense potential for the future energy needs of the country. Non-edible jatropha biodiesel oil has been identified as one of the suitable bio-fuel options. In this work, experimental measurements were performed to determine the total hydrogen content of jatropha oil and jatropha-synthetic diesel oil mixture. The work was carried out using a neutron reflection facility at the Centre for Energy Research and Training, Ahmadu Bello University, Zaria. Jatropha oil and jatropha-synthetic diesel mixture were subjected to experimental measurements for the purpose of determining bulk hydrogen content using neutron reflection facility that had been previously calibrated using various hydrocarbon materials of known hydrogen content. The hydrogen content of the sample were subsequently determined using their measured neutron reflection coefficient values and calibration data. In general, results obtained indicate high hydrogen content range of 10.68-12.16wt% for jatropha oil and the various jatropha-synthetic diesel mixtures. The implication of this is that jatropha oil or jatrophal-synthetic diesel mixture can be used as alternative fuel to mitigate high carbon monoxide emission.

  13. Linearized inversion frameworks toward high-resolution seismic imaging

    KAUST Repository

    Aldawood, Ali

    2016-01-01

    installed along the earth surface or down boreholes. Seismic imaging is a powerful tool to map these reflected and scattered energy back to their subsurface scattering or reflection points. Seismic imaging is conventionally based on the single

  14. Thermal diffusivity of a metallic thin layer using the time-domain thermo reflectance technique

    International Nuclear Information System (INIS)

    Battaglia, J-L; Kusiak, A; Rossignol, C; Chigarev, N

    2007-01-01

    The time domain thermo reflectance (TDTR) is widely used in the field of acoustic and thermal characterization of thin layers at the nano and micro scale. In this paper, we propose to derive a simple analytical expression of the thermal diffusivity of the layer. This relation is based on the analytical solution of one-dimensional heat transfer in the medium using integral transforms. For metals, the two-temperature model shows that the capacitance effect at the short times is essentially governed by the electronic contribution

  15. Coherent Waves in Seismic Researches

    Science.gov (United States)

    Emanov, A.; Seleznev, V. S.

    2013-05-01

    Development of digital processing algorithms of seismic wave fields for the purpose of useful event picking to study environment and other objects is the basis for the establishment of new seismic techniques. In the submitted paper a fundamental property of seismic wave field coherence is used. The authors extended conception of coherence types of observed wave fields and devised a technique of coherent component selection from observed wave field. Time coherence and space coherence are widely known. In this paper conception "parameter coherence" has been added. The parameter by which wave field is coherent can be the most manifold. The reason is that the wave field is a multivariate process described by a set of parameters. Coherence in the first place means independence of linear connection in wave field of parameter. In seismic wave fields, recorded in confined space, in building-blocks and stratified mediums time coherent standing waves are formed. In prospecting seismology at observation systems with multiple overlapping head waves are coherent by parallel correlation course or, in other words, by one measurement on generalized plane of observation system. For detail prospecting seismology at observation systems with multiple overlapping on basis of coherence property by one measurement of area algorithms have been developed, permitting seismic records to be converted to head wave time sections which have neither reflected nor other types of waves. Conversion in time section is executed on any specified observation base. Energy storage of head waves relative to noise on basis of multiplicity of observation system is realized within area of head wave recording. Conversion on base below the area of wave tracking is performed with lack of signal/noise ratio relative to maximum of this ratio, fit to observation system. Construction of head wave time section and dynamic plots a basis of automatic processing have been developed, similar to CDP procedure in method of

  16. Multi-technique application of a double reflection electron emission microscope

    International Nuclear Information System (INIS)

    Jian-liang, J.; Bao-gui, S.; Guo-jun, Z

    2002-01-01

    Full text: In this paper the results acquired with the most recently developed double reflection electron emission microscope applied in different imaging modes are presented. The novel illumination system is based on a (100)-oriented single crystalline W wire electron microreflector and an electron gun placed in the back focal plane of the immersion objective. After being elastically reflected from the W tip surface, the primary electrons of energy ranging from 1 to 6 keV are decelerated to the desired impact energy in the range 0 to 200 eV for mirror electron microscopy (MEM), low energy electron emission microscopy (LEEM) and low energy electron diffraction (LEED) modes or to 5 keV for the secondary electron imaging mode. Photoelectron emission microscopy (PEEM), MEM, LEEM, secondary images of Pd/Si(111) and a set of selected area LEED patterns of the W(100) surface taken at energies ranging from 5 to 40 eV are presented for the first time. Copyright (2002) Australian Society for Electron Microscopy Inc

  17. A comparison of transmission, reflection and photoacoustic FTIR techniques in the analysis of recycled and irradiated polyamide-6

    International Nuclear Information System (INIS)

    Evora, Maria C.; Goncalez, Odair L.

    2002-01-01

    A comparative study involving transmission, reflection and photoacoustic FTIR techniques is presented with analysis of polyamide-6. The potential and limitations of these methods are investigated by analyzing structural variations that take place at the surface in the bulk in recycled and irradiated polyamide-6 with a 1.5 MeV electron beam with a 500kGY dose, in the presence of O 2 . FTIR techniques appear to be sensitive in detecting small structural changes that occur in recycled and irradiated polyamide-6. The analysis of samples indicated the formation of OH, HOC=O-, - C=O groups. Also, small structural changes were detected which are characterisitic of NH and CN-C=O groups. Transmission techniques show better the structural changes in the bulk, and microscopy-FTIR appears to be more sensitive in detecting what occurs at the sample surface. (author)

  18. Problematising Ethnography and Case Study: Reflections on Using Ethnographic Techniques and Researcher Positioning

    Science.gov (United States)

    Parker-Jenkins, Marie

    2018-01-01

    This paper was prompted by the question, what do we mean by conducting "ethnography"? Is it in fact "case study" drawing on ethnographic techniques? My contention is that in many cases, researchers are not actually conducting ethnography as understood within a traditional sense but rather are engaging in case study, drawing on…

  19. Cavity ring-down technique for measurement of reflectivity of high

    Indian Academy of Sciences (India)

    grade mirrors ( > 99.5 %) based on cavity ring-down (CRD) technique has been success-fully demonstrated in our laboratory using a pulsed Nd:YAG laser. A fast photomultiplier tube with an oscilloscope was used to detect and analyse the CRD ...

  20. A comparison of hyperspectral reflectance and fluorescence imaging techniques for detection of contaminants on leafy greens

    Science.gov (United States)

    Ensuring the supply of safe, contaminant free fresh fruit and vegetables is of importance to consumers, suppliers and governments worldwide. In this study, three hyperspectral imaging (HSI) configurations coupled with two multivariate image analysis techniques are compared for detection of fecal con...

  1. Neoarchaean tectonic history of the Witwatersrand Basin and Ventersdorp Supergroup: New constraints from high-resolution 3D seismic reflection data

    CSIR Research Space (South Africa)

    Manzi, MSD

    2013-04-01

    Full Text Available Rand Group (ca. 2985–2902 Ma) is unconformably overlain by the Central Rand Group (ca. 2902–2849 Ma), with tilting of the West Rand Group syn- to post-erosion at ca. 2.9 Ga. The seismic sections also confirm that an unconformable relationship exists...

  2. Reflectance spectra characteristics from an SPR grating fabricated by nano-imprint lithography technique for biochemical nanosensor applications

    Science.gov (United States)

    Setiya Pradana, Jalu; Hidayat, Rahmat

    2018-04-01

    In this paper, we report our research work on developing a Surface Plasmon Resonance (SPR) element with sub-micron (hundreds of nanometers) periodicity grating structure. This grating structure was fabricated by using a simple nano-imprint lithography technique from an organically siloxane polymers, which was then covered by nanometer thin gold layer. The formed grating structure was a very well defined square-shaped periodic structure. The measured reflectance spectra indicate the SPR wave excitation on this grating structure. For comparison, the simulations of reflectance spectra have been also carried out by using Rigorous Coupled-Wave Analysis (RCWA) method. The experimental results are in very good agreement with the simulation results.

  3. Subsurface imaging in a sector of Cerro Prieto transform fault near to pull-apart basin, Mexicali Valley, Baja California, Mexico, based on crooked lines 2D seismic reflection.

    Science.gov (United States)

    Mares-Agüero, M. A.; González-Escobar, M.; Arregui, S.

    2016-12-01

    In the transition zone between San Andres continental transformation system and the coupled transform faults system and rifting of Gulf of California is located the Cerro Prieto pull-apart basin delimitated by Imperial fault (northeast) and Cerro Prieto fault (CPF) (southwest), this last, is the limit west of Cerro Prieto geothermic field (CPGF). Crooked lines 2D seismic reflection, covering a portion near the intersection of CPF and CPGF are processed and interpreted. The seismic data were obtained in the early 80's by Petróleos Mexicanos (PEMEX). By decades, technical and investigation works in Cerro Prieto geothermic field and its vicinity had mapped faults at several depths but do not stablish a clear limit where this faults and CPF interact due the complex hydrothermal effects imaging the subsurface. The profiles showing the presence of a zone of uplift effect due to CPF. Considering the proximity of the profiles to CPF, it is surprising almost total absence of faults. A strong reflector around 2 km of depth, it is present in all profiles. This seismic reflector is considered a layer of shale, result of the correlation with a well located in the same region.

  4. The utility of petroleum seismic exploration data in delineating structural features within salt anticlines

    Science.gov (United States)

    Stockton, S.L.; Balch, Alfred H.

    1978-01-01

    mapping the thin beds because of the lack of sufficient resolution to provide direct evidence of the presence of the thin beds. However, indirect evidence, present in these data as discontinuous seismic events, suggests that two geophysical techniques designed for this specific problem would allow direct detection of the interbeds in salt. These techniques are vertical seismic profiling and shallow, short-offset, high-frequency, seismic-reflection recording.

  5. Seismic data acquisition systems

    International Nuclear Information System (INIS)

    Kolvankar, V.G.; Nadre, V.N.; Rao, D.S.

    1989-01-01

    Details of seismic data acquisition systems developed at the Bhabha Atomic Research Centre, Bombay are reported. The seismic signals acquired belong to different signal bandwidths in the band from 0.02 Hz to 250 Hz. All these acquisition systems are built around a unique technique of recording multichannel data on to a single track of an audio tape and in digital form. Techniques of how these signals in different bands of frequencies were acquired and recorded are described. Method of detecting seismic signals and its performance is also discussed. Seismic signals acquired in different set-ups are illustrated. Time indexing systems for different set-ups and multichannel waveform display systems which form essential part of the data acquisition systems are also discussed. (author). 13 refs., 6 figs., 1 tab

  6. Structure and Stratigraphy of the Rift Basins in the Northern Gulf of California: Results from Analysis of Seismic Reflection and Borehole Data.

    Science.gov (United States)

    Martín, A.; González, M.; Helenes, J.; García, J.; Aragón, M.; Carreño, A.

    2008-12-01

    The northern Gulf of California contains two parallel, north-south trending rift basin systems separated by a basement-high. The interpretation of several exploration wells, and ~4500 km of seismic reflection data from PEMEX (Mexican national oil company) indicate that the tectonically active basins to the west (Wagner- Consag and Upper Delfin basins) may have initiated synchronously with the now abandoned Tiburón- Tepoca-Altar basins to the east in the Sonora margin. In both basin systems the lower sequence (A) is marine mudstone-siltstone, has parallel reflectors and a largely uniform thickness that reaches up to1.5 km, and gradually pinches out toward the lateral margins. This suggests that the unit was deposited prior to their segmentation by transtensional faulting. Marine microfossils from borehole samples from sequence A in the Tiburón and Consag basins indicates middle Miocene (>11.2 Ma) proto-Gulf conditions. Sequence B conformably overlies sequence A, and is characterized by up to 2 km growth strata with a fanning geometry that show a clear genetic relationship to the major transtensional faults that control the segmentation of the two basin systems. Sequence C in the Tiburón and Tepoca basins is comparatively thin (<800 m) and includes several unconformities, but is much less affected by faulting. In contrast, sequence C in the active Wagner, Consag and Upper Delfin basin is a much thicker (up to 2 km) growth sequence with abundant volcanic intrusions. Marked variations in sequence C in the different basin systems clearly demonstrate a major westward shift of deformation and subsidence at this time. The modern depocenter in Wagner-Consag basins is controlled by the Consag and Wagner faults, which trend parallel to the north ~20 km apart, and show opposite normal offset. These two faults merge at an oblique angle (70°-50°, respectively) into the Cerro Prieto transform fault to the north and likely accommodate an important amount of dextral shear. To

  7. Green's function representations for seismic interferometry

    NARCIS (Netherlands)

    Wapenaar, C.P.A.; Fokkema, J.T.

    2006-01-01

    The term seismic interferometry refers to the principle of generating new seismic responses by crosscorrelating seismic observations at different receiver locations. The first version of this principle was derived by Claerbout (1968), who showed that the reflection response of a horizontally layered

  8. Bayesian seismic AVO inversion

    Energy Technology Data Exchange (ETDEWEB)

    Buland, Arild

    2002-07-01

    A new linearized AVO inversion technique is developed in a Bayesian framework. The objective is to obtain posterior distributions for P-wave velocity, S-wave velocity and density. Distributions for other elastic parameters can also be assessed, for example acoustic impedance, shear impedance and P-wave to S-wave velocity ratio. The inversion algorithm is based on the convolutional model and a linearized weak contrast approximation of the Zoeppritz equation. The solution is represented by a Gaussian posterior distribution with explicit expressions for the posterior expectation and covariance, hence exact prediction intervals for the inverted parameters can be computed under the specified model. The explicit analytical form of the posterior distribution provides a computationally fast inversion method. Tests on synthetic data show that all inverted parameters were almost perfectly retrieved when the noise approached zero. With realistic noise levels, acoustic impedance was the best determined parameter, while the inversion provided practically no information about the density. The inversion algorithm has also been tested on a real 3-D dataset from the Sleipner Field. The results show good agreement with well logs but the uncertainty is high. The stochastic model includes uncertainties of both the elastic parameters, the wavelet and the seismic and well log data. The posterior distribution is explored by Markov chain Monte Carlo simulation using the Gibbs sampler algorithm. The inversion algorithm has been tested on a seismic line from the Heidrun Field with two wells located on the line. The uncertainty of the estimated wavelet is low. In the Heidrun examples the effect of including uncertainty of the wavelet and the noise level was marginal with respect to the AVO inversion results. We have developed a 3-D linearized AVO inversion method with spatially coupled model parameters where the objective is to obtain posterior distributions for P-wave velocity, S

  9. Sample preparation for total reflection X-ray fluorescence analysis using resist pattern technique

    Science.gov (United States)

    Tsuji, K.; Yomogita, N.; Konyuba, Y.

    2018-06-01

    A circular resist pattern layer with a diameter of 9 mm was prepared on a glass substrate (26 mm × 76 mm; 1.5 mm thick) for total reflection X-ray fluorescence (TXRF) analysis. The parallel cross pattern was designed with a wall thickness of 10 μm, an interval of 20 μm, and a height of 1.4 or 0.8 μm. This additional resist layer did not significantly increase background intensity on the XRF peaks in TXRF spectra. Dotted residue was obtained from a standard solution (10 μL) containing Ti, Cr, Ni, Pb, and Ga, each at a final concentration of 10 ppm, on a normal glass substrate with a silicone coating layer. The height of the residue was more than 100 μm, where self-absorption in the large residue affected TXRF quantification (intensity relative standard deviation (RSD): 12-20%). In contrast, from a droplet composed of a small volume of solution dropped and cast on the resist pattern structure, the obtained residue was not completely film but a film-like residue with a thickness less than 1 μm, where self-absorption was not a serious problem. In the end, this sample preparation was demonstrated to improve TXRF quantification (intensity RSD: 2-4%).

  10. Portable (handheld) clinical device for quantitative spectroscopy of skin, utilizing spatial frequency domain reflectance techniques

    Science.gov (United States)

    Saager, Rolf B.; Dang, An N.; Huang, Samantha S.; Kelly, Kristen M.; Durkin, Anthony J.

    2017-09-01

    Spatial Frequency Domain Spectroscopy (SFDS) is a technique for quantifying in-vivo tissue optical properties. SFDS employs structured light patterns that are projected onto tissues using a spatial light modulator, such as a digital micromirror device. In combination with appropriate models of light propagation, this technique can be used to quantify tissue optical properties (absorption, μa, and scattering, μs', coefficients) and chromophore concentrations. Here we present a handheld implementation of an SFDS device that employs line (one dimensional) imaging. This instrument can measure 1088 spatial locations that span a 3 cm line as opposed to our original benchtop SFDS system that only collects a single 1 mm diameter spot. This imager, however, retains the spectral resolution (˜1 nm) and range (450-1000 nm) of our original benchtop SFDS device. In the context of homogeneous turbid media, we demonstrate that this new system matches the spectral response of our original system to within 1% across a typical range of spatial frequencies (0-0.35 mm-1). With the new form factor, the device has tremendously improved mobility and portability, allowing for greater ease of use in a clinical setting. A smaller size also enables access to different tissue locations, which increases the flexibility of the device. The design of this portable system not only enables SFDS to be used in clinical settings but also enables visualization of properties of layered tissues such as skin.

  11. Continuous distribution of elastic parameters of the shallow quaternary layers along the 3C seismic profile of east Bucharest

    International Nuclear Information System (INIS)

    Bala, A.; Raileanu, V.; Cristea, P.; Nitica, C.

    2008-01-01

    Processing techniques applied to seismic data acquired by reflection methods. Seismic methods are efficient research methods for civil engineering and environmental geology, which invite to develop specific methodologies. Therefore, programs for processing data collected with refraction seismic techniques (based on head and transmitted waves) and by transmission tomography for velocity were developed. The visual programming medium Borland Delphi was utilized to create the program MEDCONT, whose abilities, by menus and dialog windows, are both commanded and controlled. The accuracy and the adaptability of the program to field cases are validated by data resulted from forward models and also collected by applications on field objectives. (authors)

  12. Seismic monitoring of hydraulic fracturing: techniques for determining fluid flow paths and state of stress away from a wellbore

    Energy Technology Data Exchange (ETDEWEB)

    Fehler, M.; House, L.; Kaieda, H.

    1986-01-01

    Hydraulic fracturing has gained in popularity in recent years as a way to determine the orientations and magnitudes of tectonic stresses. By augmenting conventional hydraulic fracturing measurements with detection and mapping of the microearthquakes induced by fracturing, we can supplement and idependently confirm information obtained from conventional analysis. Important information obtained from seismic monitoring includes: the state of stress of the rock, orientation and spacing of the major joint sets, and measurements of rock elastic parameters at locations distant from the wellbore. While conventional well logging operations can provide information about several of these parameters, the zone of interrogation is usually limited to the immediate proximity of the borehole. The seismic waveforms of the microearthquakes contain a wealth of information about the rock in regions that are otherwise inaccessible for study. By reliably locating the hypocenters of many microearthquakes, we have inferred the joint patterns in the rock. We observed that microearthquake locations do not define a simple, thin, planar distribution, that the fault plane solutions are consistent with shear slippage, and that spectral analysis indicates that the source dimensions and slip along the faults are small. Hence we believe that the microearthquakes result from slip along preexisting joints, and not from tensile extension at the tip of the fracture. Orientations of the principal stresses can be estimated by using fault plane solutions of the larger microearthquakes. By using a joint earthquake location scheme, and/or calibrations with downhole detonators, rock velocities and heterogeneities thereof can be investigated in rock volumes that are far enough from the borehole to be representative of intrincis rock properties.

  13. Very Fast Estimation of Epicentral Distance and Magnitude from a Single Three Component Seismic Station Using Machine Learning Techniques

    Science.gov (United States)

    Ochoa Gutierrez, L. H.; Niño Vasquez, L. F.; Vargas-Jimenez, C. A.

    2012-12-01

    To minimize adverse effects originated by high magnitude earthquakes, early warning has become a powerful tool to anticipate a seismic wave arrival to an specific location and lets to bring people and government agencies opportune information to initiate a fast response. To do this, a very fast and accurate characterization of the event must be done but this process is often made using seismograms recorded in at least 4 stations where processing time is usually greater than the wave travel time to the interest area, mainly in coarse networks. A faster process can be done if only one three component seismic station is used that is the closest unsaturated station respect to the epicenter. Here we present a Support Vector Regression algorithm which calculates Magnitude and Epicentral Distance using only 5 seconds of signal since P wave onset. This algorithm was trained with 36 records of historical earthquakes where the input were regression parameters of an exponential function estimated by least squares, corresponding to the waveform envelope and the maximum value of the observed waveform for each component in one single station. A 10 fold Cross Validation was applied for a Normalized Polynomial Kernel obtaining the mean absolute error for different exponents and complexity parameters. Magnitude could be estimated with 0.16 of mean absolute error and the distance with an error of 7.5 km for distances within 60 to 120 km. This kind of algorithm is easy to implement in hardware and can be used directly in the field station to make possible the broadcast of estimations of this values to generate fast decisions at seismological control centers, increasing the possibility to have an effective reactiontribute and Descriptors calculator for SVR model training and test

  14. Fast Estimation of Epicentral Distance and Magnitude from a Single Three Component Seismic Station Using Machine Learning Techniques

    Science.gov (United States)

    Ochoa Gutierrez, L. H.; Niño, L. F.; Vargas-Jimenez, C. A.

    2013-05-01

    To minimize adverse effects originated by high magnitude earthquakes, early warning has become a powerful tool to anticipate a seismic wave arrival to an specific location, bringing opportune information to people and government agencies to initiate a fast response. To do this, a very fast and accurate characterization of the event must be done but this process is often made using seismograms recorded in at least four stations where processing time is usually greater than the wave arrival time to the interest area, mainly in seismological coarse networks. A faster process can be done if only one three component seismic station, the closest unsaturated station with respect to the epicenter, is used. Here, we present a Support Vector Regression algorithm which calculates Magnitude and Epicentral Distance using only five seconds of signal since P wave onset. This algorithm was trained with 36 records of historical earthquakes, where the input included regression parameters of an exponential function estimated by least squares, of the waveform envelope and the maximum value of the observed waveform for each component in a single station. A ten-fold Cross Validation was applied for a Normalized Polynomial Kernel obtaining the mean absolute error for different exponents and complexity parameters. The Magnitude could be estimated with 0.16 units of mean absolute error and the distance with an error of 7.5 km for distances within 60 to 120 km. This kind of algorithm is easy to implement in hardware and can be used directly in the field seismological sensor to make the broadcast of estimations of these values possible to generate fast decisions at seismological control centers, increasing the possibility of having an effective reaction.

  15. Elements of seismic imaging and velocity analysis – Forward modeling and diffraction analysis of conventional seismic data from the North Sea

    DEFF Research Database (Denmark)

    Montazeri, Mahboubeh

    2018-01-01

    comprises important oil and gas reservoirs. By application of well-established conventional velocity analysis methods and high-quality diffraction imaging techniques, this study aims to increase the resolution and the image quality of the seismic data. In order to analyze seismic wave propagation......-outs and salt delineations, which can be extracted from the diffractions. The potential of diffraction imaging techniques was studied for 2D seismic stacked data from the North Sea. In this approach, the applied plane-wave destruction method was successful in order to suppress the reflections from the stacked....... This improved seismic imaging is demonstrated for a salt structure as well as for Overpressured Shale structures and the Top Chalk of the North Sea....

  16. Evaluation and study of advanced optical contamination, deposition, measurement, and removal techniques. [including computer programs and ultraviolet reflection analysis

    Science.gov (United States)

    Linford, R. M. F.; Allen, T. H.; Dillow, C. F.

    1975-01-01

    A program is described to design, fabricate and install an experimental work chamber assembly (WCA) to provide a wide range of experimental capability. The WCA incorporates several techniques for studying the kinetics of contaminant films and their effect on optical surfaces. It incorporates the capability for depositing both optical and contaminant films on temperature-controlled samples, and for in-situ measurements of the vacuum ultraviolet reflectance. Ellipsometer optics are mounted on the chamber for film thickness determinations, and other features include access ports for radiation sources and instrumentation. Several supporting studies were conducted to define specific chamber requirements, to determine the sensitivity of the measurement techniques to be incorporated in the chamber, and to establish procedures for handling samples prior to their installation in the chamber. A bibliography and literature survey of contamination-related articles is included.

  17. SEISMIC DESIGN CRITERIA FOR NUCLEAR POWER REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, R. A.

    1963-10-15

    The nature of nuclear power reactors demands an exceptionally high degree of seismic integrity. Considerations involved in defining earthquake resistance requirements are discussed. Examples of seismic design criteria and applications of the spectrum technique are described. (auth)

  18. Analysis of deep seismic reflection and other data from the southern Washington Cascades. Final report, September 15, 1992--December 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, W.D.; Johnson, S.Y.; Nuccio, V.F.

    1993-12-01

    This report describes results of a synthesis of geological, geological, geophysical and geochemical data from a largely volcanic rock covered region in southwestern Washington that has been identified as a underlain by thick marine sedimentary rocks. The work was funded by the Deep Source Gas projects at the Morgantown Energy Technology Center (METC). The subproject which resulted in this report is centered in the Branch of Geophysics, US Geological Survey (USGS) has involved one task focused on the application of geophysical methods to the study of phenomena associated with fossil and active subduction zones and non-subduction suture zones that may have deeply emplaced sedimentary rocks. This report represents a summary synthesis of several geophysical and geological data sets. The Southern Washington Cascades Conductor (SWCC) has been examined using several types of data in addition to MT, seismic, magnetic, and gravity Specific geological mapping tasks have been completed trough funding by the Department of Energy and the USGS in the western part of the proposed basin near Morton, WA. Other regional geological studies using wells and outcrops done as part of the USGS Evolution of Sedimentary Basins programs have added information that constraint the possible nature of the SWCC rocks and their tectonic setting. Recently, evaluation of patterns of seismicity in the SWCC region has demonstrated the likelihood of several parallel and step-over strike-slip faults that may have produced the proposed basin or altered its geometry. In addition, the seismicity patterns trace the axis of key anticlinal structures and thrusts.

  19. [Reflections on maternal techniques and the rearing of infants and young children in the Ivory Coast].

    Science.gov (United States)

    Dubois Le Bronnec, C; Ferrari, P

    1991-01-01

    The core hypothesis of the authors is that certain particularities of the traditional bringing up of infants and young children in Côte-d'Ivoire modify its affective experiencing and therefore its libidinal organization. Ivorian breast feeding is extremely permissive, subjected to the sole wish of the child, traditionally until the age of 2. It maintains a belated mother-infant fusion in the context of intense oral satisfaction. The end of this idyllic fusion state generally is brought about brutally. When it is contemporary to the ending of carrying the child on the back, this milk weaning constitutes a true traumatic experience. The authors suggest that it functions as an "organizor" in the sense of Spitz: interdiction is concerned with access to the maternal body. The child's renouncing of possession of the mother's body thus leads him through replacement to adhere to the socialized and socializing body of the group (age group, siblings group). The main anxiety would be of abandonment as we constantly see in psychiatric clinical experience. Carrying on the back is not only an easy means of transportation of the infants. The fabric pocket which berths the infant since it is born is a privileged place of comfort, of exchange, of maturing and the authors suggest that it functions as a structuring of the body-ego of the infant. They also suggest that so gratifying a technique of back-carrying could lead to a shifting of the erogeneous zone to the body, thus making it apt to express all the richesses of the affective life. Language education is traditionally not the task of the parents but of the grand-parents and of the child community. The latter contributes to the building of a social-ego and of an identity which is defined along ethnical criteria. The enema technique is equally of interest at it is administered since birth and thereon almost daily, thus focusing the infants' interest on an erogeneous zone which in other cultures is less intensely and less early

  20. Seismic evaluation of the Mors Dome

    International Nuclear Information System (INIS)

    Kreitz, E.

    1982-01-01

    The ''Seismic Case History'' of the Mors saltdome was already published in detail by ELSAM/ELKRAFT so only a few important points need to be mentioned here: (a) Processing and interpretation of the seismic material. (b) Stratigraphic classification of the most important seismic reflection horizons. (c) Construction of the depth sections and description of the saltdome model. (d) Investigations of the problematic salt overhang using interactive seismic modelling. (EG)

  1. Hyperspectral Reflectance Imaging Technique for Visualization of Moisture Distribution in Cooked Chicken Breast

    Directory of Open Access Journals (Sweden)

    Byoung-Kwan Cho

    2013-09-01

    Full Text Available Spectroscopy has proven to be an efficient tool for measuring the properties of meat. In this article, hyperspectral imaging (HSI techniques are used to determine the moisture content in cooked chicken breast over the VIS/NIR (400–1,000 nm spectral range. Moisture measurements were performed using an oven drying method. A partial least squares regression (PLSR model was developed to extract a relationship between the HSI spectra and the moisture content. In the full wavelength range, the PLSR model possessed a maximum  of 0.90 and an SEP of 0.74%. For the NIR range, the PLSR model yielded an  of 0.94 and an SEP of 0.71%. The majority of the absorption peaks occurred around 760 and 970 nm, representing the water content in the samples. Finally, PLSR images were constructed to visualize the dehydration and water distribution within different sample regions. The high correlation coefficient and low prediction error from the PLSR analysis validates that HSI is an effective tool for visualizing the chemical properties of meat.

  2. Perineal colostomy: an alternative to avoid permanent abdominal colostomy: operative technique, results and reflection.

    Science.gov (United States)

    da Silva, Alcino Lázaro; Hayck, Johnny; Deoti, Beatriz

    2014-01-01

    The most common injury to indicate definitive stoma is rectal cancer. Despite advances in surgical treatment, the abdominoperineal resection is still the most effective operation in radical treatment of malignancies of the distal rectum invading the sphincter and anal canal. Even with all the effort that surgeons have to preserve anal sphincters, abdominoperineal amputation is still indicated, and a definitive abdominal colostomy is necessary. This surgery requires patients to live with a definitive abdominal colostomy, which is a condition that modify body image, is not without morbidity and has great impact on the quality of life. To evaluate the technique of abdominoperineal amputation with perineal colostomy with irrigation as an alternative to permanent abdominal colostomy. Retrospective analysis of medical records of 55 patients underwent abdominoperineal resection of the rectum with perineal colostomy in the period 1989-2010. The mean age was 58 years, 40 % men and 60 % women. In 94.5% of patients the indication for surgery was for cancer of the rectum. In some patients were made three valves, other two valves and in the remaining no valve at all. Complications were: mucosal prolapse, necrosis of the lowered segment and stenosis. The abdominoperineal amputation with perineal colostomy is a good therapeutic option in the armamentarium of the surgical treatment of rectal cancer.

  3. 3D Reservoir Modeling of Semutang Gas Field: A lonely Gas field in Chittagong-Tripura Fold Belt, with Integrated Well Log, 2D Seismic Reflectivity and Attributes.

    Science.gov (United States)

    Salehin, Z.; Woobaidullah, A. S. M.; Snigdha, S. S.

    2015-12-01

    Bengal Basin with its prolific gas rich province provides needed energy to Bangladesh. Present energy situation demands more Hydrocarbon explorations. Only 'Semutang' is discovered in the high amplitude structures, where rest of are in the gentle to moderate structures of western part of Chittagong-Tripura Fold Belt. But it has some major thrust faults which have strongly breached the reservoir zone. The major objectives of this research are interpretation of gas horizons and faults, then to perform velocity model, structural and property modeling to obtain reservoir properties. It is needed to properly identify the faults and reservoir heterogeneities. 3D modeling is widely used to reveal the subsurface structure in faulted zone where planning and development drilling is major challenge. Thirteen 2D seismic and six well logs have been used to identify six gas bearing horizons and a network of faults and to map the structure at reservoir level. Variance attributes were used to identify faults. Velocity model is performed for domain conversion. Synthetics were prepared from two wells where sonic and density logs are available. Well to seismic tie at reservoir zone shows good match with Direct Hydrocarbon Indicator on seismic section. Vsh, porosity, water saturation and permeability have been calculated and various cross plots among porosity logs have been shown. Structural modeling is used to make zone and layering accordance with minimum sand thickness. Fault model shows the possible fault network, those liable for several dry wells. Facies model have been constrained with Sequential Indicator Simulation method to show the facies distribution along the depth surfaces. Petrophysical models have been prepared with Sequential Gaussian Simulation to estimate petrophysical parameters away from the existing wells to other parts of the field and to observe heterogeneities in reservoir. Average porosity map for each gas zone were constructed. The outcomes of the research

  4. SCARDEC: a new technique for the rapid determination of seismic moment magnitude, focal mechanism and source time functions for large earthquakes using body-wave deconvolution

    Science.gov (United States)

    Vallée, M.; Charléty, J.; Ferreira, A. M. G.; Delouis, B.; Vergoz, J.

    2011-01-01

    Accurate and fast magnitude determination for large, shallow earthquakes is of key importance for post-seismic response and tsumami alert purposes. When no local real-time data are available, which is today the case for most subduction earthquakes, the first information comes from teleseismic body waves. Standard body-wave methods give accurate magnitudes for earthquakes up to Mw= 7-7.5. For larger earthquakes, the analysis is more complex, because of the non-validity of the point-source approximation and of the interaction between direct and surface-reflected phases. The latter effect acts as a strong high-pass filter, which complicates the magnitude determination. We here propose an automated deconvolutive approach, which does not impose any simplifying assumptions about the rupture process, thus being well adapted to large earthquakes. We first determine the source duration based on the length of the high frequency (1-3 Hz) signal content. The deconvolution of synthetic double-couple point source signals—depending on the four earthquake parameters strike, dip, rake and depth—from the windowed real data body-wave signals (including P, PcP, PP, SH and ScS waves) gives the apparent source time function (STF). We search the optimal combination of these four parameters that respects the physical features of any STF: causality, positivity and stability of the seismic moment at all stations. Once this combination is retrieved, the integration of the STFs gives directly the moment magnitude. We apply this new approach, referred as the SCARDEC method, to most of the major subduction earthquakes in the period 1990-2010. Magnitude differences between the Global Centroid Moment Tensor (CMT) and the SCARDEC method may reach 0.2, but values are found consistent if we take into account that the Global CMT solutions for large, shallow earthquakes suffer from a known trade-off between dip and seismic moment. We show by modelling long-period surface waves of these events that

  5. Reflection electron energy loss spectroscopy as efficient technique for the determination of optical properties of polystyrene intermixed with gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Deris, Jamileh [Department of Physics, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Hajati, Shaaker, E-mail: Hajati@mail.yu.ac.ir [Department of Physics, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Department of Semiconductors, Materials and Energy Research Center, Karaj 3177983634 (Iran, Islamic Republic of)

    2017-01-15

    Highlights: • Reflection Electron Energy Loss Spectroscopy of nano-metalized polymer. • Determination of real part of the dielectric function of nanostructured sample. • Determination of imaginary part of the dielectric function of nanostructured sample. • Determination of refractive index and coefficient of extinction of the sample. • Determination of reflection and absorption coefficients of nano-metalized Polymer. - Abstract: The electronic properties (electron inelastic cross section, energy loss function) of a nano-metalized polystyrene obtained by reflection electron energy loss spectroscopy (REELS) in a previous study [J. Deris, S. Hajati, S. Tougaard, V. Zaporojtchenko, Appl. Surf. Sci. 377 (2016) 44–47], which relies on the Yubero-Tougaard method, were used in the complementary application of Kramers-Kronig transformation to determine its optical properties such as the real part (ε{sub 1}) and imaginary part (ε{sub 2}) of the dielectric function (ε), refractive index (n), coefficients of extinction (k), reflection (R) and absorption (μ). The degree of intermixing of polystyrene thin film and gold nanoparticles of sizes 5.5 nm was controlled by annealing the sample to achieve a morphology in which the nanoparticles were homogeneously distributed within polystyrene. It is worth noting that no data are available on the optical properties of metalized polymers such as gold nanoparticles intermixed with polystyrene. Therefore, this work is of high importance in terms of both the sample studied here and the method applied. The advantage of the method applied here is that no information on the lateral distribution of the nanocomposite sample is required. This means that the REELS technique has been presented here to suitably, efficiently and easily obtain the optical properties of such nano-metalized polymer in which the metal nanoparticles have been vertically well distributed (homogeneous in depth). Therefore, for vertically homogeneous and

  6. The Global Detection Capability of the IMS Seismic Network in 2013 Inferred from Ambient Seismic Noise Measurements

    Science.gov (United States)

    Gaebler, P. J.; Ceranna, L.

    2016-12-01

    All nuclear explosions - on the Earth's surface, underground, underwater or in the atmosphere - are banned by the Comprehensive Nuclear-Test-Ban Treaty (CTBT). As part of this treaty, a verification regime was put into place to detect, locate and characterize nuclear explosion testings at any time, by anyone and everywhere on the Earth. The International Monitoring System (IMS) plays a key role in the verification regime of the CTBT. Out of the different monitoring techniques used in the IMS, the seismic waveform approach is the most effective technology for monitoring nuclear underground testing and to identify and characterize potential nuclear events. This study introduces a method of seismic threshold monitoring to assess an upper magnitude limit of a potential seismic event in a certain given geographical region. The method is based on ambient seismic background noise measurements at the individual IMS seismic stations as well as on global distance correction terms for body wave magnitudes, which are calculated using the seismic reflectivity method. From our investigations we conclude that a global detection threshold of around mb 4.0 can be achieved using only stations from the primary seismic network, a clear latitudinal dependence for the detection thresholdcan be observed between northern and southern hemisphere. Including the seismic stations being part of the auxiliary seismic IMS network results in a slight improvement of global detection capability. However, including wave arrivals from distances greater than 120 degrees, mainly PKP-wave arrivals, leads to a significant improvement in average global detection capability. In special this leads to an improvement of the detection threshold on the southern hemisphere. We further investigate the dependence of the detection capability on spatial (latitude and longitude) and temporal (time) parameters, as well as on parameters such as source type and percentage of operational IMS stations.

  7. Development of Vertical Cable Seismic System

    Science.gov (United States)

    Asakawa, E.; Murakami, F.; Sekino, Y.; Okamoto, T.; Ishikawa, K.; Tsukahara, H.; Shimura, T.

    2011-12-01

    In 2009, Ministry of Education, Culture, Sports, Science and Technology(MEXT) started the survey system development for Hydrothermal deposit. We proposed the Vertical Cable Seismic (VCS), the reflection seismic survey with vertical cable above seabottom. VCS has the following advantages for hydrothermal deposit survey. (1) VCS is an efficient high-resolution 3D seismic survey in limited area. (2) It achieves high-resolution image because the sensors are closely located to the target. (3) It avoids the coupling problems between sensor and seabottom that cause serious damage of seismic data quality. (4) Because of autonomous recording system on sea floor, various types of marine source are applicable with VCS such as sea-surface source (GI gun etc.) , deep-towed or ocean bottom source. Our first experiment of 2D/3D VCS surveys has been carried out in Lake Biwa, JAPAN, in November 2009. The 2D VCS data processing follows the walk-away VSP, including wave field separation and depth migration. Seismic Interferometry technique is also applied. The results give much clearer image than the conventional surface seismic. Prestack depth migration is applied to 3D data to obtain good quality 3D depth volume. Seismic Interferometry technique is applied to obtain the high resolution image in the very shallow zone. Based on the feasibility study, we have developed the autonomous recording VCS system and carried out the trial experiment in actual ocean at the water depth of about 400m to establish the procedures of deployment/recovery and to examine the VC position or fluctuation at seabottom. The result shows that the VC position is estimated with sufficient accuracy and very little fluctuation is observed. Institute of Industrial Science, the University of Tokyo took the research cruise NT11-02 on JAMSTEC R/V Natsushima in February, 2011. In the cruise NT11-02, JGI carried out the second VCS survey using the autonomous VCS recording system with the deep towed source provided by

  8. Seismic Fracture Characterization Methodologies for Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Queen, John H. [Hi-Geophysical, Inc., Ponca, OK (United States)

    2016-05-09

    Executive Summary The overall objective of this work was the development of surface and borehole seismic methodologies using both compressional and shear waves for characterizing faults and fractures in Enhanced Geothermal Systems. We used both surface seismic and vertical seismic profile (VSP) methods. We adapted these methods to the unique conditions encountered in Enhanced Geothermal Systems (EGS) creation. These conditions include geological environments with volcanic cover, highly altered rocks, severe structure, extreme near surface velocity contrasts and lack of distinct velocity contrasts at depth. One of the objectives was the development of methods for identifying more appropriate seismic acquisition parameters for overcoming problems associated with these geological factors. Because temperatures up to 300º C are often encountered in these systems, another objective was the testing of VSP borehole tools capable of operating at depths in excess of 1,000 m and at temperatures in excess of 200º C. A final objective was the development of new processing and interpretation techniques based on scattering and time-frequency analysis, as well as the application of modern seismic migration imaging algorithms to seismic data acquired over geothermal areas. The use of surface seismic reflection data at Brady's Hot Springs was found useful in building a geological model, but only when combined with other extensive geological and geophysical data. The use of fine source and geophone spacing was critical in producing useful images. The surface seismic reflection data gave no information about the internal structure (extent, thickness and filling) of faults and fractures, and modeling suggests that they are unlikely to do so. Time-frequency analysis was applied to these data, but was not found to be significantly useful in their interpretation. Modeling does indicate that VSP and other seismic methods with sensors located at depth in wells will be the most

  9. In situ anisotropic parameter determination using refraction seismic and VSP methods

    Energy Technology Data Exchange (ETDEWEB)

    Leslie, J.M.; Lawton, D.C. (Calgary Univ., AB (Canada))

    1999-01-01

    A prime concern in the time-to-depth conversion of reflection seismic data is seismic anisotropy, because it can produce velocity anomalies in seismic data that mimic the structural plays of interest to the petroleum prospector in both size and shape. Ongoing techniques of time-to-depth conversion of P-wave seismic data do not handle the travel time and velocity distortions caused by seismic anisotropy, particularly in areas of complex geologic structures. To address this problem, the first step is to know which rock units are anisotropic and measure their anisotropic parameters. Laboratory means are available, but there are problems with these mainly with shales because of their fissile nature. In situ measurements are preferable because they yield a more robust value, and at the University of Calgary such measurements were undertaken using refraction seismic and vertical seismic profiling (VSP) methods. Results indicate that the two Thomsen anisotropic parameters of interest can be determined from the VSP experiment, but these values are slightly less than those obtained using the refraction technique. This may be because of the sensitivity of the shot statics which arises from the direct travel time measurement of the technique. The experiment yields another method to measure velocity anisotropy, in situ, where steeply dipping strata outcrop, which allows for the accurate measurement of the anisotropic parameters for use in depth migration routines. 4 refs.

  10. In situ anisotropic parameter determination using refraction seismic and VSP methods

    Energy Technology Data Exchange (ETDEWEB)

    Leslie, J.M.; Lawton, D.C. [Calgary Univ., AB (Canada)

    1999-11-01

    A prime concern in the time-to-depth conversion of reflection seismic data is seismic anisotropy, because it can produce velocity anomalies in seismic data that mimic the structural plays of interest to the petroleum prospector in both size and shape. Ongoing techniques of time-to-depth conversion of P-wave seismic data do not handle the travel time and velocity distortions caused by seismic anisotropy, particularly in areas of complex geologic structures. To address this problem, the first step is to know which rock units are anisotropic and measure their anisotropic parameters. Laboratory means are available, but there are problems with these mainly with shales because of their fissile nature. In situ measurements are preferable because they yield a more robust value, and at the University of Calgary such measurements were undertaken using refraction seismic and vertical seismic profiling (VSP) methods. Results indicate that the two Thomsen anisotropic parameters of interest can be determined from the VSP experiment, but these values are slightly less than those obtained using the refraction technique. This may be because of the sensitivity of the shot statics which arises from the direct travel time measurement of the technique. The experiment yields another method to measure velocity anisotropy, in situ, where steeply dipping strata outcrop, which allows for the accurate measurement of the anisotropic parameters for use in depth migration routines. 4 refs.

  11. Seismic Ecology

    Science.gov (United States)

    Seleznev, V. S.; Soloviev, V. M.; Emanov, A. F.

    The paper is devoted to researches of influence of seismic actions for industrial and civil buildings and people. The seismic actions bring influence directly on the people (vibration actions, force shocks at earthquakes) or indirectly through various build- ings and the constructions and can be strong (be felt by people) and weak (be fixed by sensing devices). The great number of work is devoted to influence of violent seismic actions (first of all of earthquakes) on people and various constructions. This work is devoted to study weak, but long seismic actions on various buildings and people. There is a need to take into account seismic oscillations, acting on the territory, at construction of various buildings on urbanized territories. Essential influence, except for violent earthquakes, man-caused seismic actions: the explosions, seismic noise, emitted by plant facilities and moving transport, radiation from high-rise buildings and constructions under action of a wind, etc. can exert. Materials on increase of man- caused seismicity in a number of regions in Russia, which earlier were not seismic, are presented in the paper. Along with maps of seismic microzoning maps to be built indicating a variation of amplitude spectra of seismic noise within day, months, years. The presence of an information about amplitudes and frequencies of oscillations from possible earthquakes and man-caused oscillations in concrete regions allows carry- ing out soundly designing and construction of industrial and civil housing projects. The construction of buildings even in not seismically dangerous regions, which have one from resonance frequencies coincident on magnitude to frequency of oscillations, emitted in this place by man-caused objects, can end in failure of these buildings and heaviest consequences for the people. The practical examples of detail of engineering- seismological investigation of large industrial and civil housing projects of Siberia territory (hydro power

  12. New optical sensing technique of tissue viability and blood flow based on nanophotonic iterative multi-plane reflectance measurements

    Directory of Open Access Journals (Sweden)

    Yariv I

    2016-10-01

    Full Text Available Inbar Yariv,1 Menashe Haddad,2,3 Hamootal Duadi,1 Menachem Motiei,1 Dror Fixler1 1Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, Israel; 2Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; 3Mayanei Hayeshua Medical Center, Benei Brak, Israel Abstract: Physiological substances pose a challenge for researchers since their optical properties change constantly according to their physiological state. Examination of those substances noninvasively can be achieved by different optical methods with high sensitivity. Our research suggests the application of a novel noninvasive nanophotonics technique, ie, iterative multi-plane optical property extraction (IMOPE based on reflectance measurements, for tissue viability examination and gold nanorods (GNRs and blood flow detection. The IMOPE model combines an experimental setup designed for recording light intensity images with the multi-plane iterative Gerchberg-Saxton algorithm for reconstructing the reemitted light phase and calculating its standard deviation (STD. Changes in tissue composition affect its optical properties which results in changes in the light phase that can be measured by its STD. We have demonstrated this new concept of correlating the light phase STD and the optical properties of a substance, using transmission measurements only. This paper presents, for the first time, reflectance based IMOPE tissue viability examination, producing a decrease in the computed STD for older tissues, as well as investigating their organic material absorption capability. Finally, differentiation of the femoral vein from adjacent tissues using GNRs and the detection of their presence within blood circulation and tissues are also presented with high sensitivity (better than computed tomography to low quantities of GNRs (<3 mg. Keywords: Gerchberg-Saxton, optical properties, gold nanorods, blood vessel, tissue viability

  13. Evaluating a nursing erasmus exchange experience: Reflections on the use and value of the Nominal Group Technique for evaluation.

    Science.gov (United States)

    Cunningham, Sheila

    2017-09-01

    This paper discusses the use of Nominal Group Technique (NGT) for European nursing exchange evaluation at one university. The NGT is a semi-quantitative evaluation method derived from the Delphi method popular in the 1970s and 1980s. The NGT was modified from the traditional version retaining the structured cycles and but adding a broader group discussion. The NGT had been used for 2 successive years but required analysis and evaluation itself for credibility and 'fit' for purpose which is presented here. It aimed to explore nursing students' exchange experiences and aid programme development futures exchanges and closure from exchange. Results varied for the cohorts and students as participants enthusiastically engaged generating ample data which they ranked and categorised collectively. Evaluation of the NGT itself was two fold: by the programme team who considered purpose, audience, inclusivity, context and expertise. Secondly, students were asked for their thoughts using a graffiti board. Students avidly engaged with NGT but importantly also reported an effect from the process itself as an opportunity to reflect and share their experiences. The programme team concluded the NGT offered a credible evaluation tool which made use of authentic student voice and offered interactive group processes. Pedagogially, it enabled active reflection thus aiding reorientation back to the United Kingdom and awareness of 'transformative' consequences of their exchange experiences. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Contribution à l'étude d'une partie du bassin d'Essaouira (Maroc) par sismique réflexionContribution to part of the Essaouira Basin (Morocco) by seismic reflection

    Science.gov (United States)

    Jaffal, Mohammed; Kchikach, Azzouz; Lefort, Jean-Pierre; Hanich, Lahoucine

    A large number of seismic reflection lines and boreholes have been carried out in the Essaouira Basin by the oil industry. The present study concentrates on the reinterpretation of these data in the restricted area of Khemis Meskala, in order to better characterise the structure of the Cretaceous aquiferous system. The reflector corresponding to the bottom of the Vraconian formation has been identified on the different seismic sections. This horizon, which marks the base of the aquiferous system, was first digitised on time migration sections and then converted to depth sections using a suitable linear velocity law. The isobath map of the bottom of the Vraconian resulting from this study images the 3D geometrical structure of this horizon and shows that it is slightly folded in domes and basins. This document will be useful for rationalising the future hydrogeological researches that will be undertaken in the Khemis Meskala area. To cite this article: M. Jaffal et al., C. R. Geoscience 334 (2002) 229-234.

  15. Adaptive prediction applied to seismic event detection

    International Nuclear Information System (INIS)

    Clark, G.A.; Rodgers, P.W.

    1981-01-01

    Adaptive prediction was applied to the problem of detecting small seismic events in microseismic background noise. The Widrow-Hoff LMS adaptive filter used in a prediction configuration is compared with two standard seismic filters as an onset indicator. Examples demonstrate the technique's usefulness with both synthetic and actual seismic data

  16. Adaptive prediction applied to seismic event detection

    Energy Technology Data Exchange (ETDEWEB)

    Clark, G.A.; Rodgers, P.W.

    1981-09-01

    Adaptive prediction was applied to the problem of detecting small seismic events in microseismic background noise. The Widrow-Hoff LMS adaptive filter used in a prediction configuration is compared with two standard seismic filters as an onset indicator. Examples demonstrate the technique's usefulness with both synthetic and actual seismic data.

  17. Seismic signatures of the Lodgepole fractured reservoir in Utah-Wyoming overthrust belt

    Energy Technology Data Exchange (ETDEWEB)

    Parra, J.; Collier, H.; Angstman, B.

    1997-08-01

    In low porosity, low permeability zones, natural fractures are the primary source of permeability which affect both production and injection of fluids. The open fractures do not contribute much to porosity, but they provide an increased drainage network to any porosity. An important approach to characterizing the fracture orientation and fracture permeability of reservoir formations is one based upon the effects of such conditions on the propagation of acoustic and seismic waves in the rock. We present the feasibility of using seismic measurement techniques to map the fracture zones between wells spaced 2400 ft at depths of about 1000 ft. For this purpose we constructed computer models (which include azimuthal anisotropy) using Lodgepole reservoir parameters to predict seismic signatures recorded at the borehole scale, crosswell scale, and 3 D seismic scale. We have integrated well logs with existing 2D surfaces seismic to produce petrophysical and geological cross sections to determine the reservoir parameters and geometry for the computer models. In particular, the model responses are used to evaluate if surface seismic and crosswell seismic measurements can capture the anisotropy due to vertical fractures. Preliminary results suggested that seismic waves transmitted between two wells will propagate in carbonate fracture reservoirs, and the signal can be received above the noise level at the distance of 2400 ft. In addition, the large velocities contrast between the main fracture zone and the underlying unfractured Boundary Ridge Member, suggested that borehole reflection imaging may be appropriate to map and fracture zone thickness variation and fracture distributions in the reservoir.

  18. Depth imaging system for seismic reflection data. Part 1. Outline of system; Hanshaho jishin tansa data no tame no shindo imaging system. 1. System no gaiyo

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, N [Japex Jeoscience Institute, Tokyo (Japan); Matsuoka, T [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsuru, T [Japan National Oil Corp., Tokyo (Japan)

    1996-10-01

    Structures of oil and gas fields to be recently explored have changed from simple structures represented by anticline into more complicated and more delicate structures in the deeper underground. In order to discover and develop prospective oil and gas fields among such geological structures, it is indispensable to construct a system which can treat seismic exploration date collectively before stacking and can easily perform imaging of underground structures accurately. Based on the advancement of hardware, Japan National Oil Corporation and Japan Petroleum Exploration Co., Ltd. have developed a depth imaging system as an interactive tool for constructing underground structures accurately through a cooperation of highly accurate imaging technology. Using this system, two-dimensional underground structure models can be easily given and modified by interactively referring to results of depth migration velocity analysis and stacking velocity analysis, well data, cross sections after depth transform, etc. 1 fig.

  19. Investigating The Relationship Between Structural Geology and Wetland Loss Near Golden Meadow, Louisiana By Utilizing 3D Seismic Reflection and Well Log Data

    Science.gov (United States)

    Johnston, A. S.; Zhang, R.; Gottardi, R.; Dawers, N. H.

    2017-12-01

    Wetland loss is one of the greatest environmental and economic threats in the deltaic plain of the Gulf Coast. This loss is controlled by subsidence, sea level rise, decreased sediment supply rates, movement along normal faults, salt tectonics, fluid extraction related to oil, gas and water exploration, and compaction. However, the interplay and feedback between these different processes are still poorly understood. In this study, we investigate the role of active faulting and salt tectonics on wetland loss in an area located between Golden Meadow and Leeville, Louisiana. Using industry 3D seismic and well log data, we investigate key segments of the Golden Meadow fault zone and map shallow faults that overlie the Leeville salt dome, to compare those fault planes with areas of wetland loss and subsidence. Faults were mapped to a depth of 1200 m, and well logs were tied to the upper 180 m of the seismic data to make accurate projections of the faults to the surface. Preliminary results highlight a graben structure south of a segment of the Golden Meadow fault. Well log and published data from shallow borings reveal a thicker Holocene accumulation at the center of the graben, up to 45 m than on the flanks of the graben. The location of this graben spatially correlates with Catfish Lake, and part of it overlies salt adjacent to the main fault surface. Bayou Lafourche, the main distributary channel of the Lafourche lobe of the Mississippi River delta complex, appears to have its path controlled by faults. Bayou Lafourche changes orientation and flows parallel to, and on the downthrown side of, two radial faults associated with the Leeville salt dome. These preliminary results indicate that there is a relationship between surface geomorphology and subsurface structures that, at least in part, exert a control on wetland loss in southern Louisiana.

  20. Novel Techniques for Seismic Performance of High Rise Structures in 21st Century: State-Of-The Art Review

    Science.gov (United States)

    Patil, R.; Naringe, A.; Kalyana Rama, J. S.

    2018-03-01

    Natural disasters like earthquakes are causing catastrophic failure for various structures in and around the world because of its unpredictable nature. Even in India, almost 80% of, India’s capital, Delhi’s buildings are not earthquake resistant. If at all there is a moderate earthquake in Delhi, millions of lives and huge of property will be lost. There are many places in India including four metropolitan cities, in which majority of high rise buildings are not earthquake resistant. It is important to account for damage caused by earthquakes, incorporating suitable resistant techniques for the safeguard of the people. The present study deals with highlighting the novel techniques adopted in the recent past to make the structures earthquake resistant. Performance based design is one such approach where in performance of structure is given the utmost importance unlike the existing standards. Lateral load resisting systems like chevron braces, knee braces in combination with aluminium shear links are found to reduce the impact of earthquake on the structures w.r.t its drift. It is also observed that the use of economical and feasible passive and active control vibration systems like dampers, isolation techniques led to revolutionary changes in the overall performance of high rise.

  1. Shallow Reflection Method for Water-Filled Void Detection and Characterization

    Science.gov (United States)

    Zahari, M. N. H.; Madun, A.; Dahlan, S. H.; Joret, A.; Hazreek, Z. A. M.; Mohammad, A. H.; Izzaty, R. A.

    2018-04-01

    Shallow investigation is crucial in enhancing the characteristics of subsurface void commonly encountered in civil engineering, and one such technique commonly used is seismic-reflection technique. An assessment of the effectiveness of such an approach is critical to determine whether the quality of the works meets the prescribed requirements. Conventional quality testing suffers limitations including: limited coverage (both area and depth) and problems with resolution quality. Traditionally quality assurance measurements use laboratory and in-situ invasive and destructive tests. However geophysical approaches, which are typically non-invasive and non-destructive, offer a method by which improvement of detection can be measured in a cost-effective way. Of this seismic reflection have proved useful to assess void characteristic, this paper evaluates the application of shallow seismic-reflection method in characterizing the water-filled void properties at 0.34 m depth, specifically for detection and characterization of void measurement using 2-dimensional tomography.

  2. Using Seismic Interferometry to Investigate Seismic Swarms

    Science.gov (United States)

    Matzel, E.; Morency, C.; Templeton, D. C.

    2017-12-01

    Seismicity provides a direct means of measuring the physical characteristics of active tectonic features such as fault zones. Hundreds of small earthquakes often occur along a fault during a seismic swarm. This seismicity helps define the tectonically active region. When processed using novel geophysical techniques, we can isolate the energy sensitive to the fault, itself. Here we focus on two methods of seismic interferometry, ambient noise correlation (ANC) and the virtual seismometer method (VSM). ANC is based on the observation that the Earth's background noise includes coherent energy, which can be recovered by observing over long time periods and allowing the incoherent energy to cancel out. The cross correlation of ambient noise between a pair of stations results in a waveform that is identical to the seismogram that would result if an impulsive source located at one of the stations was recorded at the other, the Green function (GF). The calculation of the GF is often stable after a few weeks of continuous data correlation, any perturbations to the GF after that point are directly related to changes in the subsurface and can be used for 4D monitoring.VSM is a style of seismic interferometry that provides fast, precise, high frequency estimates of the Green's function (GF) between earthquakes. VSM illuminates the subsurface precisely where the pressures are changing and has the potential to image the evolution of seismicity over time, including changes in the style of faulting. With hundreds of earthquakes, we can calculate thousands of waveforms. At the same time, VSM collapses the computational domain, often by 2-3 orders of magnitude. This allows us to do high frequency 3D modeling in the fault region. Using data from a swarm of earthquakes near the Salton Sea, we demonstrate the power of these techniques, illustrating our ability to scale from the far field, where sources are well separated, to the near field where their locations fall within each other

  3. Quasi-3-D Seismic Reflection Imaging and Wide-Angle Velocity Structure of Nearly Amagmatic Oceanic Lithosphere at the Ultraslow-Spreading Southwest Indian Ridge

    Science.gov (United States)

    Momoh, Ekeabino; Cannat, Mathilde; Watremez, Louise; Leroy, Sylvie; Singh, Satish C.

    2017-12-01

    We present results from 3-D processing of 2-D seismic data shot along 100 m spaced profiles in a 1.8 km wide by 24 km long box during the SISMOSMOOTH 2014 cruise. The study is aimed at understanding the oceanic crust formed at an end-member mid-ocean ridge environment of nearly zero melt supply. Three distinct packages of reflectors are imaged: (1) south facing reflectors, which we propose correspond to the damage zone induced by the active axial detachment fault: reflectors in the damage zone have dips up to 60° and are visible down to 5 km below the seafloor; (2) series of north dipping reflectors in the hanging wall of the detachment fault: these reflectors may correspond to damage zone inherited from a previous, north dipping detachment fault, or small offset recent faults, conjugate from the active detachment fault, that served as conduits for isolated magmatic dykes; and (3) discontinuous but coherent flat-lying reflectors at shallow depths (serpentinization and fracturation of the exhumed mantle-derived peridotites in the footwall of active and past detachment faults.

  4. Crustal structure across the Three Gorges area of the Yangtze platform, central China, from seismic refraction/wide-angle reflection data

    Science.gov (United States)

    Zhang, Z.; Bai, Z.; Mooney, W.; Wang, C.; Chen, X.; Wang, E.; Teng, J.; Okaya, N.

    2009-01-01

    We present active-source seismic data recorded along a 300??km-long profile across the Three Gorges area of the western Yangtze platform, central China. From west to east, the profile crosses the Zigui basin, Huangling dome and Jianghan basin. The derived crustal P-wave velocity structure changes significantly across the Tongchenghe fault that lies at the transition from the Huangling dome to the Jianghan basin. West of the Tongchenghe fault, beneath the Zigui basin and the Huangling dome, we observe a ~ 42??km thick crust of relatively low average velocity (6.3-6.4??km/s). In contrast, east of the Tongchenghe fault, beneath the Jianghan basin, the crust is only 30??km thick and has a high average velocity (6.6-6.7??km/s). A west-east variation in crustal composition along the Tongchenghe fault is also inferred. West of the fault, P-wave velocities suggest a felsic composition with an intermediate layer at the base of the crust, whilst, east of the fault, felsic, intermediate, and mafic crustal layers are apparent. Our results suggest that the crust beneath the Jianghan basin has been thinned by rifting, accompanied by intrusion of the lower crust by mafic dikes and sills. The west-to-east division of the crust in the Three Gorges area coincides with first-order geophysical contrasts in gravity, topography, crustal and lithospheric thickness. ?? 2009 Elsevier B.V.

  5. Comparing Seismic And Magnetic Responses To Copper Gold Deposits Under Different Cover Sequences

    Directory of Open Access Journals (Sweden)

    Okan Evans Onojasun

    2015-08-01

    Full Text Available Appropriate application of geophysical techniques is required to effectively explore through the cover sequences that will allow the discovery of deep seated orebodies within the 1-3km depth range. Whilst potential field methods that are traditionally used for Cu-Au exploration seems effective they lack the expected resolution required to detect deeper mineral deposits under 500 m cover. Seismic reflection techniques offers a distinct advantage over all other geophysical techniques because of its ability to penetrate deeper into the subsurface without losing its resolution. We present in this report modelling results from magnetic and seismic responses to Cu-Au deposits when located within 100-1000m depth range. In the case of magnetic modelling we apply upward continuation filters which calculate the potential field that would have been recorded at 100m 250m 500m and 1000 m levels by filtering away shallow anomalies from the initial data. For seismic modelling simple but realistic geological model with varying cover thicknesses 100m 250m 500m and 1000m were created and then populate these models with petrophysical data. Simulated synthetic seismic responses from the models was processed using basic processing flows to obtained depth migrated images. Results show that for shower depths 0-100m good correlation exist between the magnetic and the seismic responses. From 100-250m depth cover though we can still see some magnetic anomalies within the target zone its effectiveness decreases with depths whereas seismic responses was maintain within the depth range. From 500m to 1000m magnetic response becomes spear or fuzzy as much useful information is practically missed out. Similarly high resolution power of seismic was ably demonstrated as the depth of even 2km did not degrade its resolution. Thus both magnetic and seismic methods are very useful for shallow investigation but at greater depth seismic method appears to be a more valid exploration

  6. The Advantages of an Attenuated Total Internal Reflection Infrared Microspectroscopic Imaging Technique for the Analysis of Polymer Laminates.

    Science.gov (United States)

    Ling, Chen; Sommer, André J

    2015-06-01

    Until recently, the analysis of polymer laminates using infrared microspectroscopy involved the painstaking separation of individual layers by dissection or by obtaining micrometer thin cross-sections. The latter usually requires the expertise of an individual trained in microtomy and even then, the very structure of the laminate could affect the outcome of the spectral results. The recent development of attenuated total internal reflection (ATR) infrared microspectroscopy imaging has provided a new avenue for the analysis of these multilayer structures. This report compares ATR infrared microspectroscopy imaging with conventional transmission infrared microspectroscopy imaging. The results demonstrate that the ATR method offers improved spatial resolution, eliminates a variety of competing optical processes, and requires minimal sample preparation relative to transmission measurements. These advantages were illustrated using a polymer laminate consisting of 11 different layers whose thickness ranged in size from 4-20 μm. The spatial resolution achieved by using an ATR-FTIR (Fourier transform infrared spectroscopy) imaging technique was diffraction limited. Contrast in the ATR images was enhanced by principal component analysis.

  7. Tunable All Reflective Spatial Heterodyne Spectroscopy, A Technique For High Resolving Power Observation OI Defused Emission Line Sources

    Science.gov (United States)

    Hosseini, Seyedeh Sona

    The solar system presents a challenge to spectroscopic observers, because it is an astrophysically low energy environment populated with often angularly extended targets (e.g, interplanetary medium, comets, planetary upper atmospheres, and planet and satellite near space environments). Spectroscopy is a proven tool for determining compositional and other properties of remote objects. Narrow band imaging and low resolving spectroscopic measurements provide information about composition, photochemical evolution, energy distribution and density. The extension to high resolving power provides further access to temperature, velocity, isotopic ratios, separation of blended sources, and opacity effects. The drawback of high-resolution spectroscopy comes from the instrumental limitations of lower throughput, the necessity of small entrance apertures, sensitivity, field of view, and large physical instrumental size. These limitations quickly become definitive for faint and/or extended targets and for spacecraft encounters. An emerging technique with promise for the study of faint, extended sources at high resolving power is the all-reflective form of the Spatial Heterodyne Spectrometer (SHS). SHS instruments are compact and naturally possess both high etendue and high resolving power. To achieve similar spectral grasp, grating spectrometers require big telescopes. SHS is a common-path beam Fourier transform interferometer that produces Fizeau fringe pattern for all other wavelengths except the tuned wavelength. Compared to similar Fourier transform Spectrometers (FTS), SHS has considerably relaxed optical tolerances that make it easier to use in the visible and UV spectral ranges. The large etendue of SHS instruments makes them ideal for observations of extended, low surface brightness, isolated emission line sources, while their intrinsically high spectral resolution enables the study of the dynamical and spectral characteristics described above. SHS also combines very

  8. Acoustic reflections in the water column of Krishna-Godavari offshore basin, Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sinha, S.K.; Dewangan, P.; Sain, K.

    reflection seismic data. Remarkable similarities between the reflection seismic and the salinity profile in the upper thermocline suggest the importance of salinity variations on the water column reflection. Furthermore, impedance inversion...

  9. Evaluation stationariness of triaxial seismic while drilling and detection of reflected wave; Kosei kussaku ni tomonau danseiha no sanjiku kaiseki ni yoru hiteijo hyoka to hanshaha no kenshutsu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, T; Asanuma, H; Niitsuma, H [Tohoku University, Sendai (Japan). Faculty of Engineering

    1996-05-01

    This paper reports a method to detect reflected wave components contained in an elastic wave caused in association with well drilling. Measurement was made on an elastic wave caused in association with well drilling in an experimental field by using a triaxial elastic wave detector disposed in a measurement well. Analyzing the particle motion tracks in the derived elastic wave signals (to derive the main axial direction of a three-dimensional hologram) revealed that oscillation direction of the signals changes non-steadily by time centering around the S-wave oscillation direction. In addition, a sound source position was estimated during the drilling. Existence probability of the S-wave signal in the non-steady continuous signals was estimated by handling the particle motion tracks stochastically. In addition, this existence probability was used as a weighting function for a correlative analysis to detect a reflected wave from directly reaching wave components in the non-steady continuous signals. Thus, improvement in reliability of reflected wave detection was attempted. Effectiveness of this method was endorsed by the field data. 3 refs., 7 figs.

  10. Mobile seismic exploration

    Energy Technology Data Exchange (ETDEWEB)

    Dräbenstedt, A., E-mail: a.draebenstedt@polytec.de, E-mail: rembe@iei.tu-clausthal.de, E-mail: ulrich.polom@liag-hannover.de; Seyfried, V. [Research & Development, Polytec GmbH, Waldbronn (Germany); Cao, X.; Rembe, C., E-mail: a.draebenstedt@polytec.de, E-mail: rembe@iei.tu-clausthal.de, E-mail: ulrich.polom@liag-hannover.de [Institute of Electrical Information Technology, TU Clausthal, Clausthal-Zellerfeld (Germany); Polom, U., E-mail: a.draebenstedt@polytec.de, E-mail: rembe@iei.tu-clausthal.de, E-mail: ulrich.polom@liag-hannover.de [Leibniz Institute of Applied Geophysics, Hannover (Germany); Pätzold, F.; Hecker, P. [Institute of Flight Guidance, TU Braunschweig, Braunschweig (Germany); Zeller, T. [Clausthaler Umwelttechnik Institut CUTEC, Clausthal-Zellerfeld (Germany)

    2016-06-28

    Laser-Doppler-Vibrometry (LDV) is an established technique to measure vibrations in technical systems with picometer vibration-amplitude resolution. Especially good sensitivity and resolution can be achieved at an infrared wavelength of 1550 nm. High-resolution vibration measurements are possible over more than 100 m distance. This advancement of the LDV technique enables new applications. The detection of seismic waves is an application which has not been investigated so far because seismic waves outside laboratory scales are usually analyzed at low frequencies between approximately 1 Hz and 250 Hz and require velocity resolutions in the range below 1 nm/s/√Hz. Thermal displacements and air turbulence have critical influences to LDV measurements at this low-frequency range leading to noise levels of several 100 nm/√Hz. Commonly seismic waves are measured with highly sensitive inertial sensors (geophones or Micro Electro-Mechanical Sensors (MEMS)). Approaching a laser geophone based on LDV technique is the topic of this paper. We have assembled an actively vibration-isolated optical table in a minivan which provides a hole in its underbody. The laser-beam of an infrared LDV assembled on the optical table impinges the ground below the car through the hole. A reference geophone has detected remaining vibrations on the table. We present the results from the first successful experimental demonstration of contactless detection of seismic waves from a movable vehicle with a LDV as laser geophone.

  11. Submarine seismic monitoring of El Hierro volcanic eruption with a 3C-geophone string: applying new acquisition and data processing techniques to volcano monitoring

    Science.gov (United States)

    Jurado, Maria Jose; Ripepe, Maurizio; Lopez, Carmen; Blanco, Maria Jose; Crespo, Jose

    2015-04-01

    A submarine volcanic eruption took place near the southernmost emerged land of the El Hierro Island (Canary Islands, Spain), from October 2011 to February 2012. The Instituto Geografico Nacional (IGN) seismic stations network evidenced seismic unrest since July 2011 and was a reference also to follow the evolution of the seismic activity associated with the volcanic eruption. Right after the eruption onset, in October 2011 a geophone string was deployed by the CSIC-IGN to monitor seismic activity. Monitoring with the seismic array continued till May 2012. The array was installed less than 2 km away from the new vol¬cano, next to La Restinga village shore in the harbor from 6 to 12m deep into the water. Our purpose was to record seismic activity related to the volcanic activity, continuously and with special interest on high frequency events. The seismic array was endowed with 8, high frequency, 3 component, 250 Hz, geophone cable string with a separation of 6 m between them. Each geophone consists on a 3-component module based on 3 orthogonal independent sensors that measures ground velocity. Some of the geophones were placed directly on the seabed, some were buried. Due to different factors, as the irregular characteristics of the seafloor. The data was recorded on the surface with a seismometer and stored on a laptop computer. We show how acoustic data collected underwater show a great correlation with the seismic data recorded on land. Finally we compare our data analysis results with the observed sea surface activity (ash and lava emission and degassing). This evidence is disclosing new and innovative tecniques on monitoring submarine volcanic activity. Reference Instituto Geográfico Nacional (IGN), "Serie El Hierro." Internet: http://www.ign.es/ign/resources /volcanologia/HIERRO.html [May, 17. 2013

  12. REVIEW ARTICLE: A comparison of site response techniques using earthquake data and ambient seismic noise analysis in the large urban areas of Santiago de Chile

    Science.gov (United States)

    Pilz, Marco; Parolai, Stefano; Leyton, Felipe; Campos, Jaime; Zschau, Jochen

    2009-08-01

    Situated in an active tectonic region, Santiago de Chile, the country's capital with more than six million inhabitants, faces tremendous earthquake risk. Macroseismic data for the 1985 Valparaiso event show large variations in the distribution of damage to buildings within short distances, indicating strong effects of local sediments on ground motion. Therefore, a temporary seismic network was installed in the urban area for recording earthquake activity and a study was carried out aiming to estimate site amplification derived from horizontal-to-vertical (H/V) spectral ratios from earthquake data (EHV) and ambient noise (NHV), as well as using the standard spectral ratio (SSR) technique with a nearby reference station located on igneous rock. The results lead to the following conclusions: (1) The analysis of earthquake data shows significant dependence on the local geological structure with respect to amplitude and duration. (2) An amplification of ground motion at frequencies higher than the fundamental one can be found. This amplification would not be found when looking at NHV ratios alone. (3) The analysis of NHV spectral ratios shows that they can only provide a lower bound in amplitude for site amplification. (4) P-wave site responses always show lower amplitudes than those derived by S waves, and sometimes even fail to provide some frequencies of amplification. (5) No variability in terms of time and amplitude is observed in the analysis of the H/V ratio of noise. (6) Due to the geological conditions in some parts of the investigated area, the fundamental resonance frequency of a site is difficult to estimate following standard criteria proposed by the SESAME consortium, suggesting that these are too restrictive under certain circumstances.

  13. Study on Development of Non-Destructive Measurement Technique for Viability of Lettuce Seed (Lactuca sativa L) Using Hyperspectral Reflectance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Chi Kook; Cho, Byoung Kwan [College of Agriculture and Life Science, Chungnam National University, Daejeon (Korea, Republic of); Mo, Chang Yeon [National Acadamy of Agricultural Science, Daejeon (Korea, Republic of); Kim, Moon S. [Environmental Microbial and Food Safety Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agriculture, Washington (United States)

    2012-10-15

    In this study, the feasibility of hyperspectral reflectance imaging technique was investigated for the discrimination of viable and non-viable lettuce seeds. The spectral data of hyperspectral reflectance images with the spectral range between 750 nm and 1000 nm were used to develop PLS-DA model for the classification of viable and non-viable lettuce seeds. The discrimination accuracy of the calibration set was 81.6% and that of the test set was 81.2%. The image analysis method was developed to construct the discriminant images of non-viable seeds with the developed PLS-DA model. The discrimination accuracy obtained from the resultant image were 91%, which showed the feasibility of hyperspectral reflectance imaging technique for the mass discrimination of non-viable lettuce seeds from viable ones.

  14. Study on Development of Non-Destructive Measurement Technique for Viability of Lettuce Seed (Lactuca sativa L) Using Hyperspectral Reflectance Imaging

    International Nuclear Information System (INIS)

    Ahn, Chi Kook; Cho, Byoung Kwan; Mo, Chang Yeon; Kim, Moon S.

    2012-01-01

    In this study, the feasibility of hyperspectral reflectance imaging technique was investigated for the discrimination of viable and non-viable lettuce seeds. The spectral data of hyperspectral reflectance images with the spectral range between 750 nm and 1000 nm were used to develop PLS-DA model for the classification of viable and non-viable lettuce seeds. The discrimination accuracy of the calibration set was 81.6% and that of the test set was 81.2%. The image analysis method was developed to construct the discriminant images of non-viable seeds with the developed PLS-DA model. The discrimination accuracy obtained from the resultant image were 91%, which showed the feasibility of hyperspectral reflectance imaging technique for the mass discrimination of non-viable lettuce seeds from viable ones.

  15. Seismic protection

    International Nuclear Information System (INIS)

    Herbert, R.

    1988-01-01

    To ensure that a nuclear reactor or other damage-susceptible installation is, so far as possible, tripped and already shut down before the arrival of an earthquake shock at its location, a ring of monitoring seismic sensors is provided around it, each sensor being spaced from it by a distance (possibly several kilometres) such that (taking into account the seismic-shock propagation velocity through the intervening ground) a shock monitored by the sensor and then advancing to the installation site will arrive there later than a warning signal emitted by the sensor and received at the installation, by an interval sufficient to allow the installation to trip and shut down, or otherwise assume an optimum anti-seismic mode, in response to the warning signal. Extra sensors located in boreholes may define effectively a three-dimensional (hemispherical) sensing boundary rather than a mere two-dimensional ring. (author)

  16. Induced Seismicity

    Science.gov (United States)

    Keranen, Katie M.; Weingarten, Matthew

    2018-05-01

    The ability of fluid-generated subsurface stress changes to trigger earthquakes has long been recognized. However, the dramatic rise in the rate of human-induced earthquakes in the past decade has created abundant opportunities to study induced earthquakes and triggering processes. This review briefly summarizes early studies but focuses on results from induced earthquakes during the past 10 years related to fluid injection in petroleum fields. Study of these earthquakes has resulted in insights into physical processes and has identified knowledge gaps and future research directions. Induced earthquakes are challenging to identify using seismological methods, and faults and reefs strongly modulate spatial and temporal patterns of induced seismicity. However, the similarity of induced and natural seismicity provides an effective tool for studying earthquake processes. With continuing development of energy resources, increased interest in carbon sequestration, and construction of large dams, induced seismicity will continue to pose a hazard in coming years.

  17. Vertical Cable Seismic Survey for Hydrothermal Deposit

    Science.gov (United States)

    Asakawa, E.; Murakami, F.; Sekino, Y.; Okamoto, T.; Ishikawa, K.; Tsukahara, H.; Shimura, T.

    2012-04-01

    The vertical cable seismic is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. This type of survey is generally called VCS (Vertical Cable Seismic). Because VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed the method for the hydrothermal deposit survey tool development program that the Ministry of Education, Culture, Sports, Science and Technology (MEXT) started in 2009. We are now developing a VCS system, including not only data acquisition hardware but data processing and analysis technique. Our first experiment of VCS surveys has been carried out in Lake Biwa, JAPAN in November 2009 for a feasibility study. Prestack depth migration is applied to the 3D VCS data to obtain a high quality 3D depth volume. Based on the results from the feasibility study, we have developed two autonomous recording VCS systems. After we carried out a trial experiment in the actual ocean at a water depth of about 400m and we carried out the second VCS survey at Iheya Knoll with a deep-towed source. In this survey, we could establish the procedures for the deployment/recovery of the system and could examine the locations and the fluctuations of the vertical cables at a water depth of around 1000m. The acquired VCS data clearly shows the reflections from the sub-seafloor. Through the experiment, we could confirm that our VCS system works well even in the severe circumstances around the locations of seafloor hydrothermal deposits. We have, however, also confirmed that the uncertainty in the locations of the source and of the hydrophones could lower the quality of subsurface image. It is, therefore, strongly necessary to develop a total survey system that assures a accurate positioning and a deployment techniques

  18. Subsurface geology by shallow seismic reflection survey and microgravity survey in Kobe area; Senso hanshaho danseiha tansa oyobi seimitsu juryoku tansa ni yoru Kobe chiiki no chika chishitsu

    Energy Technology Data Exchange (ETDEWEB)

    Endo, H; Makino, M; Murata, Y; Watanabe, S [Geological Survey of Japan, Tsukuba (Japan)

    1996-05-01

    This paper reports discussions on subsurface structure of the Kobe area by means of microgravity survey. A Bouguer anomaly distribution graph was obtained (which is close to a near straight line) by measuring the gravity at measurement points with an interval of about 25 m along a traverse line (with a total length of about 1.7 km) in an approximately NNW-SSE direction crossing the downtown of the city of Kobe. Viewing the residuals to a straight line linking the values at both ends of the traverse line revealed that the gradient in the Bouguer anomaly distribution changes as if it is bent at a point near the center of the traverse line as a boundary. Deriving the residuals from fine changes seen in a distribution graph for the residuals made clear that this residual distribution has two discontinuous points. The paper indicates that the bending point in the former case corresponds to a reverse fault in a base bed of a flat land as compared with the result of model calculation on the base structure and gravity distribution. The discontinuous points in the latter case agree with positions of fault distribution derived by a reflection elastic wave survey. 6 refs., 4 figs.

  19. CMP reflection imaging via interferometry of distributed subsurface sources

    Science.gov (United States)

    Kim, D.; Brown, L. D.; Quiros, D. A.

    2015-12-01

    The theoretical foundations of recovering body wave energy via seismic interferometry are well established. However in practice, such recovery remains problematic. Here, synthetic seismograms computed for subsurface sources are used to evaluate the geometrical combinations of realistic ambient source and receiver distributions that result in useful recovery of virtual body waves. This study illustrates how surface receiver arrays that span a limited distribution suite of sources, can be processed to reproduce virtual shot gathers that result in CMP gathers which can be effectively stacked with traditional normal moveout corrections. To verify the feasibility of the approach in practice, seismic recordings of 50 aftershocks following the magnitude of 5.8 Virginia earthquake occurred in August, 2011 have been processed using seismic interferometry to produce seismic reflection images of the crustal structure above and beneath the aftershock cluster. Although monotonic noise proved to be problematic by significantly reducing the number of usable recordings, the edited dataset resulted in stacked seismic sections characterized by coherent reflections that resemble those seen on a nearby conventional reflection survey. In particular, "virtual" reflections at travel times of 3 to 4 seconds suggest reflector sat approximately 7 to 12 km depth that would seem to correspond to imbricate thrust structures formed during the Appalachian orogeny. The approach described here represents a promising new means of body wave imaging of 3D structure that can be applied to a wide array of geologic and energy problems. Unlike other imaging techniques using natural sources, this technique does not require precise source locations or times. It can thus exploit aftershocks too small for conventional analyses. This method can be applied to any type of microseismic cloud, whether tectonic, volcanic or man-made.

  20. Near-field reflection backscattering apertureless optical microscopy: Application to spectroscopy experiments on opaque samples, comparison between lock-in and digital photon counting detection techniques

    International Nuclear Information System (INIS)

    Diziain, S.; Bijeon, J.-L.; Adam, P.-M.; Lamy de la Chapelle, M.; Thomas, B.; Deturche, R.; Royer, P.

    2007-01-01

    An apertureless scanning near-field optical microscope (ASNOM) in reflection backscattering configuration is designed to conduct spectroscopic experiments on opaque samples constituted of latex beads. The ASNOM proposed takes advantage of the depth-discrimination properties of confocal microscopes to efficiently extract the near-field optical signal. Given their importance in a spectroscopic experiment, we systematically compare the lock-in and synchronous photon counting detection methods. Some results of Rayleigh's scattering in the near field of the test samples are used to illustrate the possibilities of this technique for reflection backscattering spectroscopy

  1. Near-field reflection backscattering apertureless optical microscopy: Application to spectroscopy experiments on opaque samples, comparison between lock-in and digital photon counting detection techniques

    Energy Technology Data Exchange (ETDEWEB)

    Diziain, S. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France); Bijeon, J.-L. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France)]. E-mail: bijeon@utt.fr; Adam, P.-M. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France); Lamy de la Chapelle, M. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex