Combined interpretation of SkyTEM and high-resolution seismic data

DEFF Research Database (Denmark)

Høyer, Anne-Sophie; Lykke-Andersen, Holger; Jørgensen, Flemming Voldum

2011-01-01

made based on AEM (SkyTEM) and high-resolution seismic data from an area covering 10 km2 in the western part of Denmark. As support for the interpretations, an exploration well was drilled to provide lithological and logging information in the form of resistivity and vertical seismic profiling. Based...... on the resistivity log, synthetic SkyTEM responses were calculated with a varying number of gate-times in order to illustrate the effect of the noise-level. At the exploration well geophysical data were compared to the lithological log; in general there is good agreement. The same tendency was recognised when Sky...

Enhancing Seismic Calibration Research Through Software Automation and Scientific Information Management

Energy Technology Data Exchange (ETDEWEB)

Ruppert, S D; Dodge, D A; Ganzberger, M D; Harris, D B; Hauk, T F

2009-07-07

The National Nuclear Security Administration (NNSA) Ground-Based Nuclear Explosion Monitoring Research and Development (GNEMRD) Program at LLNL continues to make significant progress enhancing the process of deriving seismic calibrations and performing scientific integration, analysis, and information management with software automation tools. Our tool efforts address the problematic issues of very large datasets and varied formats encountered during seismic calibration research. New information management and analysis tools have resulted in demonstrated gains in efficiency of producing scientific data products and improved accuracy of derived seismic calibrations. In contrast to previous years, software development work this past year has emphasized development of automation at the data ingestion level. This change reflects a gradually-changing emphasis in our program from processing a few large data sets that result in a single integrated delivery, to processing many different data sets from a variety of sources. The increase in the number of sources had resulted in a large increase in the amount of metadata relative to the final volume of research products. Software developed this year addresses the problems of: (1) Efficient metadata ingestion and conflict resolution; (2) Automated ingestion of bulletin information; (3) Automated ingestion of waveform information from global data centers; and (4) Site Metadata and Response transformation required for certain products. This year, we also made a significant step forward in meeting a long-standing goal of developing and using a waveform correlation framework. Our objective for such a framework is to extract additional calibration data (e.g. mining blasts) and to study the extent to which correlated seismicity can be found in global and regional scale environments.

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

Advancing New 3D Seismic Interpretation Methods for Exploration and Development of Fractured Tight Gas Reservoirs

Energy Technology Data Exchange (ETDEWEB)

James Reeves

2005-01-31

In a study funded by the U.S. Department of Energy and GeoSpectrum, Inc., new P-wave 3D seismic interpretation methods to characterize fractured gas reservoirs are developed. A data driven exploratory approach is used to determine empirical relationships for reservoir properties. Fractures are predicted using seismic lineament mapping through a series of horizon and time slices in the reservoir zone. A seismic lineament is a linear feature seen in a slice through the seismic volume that has negligible vertical offset. We interpret that in regions of high seismic lineament density there is a greater likelihood of fractured reservoir. Seismic AVO attributes are developed to map brittle reservoir rock (low clay) and gas content. Brittle rocks are interpreted to be more fractured when seismic lineaments are present. The most important attribute developed in this study is the gas sensitive phase gradient (a new AVO attribute), as reservoir fractures may provide a plumbing system for both water and gas. Success is obtained when economic gas and oil discoveries are found. In a gas field previously plagued with poor drilling results, four new wells were spotted using the new methodology and recently drilled. The wells have estimated best of 12-months production indicators of 2106, 1652, 941, and 227 MCFGPD. The latter well was drilled in a region of swarming seismic lineaments but has poor gas sensitive phase gradient (AVO) and clay volume attributes. GeoSpectrum advised the unit operators that this location did not appear to have significant Lower Dakota gas before the well was drilled. The other three wells are considered good wells in this part of the basin and among the best wells in the area. These new drilling results have nearly doubled the gas production and the value of the field. The interpretation method is ready for commercialization and gas exploration and development. The new technology is adaptable to conventional lower cost 3D seismic surveys.

Experimental processing of a model data set using Geobit seismic software

Energy Technology Data Exchange (ETDEWEB)

Suh, Sang Yong [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-12-01

A seismic data processing software, Geobit, has been developed and is continuously updated to implement newer processing techniques and to support more hardware platforms. Geobit is intended to support all Unix platforms ranging from PC to CRAY. The current version supports two platform, i.e., PC/Linux and Sun Sparc based Sun OS 4.1.x. PC/Linux attracted geophysicists in some universities trying to install Geobit in their laboratories to be used as their research tool. However, one of the problem is the difficulty in getting the seismic data. The primary reason is its huge volume. The field data is too bulky to fit their relatively small storage media, such as PC disk. To solve the problem, KIGAM released a model seismic data set via ftp.kigam.re.kr. This study aims two purposes. The first one is testing Geobit software for its suitability in seismic data processing. The test includes reproducing the model through the seismic data processing. If it fails to reproduce the original model, the software is considered buggy and incomplete. However, if it can successfully reproduce the input model, I would be proud of what I have accomplished for the last few years in writing Geobit. The second purpose is to give a guide on Geobit usage by providing an example set of job files needed to process a given data. This example will help scientists lacking Geobit experience to concentrate on their study more easily. Once they know the Geobit processing technique, and later on Geobit programming, they can implement their own processing idea, contributing newer technologies to Geobit. The complete Geobit job files needed to process the model data is written, in the following job sequence: (1) data loading, (2) CDP sort, (3) decon analysis, (4) velocity analysis, (5) decon verification, (6) stack, (7) filter analysis, (8) filtered stack, (9) time migration, (10) depth migration. The control variables in the job files are discussed. (author). 10 figs., 1 tab.

Integrated software system for seismic evaluation of nuclear power plant structures

International Nuclear Information System (INIS)

Xu, J.; Graves, H.L.

1993-01-01

The computer software CARES (Computer Analysis for Rapid Evaluation of Structures) was developed by the Brookhaven National Laboratory for the U.S. Nuclear Regulatory Commission. It represents an effort to utilize established numerical methodologies commonly employed by industry for structural safety evaluations of nuclear power plant facilities and incorporates them into an integrated computer software package operated on personal computers. CARES was developed with the objective of including all aspects of seismic performance evaluation of nuclear power structures. It can be used to evaluate the validity and accuracy of analysis methodologies used for structural safety evaluations of nuclear power plants by various utilities. CARES has a modular format, each module performing a specific type of analysis. The seismic module integrates all the steps of a complete seismic analysis into a single package with many user-friendly features such as interactiveness and quick turnaround. Linear structural theory and pseudo-linear convolution theory are utilized as the bases for the development with a special emphasis on the nuclear regulatory requirements for structural safety of nuclear plants. The organization of the seismic module is arranged in eight options, each performing a specific step of the analysis with most of input/output interfacing processed by the general manager. Finally, CARES provides comprehensive post-processing capability for displaying results graphically or in tabular form so that direct comparisons can be easily made. (author)

Highly-optimized TWSM software package for seismic diffraction modeling adapted for GPU-cluster

Science.gov (United States)

Zyatkov, Nikolay; Ayzenberg, Alena; Aizenberg, Arkady

2015-04-01

Oil producing companies concern to increase resolution capability of seismic data for complex oil-and-gas bearing deposits connected with salt domes, basalt traps, reefs, lenses, etc. Known methods of seismic wave theory define shape of hydrocarbon accumulation with nonsufficient resolution, since they do not account for multiple diffractions explicitly. We elaborate alternative seismic wave theory in terms of operators of propagation in layers and reflection-transmission at curved interfaces. Approximation of this theory is realized in the seismic frequency range as the Tip-Wave Superposition Method (TWSM). TWSM based on the operator theory allows to evaluate of wavefield in bounded domains/layers with geometrical shadow zones (in nature it can be: salt domes, basalt traps, reefs, lenses, etc.) accounting for so-called cascade diffraction. Cascade diffraction includes edge waves from sharp edges, creeping waves near concave parts of interfaces, waves of the whispering galleries near convex parts of interfaces, etc. The basic algorithm of TWSM package is based on multiplication of large-size matrices (make hundreds of terabytes in size). We use advanced information technologies for effective realization of numerical procedures of the TWSM. In particular, we actively use NVIDIA CUDA technology and GPU accelerators allowing to significantly improve the performance of the TWSM software package, that is important in using it for direct and inverse problems. The accuracy, stability and efficiency of the algorithm are justified by numerical examples with curved interfaces. TWSM package and its separate components can be used in different modeling tasks such as planning of acquisition systems, physical interpretation of laboratory modeling, modeling of individual waves of different types and in some inverse tasks such as imaging in case of laterally inhomogeneous overburden, AVO inversion.

Did you smooth your well logs the right way for seismic interpretation?

International Nuclear Information System (INIS)

Duchesne, Mathieu J; Gaillot, Philippe

2011-01-01

Correlations between physical properties and seismic reflection data are useful to determine the geological nature of seismic reflections and the lateral extent of geological strata. The difference in resolution between well logs and seismic data is a major hurdle faced by seismic interpreters when tying both data sets. In general, log data have a resolution of at least two orders of magnitude greater than seismic data. Smoothing physical property logs improves correlation at the seismic scale. Three different approaches were used and compared to smooth a density log: binomial filtering, seismic wavelet filtering and discrete wavelet transform (DWT) filtering. Regression plots between the density logs and the acoustic impedance show that the data smoothed with the DWT is the only method that preserves the original relationship between the raw density data and the acoustic impedance. Smoothed logs were then used to generate synthetic seismograms that were tied to seismic data at the borehole site. Best ties were achieved using the synthetic seismogram computed with the density log processed with the DWT. The good performance of the DWT is explained by its adaptive multi-scale characteristic which preserved significant local changes of density on the high-resolution data series that were also pictured at the seismic scale. Since synthetic seismograms are generated using smoothed logs, the choice of the smoothing method impacts on the quality of seismic-to-well ties. This ultimately can have economical implications during hydrocarbon exploration or exploitation phases

Analysis of the seismicity of Southeastern Sicily: a proposed tectonic interpretation

Directory of Open Access Journals (Sweden)

M. S. Barbano

2000-06-01

Full Text Available Southeastern Sicily is one of the Italian regions with high seismic risk and is characterised by the occurrence in the past of large destructive events (MS = 6.4-7.3 over a territory which is densely urbanised today. The main earthquakes were analysed and some minor damaging shocks reviewed to investigate the main seismogenic features of the region. The comparison between the pattern of seismicity and evidence of Quaternary tectonics allowed us to propose a first tentative, tectonic interpretation of the earthquakes. On the whole, the seismicity of SE Sicily seems distributed along regional fault systems which have had a role in the recent geodynamic evolution of the area. The Malta escarpment, the only structure whose late Quaternary-recent activity is currently known, appears the most probable source for earthquakes with about 7 magnitude. Although no evidence of tectonics subsequent to the middle Pleistocene is available for them, the Scicli line and the NE-SW fault system delimiting the northern sector of the Hyblean plateau seem seismically active with events with maximum magnitude of 5.2 and 6.4, respectively.

Pliocene paleoenvironment evolution as interpreted from 3D-seismic data in the southern North Sea, Dutch offshore sector

Energy Technology Data Exchange (ETDEWEB)

Kuhlmann, Gesa [Faculty of Earth Sciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht (Netherlands); Wong, Theo E. [Faculty of Earth Sciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht (Netherlands); TNO-NITG, National Geological Survey of the Netherlands, Princetonlaan 6, 3584 CB Utrecht (Netherlands)

2008-02-15

A high-resolution 3D-seismic survey from the Dutch offshore sector has been interpreted and subsequently correlated with existing regional seismo-stratigraphic concepts derived from conventional 2D-seismic data sets. The interpreted 13 seismic units have been related to a newly established chrono-stratigraphic framework [Kuhlmann et al., 2006a, b. Chronostratigraphy of Late Neogene sediments in the southern North Sea Basin and paleoenvironmental interpretations. Palaeogeography, Palaeoclimatology, Palaeoecology, 239, 426-455; Integrated chronostratigraphy of the Pliocene-Pleistocene interval and its relation to the regional stratigraphical stages in the southern North Sea region. Netherlands Journal of Geosciences-Geologie en Mijnbouw, 85(1), 19-35] resulting in up-dated age control for the seismic units. The generation of amplitude maps, time slices and isopach maps from the 3D-seismic data enabled detailed spatial and temporal reconstruction regarding the paleoenvironmental and climatological development as depicted by Kuhlmann et al. [2006a. Chronostratigraphy of Late Neogene sediments in the southern North Sea Basin and paleoenvironmental interpretations. Palaeogeography, Palaeoclimatology, Palaeoecology, 239, 426-455]. The lowermost seismic units S1-S4 comprise condensed Middle Miocene to Piacencian sediments, deposited under warm open marine conditions. These sediments show a uniform seismic facies of low-amplitude reflectors. The boundary of seismic unit S4-S5 (around 2.6 Ma) delineates a shift towards generally colder climate conditions that are connected to the onset of Northern Hemisphere Glaciation. Seismic unit S5 includes alternations of warmer and colder periods. During warmer periods, bottom currents generated elongated structures (2.5-4 km long, 300-500 m wide) on the horizon display. These layers show as well shallow gas accumulations with a more regional extent and are related to coarser-grained sediments sealed by clayey sediments of the cold

Processing of Mining Induced Seismic Events by Spectra Analyzer Software

Czech Academy of Sciences Publication Activity Database

Kaláb, Zdeněk; Lednická, Markéta; Lyubushin, A. A.

2011-01-01

Roč. 6, č. 1 (2011), s. 75-83 ISSN 1896-3145. [Ochrona środowiska w górnictwie podziemnym, odkrywkowym i otworowym. Walbrzych, 18.05.2011-20.05.2011] Institutional research plan: CEZ:AV0Z30860518 Keywords : mining seismicity * Spectra Analyzer Software * wavelet decomposition * time-frequency map Subject RIV: DC - Siesmology, Volcanology, Earth Structure

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

Open Online Research: Developing Software and Method for Collaborative Interpretation

Directory of Open Access Journals (Sweden)

Christian Bröer

2016-09-01

Full Text Available Inspired by the potentials of web-based collaboration, in 2014, a group of social scientists, students and information specialists started tinkering with software and methodology for open online collaborative research. The results of their research led to a gathering of academics at the #ethnography Conference Amsterdam 2014, where new material was collected, shared and collaboratively interpreted. Following the conference, they continued to develop software and methodology. In this contribution, we report on the aims, methodology, inspiring examples, caveats and results from testing several prototypes of open online research software. We conclude that open online collaborative interpretation is both feasible and desirable. Dialogue and reflexivity, we hold, are able to transcend separated perspectives and stimulate agreement on a set of distinct interpretations; they simultaneously respect the multiplicity of understandings of social phenomena whilst bringing order into this diversity. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs160327

SEISVIZ3D: Stereoscopic system for the representation of seismic data - Interpretation and Immersion

Science.gov (United States)

von Hartmann, Hartwig; Rilling, Stefan; Bogen, Manfred; Thomas, Rüdiger

2015-04-01

The seismic method is a valuable tool for getting 3D-images from the subsurface. Seismic data acquisition today is not only a topic for oil and gas exploration but is used also for geothermal exploration, inspections of nuclear waste sites and for scientific investigations. The system presented in this contribution may also have an impact on the visualization of 3D-data of other geophysical methods. 3D-seismic data can be displayed in different ways to give a spatial impression of the subsurface.They are a combination of individual vertical cuts, possibly linked to a cubical portion of the data volume, and the stereoscopic view of the seismic data. By these methods, the spatial perception for the structures and thus of the processes in the subsurface should be increased. Stereoscopic techniques are e. g. implemented in the CAVE and the WALL, both of which require a lot of space and high technical effort. The aim of the interpretation system shown here is stereoscopic visualization of seismic data at the workplace, i.e. at the personal workstation and monitor. The system was developed with following criteria in mind: • Fast rendering of large amounts of data so that a continuous view of the data when changing the viewing angle and the data section is possible, • defining areas in stereoscopic view to translate the spatial impression directly into an interpretation, • the development of an appropriate user interface, including head-tracking, for handling the increased degrees of freedom, • the possibility of collaboration, i.e. teamwork and idea exchange with the simultaneous viewing of a scene at remote locations. The possibilities offered by the use of a stereoscopic system do not replace a conventional interpretation workflow. Rather they have to be implemented into it as an additional step. The amplitude distribution of the seismic data is a challenge for the stereoscopic display because the opacity level and the scaling and selection of the data have to

Writing Compilers and Interpreters A Software Engineering Approach

CERN Document Server

Mak, Ronald

2011-01-01

Long-awaited revision to a unique guide that covers both compilers and interpreters Revised, updated, and now focusing on Java instead of C++, this long-awaited, latest edition of this popular book teaches programmers and software engineering students how to write compilers and interpreters using Java. You?ll write compilers and interpreters as case studies, generating general assembly code for a Java Virtual Machine that takes advantage of the Java Collections Framework to shorten and simplify the code. In addition, coverage includes Java Collections Framework, UML modeling, object-oriented p

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...

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

Seismic interpretation of the Rocky Mountain thrust front near the Crowsnest deflection, southern Alberta

Energy Technology Data Exchange (ETDEWEB)

Begin, N.J.; Lawton, D.C.; Spratt, D.A. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

1996-03-01

Interpretation of reflection seismic data from the southwestern Alberta Foothills near the Crowsnest Deflection provided insight into the structural relationship between the triangle zone and the foreland basin. Six seismic lines were interpreted which show autochtonous Paleozoic rocks overlain by thrust sheets of upper Mesozoic and Tertiary strata. The overall structural geometry consists of an allochtonous wedge with east-verging shingles that are sandwiched between undeformed Paleozoic strata and the Alberta Syncline. The Big Coulee Fault, which rides within the Bearpaw Formation, represents the boundary between the east and west-verging structures and is the main upper detachment of the triangle zone. A lateral ramp occurs in the lower detachment which is evidence for southward thickening of the allochtonous wedge. 24 refs., 2 tabs., 8 figs.

Integrating sequence stratigraphy and rock-physics to interpret seismic amplitudes and predict reservoir quality

Science.gov (United States)

Dutta, Tanima

This dissertation focuses on the link between seismic amplitudes and reservoir properties. Prediction of reservoir properties, such as sorting, sand/shale ratio, and cement-volume from seismic amplitudes improves by integrating knowledge from multiple disciplines. The key contribution of this dissertation is to improve the prediction of reservoir properties by integrating sequence stratigraphy and rock physics. Sequence stratigraphy has been successfully used for qualitative interpretation of seismic amplitudes to predict reservoir properties. Rock physics modeling allows quantitative interpretation of seismic amplitudes. However, often there is uncertainty about selecting geologically appropriate rock physics model and its input parameters, away from the wells. In the present dissertation, we exploit the predictive power of sequence stratigraphy to extract the spatial trends of sedimentological parameters that control seismic amplitudes. These spatial trends of sedimentological parameters can serve as valuable constraints in rock physics modeling, especially away from the wells. Consequently, rock physics modeling, integrated with the trends from sequence stratigraphy, become useful for interpreting observed seismic amplitudes away from the wells in terms of underlying sedimentological parameters. We illustrate this methodology using a comprehensive dataset from channelized turbidite systems, deposited in minibasin settings in the offshore Equatorial Guinea, West Africa. First, we present a practical recipe for using closed-form expressions of effective medium models to predict seismic velocities in unconsolidated sandstones. We use an effective medium model that combines perfectly rough and smooth grains (the extended Walton model), and use that model to derive coordination number, porosity, and pressure relations for P and S wave velocities from experimental data. Our recipe provides reasonable fits to other experimental and borehole data, and specifically

Structural interpretation of seismic data of Abu Rudeis-Sidri area, Northern Central Gulf of Suez, Egypt

Directory of Open Access Journals (Sweden)

Hesham Shaker Zahra

2016-12-01

Full Text Available The 2D and 3D seismic data are interpreted to evaluate the subsurface geologic structures in the Abu Rudeis-Sidri area that occupy the northern central part of the Gulf of Suez. The 2D seismic data are used for determination of the structural configurations and the tectonic features which is analyzed through the study of interpretation with the available geologic data, in which the geo-seismic depth maps for the main interesting tops (Kareem, Nukhul, Matulla, Raha and Nubia Formations are represented. Such maps reflect that, the Miocene structure of Abu Rudeis-Sidri area is an asymmetrical NW-SE trending anticlinal feature dissected by a set of NW-SE fault system (clysmic. Added, the Pre-Miocene structure of the studied area is very complex, where the area is of NE dip and affected by severe faulting through varying stratigraphic levels.

ENHANCING SEISMIC CALIBRATION RESEARCH THROUGH SOFTWARE AUTOMATION AND SCIENTIFIC INFORMATION MANAGEMENT

Energy Technology Data Exchange (ETDEWEB)

Ruppert, S; Dodge, D A; Ganzberger, M D; Hauk, T F; Matzel, E M

2008-07-03

The National Nuclear Security Administration (NNSA) Ground-Based Nuclear Explosion Monitoring Research and Development (GNEMRD) Program at LLNL continues to make significant progress enhancing the process of deriving seismic calibrations and performing scientific integration, analysis, and information management with software automation tools. Our tool efforts address the problematic issues of very large datasets and varied formats encountered during seismic calibration research. New information management and analysis tools have resulted in demonstrated gains in efficiency of producing scientific data products and improved accuracy of derived seismic calibrations. The foundation of a robust, efficient data development and processing environment is comprised of many components built upon engineered versatile libraries. We incorporate proven industry 'best practices' throughout our code and apply source code and bug tracking management as well as automatic generation and execution of unit tests for our experimental, development and production lines. Significant software engineering and development efforts have produced an object-oriented framework that provides database centric coordination between scientific tools, users, and data. Over a half billion parameters, signals, measurements, and metadata entries are all stored in a relational database accessed by an extensive object-oriented multi-technology software framework that includes stored procedures, real-time transactional database triggers and constraints, as well as coupled Java and C++ software libraries to handle the information interchange and validation requirements. Significant resources were applied to schema design to enable management of processing methods and station parameters, responses and metadata. This allowed for the development of merged ground-truth (GT) data sets compiled by the NNSA labs and AFTAC that include hundreds of thousands of events and tens of millions of arrivals. The

New geological interpretation of multi-channel seismic profiles from the Pacific Margin of the Antarctic Peninsula

Directory of Open Access Journals (Sweden)

Okoń Jan

2016-06-01

Full Text Available The Polish Geophysical Expedition to West Antarctica in 1979–1980 was carried out by the Institute of Geophysics, Polish Academy of Sciences. Beside deep seismic soundings, 12 multi-channel seismic profiles, with a total length of ca 1000 km have been recorded north and east of the South Shetland Islands and in the Bransfield Strait, but they have never before been completely interpreted and published. All profiles have been processed with modern processing flow including time migration. Profiles crossing the South Shetland Trench revealed distinct reflector inside continental slope, which has been interpreted as border between buried accretionary prism and overlying slope sediments of glacial-marine origin. Profiles in the Bransfield Strait show traces of the Last Glacial Maximum (LGM in the form of glacial foreground valleys, with some of them used as weak spots for young age volcanic intrusions. This paper is the first comprehensive geological interpretation of collected dataset and differences between results from other expeditions are discussed.

The SCEC Unified Community Velocity Model (UCVM) Software Framework for Distributing and Querying Seismic Velocity Models

Science.gov (United States)

Maechling, P. J.; Taborda, R.; Callaghan, S.; Shaw, J. H.; Plesch, A.; Olsen, K. B.; Jordan, T. H.; Goulet, C. A.

2017-12-01

Crustal seismic velocity models and datasets play a key role in regional three-dimensional numerical earthquake ground-motion simulation, full waveform tomography, modern physics-based probabilistic earthquake hazard analysis, as well as in other related fields including geophysics, seismology, and earthquake engineering. The standard material properties provided by a seismic velocity model are P- and S-wave velocities and density for any arbitrary point within the geographic volume for which the model is defined. Many seismic velocity models and datasets are constructed by synthesizing information from multiple sources and the resulting models are delivered to users in multiple file formats, such as text files, binary files, HDF-5 files, structured and unstructured grids, and through computer applications that allow for interactive querying of material properties. The Southern California Earthquake Center (SCEC) has developed the Unified Community Velocity Model (UCVM) software framework to facilitate the registration and distribution of existing and future seismic velocity models to the SCEC community. The UCVM software framework is designed to provide a standard query interface to multiple, alternative velocity models, even if the underlying velocity models are defined in different formats or use different geographic projections. The UCVM framework provides a comprehensive set of open-source tools for querying seismic velocity model properties, combining regional 3D models and 1D background models, visualizing 3D models, and generating computational models in the form of regular grids or unstructured meshes that can be used as inputs for ground-motion simulations. The UCVM framework helps researchers compare seismic velocity models and build equivalent simulation meshes from alternative velocity models. These capabilities enable researchers to evaluate the impact of alternative velocity models in ground-motion simulations and seismic hazard analysis applications

Enhanced Structural Interpretation Using Multitrace Seismic Attribute For Oligo-Miocene Target at Madura Strait Offshore

Science.gov (United States)

Pratama Wahyu Hidayat, Putra; Hary Murti, Antonius; Sudarmaji; Shirly, Agung; Tiofan, Bani; Damayanti, Shinta

2018-03-01

Geometry is an important parameter for the field of hydrocarbon exploration and exploitation, it has significant effect to the amount of resources or reserves, rock spreading, and risk analysis. The existence of geological structure or fault becomes one factor affecting geometry. This study is conducted as an effort to enhance seismic image quality in faults dominated area namely offshore Madura Strait. For the past 10 years, Oligo-Miocene carbonate rock has been slightly explored on Madura Strait area, the main reason because migration and trap geometry still became risks to be concern. This study tries to determine the boundary of each fault zone as subsurface image generated by converting seismic data into variance attribute. Variance attribute is a multitrace seismic attribute as the derivative result from amplitude seismic data. The result of this study shows variance section of Madura Strait area having zero (0) value for seismic continuity and one (1) value for discontinuity of seismic data. Variance section shows the boundary of RMKS fault zone with Kendeng zone distinctly. Geological structure and subsurface geometry for Oligo-Miocene carbonate rock could be identified perfectly using this method. Generally structure interpretation to identify the boundary of fault zones could be good determined by variance attribute.

Generalized component analysis applied to the generation of seismic attributes for AVO and 4D reservoir interpretations; Mise au point d'attributs sismiques pour l'interpretation AVO et 4D des reservoirs petroliers par analyse en composantes generalisee

Energy Technology Data Exchange (ETDEWEB)

Voutay, O.

2003-02-01

Seismic data contain further geological information than well, due to their good spatial extent. But the seismic measure is band pass limited and the contrasts in acoustic or elastic properties derived from seismic are not directly linked to the reservoir properties. Thus, it is difficult to give a geological interpretation to seismic data. Basically, relevant seismic attributes are extracted at the reservoir level, and then are calibrated with information available at wells by using pattern recognition and statistical estimation techniques. These methods are successfully used in the post-stack domain. But, for multi-cube seismic information such as pre-stack or 4D data, the number of attributes can considerably increase and statistical methods are not often used. It is necessary to find a parameterization allowing an optimal description the seismic variability in the time window of interest. We propose to extract new attributes from seismic multi-cube data with Generalised Principal Analysis and to use them for reservoir interpretation with statistical techniques. The new attributes can be clearly related to the initial data set, and then be physically interpreted, while optimally summarizing the initial seismic information. By applying the Generalised Principal Analysis to 3D pre-stack surveys, the contribution of the pre-stack seismic information to reservoir characterisation is compared to the post-stack seismic one, in both synthetic and real cases. By applying the Generalised Principal Analysis to real 4D surveys, the seismic repeatability is quantified and the seismic changes in the reservoir with calendar time are highlighted and interpreted. A coherency cube has also been defined, based on the Generalised Principal Analysis. This attribute is a coherence measurement in three dimensions representing the local similarity between 4D or AVO surveys. (author)

Properties of an improved Gabor wavelet transform and its applications to seismic signal processing and interpretation

Science.gov (United States)

Ji, Zhan-Huai; Yan, Sheng-Gang

2017-12-01

This paper presents an analytical study of the complete transform of improved Gabor wavelets (IGWs), and discusses its application to the processing and interpretation of seismic signals. The complete Gabor wavelet transform has the following properties. First, unlike the conventional transform, the improved Gabor wavelet transform (IGWT) maps time domain signals to the time-frequency domain instead of the time-scale domain. Second, the IGW's dominant frequency is fixed, so the transform can perform signal frequency division, where the dominant frequency components of the extracted sub-band signal carry essentially the same information as the corresponding components of the original signal, and the subband signal bandwidth can be regulated effectively by the transform's resolution factor. Third, a time-frequency filter consisting of an IGWT and its inverse transform can accurately locate target areas in the time-frequency field and perform filtering in a given time-frequency range. The complete IGW transform's properties are investigated using simulation experiments and test cases, showing positive results for seismic signal processing and interpretation, such as enhancing seismic signal resolution, permitting signal frequency division, and allowing small faults to be identified.

Seismic network at the Olkiluoto site and microearthquake observations in 2002-2013

International Nuclear Information System (INIS)

Saari, J.; Malm, M.

2014-05-01

magnitudes of the earthquakes were M L = -2.1 - 0.0 and the depths 66 - 450 m underground. The small number of induced seismic events shows that the rock mechanical conditions in the rock mass surrounding the ONKALO have been stable. This is an indication of both the characteristics of the bedrock as well as the quality of the design and realisation of the conducted excavations of the ONKALO. This report updates and summarises interpretations of induced microearthquakes based on the latest versions of the bedrock model and software as well as experience gained in interpretation. (orig.)

Static analysis of software the abstract interpretation

CERN Document Server

Boulanger, Jean-Louis

2013-01-01

The existing literature currently available to students and researchers is very general, covering only the formal techniques of static analysis. This book presents real examples of the formal techniques called ""abstract interpretation"" currently being used in various industrial fields: railway, aeronautics, space, automotive, etc. The purpose of this book is to present students and researchers, in a single book, with the wealth of experience of people who are intrinsically involved in the realization and evaluation of software-based safety critical systems. As the authors are people curr

Seismic Evaluation of A Historical Structure In Kastamonu - Turkey

Science.gov (United States)

Pınar, USTA; Işıl ÇARHOĞLU, Asuman; EVCİ, Ahmet

2018-01-01

The Kastomonu province is a seismically active zone. the city has many historical buildings made of stone-masonry. In case of any probable future earthquakes, existing buildings may suffer substantial or heavy damages. In the present study, one of the historical traditional house located in Kastamonu were structurally investigated through probabilistic seismic risk assessment methodology. In the study, the building was modeled by using the Finite Element Modeling (FEM) software, SAP2000. Time history analyses were carried out using 10 different ground motion data on the FEM models. Displacements were interpreted, and the results were displayed graphically and discussed.

INCREASING OIL RECOVERY THROUGH ADVANCED REPROCESSING OF 3D SEISMIC, GRANT CANYON AND BACON FLAT FIELDS, NYE COUNTY, NEVADA

Energy Technology Data Exchange (ETDEWEB)

Eric H. Johnson; Don E. French

2001-06-01

Makoil, Inc., of Orange, California, with the support of the U.S. Department of Energy has reprocessed and reinterpreted the 3D seismic survey of the Grant Canyon area, Railroad Valley, Nye County, Nevada. The project was supported by Dept. of Energy Grant DE-FG26-00BC15257. The Grant Canyon survey covers an area of 11 square miles, and includes Grant Canyon and Bacon Flat oil fields. These fields have produced over 20 million barrels of oil since 1981, from debris slides of Devonian rocks that are beneath 3,500 to 5,000 ft of Tertiary syntectonic deposits that fill the basin of Railroad Valley. High-angle and low-angle normal faults complicate the trap geometry of the fields, and there is great variability in the acoustic characteristics of the overlying valley fill. These factors combine to create an area that is challenging to interpret from seismic reflection data. A 3D seismic survey acquired in 1992-93 by the operator of the fields has been used to identify development and wildcat locations with mixed success. Makoil believed that improved techniques of processing seismic data and additional well control could enhance the interpretation enough to improve the chances of success in the survey area. The project involved the acquisition of hardware and software for survey interpretation, survey reprocessing, and reinterpretation of the survey. SeisX, published by Paradigm Geophysical Ltd., was chosen as the interpretation software, and it was installed on a Dell Precision 610 computer work station with the Windows NT operating system. The hardware and software were selected based on cost, possible addition of compatible modeling software in the future, and the experience of consulting geophysicists in the Billings area. Installation of the software and integration of the hardware into the local office network was difficult at times but was accomplished with some technical support from Paradigm and Hewlett Packard, manufacturer of some of the network equipment. A

INCREASING OIL RECOVERY THROUGH ADVANCED REPROCESSING OF 3D SEISMIC, GRANT CANYON AND BACON FLAT FIELDS, NYE COUNTY, NEVADA

International Nuclear Information System (INIS)

Johnson, Eric H.; French, Don E.

2001-01-01

Makoil, Inc., of Orange, California, with the support of the U.S. Department of Energy has reprocessed and reinterpreted the 3D seismic survey of the Grant Canyon area, Railroad Valley, Nye County, Nevada. The project was supported by Dept. of Energy Grant DE-FG26-00BC15257. The Grant Canyon survey covers an area of 11 square miles, and includes Grant Canyon and Bacon Flat oil fields. These fields have produced over 20 million barrels of oil since 1981, from debris slides of Devonian rocks that are beneath 3,500 to 5,000 ft of Tertiary syntectonic deposits that fill the basin of Railroad Valley. High-angle and low-angle normal faults complicate the trap geometry of the fields, and there is great variability in the acoustic characteristics of the overlying valley fill. These factors combine to create an area that is challenging to interpret from seismic reflection data. A 3D seismic survey acquired in 1992-93 by the operator of the fields has been used to identify development and wildcat locations with mixed success. Makoil believed that improved techniques of processing seismic data and additional well control could enhance the interpretation enough to improve the chances of success in the survey area. The project involved the acquisition of hardware and software for survey interpretation, survey reprocessing, and reinterpretation of the survey. SeisX, published by Paradigm Geophysical Ltd., was chosen as the interpretation software, and it was installed on a Dell Precision 610 computer work station with the Windows NT operating system. The hardware and software were selected based on cost, possible addition of compatible modeling software in the future, and the experience of consulting geophysicists in the Billings area. Installation of the software and integration of the hardware into the local office network was difficult at times but was accomplished with some technical support from Paradigm and Hewlett Packard, manufacturer of some of the network equipment. A

Geological and Seismic Data Mining For The Development of An Interpretation System Within The Alptransit Project

Science.gov (United States)

Klose, C. D.; Giese, R.; Löw, S.; Borm, G.

Especially for deep underground excavations, the prediction of the locations of small- scale hazardous geotechnical structures is nearly impossible when exploration is re- stricted to surface based methods. Hence, for the AlpTransit base tunnels, exploration ahead has become an essential component of the excavation plan. The project de- scribed in this talk aims at improving the technology for the geological interpretation of reflection seismic data. The discovered geological-seismic relations will be used to develop an interpretation system based on artificial intelligence to predict hazardous geotechnical structures of the advancing tunnel face. This talk gives, at first, an overview about the data mining of geological and seismic properties of metamorphic rocks within the Penninic gneiss zone in Southern Switzer- land. The data results from measurements of a specific geophysical prediction system developed by the GFZ Potsdam, Germany, along the 2600 m long and 1400 m deep Faido access tunnel. The goal is to find those seismic features (i.e. compression and shear wave velocities, velocity ratios and velocity gradients) which show a significant relation to geological properties (i.e. fracturing and fabric features). The seismic properties were acquired from different tomograms, whereas the geolog- ical features derive from tunnel face maps. The features are statistically compared with the seismic rock properties taking into account the different methods used for the tunnel excavation (TBM and Drill/Blast). Fracturing and the mica content stay in a positive relation to the velocity values. Both, P- and S-wave velocities near the tunnel surface describe the petrology better, whereas in the interior of the rock mass they correlate to natural micro- and macro-scopic fractures surrounding tectonites, i.e. cataclasites. The latter lie outside of the excavation damage zone and the tunnel loos- ening zone. The shear wave velocities are better indicators for rock

Exploring the Gross Schoenebeck (Germany) geothermal site using a statistical joint interpretation of magnetotelluric and seismic tomography models

Energy Technology Data Exchange (ETDEWEB)

Munoz, Gerard; Bauer, Klaus; Moeck, Inga; Schulze, Albrecht; Ritter, Oliver [Deutsches GeoForschungsZentrum (GFZ), Telegrafenberg, 14473 Potsdam (Germany)

2010-03-15

Exploration for geothermal resources is often challenging because there are no geophysical techniques that provide direct images of the parameters of interest, such as porosity, permeability and fluid content. Magnetotelluric (MT) and seismic tomography methods yield information about subsurface distribution of resistivity and seismic velocity on similar scales and resolution. The lack of a fundamental law linking the two parameters, however, has limited joint interpretation to a qualitative analysis. By using a statistical approach in which the resistivity and velocity models are investigated in the joint parameter space, we are able to identify regions of high correlation and map these classes (or structures) back onto the spatial domain. This technique, applied to a seismic tomography-MT profile in the area of the Gross Schoenebeck geothermal site, allows us to identify a number of classes in accordance with the local geology. In particular, a high-velocity, low-resistivity class is interpreted as related to areas with thinner layers of evaporites; regions where these sedimentary layers are highly fractured may be of higher permeability. (author)

Data processing of natural and induced events recorded at the seismic station Ostrava-Kr¨¢sn¨¦ Pole (OKC

Directory of Open Access Journals (Sweden)

Nov¨¢k Josef

2001-09-01

Full Text Available The operation of the seismic station Ostrava-Kr¨¢sn¨¦ Pole (OKC (¦Õ = 49.8352¡ãN; ¦Ë = 18.1422¡ãE which is situated at present in an experimental gallery nearby the Ostrava planetarium started in the year 1983 being equiped initially by analogue instrumentation. Modernization of instrumentation at the station was aimed at the installation of a new digital data acquisition system and the respective software packages for data interpretation and transmission.Data acquisition system VISTEC is based on PC which enables continuous recording of three- component short-period and medium-period systems with the sampling frequency of 20 Hz. The basic advantage of the OS Linux adopted allows remote access (telnet and the possibility of the recorded data transmission (ftp. Possible troubles in the seismic station operation can be quickly detected (even automatically and all recorded data are with minimum delay on disposal. The use of the remote access makes possible also to change the parameters of measuring set-up. The standard form of output data allows the application of standard software packages for visualisation and evaluation. There are on disposal following formates: GSE2/CM6, GSE2/INT and MiniSEED. The output data sets can be compressed by a special procedure. For interactive interpretation od digital seismic data, software package EVENT developed in the Geophysical Institute AS CR and package WAVE developed in the Institute of Geonics AS CR are used.Experimental operation of digital seismographs at the station OKC confirmed justification of its incorporation into the seismic stations of the Czech national seismological network (CNSN. Based on the preliminary analysis of digital data it proved that following groups of seismic events are recorded: earthquakes, induced seismic events from Polish copper and coal mines, induced seismic events from the Ostrava-Karvin¨¢ Coal Basin, quarry blasts and weak regional seismic events of the

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)

Integrated interpretation of 3D seismic data to enhance the detection of the gold-bearing reef: Mponeng Gold mine, Witwatersrand Basin (South Africa)

CSIR Research Space (South Africa)

Manzi, M

2015-07-01

Full Text Available The authors present an integrated approach to the seismic interpretation of one of the world's deepest gold ore body (Carbon Leader Reef) using three-dimensional seismic data, ultrasonic velocity measurements at elevated stresses, and modified...

Using recurrence plot analysis for software execution interpretation and fault detection

Science.gov (United States)

Mosdorf, M.

2015-09-01

This paper shows a method targeted at software execution interpretation and fault detection using recurrence plot analysis. In in the proposed approach recurrence plot analysis is applied to software execution trace that contains executed assembly instructions. Results of this analysis are subject to further processing with PCA (Principal Component Analysis) method that simplifies number coefficients used for software execution classification. This method was used for the analysis of five algorithms: Bubble Sort, Quick Sort, Median Filter, FIR, SHA-1. Results show that some of the collected traces could be easily assigned to particular algorithms (logs from Bubble Sort and FIR algorithms) while others are more difficult to distinguish.

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.

Geomechanics for interpreting SAGD monitoring using micro-seismicity and surface tiltmeters

International Nuclear Information System (INIS)

De Pater, H.; De Koning, J.; Maxwell, S.; Walters, D.

2008-01-01

This paper described a procedures for history matching surface movements resulting from the warm-up phases of a steam assisted gravity drainage (SAGD) project in Saskatchewan. Surface movements were measured using tilt meters that covered the area influenced by the steam injection processes. A thermal reservoir model was then coupled to a geo-mechanical model in order to calculate the surface movements. Surface heave was computed by matching a minimum curvature surface to the tilt vectors. Surface heave data were extracted in order to facilitate comparisons between observed and simulated heave. Injection constraints were defined from measured injection rates in order to match pressure histories. The study showed that the coupled model accurately interpreted monitoring data. Seismic signatures indicated strike slip and potential overthrust fault slippage or casing failures. Uplift was largest at the heel of the well. Results were explained by reservoir heterogeneities. Surface heave was accurately measured using the tiltmeters. Micro-seismic data were used to constrain failure mechanisms and provide information needed to identify conformance and potential cap rock breaches. It was concluded that the model can be used effectively to optimize injection conformance and recovery. 10 refs., 4 tabs., 28 figs

Geomechanics for interpreting SAGD monitoring using micro-seismicity and surface tiltmeters

Energy Technology Data Exchange (ETDEWEB)

De Pater, H.; De Koning, J.; Maxwell, S. [Pinnacle Technologies, Calgary, AB (Canada); Walters, D. [Taurus Reservoir Solutions Ltd., Calgary, AB (Canada)

2008-10-15

This paper described a procedures for history matching surface movements resulting from the warm-up phases of a steam assisted gravity drainage (SAGD) project in Saskatchewan. Surface movements were measured using tilt meters that covered the area influenced by the steam injection processes. A thermal reservoir model was then coupled to a geo-mechanical model in order to calculate the surface movements. Surface heave was computed by matching a minimum curvature surface to the tilt vectors. Surface heave data were extracted in order to facilitate comparisons between observed and simulated heave. Injection constraints were defined from measured injection rates in order to match pressure histories. The study showed that the coupled model accurately interpreted monitoring data. Seismic signatures indicated strike slip and potential overthrust fault slippage or casing failures. Uplift was largest at the heel of the well. Results were explained by reservoir heterogeneities. Surface heave was accurately measured using the tiltmeters. Micro-seismic data were used to constrain failure mechanisms and provide information needed to identify conformance and potential cap rock breaches. It was concluded that the model can be used effectively to optimize injection conformance and recovery. 10 refs., 4 tabs., 28 figs.

Integrating 3D seismic curvature and curvature gradient attributes for fracture characterization: Methodologies and interpretational implications

Energy Technology Data Exchange (ETDEWEB)

Gao, Dengliang

2013-03-01

In 3D seismic interpretation, curvature is a popular attribute that depicts the geometry of seismic reflectors and has been widely used to detect faults in the subsurface; however, it provides only part of the solutions to subsurface structure analysis. This study extends the curvature algorithm to a new curvature gradient algorithm, and integrates both algorithms for fracture detection using a 3D seismic test data set over Teapot Dome (Wyoming). In fractured reservoirs at Teapot Dome known to be formed by tectonic folding and faulting, curvature helps define the crestal portion of the reservoirs that is associated with strong seismic amplitude and high oil productivity. In contrast, curvature gradient helps better define the regional northwest-trending and the cross-regional northeast-trending lineaments that are associated with weak seismic amplitude and low oil productivity. In concert with previous reports from image logs, cores, and outcrops, the current study based on an integrated seismic curvature and curvature gradient analysis suggests that curvature might help define areas of enhanced potential to form tensile fractures, whereas curvature gradient might help define zones of enhanced potential to develop shear fractures. In certain fractured reservoirs such as at Teapot Dome where faulting and fault-related folding contribute dominantly to the formation and evolution of fractures, curvature and curvature gradient attributes can be potentially applied to differentiate fracture mode, to predict fracture intensity and orientation, to detect fracture volume and connectivity, and to model fracture networks.

The Application of Seismic Attributes and Wheeler Transformations for the Geomorphological Interpretation of Stratigraphic Surfaces: A Case Study of the F3 Block, Dutch Offshore Sector, North Sea

OpenAIRE

Mohammad Afifi Ishak; Md. Aminul Islam; Mohamed Ragab Shalaby; Nurul Hasan

2018-01-01

This study was carried out in the Pliocene interval of the southern North Sea F3 Block in the Netherlands. This research paper demonstrates how an integrated interpretation of geological information using seismic attributes, sequence stratigraphic interpretation and Wheeler transformation methods allow for the accurate interpretation of the depositional environment of a basin, as well as locating seismic geomorphological features. The methodology adopted here is to generate a 3D dip-steered H...

Spatial pattern recognition of seismic events in South West Colombia

Science.gov (United States)

Benítez, Hernán D.; Flórez, Juan F.; Duque, Diana P.; Benavides, Alberto; Lucía Baquero, Olga; Quintero, Jiber

2013-09-01

Recognition of seismogenic zones in geographical regions supports seismic hazard studies. This recognition is usually based on visual, qualitative and subjective analysis of data. Spatial pattern recognition provides a well founded means to obtain relevant information from large amounts of data. The purpose of this work is to identify and classify spatial patterns in instrumental data of the South West Colombian seismic database. In this research, clustering tendency analysis validates whether seismic database possesses a clustering structure. A non-supervised fuzzy clustering algorithm creates groups of seismic events. Given the sensitivity of fuzzy clustering algorithms to centroid initial positions, we proposed a methodology to initialize centroids that generates stable partitions with respect to centroid initialization. As a result of this work, a public software tool provides the user with the routines developed for clustering methodology. The analysis of the seismogenic zones obtained reveals meaningful spatial patterns in South-West Colombia. The clustering analysis provides a quantitative location and dispersion of seismogenic zones that facilitates seismological interpretations of seismic activities in South West Colombia.

Development of a software for monitoring of seismic activity through the analysis of satellite images

Science.gov (United States)

Soto-Pinto, C.; Poblete, A.; Arellano-Baeza, A. A.; Sanchez, G.

2010-12-01

A software for extraction and analysis of the lineaments has been developed and applied for the tracking of the accumulation/relaxation of stress in the Earth’s crust due to seismic and volcanic activity. A lineament is a straight or a somewhat curved feature in a satellite image, which reflects, at least partially, presence of faults in the crust. The technique of lineament extraction is based on the application of directional filters and Hough transform. The software has been checked for several earthquakes occurred in the Pacific coast of the South America with the magnitude > 4 Mw, analyzing temporal sequences of the ASTER/TERRA multispectral satellite images for the regions around an epicenter. All events were located in the regions with small seasonal variations and limited vegetation to facilitate the tracking of features associated with the seismic activity only. It was found that the number and orientation of lineaments changes significantly about one month before an earthquake approximately, and a few months later the system returns to its initial state. This effect increases with the earthquake magnitude. It also was shown that the behavior of lineaments associated to the volcano seismic activity is opposite to that obtained previously for earthquakes. This discrepancy can be explained assuming that in the last case the main reason of earthquakes is compression and accumulation of strength in the Earth’s crust due to subduction of tectonic plates, whereas in the first case we deal with the inflation of a volcano edifice due to elevation of pressure and magma intrusion.

Romanian Educational Seismic Network Project

Science.gov (United States)

Tataru, Dragos; Ionescu, Constantin; Zaharia, Bogdan; Grecu, Bogdan; Tibu, Speranta; Popa, Mihaela; Borleanu, Felix; Toma, Dragos; Brisan, Nicoleta; Georgescu, Emil-Sever; Dobre, Daniela; Dragomir, Claudiu-Sorin

2013-04-01

Romania is one of the most active seismic countries in Europe, with more than 500 earthquakes occurring every year. The seismic hazard of Romania is relatively high and thus understanding the earthquake phenomena and their effects at the earth surface represents an important step toward the education of population in earthquake affected regions of the country and aims to raise the awareness about the earthquake risk and possible mitigation actions. In this direction, the first national educational project in the field of seismology has recently started in Romania: the ROmanian EDUcational SEISmic NETwork (ROEDUSEIS-NET) project. It involves four partners: the National Institute for Earth Physics as coordinator, the National Institute for Research and Development in Construction, Urban Planning and Sustainable Spatial Development " URBAN - INCERC" Bucharest, the Babeş-Bolyai University (Faculty of Environmental Sciences and Engineering) and the software firm "BETA Software". The project has many educational, scientific and social goals. The main educational objectives are: training students and teachers in the analysis and interpretation of seismological data, preparing of several comprehensive educational materials, designing and testing didactic activities using informatics and web-oriented tools. The scientific objective is to introduce into schools the use of advanced instruments and experimental methods that are usually restricted to research laboratories, with the main product being the creation of an earthquake waveform archive. Thus a large amount of such data will be used by students and teachers for educational purposes. For the social objectives, the project represents an effective instrument for informing and creating an awareness of the seismic risk, for experimentation into the efficacy of scientific communication, and for an increase in the direct involvement of schools and the general public. A network of nine seismic stations with SEP seismometers

Acoustic/seismic signal propagation and sensor performance modeling

Science.gov (United States)

Wilson, D. Keith; Marlin, David H.; Mackay, Sean

2007-04-01

Performance, optimal employment, and interpretation of data from acoustic and seismic sensors depend strongly and in complex ways on the environment in which they operate. Software tools for guiding non-expert users of acoustic and seismic sensors are therefore much needed. However, such tools require that many individual components be constructed and correctly connected together. These components include the source signature and directionality, representation of the atmospheric and terrain environment, calculation of the signal propagation, characterization of the sensor response, and mimicking of the data processing at the sensor. Selection of an appropriate signal propagation model is particularly important, as there are significant trade-offs between output fidelity and computation speed. Attenuation of signal energy, random fading, and (for array systems) variations in wavefront angle-of-arrival should all be considered. Characterization of the complex operational environment is often the weak link in sensor modeling: important issues for acoustic and seismic modeling activities include the temporal/spatial resolution of the atmospheric data, knowledge of the surface and subsurface terrain properties, and representation of ambient background noise and vibrations. Design of software tools that address these challenges is illustrated with two examples: a detailed target-to-sensor calculation application called the Sensor Performance Evaluator for Battlefield Environments (SPEBE) and a GIS-embedded approach called Battlefield Terrain Reasoning and Awareness (BTRA).

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.

WheelerLab: An interactive program for sequence stratigraphic analysis of seismic sections, outcrops and well sections and the generation of chronostratigraphic sections and dynamic chronostratigraphic sections

Science.gov (United States)

Amosu, Adewale; Sun, Yuefeng

WheelerLab is an interactive program that facilitates the interpretation of stratigraphic data (seismic sections, outcrop data and well sections) within a sequence stratigraphic framework and the subsequent transformation of the data into the chronostratigraphic domain. The transformation enables the identification of significant geological features, particularly erosional and non-depositional features that are not obvious in the original seismic domain. Although there are some software products that contain interactive environments for carrying out chronostratigraphic analysis, none of them are open-source codes. In addition to being open source, WheelerLab adds two important functionalities not present in currently available software: (1) WheelerLab generates a dynamic chronostratigraphic section and (2) WheelerLab enables chronostratigraphic analysis of older seismic data sets that exist only as images and not in the standard seismic file formats; it can also be used for the chronostratigraphic analysis of outcrop images and interpreted well sections. The dynamic chronostratigraphic section sequentially depicts the evolution of the chronostratigraphic chronosomes concurrently with the evolution of identified genetic stratal packages. This facilitates a better communication of the sequence-stratigraphic process. WheelerLab is designed to give the user both interactive and interpretational control over the transformation; this is most useful when determining the correct stratigraphic order for laterally separated genetic stratal packages. The program can also be used to generate synthetic sequence stratigraphic sections for chronostratigraphic analysis.

WheelerLab: An interactive program for sequence stratigraphic analysis of seismic sections, outcrops and well sections and the generation of chronostratigraphic sections and dynamic chronostratigraphic sections

Directory of Open Access Journals (Sweden)

Adewale Amosu

2017-01-01

Full Text Available WheelerLab is an interactive program that facilitates the interpretation of stratigraphic data (seismic sections, outcrop data and well sections within a sequence stratigraphic framework and the subsequent transformation of the data into the chronostratigraphic domain. The transformation enables the identification of significant geological features, particularly erosional and non-depositional features that are not obvious in the original seismic domain. Although there are some software products that contain interactive environments for carrying out chronostratigraphic analysis, none of them are open-source codes. In addition to being open source, WheelerLab adds two important functionalities not present in currently available software: (1 WheelerLab generates a dynamic chronostratigraphic section and (2 WheelerLab enables chronostratigraphic analysis of older seismic data sets that exist only as images and not in the standard seismic file formats; it can also be used for the chronostratigraphic analysis of outcrop images and interpreted well sections. The dynamic chronostratigraphic section sequentially depicts the evolution of the chronostratigraphic chronosomes concurrently with the evolution of identified genetic stratal packages. This facilitates a better communication of the sequence-stratigraphic process. WheelerLab is designed to give the user both interactive and interpretational control over the transformation; this is most useful when determining the correct stratigraphic order for laterally separated genetic stratal packages. The program can also be used to generate synthetic sequence stratigraphic sections for chronostratigraphic analysis.

Seismic and geological interpretation on petroleum exploration in the Cuban economic area in the Gulf of Mexico

Energy Technology Data Exchange (ETDEWEB)

Sora Monroy, America; Lopez, Sofia; Dominguez, Rene; Socorro, Rafael; Sanchez, Jorge; Toucet, Sonia [Cupet -Companhia Cubana de Petroleo, Havana (Cuba)

2004-07-01

From the decade of the 50'up to now, many seismic survey were acquired in the Cuban Economic area in the Gulf of Mexico, both, deep water and near short along the littoral, which have contribute to prepare the structural model as well the evolutional one. During the period comprise from June to December 2000, 7330 Km. of seismic lines were acquired over 70 lines in an area of 110000 square Km. that covers the Exclusive Economic area of Cuba. In this area the water depth varies from 500 m to 3500 m. The biggest depth is located at the central part of the whole area. The depth decreases toward the shell and the island's littoral (up to less than 1000 m). Seismic data were processed at CGG' processing in France. Geovector Plus was used as seismic processing software. All the information was calibrate by the wells in the area. The principal wells were DP535 and DP540. The general featuring of seismic image let us to get the map from the main geological elements in this area. In the area we were following two principal horizons: the green one associated to the Middle Cretaceous and the blue one associated to the top of Jurassic. We made the structural maps from the Middle Cretaceous and the Top of Jurassic, and did the seism stratigraphic analysis. We found 16 sequences. We did the chronograph table in this area and we made six maps from different seismic sequences. This analysis let us to define the most important area to continue studying in the Cuban economic area in the Gulf of Mexico on the petroleum exploration. (author)

Detailed geological characterisation from seismic data

Energy Technology Data Exchange (ETDEWEB)

Peter Hatherly; Binzhong Zhou; Troy Peters; Milovan Urosevic [CRC Mining (Australia)

2009-02-15

The use of seismic reflection surveying continues to grow within Australia's underground coal mining regions of the Sydney and Bowen Basins. For this project, the potential for acoustic impedance inversion to complement the information available from conventional seismic surveys was investigated. Acoustic impedance is defined by the product of seismic P-wave velocity and rock density. The methods of seismic inversion have been developed mainly for the investigation of petroleum reservoirs. Commercial software packages are available and for this project we utilised the Hampson and Russell software available at Curtin University of Technology. For the true amplitude processing of the seismic data, the Promax software operated at Velseis Processing was used. Inversions were undertaken for three 3D seismic surveys and two 2D surveys. The sites were at Grasstree and North Goonyella Mines in the Bowen Basin and at West Cliff and Dendrobium Collieries in the Sydney Basin. An empirical relationship was derived between acoustic impedance and the newly developed Geophysical Strata Rating (GSR). This allows impedance values to be converted into GSR values that have more meaning in geotechnical assessment. To obtain satisfactory inversions, we used the model based approach.

WheelerLab: An interactive program for sequence stratigraphic analysis of seismic sections, outcrops and well sections and the generation of chronostratigraphic sections and dynamic chronostratigraphic sections

OpenAIRE

Adewale Amosu; Yuefeng Sun

2017-01-01

WheelerLab is an interactive program that facilitates the interpretation of stratigraphic data (seismic sections, outcrop data and well sections) within a sequence stratigraphic framework and the subsequent transformation of the data into the chronostratigraphic domain. The transformation enables the identification of significant geological features, particularly erosional and non-depositional features that are not obvious in the original seismic domain. Although there are some software produ...

Automatic Processing and Interpretation of Long Records of Endogenous Micro-Seismicity: the Case of the Super-Sauze Soft-Rock Landslide.

Science.gov (United States)

Provost, F.; Malet, J. P.; Hibert, C.; Doubre, C.

2017-12-01

The Super-Sauze landslide is a clay-rich landslide located the Southern French Alps. The landslide exhibits a complex pattern of deformation: a large number of rockfalls are observed in the 100 m height main scarp while the deformation of the upper part of the accumulated material is mainly affected by material shearing along stable in-situ crests. Several fissures are locally observed. The shallowest layer of the accumulated material tends to behave in a brittle manner but may undergo fluidization and/or rapid acceleration. Previous studies have demonstrated the presence of a rich endogenous micro-seismicity associated to the deformation of the landslide. However, the lack of long-term seismic records and suitable processing chains prevented a full interpretation of the links between the external forcings, the deformation and the recorded seismic signals. Since 2013, two permanent seismic arrays are installed in the upper part of the landslide. We here present the methodology adopted to process this dataset. The processing chain consists of a set of automated methods for automatic and robust detection, classification and location of the recorded seismicity. Thousands of events are detected and further automatically classified. The classification method is based on the description of the signal through attributes (e.g. waveform, spectral content properties). These attributes are used as inputs to classify the signal using a Random Forest machine-learning algorithm in four classes: endogenous micro-quakes, rockfalls, regional earthquakes and natural/anthropogenic noises. The endogenous landslide sources (i.e. micro-quake and rockfall) are further located. The location method is adapted to the type of event. The micro-quakes are located with a 3D velocity model derived from a seismic tomography campaign and an optimization of the first arrival picking with the inter-trace correlation of the P-wave arrivals. The rockfalls are located by optimizing the inter

Critical Assessment of Metagenome Interpretation-a benchmark of metagenomics software.

Science.gov (United States)

Sczyrba, Alexander; Hofmann, Peter; Belmann, Peter; Koslicki, David; Janssen, Stefan; Dröge, Johannes; Gregor, Ivan; Majda, Stephan; Fiedler, Jessika; Dahms, Eik; Bremges, Andreas; Fritz, Adrian; Garrido-Oter, Ruben; Jørgensen, Tue Sparholt; Shapiro, Nicole; Blood, Philip D; Gurevich, Alexey; Bai, Yang; Turaev, Dmitrij; DeMaere, Matthew Z; Chikhi, Rayan; Nagarajan, Niranjan; Quince, Christopher; Meyer, Fernando; Balvočiūtė, Monika; Hansen, Lars Hestbjerg; Sørensen, Søren J; Chia, Burton K H; Denis, Bertrand; Froula, Jeff L; Wang, Zhong; Egan, Robert; Don Kang, Dongwan; Cook, Jeffrey J; Deltel, Charles; Beckstette, Michael; Lemaitre, Claire; Peterlongo, Pierre; Rizk, Guillaume; Lavenier, Dominique; Wu, Yu-Wei; Singer, Steven W; Jain, Chirag; Strous, Marc; Klingenberg, Heiner; Meinicke, Peter; Barton, Michael D; Lingner, Thomas; Lin, Hsin-Hung; Liao, Yu-Chieh; Silva, Genivaldo Gueiros Z; Cuevas, Daniel A; Edwards, Robert A; Saha, Surya; Piro, Vitor C; Renard, Bernhard Y; Pop, Mihai; Klenk, Hans-Peter; Göker, Markus; Kyrpides, Nikos C; Woyke, Tanja; Vorholt, Julia A; Schulze-Lefert, Paul; Rubin, Edward M; Darling, Aaron E; Rattei, Thomas; McHardy, Alice C

2017-11-01

Methods for assembly, taxonomic profiling and binning are key to interpreting metagenome data, but a lack of consensus about benchmarking complicates performance assessment. The Critical Assessment of Metagenome Interpretation (CAMI) challenge has engaged the global developer community to benchmark their programs on highly complex and realistic data sets, generated from ∼700 newly sequenced microorganisms and ∼600 novel viruses and plasmids and representing common experimental setups. Assembly and genome binning programs performed well for species represented by individual genomes but were substantially affected by the presence of related strains. Taxonomic profiling and binning programs were proficient at high taxonomic ranks, with a notable performance decrease below family level. Parameter settings markedly affected performance, underscoring their importance for program reproducibility. The CAMI results highlight current challenges but also provide a roadmap for software selection to answer specific research questions.

Approaches that use seismic hazard results to address topics of nuclear power plant seismic safety, with application to the Charleston earthquake issue

International Nuclear Information System (INIS)

Sewell, R.T.; McGuire, R.K.; Toro, G.R.; Stepp, J.C.; Cornell, C.A.

1990-01-01

Plant seismic safety indicators include seismic hazard at the SSE (safe shut-down earthquake) acceleration, seismic margin, reliability against core damage, and reliability against offsite consequences. This work examines the key role of hazard analysis in evaluating these indicators and in making rational decisions regarding plant safety. The paper outlines approaches that use seismic hazard results as a basis for plant seismic safety evaluation and applies one of these approaches to the Charleston earthquake issue. This approach compares seismic hazard results that account for the Charleston tectonic interpretation, using the EPRI-Seismicity Owners Group (SOG) methodology, with hazard results that are consistent with historical tectonic interpretations accepted in regulation. Based on hazard results for a set of 21 eastern U.S. nuclear power plant sites, the comparison shows that no systematic 'plant-to-plant' increase in hazard accompanies the Charleston hypothesis; differences in mean hazards for the two interpretations are generally insignificant relative to current uncertainties in seismic hazard. (orig.)

Seismic changes industry

International Nuclear Information System (INIS)

Taylor, G.

1992-01-01

This paper discusses the growth in the seismic industry as a result of the recent increases in the foreign market. With the decline of communism and the opening of Latin America to exploration, seismic teams have moved out into these areas in support of the oil and gas industry. The paper goes on to discuss the improved technology available for seismic resolution and the subsequent use of computers to field-proof the data while the seismic team is still on-site. It also discusses the effects of new computer technology on reducing the amount of support staff that is required to both conduct and interpret seismic information

Geophysical interpretation: From bits and bytes to the big picture

Energy Technology Data Exchange (ETDEWEB)

James, Huw; Tellez, Mark (GeoQuest, Houston, TX (United States)); Schaetzlein, Gabi (GeoQuest, Mexico City (Mexico)); Stark, Tracy (Exxon Production Research Company, Houston, TX (United States))

1994-07-01

Seismic interpretation workstations help geophysicists mold massive volumes of seismic data into reservoir models that can guide recovery decisions. Fast, new visualization tools that let the interpreter enter the realm of the subsurface make seismic interpretation as interactive as a video game. Tasks that used to require weeks or months of manual keyboard clicks are now accomplished in hours. In this article, the process from data loading through interpretation and visualization to final output is tracked. 12 figs., 13 refs.

Seismic investigations for the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Barrows, L.J.

1984-01-01

Evaporite rocks in the Delaware Basin in southeastern New Mexico are being investigated as a possible site for nuclear waste disposal. Seismic studies have been conducted to establish seismic design criteria and to investigate relations between seismicity and geologic structures. In the initial phase of this study, historical and available seismic data were interpreted with respect to geology. Local instrumentation became available in 1974 when New Mexico Tech installed and began operating a seismic station in the area. Data and interpretation for 1974 through 1979 have been published. In 1980 seismic monitoring of the Northern Delaware Basin was extended to include a six station network of self-contained radio-telemetered seismometers. 9 references, 13 figures

seismic-py: Reading seismic data with Python

Directory of Open Access Journals (Sweden)

2008-08-01

Full Text Available The field of seismic exploration of the Earth has changed
dramatically over the last half a century. The Society of Exploration
Geophysicists (SEG has worked to create standards to store the vast
amounts of seismic data in a way that will be portable across computer
architectures. However, it has been impossible to predict the needs of the
immense range of seismic data acquisition systems. As a result, vendors have
had to bend the rules to accommodate the needs of new instruments and
experiment types. For low level access to seismic data, there is need for a
standard open source library to allow access to a wide range of vendor data
files that can handle all of the variations. A new seismic software package,
seismic-py, provides an infrastructure for creating and managing drivers for
each particular format. Drivers can be derived from one of the known formats
and altered to handle any slight variations. Alternatively drivers can be
developed from scratch for formats that are very different from any previously
defined format. Python has been the key to making driver development easy
and efficient to implement. The goal of seismic-py is to be the base system
that will power a wide range of experimentation with seismic data and at the
same time provide clear documentation for the historical record of seismic
data formats.

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.

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...

Trade-off of Elastic Structure and Q in Interpretations of Seismic Attenuation

Science.gov (United States)

Deng, Wubing; Morozov, Igor B.

2017-10-01

The quality factor Q is an important phenomenological parameter measured from seismic or laboratory seismic data and representing wave-energy dissipation rate. However, depending on the types of measurements and models or assumptions about the elastic structure, several types of Qs exist, such as intrinsic and scattering Qs, coda Q, and apparent Qs observed from wavefield fluctuations. We consider three general types of elastic structures that are commonly encountered in seismology: (1) shapes and dimensions of rock specimens in laboratory studies, (2) geometric spreading or scattering in body-, surface- and coda-wave studies, and (3) reflectivity on fine layering in reflection seismic studies. For each of these types, the measured Q strongly trades off with the (inherently limited) knowledge about the respective elastic structure. For the third of the above types, the trade-off is examined quantitatively in this paper. For a layered sequence of reflectors (e.g., an oil or gas reservoir or a hydrothermal zone), reflection amplitudes and phases vary with frequency, which is analogous to a reflection from a contrast in attenuation. We demonstrate a quantitative equivalence between phase-shifted reflections from anelastic zones and reflections from elastic layering. Reflections from the top of an elastic layer followed by weaker reflections from its bottom can appear as resulting from a low Q within or above this layer. This apparent Q can be frequency-independent or -dependent, according to the pattern of thin layering. Due to the layering, the interpreted Q can be positive or negative, and it can depend on source-receiver offsets. Therefore, estimating Q values from frequency-dependent or phase-shifted reflection amplitudes always requires additional geologic or rock-physics constraints, such as sparseness and/or randomness of reflectors, the absence of attenuation in certain layers, or specific physical mechanisms of attenuation. Similar conclusions about the

Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume V S-Wave Measurements in Borehole C4996 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

Energy Technology Data Exchange (ETDEWEB)

Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

2007-06-06

Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (V), all S-wave measurements are presented that were performed in Borehole C4996 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume VI S-Wave Measurements in Borehole C4997 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

Energy Technology Data Exchange (ETDEWEB)

Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

2007-06-06

Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (VI), all S-wave measurements are presented that were performed in Borehole C4997 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

HEP Software Foundation Community White Paper Working Group - Data Analysis and Interpretation

Energy Technology Data Exchange (ETDEWEB)

Bauerdick, Lothar; et al.

2018-04-09

At the heart of experimental high energy physics (HEP) is the development of facilities and instrumentation that provide sensitivity to new phenomena. Our understanding of nature at its most fundamental level is advanced through the analysis and interpretation of data from sophisticated detectors in HEP experiments. The goal of data analysis systems is to realize the maximum possible scientific potential of the data within the constraints of computing and human resources in the least time. To achieve this goal, future analysis systems should empower physicists to access the data with a high level of interactivity, reproducibility and throughput capability. As part of the HEP Software Foundation Community White Paper process, a working group on Data Analysis and Interpretation was formed to assess the challenges and opportunities in HEP data analysis and develop a roadmap for activities in this area over the next decade. In this report, the key findings and recommendations of the Data Analysis and Interpretation Working Group are presented.

Seismic II over I Drop Test Program results and interpretation

International Nuclear Information System (INIS)

Thomas, B.

1993-03-01

The consequences of non-seismically qualified (Category 2) objects falling and striking essential seismically qualified (Category 1) objects has always been a significant, yet analytically difficult problem, particularly in evaluating the potential damage to equipment that may result from earthquakes. Analytical solutions for impact problems are conservative and available for mostly simple configurations. In a nuclear facility, the open-quotes sourcesclose quotes and open-quotes targetsclose quotes requiring evaluation are frequently irregular in shape and configuration, making calculations and computer modeling difficult. Few industry or regulatory rules are available on this topic even though it is a source of considerable construction upgrade costs. A drop test program was recently conducted to develop a more accurate understanding of the consequences of seismic interactions. The resulting data can be used as a means to improve the judgment of seismic qualification engineers performing interaction evaluations and to develop realistic design criteria for seismic interactions. Impact tests on various combinations of sources and targets commonly found in one Savannah River Site (SRS) nuclear facility were performed by dropping the sources from various heights onto the targets. This report summarizes results of the Drop Test Program. Force and acceleration time history data are presented as well as general observations on the overall ruggedness of various targets when subjected to impacts from different types of sources

Seismic II over I Drop Test Program results and interpretation

Energy Technology Data Exchange (ETDEWEB)

Thomas, B.

1993-03-01

The consequences of non-seismically qualified (Category 2) objects falling and striking essential seismically qualified (Category 1) objects has always been a significant, yet analytically difficult problem, particularly in evaluating the potential damage to equipment that may result from earthquakes. Analytical solutions for impact problems are conservative and available for mostly simple configurations. In a nuclear facility, the {open_quotes}sources{close_quotes} and {open_quotes}targets{close_quotes} requiring evaluation are frequently irregular in shape and configuration, making calculations and computer modeling difficult. Few industry or regulatory rules are available on this topic even though it is a source of considerable construction upgrade costs. A drop test program was recently conducted to develop a more accurate understanding of the consequences of seismic interactions. The resulting data can be used as a means to improve the judgment of seismic qualification engineers performing interaction evaluations and to develop realistic design criteria for seismic interactions. Impact tests on various combinations of sources and targets commonly found in one Savannah River Site (SRS) nuclear facility were performed by dropping the sources from various heights onto the targets. This report summarizes results of the Drop Test Program. Force and acceleration time history data are presented as well as general observations on the overall ruggedness of various targets when subjected to impacts from different types of sources.

Seismic II over I Drop Test Program results and interpretation

Energy Technology Data Exchange (ETDEWEB)

Thomas, B.

1993-03-01

The consequences of non-seismically qualified (Category 2) objects falling and striking essential seismically qualified (Category 1) objects has always been a significant, yet analytically difficult problem, particularly in evaluating the potential damage to equipment that may result from earthquakes. Analytical solutions for impact problems are conservative and available for mostly simple configurations. In a nuclear facility, the [open quotes]sources[close quotes] and [open quotes]targets[close quotes] requiring evaluation are frequently irregular in shape and configuration, making calculations and computer modeling difficult. Few industry or regulatory rules are available on this topic even though it is a source of considerable construction upgrade costs. A drop test program was recently conducted to develop a more accurate understanding of the consequences of seismic interactions. The resulting data can be used as a means to improve the judgment of seismic qualification engineers performing interaction evaluations and to develop realistic design criteria for seismic interactions. Impact tests on various combinations of sources and targets commonly found in one Savannah River Site (SRS) nuclear facility were performed by dropping the sources from various heights onto the targets. This report summarizes results of the Drop Test Program. Force and acceleration time history data are presented as well as general observations on the overall ruggedness of various targets when subjected to impacts from different types of sources.

RSEIS and RFOC: Seismic Analysis in R

Science.gov (United States)

Lees, J. M.

2015-12-01

Open software is essential for reproducible scientific exchange. R-packages provide a platform for development of seismological investigation software that can be properly documented and traced for data processing. A suite of R packages designed for a wide range of seismic analysis is currently available in the free software platform called R. R is a software platform based on the S-language developed at Bell Labs decades ago. Routines in R can be run as standalone function calls, or developed in object-oriented mode. R comes with a base set of routines, and thousands of user developed packages. The packages developed at UNC include subroutines and interactive codes for processing seismic data, analyzing geographic information (GIS) and inverting data involved in a variety of geophysical applications. On CRAN (Comprehensive R Archive Network, http://www.r-project.org/) currently available packages related to seismic analysis are RSEIS, Rquake, GEOmap, RFOC, zoeppritz, RTOMO, and geophys, Rwave, PEIP, hht, rFDSN. These include signal processing, data management, mapping, earthquake location, deconvolution, focal mechanisms, wavelet transforms, Hilbert-Huang Transforms, tomographic inversion, and Mogi deformation among other useful functionality. All software in R packages is required to have detailed documentation, making the exchange and modification of existing software easy. In this presentation, I will focus on packages RSEIS and RFOC, showing examples from a variety of seismic analyses. The R approach has similarities to the popular (and expensive) MATLAB platform, although R is open source and free to down load.

LOCACE / BALISS : un test de la cohérence géologique d'une interprétation sismique Locace / Baliss: Test of the Geologic Coherence of Seismic Interpretation

Directory of Open Access Journals (Sweden)

Moretti I.

2006-11-01

Full Text Available Durant quatre années l'Azienda Generale Italiana Petroli (AGIP, la Société Nationale Elf Aquitaine, l'Institut Français du Pétrole (IFP et Total Compagnie Française des Pétroles ont joint leurs efforts pour développer un outil de géologie structurale et un programme de rétro-déformation. Le but était d'améliorer le pointé des sections sismiques en validant l'interprétation faite par des tests de cohérence géométrique. Une section qui peut être rétro-déformée en suivant le principe de conservation de la matière est dite équilibrée. Ce projet de recherche a abouti à la réalisation de deux logiciels LOCACE et BALISS. LOCACE (LOgiciel de Construction Assistée de Coupes Equilibrées travaille à partir d'une section géologique. BALISS (BALanced Interpretation of Seismic Sections permet d'appliquer à l'image sismique profondeur les principes de l'équilibrage. Cet article rappelle les fondements de cette méthode, les différents types de déformation - rigide, couche à couche, cisaillement simple - leur mise en oeuvre dans LOCACE/BALISS et la philosophie de l'utilisation de ces logiciels. The need to use concepts of structural geology for seismic interpretation is something that is often difficult to apply because of the complexity of the zones investigated and especially because of the lack of interaction among specialists in the different areas of exploration. Likewise, quantitative geology is fairly recent, and computerized tools for structural geology are still rare although there is a multitude of them in geophysics. The existence of graphic workstations and computerized tools favoring the effective interactivity of software packages now makes it possible to integrate this implementation. The two French oil companies, Total Compagnie Française des Pétroles and Elf Aquitaine, together with Institut Français du Pétrole (IFP have joined their efforts since 1987 to develop a tool for testing the geologic and

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)

New seismic attributes and methodology for automated stratigraphic, structural, and reservoir analysis

Energy Technology Data Exchange (ETDEWEB)

Randen, Trygve; Reymond, Benoit; Sjulstad, Hans Ivar; Soenneland, Lars

1998-12-31

Seismic stratigraphy represents an attractive framework for interpretation of 3-D data. This presentation is an introduction to a set of primitives that will enable guided interpretation of seismic signals in the framework of seismic stratigraphy. A method capable of automatic detection of terminations is proposed. The new procedure can be run on the entire seismic volume or it may be restricted to a limited time interval and detects terminations in an unguided manner without prior interpretation. The density of terminations can be computed. The procedure may alternatively be guided by pre-existing interpretation, e.g. detecting terminations onto an interpreted horizon. In such a case, the density of terminations will be a new surface attribute. 6 refs., 3 figs.

New seismic attributes and methodology for automated stratigraphic, structural, and reservoir analysis

Energy Technology Data Exchange (ETDEWEB)

Randen, Trygve; Reymond, Benoit; Sjulstad, Hans Ivar; Soenneland, Lars

1999-12-31

Seismic stratigraphy represents an attractive framework for interpretation of 3-D data. This presentation is an introduction to a set of primitives that will enable guided interpretation of seismic signals in the framework of seismic stratigraphy. A method capable of automatic detection of terminations is proposed. The new procedure can be run on the entire seismic volume or it may be restricted to a limited time interval and detects terminations in an unguided manner without prior interpretation. The density of terminations can be computed. The procedure may alternatively be guided by pre-existing interpretation, e.g. detecting terminations onto an interpreted horizon. In such a case, the density of terminations will be a new surface attribute. 6 refs., 3 figs.

Subsurface Characterization using Geophysical Seismic Refraction Survey for Slope Stabilization Design with Soil Nailing

Science.gov (United States)

Ashraf Mohamad Ismail, Mohd; Ng, Soon Min; Hazreek Zainal Abidin, Mohd; Madun, Aziman

2018-04-01

The application of geophysical seismic refraction for slope stabilization design using soil nailing method was demonstrated in this study. The potential weak layer of the study area is first identify prior to determining the appropriate length and location of the soil nail. A total of 7 seismic refraction survey lines were conducted at the study area with standard procedures. The refraction data were then analyzed by using the Pickwin and Plotrefa computer software package to obtain the seismic velocity profiles distribution. These results were correlated with the complementary borehole data to interpret the subsurface profile of the study area. It has been identified that layer 1 to 3 is the potential weak zone susceptible to slope failure. Hence, soil nails should be installed to transfer the tensile load from the less stable layer 3 to the more stable layer 4. The soil-nail interaction will provide a reinforcing action to the soil mass thereby increasing the stability of the slope.

Induced Seismicity from different sources in Italy: how to interpret it?

Science.gov (United States)

Pastori, M.; De Gori, P.; Piccinini, D.; Bagh, S.; Improta, L.; Chiarabba, C.

2015-12-01

Typically the term "induced seismicity" is used to refer minor earthquakes and tremors caused by human activities that alter the stresses and strains on the Earth's crust. In the last years, the interest in the induced seismicity related to fluids (oil and gas, and geothermal resources) extraction or injection is increased, because it is believed to be responsible to enucleate earthquakes. Possible sources of induced seismicity are not only represented by the oil and gas production but also, i.e., by changes in the water level of artificial lakes. The aim of this work is to show results from two different sources, wastewater injection and changes in the water level of an artificial reservoir (Pertusillo lake), that can produce induced earthquakes observed in the Val d'Agri basin (Italy) and to compare them with variation in crustal elastic parameters. Val d'Agri basin in the Apennines extensional belt hosts the largest oilfield in onshore Europe and is bordered by NW-SE ­trending fault systems. Most of the recorded seismicity seems to be related to these structures. We correlated the seismicity rate, injection curves and changes in water levels with temporal variations of Vp/Vs and anisotropic parameters of the crustal reservoirs and in the nearby area. We analysed about 983 high-quality recordings occurred from 2002 to 2014 in Val d'Agri basin from temporary and permanent network held by INGV and ENI corporate. 3D high-precision locations and manual-revised P- and S-picking are used to estimate anisotropic parameters (delay time and fast direction polarization) and Vp/Vs ratio. Seismicity is mainly located in two areas: in the SW of the Pertusillo Lake, and near the Eni Oil field (SW and NE of the Val d'Agri basin respectively). Our correlations well recognize the seismicity diffusion process, caused by both water injection and water level changes; these findings could help to model the active and pre-existing faults failure behaviour.

Seismically integrated geologic modelling: Guntong Field, Malay Basin

Energy Technology Data Exchange (ETDEWEB)

Calvert, Craig S.; Bhuyan, K.; Sterling, J. Helwick; Hill, Rob E.; Hubbard, R. Scott; Khare, Vijay; Wahrmund, Leslie A.; Wang, Gann-Shyong

1998-12-31

This presentation relates to a research project on offshore seismically reservoir modelling. The goal of the project was to develop and test a process for interpreting reservoir properties from 3-D seismic data and for integrating these data into the building of 3-D geologic models that would be suitable for use in flow simulation studies. The project produced a 3-D geologic model for three reservoir intervals and three predominantly non-reservoir intervals. Each reservoir interval was subdivided into faces that were determined by integrating core, well log, and seismic interpretations. predictions of porosity and lithology used in building the geologic model were made using seismic attributes calculated from acoustic impedance data. 8 figs.

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

How a joint interpretation of seismic scattering, velocity, and attenuation models explains the nature of the Campi Flegrei (Italy).

Science.gov (United States)

Calo, M.; Tramelli, A.

2017-12-01

Seismic P and S velocity models (and their ratio Vp/Vs) help illuminating the geometrical structure of the bodies and give insight on the presence of water, molten or gas saturated regions. Seismic attenuation represents the anelastic behavior of the medium. Due to its dependence on temperature, fluid contents and cracks presence, this parameter is also largely used to characterize the structures of volcanoes and geothermal areas. Scattering attenuation is related, in the upper crust, to the amount, size and organization of the fractures giving complementary information on the state of the medium.Therefore a joint interpretation of these models provides an exhaustive view of the elastic parameters in volcanic regions. Campi Flegrei is an active Caldera marked by strong vertical deformations of the ground called bradyseisms and several models have been proposed to describe the nature and the geometry of the bodies responsible of the bradyseisms. Here we show Vp, Vp/Vs, Qp and scattering models carried out by applying an enhanced seismic tomography method that combines de double difference approach (Zhang and Thurber, 2003) and the Weigthed Average Method (Calò et al., 2009, Calò et al., 2011, 2013). The data used are the earthquakes recorded during the largest bradyseism crisis of the 80's. Our method allowed to image structures with linear dimension of 0.5-1.2km, resulting in an improvement of the resolving power at least two times of the other published models (e.g. Priolo et al., 2012). The joint interpretation of seismic models allowed to discern small anomalous bodies at shallow depth (0.5-2.0 km) marked by relatively low Vp, high Vp/Vs ratio and low Qp values associated with the presence of shallow geothermal water saturated reservoir from regions with low Vp, low Vp/Vs and low Qp related to the gas saturated part of the reservoir. At deeper depth (2-3.5 km) bodies with high Vp and Vp/Vs and low Qp are associated with magmatic intrusions. The Scattering

Real-time classification of signals from three-component seismic sensors using neural nets

Science.gov (United States)

Bowman, B. C.; Dowla, F.

1992-05-01

Adaptive seismic data acquisition systems with capabilities of signal discrimination and event classification are important in treaty monitoring, proliferation, and earthquake early detection systems. Potential applications include monitoring underground chemical explosions, as well as other military, cultural, and natural activities where characteristics of signals change rapidly and without warning. In these applications, the ability to detect and interpret events rapidly without falling behind the influx of the data is critical. We developed a system for real-time data acquisition, analysis, learning, and classification of recorded events employing some of the latest technology in computer hardware, software, and artificial neural networks methods. The system is able to train dynamically, and updates its knowledge based on new data. The software is modular and hardware-independent; i.e., the front-end instrumentation is transparent to the analysis system. The software is designed to take advantage of the multiprocessing environment of the Unix operating system. The Unix System V shared memory and static RAM protocols for data access and the semaphore mechanism for interprocess communications were used. As the three-component sensor detects a seismic signal, it is displayed graphically on a color monitor using X11/Xlib graphics with interactive screening capabilities. For interesting events, the triaxial signal polarization is computed, a fast Fourier Transform (FFT) algorithm is applied, and the normalized power spectrum is transmitted to a backpropagation neural network for event classification. The system is currently capable of handling three data channels with a sampling rate of 500 Hz, which covers the bandwidth of most seismic events. The system has been tested in laboratory setting with artificial events generated in the vicinity of a three-component sensor.

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.

Adding seismic broadband analysis to characterize Andean backarc seismicity in Argentina

Science.gov (United States)

Alvarado, P.; Giuliano, A.; Beck, S.; Zandt, G.

2007-05-01

Characterization of the highly seismically active Andean backarc is crucial for assessment of earthquake hazards in western Argentina. Moderate-to-large crustal earthquakes have caused several deaths, damage and drastic economic consequences in Argentinean history. We have studied the Andean backarc crust between 30°S and 36°S using seismic broadband data available from a previous ("the CHARGE") IRIS-PASSCAL experiment. We collected more than 12 terabytes of continuous seismic data from 22 broadband instruments deployed across Chile and Argentina during 1.5 years. Using free software we modeled full regional broadband waveforms and obtained seismic moment tensor inversions of crustal earthquakes testing for the best focal depth for each event. We also mapped differences in the Andean backarc crustal structure and found a clear correlation with different types of crustal seismicity (i.e. focal depths, focal mechanisms, magnitudes and frequencies of occurrence) and previously mapped terrane boundaries. We now plan to use the same methodology to study other regions in Argentina using near-real time broadband data available from the national seismic (INPRES) network and global seismic networks operating in the region. We will re-design the national seismic network to optimize short-period and broadband seismic station coverage for different network purposes. This work is an international effort that involves researchers and students from universities and national government agencies with the goal of providing more information about earthquake hazards in western Argentina.

Computational Software to Fit Seismic Data Using Epidemic-Type Aftershock Sequence Models and Modeling Performance Comparisons

Science.gov (United States)

Chu, A.

2016-12-01

Modern earthquake catalogs are often analyzed using spatial-temporal point process models such as the epidemic-type aftershock sequence (ETAS) models of Ogata (1998). My work implements three of the homogeneous ETAS models described in Ogata (1998). With a model's log-likelihood function, my software finds the Maximum-Likelihood Estimates (MLEs) of the model's parameters to estimate the homogeneous background rate and the temporal and spatial parameters that govern triggering effects. EM-algorithm is employed for its advantages of stability and robustness (Veen and Schoenberg, 2008). My work also presents comparisons among the three models in robustness, convergence speed, and implementations from theory to computing practice. Up-to-date regional seismic data of seismic active areas such as Southern California and Japan are used to demonstrate the comparisons. Data analysis has been done using computer languages Java and R. Java has the advantages of being strong-typed and easiness of controlling memory resources, while R has the advantages of having numerous available functions in statistical computing. Comparisons are also made between the two programming languages in convergence and stability, computational speed, and easiness of implementation. Issues that may affect convergence such as spatial shapes are discussed.

Comparative seismic evaluation between numerical analysis and Italian guidelines on cultural heritage applied to the case study of a masonry building compound

Science.gov (United States)

Formisano, Antonio; Chiumiento, Giovanni; Fabbrocino, Francesco; Landolfo, Raffaele

2017-07-01

The general objective of the work is to draw attention to the issue of seismic vulnerability analysis of masonry building compounds, which characterise most of the Italian historic towns. The study is based on the analysis of an aggregated construction falling in the town of Arsita (Teramo, Italy) damaged after the 2009 L'Aquila earthquake. A comparison between the seismic verifications carried out by using the 3Muri commercial software and those deriving from the application of the Italian Guidelines on Cultural Heritage has been performed. The comparison has shown that Guidelines provide results on the safe side in predicting the seismic behaviour of the building compound under study. Further analyses should be performed aiming at suggesting some modifications of the used simplified calculation method to better interpret the behaviour of building compounds under earthquake.

Supporting interpretation of dynamic simulation. Application to chemical kinetic models; Aides a l`interpretation de simulations dynamiques. Application aux modeles de cinetique chimique

Energy Technology Data Exchange (ETDEWEB)

Braunschweig, B

1998-04-22

Numerous scientific and technical domains make constant use of dynamical simulations. Such simulators are put in the hands of a growing number of users. This phenomenon is due both to the extraordinary increase in computing performance, and to better graphical user interfaces which make simulation models easy to operate. But simulators are still computer programs which produce series of numbers from other series of numbers, even if they are displayed graphically. This thesis presents new interaction paradigms between a dynamical simulator and its user. The simulator produces a self-made interpretation of its results, thanks to a dedicated representation of its domain with objects. It shows dominant cyclic mechanisms identified by their instantaneous loop gain estimates, it uses a notion of episodes for splitting the simulation into homogeneous time intervals, and completes this by animations which rely on the graphical structure of the system. These new approaches are demonstrated with examples from chemical kinetics, because of the energic and exemplary characteristics of the encountered behaviors. They are implemented in the Spike software, Software Platform for Interactive Chemical Kinetics Experiments. Similar concepts are also shown in two other domains: interpretation of seismic wave propagation, and simulation of large projects. (author) 95 refs.

Seismic refraction survey of the ANS preferred site

Energy Technology Data Exchange (ETDEWEB)

Davis, R.K. (Automated Sciences Group, Inc., Oak Ridge, TN (United States)); Hopkins, R.A. (Marrich, Inc., Knoxville, TN (United States)); Doll, W.E. (Oak Ridge National Lab., TN (United States))

1992-02-01

Between September 19, 1991 and October 8, 1991 personnel from Martin Marietta Energy Systems, Inc. (Energy Systems), Automated Sciences Group, Inc., and Marrich, Inc. performed a seismic refraction survey at the Advanced Neutron Source (ANS) preferred site. The purpose of this survey was to provide estimates of top-of-rock topography, based on seismic velocities, and to delineate variations in rock and soil velocities. Forty-four seismic refraction spreads were shot to determine top-of-rock depths at 42 locations. Nine of the seismic spreads were shot with long offsets to provide 216 top-of-rock depths for 4 seismic refraction profiles. The refraction spread locations were based on the grid for the ANS Phase I drilling program. Interpretation of the seismic refraction data supports the assumption that the top-of-rock surface generally follows the local topography. The shallow top-of-rock interface interpreted from the seismic refraction data is also supported by limited drill information at the site. Some zones of anomalous data are present that could be the result of locally variable weathering, a localized variation in shale content, or depth to top-of-rock greater than the site norm.

Capabilities of seismic and georadar 2D/3D imaging of shallow subsurface of transport route using the Seismobile system

Science.gov (United States)

Pilecki, Zenon; Isakow, Zbigniew; Czarny, Rafał; Pilecka, Elżbieta; Harba, Paulina; Barnaś, Maciej

2017-08-01

In this work, the capabilities of the Seismobile system for shallow subsurface imaging of transport routes, such as roads, railways, and airport runways, in different geological conditions were presented. The Seismobile system combines the advantages of seismic profiling using landstreamer and georadar (GPR) profiling. It consists of up to four seismic measuring lines and carriage with a suspended GPR antenna. Shallow subsurface recognition may be achieved to a maximum width of 10.5 m for a distance of 3.5 m between the measurement lines. GPR measurement is performed in the axis of the construction. Seismobile allows the measurement time, labour and costs to be reduced due to easy technique of its installation, remote data transmission from geophones to accompanying measuring modules, automated location of the system based on GPS and a highly automated method of seismic wave excitation. In this paper, the results of field tests carried out in different geological conditions were presented. The methodologies of acquisition, processing and interpretation of seismic and GPR measurements were broadly described. Seismograms and its spectrum registered by Seismobile system were compared to the ones registered by Geode seismograph of Geometrix. Seismic data processing and interpretation software allows for the obtaining of 2D/3D models of P- and S-wave velocities. Combined seismic and GPR results achieved sufficient imaging of shallow subsurface to a depth of over a dozen metres. The obtained geophysical information correlated with geological information from the boreholes with good quality. The results of performed tests proved the efficiency of the Seismobile system in seismic and GPR imaging of a shallow subsurface of transport routes under compound conditions.

Seismic facies; Facies sismicas

Energy Technology Data Exchange (ETDEWEB)

Johann, Paulo Roberto Schroeder [PETROBRAS, Rio de Janeiro, RJ (Brazil). Exploracao e Producao Corporativo. Gerencia de Reservas e Reservatorios]. E-mail: johann@petrobras.com.br

2004-11-01

The method presented herein describes the seismic facies as representations of curves and vertical matrixes of the lithotypes proportions. The seismic facies are greatly interested in capturing the spatial distributions (3D) of regionalized variables, as for example, lithotypes, sedimentary facies groups and/ or porosity and/or other properties of the reservoirs and integrate them into the 3D geological modeling (Johann, 1997). Thus when interpreted as curves or vertical matrixes of proportions, seismic facies allow us to build a very important tool for structural analysis of regionalized variables. The matrixes have an important application in geostatistical modeling. In addition, this approach provides results about the depth and scale of the wells profiles, that is, seismic data is integrated to the characterization of reservoirs in depth maps and in high resolution maps. The link between the different necessary technical phases involved in the classification of the segments of seismic traces is described herein in groups of predefined traces of two approaches: a) not supervised and b) supervised by the geological knowledge available on the studied reservoir. The multivariate statistical methods used to obtain the maps of the seismic facies units are interesting tools to be used to provide a lithostratigraphic and petrophysical understanding of a petroleum reservoir. In the case studied these seismic facies units are interpreted as representative of the depositional system as a part of the Namorado Turbiditic System, Namorado Field, Campos Basin.Within the scope of PRAVAP 19 (Programa Estrategico de Recuperacao Avancada de Petroleo - Strategic Program of Advanced Petroleum Recovery) some research work on algorithms is underway to select new optimized attributes to apply seismic facies. One example is the extraction of attributes based on the wavelet transformation and on the time-frequency analysis methodology. PRAVAP is also carrying out research work on an

MASH Suite: a user-friendly and versatile software interface for high-resolution mass spectrometry data interpretation and visualization.

Science.gov (United States)

Guner, Huseyin; Close, Patrick L; Cai, Wenxuan; Zhang, Han; Peng, Ying; Gregorich, Zachery R; Ge, Ying

2014-03-01

The rapid advancements in mass spectrometry (MS) instrumentation, particularly in Fourier transform (FT) MS, have made the acquisition of high-resolution and high-accuracy mass measurements routine. However, the software tools for the interpretation of high-resolution MS data are underdeveloped. Although several algorithms for the automatic processing of high-resolution MS data are available, there is still an urgent need for a user-friendly interface with functions that allow users to visualize and validate the computational output. Therefore, we have developed MASH Suite, a user-friendly and versatile software interface for processing high-resolution MS data. MASH Suite contains a wide range of features that allow users to easily navigate through data analysis, visualize complex high-resolution MS data, and manually validate automatically processed results. Furthermore, it provides easy, fast, and reliable interpretation of top-down, middle-down, and bottom-up MS data. MASH Suite is convenient, easily operated, and freely available. It can greatly facilitate the comprehensive interpretation and validation of high-resolution MS data with high accuracy and reliability.

Interactive web visualization tools to the results interpretation of a seismic risk study aimed at the emergency levels definition

Science.gov (United States)

Rivas-Medina, A.; Gutierrez, V.; Gaspar-Escribano, J. M.; Benito, B.

2009-04-01

Results of a seismic risk assessment study are often applied and interpreted by users unspecialised on the topic or lacking a scientific background. In this context, the availability of tools that help translating essentially scientific contents to broader audiences (such as decision makers or civil defence officials) as well as representing and managing results in a user-friendly fashion, are on indubitable value. On of such tools is the visualization tool VISOR-RISNA, a web tool developed within the RISNA project (financed by the Emergency Agency of Navarre, Spain) for regional seismic risk assessment of Navarre and the subsequent development of emergency plans. The RISNA study included seismic hazard evaluation, geotechnical characterization of soils, incorporation of site effects to expected ground motions, vulnerability distribution assessment and estimation of expected damage distributions for a 10% probability of exceedance in 50 years. The main goal of RISNA was the identification of higher risk area where focusing detailed, local-scale risk studies in the future and the corresponding urban emergency plans. A geographic information system was used to combine different information layers, generate tables of results and represent maps with partial and final results. The visualization tool VISOR-RISNA is intended to facilitate the interpretation and representation of the collection of results, with the ultimate purpose of defining actuation plans. A number of criteria for defining actuation priorities are proposed in this work. They are based on combinations of risk parameters resulting from the risk study (such as expected ground motion and damage and exposed population), as determined by risk assessment specialists. Although the values that these parameters take are a result of the risk study, their distribution in several classes depends on the intervals defined by decision takers or civil defense officials. These criteria provide a ranking of

The development of the operational program for seismic monitoring system of Uljin Unit 1 and 2

Energy Technology Data Exchange (ETDEWEB)

Lee, J.R.; Heo, T.Y.; Cho, B.H. [Korea Electric Power Research Institute, Taejeon (Korea, Republic of); Kang, T.G.; Kim, H.M.; Kim, Y.S.; Oh, S.M.; Kang, Y.S. [Korea Electric Power Data Network Co., Seoul (Korea, Republic of)

1997-12-31

Due to aging of the imported seismic monitoring system of Uljin of t 1 and 2 units it is difficult for this system to provide enough functions needed for the security of seismic safety and the evaluation of the earthquake data from the seismic instrumentation. For this reason, it is necessary to replace the seismic monitoring system of Uljin 1 and 2 units with a new system which has the localized and upgraded hardware and corresponding software. In the part of standardization of existing seismic monitoring system, furthermore, it is necessary to develop the seismic wave analysis system which incorporate newly developed software and can real-timely analyze the seismic wave. This report is the finial product of research project ``The development of the operational program for seismic monitoring system of Uljin Unit 1 and 2`` which have been performed from June 1996 to June 1997 by KEPRI and KDN. Main accomplishments - Review of regulatory criteria for seismic monitoring system -Analysis and upgrade of hardware system -Analysis and upgrade of software system - Development of seismic wave analysis system. (author). 17 refs., 49 figs., 6 tabs.

Critical Assessment of Metagenome Interpretation – a benchmark of computational metagenomics software

Science.gov (United States)

Sczyrba, Alexander; Hofmann, Peter; Belmann, Peter; Koslicki, David; Janssen, Stefan; Dröge, Johannes; Gregor, Ivan; Majda, Stephan; Fiedler, Jessika; Dahms, Eik; Bremges, Andreas; Fritz, Adrian; Garrido-Oter, Ruben; Jørgensen, Tue Sparholt; Shapiro, Nicole; Blood, Philip D.; Gurevich, Alexey; Bai, Yang; Turaev, Dmitrij; DeMaere, Matthew Z.; Chikhi, Rayan; Nagarajan, Niranjan; Quince, Christopher; Meyer, Fernando; Balvočiūtė, Monika; Hansen, Lars Hestbjerg; Sørensen, Søren J.; Chia, Burton K. H.; Denis, Bertrand; Froula, Jeff L.; Wang, Zhong; Egan, Robert; Kang, Dongwan Don; Cook, Jeffrey J.; Deltel, Charles; Beckstette, Michael; Lemaitre, Claire; Peterlongo, Pierre; Rizk, Guillaume; Lavenier, Dominique; Wu, Yu-Wei; Singer, Steven W.; Jain, Chirag; Strous, Marc; Klingenberg, Heiner; Meinicke, Peter; Barton, Michael; Lingner, Thomas; Lin, Hsin-Hung; Liao, Yu-Chieh; Silva, Genivaldo Gueiros Z.; Cuevas, Daniel A.; Edwards, Robert A.; Saha, Surya; Piro, Vitor C.; Renard, Bernhard Y.; Pop, Mihai; Klenk, Hans-Peter; Göker, Markus; Kyrpides, Nikos C.; Woyke, Tanja; Vorholt, Julia A.; Schulze-Lefert, Paul; Rubin, Edward M.; Darling, Aaron E.; Rattei, Thomas; McHardy, Alice C.

2018-01-01

In metagenome analysis, computational methods for assembly, taxonomic profiling and binning are key components facilitating downstream biological data interpretation. However, a lack of consensus about benchmarking datasets and evaluation metrics complicates proper performance assessment. The Critical Assessment of Metagenome Interpretation (CAMI) challenge has engaged the global developer community to benchmark their programs on datasets of unprecedented complexity and realism. Benchmark metagenomes were generated from ~700 newly sequenced microorganisms and ~600 novel viruses and plasmids, including genomes with varying degrees of relatedness to each other and to publicly available ones and representing common experimental setups. Across all datasets, assembly and genome binning programs performed well for species represented by individual genomes, while performance was substantially affected by the presence of related strains. Taxonomic profiling and binning programs were proficient at high taxonomic ranks, with a notable performance decrease below the family level. Parameter settings substantially impacted performances, underscoring the importance of program reproducibility. While highlighting current challenges in computational metagenomics, the CAMI results provide a roadmap for software selection to answer specific research questions. PMID:28967888

Causality between expansion of seismic cloud and maximum magnitude of induced seismicity in geothermal field

Science.gov (United States)

Mukuhira, Yusuke; Asanuma, Hiroshi; Ito, Takatoshi; Häring, Markus

2016-04-01

Occurrence of induced seismicity with large magnitude is critical environmental issues associated with fluid injection for shale gas/oil extraction, waste water disposal, carbon capture and storage, and engineered geothermal systems (EGS). Studies for prediction of the hazardous seismicity and risk assessment of induced seismicity has been activated recently. Many of these studies are based on the seismological statistics and these models use the information of the occurrence time and event magnitude. We have originally developed physics based model named "possible seismic moment model" to evaluate seismic activity and assess seismic moment which can be ready to release. This model is totally based on microseismic information of occurrence time, hypocenter location and magnitude (seismic moment). This model assumes existence of representative parameter having physical meaning that release-able seismic moment per rock volume (seismic moment density) at given field. Seismic moment density is to be estimated from microseismic distribution and their seismic moment. In addition to this, stimulated rock volume is also inferred by progress of microseismic cloud at given time and this quantity can be interpreted as the rock volume which can release seismic energy due to weakening effect of normal stress by injected fluid. Product of these two parameters (equation (1)) provide possible seismic moment which can be released from current stimulated zone as a model output. Difference between output of this model and observed cumulative seismic moment corresponds the seismic moment which will be released in future, based on current stimulation conditions. This value can be translated into possible maximum magnitude of induced seismicity in future. As this way, possible seismic moment can be used to have feedback to hydraulic stimulation operation in real time as an index which can be interpreted easily and intuitively. Possible seismic moment is defined as equation (1), where D

Gabor Deconvolution as Preliminary Method to Reduce Pitfall in Deeper Target Seismic Data

Science.gov (United States)

Oktariena, M.; Triyoso, W.

2018-03-01

Anelastic attenuation process during seismic wave propagation is the trigger of seismic non-stationary characteristic. An absorption and a scattering of energy are causing the seismic energy loss as the depth increasing. A series of thin reservoir layers found in the study area is located within Talang Akar Fm. Level, showing an indication of interpretation pitfall due to attenuation effect commonly occurred in deeper level seismic data. Attenuation effect greatly influences the seismic images of deeper target level, creating pitfalls in several aspect. Seismic amplitude in deeper target level often could not represent its real subsurface character due to a low amplitude value or a chaotic event nearing the Basement. Frequency wise, the decaying could be seen as the frequency content diminishing in deeper target. Meanwhile, seismic amplitude is the simple tool to point out Direct Hydrocarbon Indicator (DHI) in preliminary Geophysical study before a further advanced interpretation method applied. A quick-look of Post-Stack Seismic Data shows the reservoir associated with a bright spot DHI while another bigger bright spot body detected in the North East area near the field edge. A horizon slice confirms a possibility that the other bright spot zone has smaller delineation; an interpretation pitfall commonly occurs in deeper level of seismic. We evaluates this pitfall by applying Gabor Deconvolution to address the attenuation problem. Gabor Deconvolution forms a Partition of Unity to factorize the trace into smaller convolution window that could be processed as stationary packets. Gabor Deconvolution estimates both the magnitudes of source signature alongside its attenuation function. The enhanced seismic shows a better imaging in the pitfall area that previously detected as a vast bright spot zone. When the enhanced seismic is used for further advanced reprocessing process, the Seismic Impedance and Vp/Vs Ratio slices show a better reservoir delineation, in which the

Reduction of uncertainties in probabilistic seismic hazard analysis

Energy Technology Data Exchange (ETDEWEB)

Seo, Jeong Moon; Choun, Young Sun; Choi, In Kil [Korea Atomic Energy Research Institute, Taejon (Korea)

1999-02-01

An integrated research for the reduction of conservatism and uncertainties in PSHA in Korea was performed. The research consisted of five technical task areas as follows; Task 1: Earthquake Catalog Development for PSHA. Task 2: Evaluation of Seismicity and Tectonics of the Korea Region. Task 3: Development of a Ground Motion Relationships. Task 4: Improvement of PSHA Modelling Methodology. Task 5: Development of Seismic Source Interpretations for the region of Korea for Inputs to PSHA. A series of tests on an ancient wooden house and an analysis on medium size earthquake in Korea were performed intensively. Signification improvement, especially in the estimation of historical earthquake, ground motion attenuation, and seismic source interpretations, were made through this study. 314 refs., 180 figs., 54 tabs. (Author)

Development and validation of open-source software for DNA mixture interpretation based on a quantitative continuous model.

Science.gov (United States)

Manabe, Sho; Morimoto, Chie; Hamano, Yuya; Fujimoto, Shuntaro; Tamaki, Keiji

2017-01-01

In criminal investigations, forensic scientists need to evaluate DNA mixtures. The estimation of the number of contributors and evaluation of the contribution of a person of interest (POI) from these samples are challenging. In this study, we developed a new open-source software "Kongoh" for interpreting DNA mixture based on a quantitative continuous model. The model uses quantitative information of peak heights in the DNA profile and considers the effect of artifacts and allelic drop-out. By using this software, the likelihoods of 1-4 persons' contributions are calculated, and the most optimal number of contributors is automatically determined; this differs from other open-source software. Therefore, we can eliminate the need to manually determine the number of contributors before the analysis. Kongoh also considers allele- or locus-specific effects of biological parameters based on the experimental data. We then validated Kongoh by calculating the likelihood ratio (LR) of a POI's contribution in true contributors and non-contributors by using 2-4 person mixtures analyzed through a 15 short tandem repeat typing system. Most LR values obtained from Kongoh during true-contributor testing strongly supported the POI's contribution even for small amounts or degraded DNA samples. Kongoh correctly rejected a false hypothesis in the non-contributor testing, generated reproducible LR values, and demonstrated higher accuracy of the estimated number of contributors than another software based on the quantitative continuous model. Therefore, Kongoh is useful in accurately interpreting DNA evidence like mixtures and small amounts or degraded DNA samples.

Development and validation of open-source software for DNA mixture interpretation based on a quantitative continuous model.

Directory of Open Access Journals (Sweden)

Sho Manabe

Full Text Available In criminal investigations, forensic scientists need to evaluate DNA mixtures. The estimation of the number of contributors and evaluation of the contribution of a person of interest (POI from these samples are challenging. In this study, we developed a new open-source software "Kongoh" for interpreting DNA mixture based on a quantitative continuous model. The model uses quantitative information of peak heights in the DNA profile and considers the effect of artifacts and allelic drop-out. By using this software, the likelihoods of 1-4 persons' contributions are calculated, and the most optimal number of contributors is automatically determined; this differs from other open-source software. Therefore, we can eliminate the need to manually determine the number of contributors before the analysis. Kongoh also considers allele- or locus-specific effects of biological parameters based on the experimental data. We then validated Kongoh by calculating the likelihood ratio (LR of a POI's contribution in true contributors and non-contributors by using 2-4 person mixtures analyzed through a 15 short tandem repeat typing system. Most LR values obtained from Kongoh during true-contributor testing strongly supported the POI's contribution even for small amounts or degraded DNA samples. Kongoh correctly rejected a false hypothesis in the non-contributor testing, generated reproducible LR values, and demonstrated higher accuracy of the estimated number of contributors than another software based on the quantitative continuous model. Therefore, Kongoh is useful in accurately interpreting DNA evidence like mixtures and small amounts or degraded DNA samples.

Interpretation of Seismic Cone Penetration Testing in Silty Soil

DEFF Research Database (Denmark)

Holmsgaard, Rikke; Ibsen, Lars Bo; Nielsen, Benjaminn Nordahl

2016-01-01

Five Seismic Cone Penetration Tests (SCPT) were conducted at a test site in northern Denmark where the subsoil consists primarily of sandy silt with clay bands. A portion of the test data were collected every 0.5 m to compare the efficacy of closely-spaced down-hole data collection on the computa...

Intraplate seismicity in Canada: a graph theoretic approach to data analysis and interpretation

Directory of Open Access Journals (Sweden)

K. Vasudevan

2010-10-01

Full Text Available Intraplate seismicity occurs in central and northern Canada, but the underlying origin and dynamics remain poorly understood. Here, we apply a graph theoretic approach to characterize the statistical structure of spatiotemporal clustering exhibited by intraplate seismicity, a direct consequence of the underlying nonlinear dynamics. Using a recently proposed definition of "recurrences" based on record breaking processes (Davidsen et al., 2006, 2008, we have constructed directed graphs using catalogue data for three selected regions (Region 1: 45°−48° N/74°−80° W; Region 2: 51°−55° N/77°−83° W; and Region 3: 56°−70° N/65°−95° W, with attributes drawn from the location, origin time and the magnitude of the events. Based on comparisons with a null model derived from Poisson distribution or Monte Carlo shuffling of the catalogue data, our results provide strong evidence in support of spatiotemporal correlations of seismicity in all three regions considered. Similar evidence for spatiotemporal clustering has been documented using seismicity catalogues for southern California, suggesting possible similarities in underlying earthquake dynamics of both regions despite huge differences in the variability of seismic activity.

Analysis of the geometry of diabase sills of the Serra Geral magmatism, by 2D seismic interpretation, in Guareí region, São Paulo, Paraná basin, Brazil

Directory of Open Access Journals (Sweden)

Diego Felipe Bezerra da Costa

Full Text Available ABSTRACT: The Paraná Basin holds in its stratigraphic record a thick layer of volcanic rocks related to the opening of the Gondwana Supercontinent, which occurred during the Eocretaceous. Based on the interpretation of three two-dimensional (2D seismic lines in the region of Guareí, East-Central São Paulo state, in the Southeast of Brazil, the subsurface geometries of these volcanic rocks were identified. Since the original seismic resolution quality was low, alternative techniques were utilized to improve the seismic imaging, such as isolating maximum and minimum amplitude values by manipulating the color scale, and using the root mean square (RMS attribute and the Amplitude Volume technique (tecVA, which emphasize the seismic signature of igneous rocks in relation to sedimentary layers. The use of such techniques allowed the identification of different geometries of diabase sills and showed a relationship between these intrusive and organic matter maturation of the source rock.

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.

Seismic VSP Investigations at Olkiluoto, 2005

Energy Technology Data Exchange (ETDEWEB)

Enescu, N.; Cosma, C.; Balu, L. (Vibrometric, Vantaa (Finland))

2007-08-15

Posiva Oy carries out R and D related tasks for spent nuclear fuel disposal in Finland. The site characterization has been conducted since 1987 in Olkiluoto in western Finland. The ONKALO underground characterization facility has been under construction since 2004. Vibrometric Oy has been contracted to carry out seismic VSP survey in four drillholes in the immediate vicinity of ONKALO, for the characterization of the seismically responsive structures. Four drillholes, KR8, KR27, KR29 and KR38 were included to the project. Seven seismic source locations on ground surface were used for each drillhole. The source locations were optimized with respect to the drillhole and ONKALO and were configured as linear arrays to produce optimum imaging focused on the ONKALO volume. A mechanical Vibsist source, using a hydraulic rock breaker mounted on a 22 t excavator, was used as source of seismic signal. The signal was recorded with downhole 3-component geophones. The recording array was 8-level long, with 5 m spacing between levels. Acquisition was run throughout the drillholes. Processing of the VSP profiles consisted of time decoding of the impact sequences, filtering and image point (IP) transform. The interpretation was carried out interactively, seeking for best match of orientation of each reflection according to different borehole profiles where the features were seen. The interpretations were built as an add-on to a previous seismic model of the site. The most distinct reflectors were interpreted, compiled to as a part of a terrain model composed of 3D surfaces, and transferred digitally together with other results (3D elements of reflector locations) into Posiva's 3D modeling system. Some of the reflectors have already received direct confirmation from ONKALO observations. (orig.)

Seismic VSP Investigations at Olkiluoto, 2005

International Nuclear Information System (INIS)

Enescu, N.; Cosma, C.; Balu, L.

2007-08-01

Posiva Oy carries out R and D related tasks for spent nuclear fuel disposal in Finland. The site characterization has been conducted since 1987 in Olkiluoto in western Finland. The ONKALO underground characterization facility has been under construction since 2004. Vibrometric Oy has been contracted to carry out seismic VSP survey in four drillholes in the immediate vicinity of ONKALO, for the characterization of the seismically responsive structures. Four drillholes, KR8, KR27, KR29 and KR38 were included to the project. Seven seismic source locations on ground surface were used for each drillhole. The source locations were optimized with respect to the drillhole and ONKALO and were configured as linear arrays to produce optimum imaging focused on the ONKALO volume. A mechanical Vibsist source, using a hydraulic rock breaker mounted on a 22 t excavator, was used as source of seismic signal. The signal was recorded with downhole 3-component geophones. The recording array was 8-level long, with 5 m spacing between levels. Acquisition was run throughout the drillholes. Processing of the VSP profiles consisted of time decoding of the impact sequences, filtering and image point (IP) transform. The interpretation was carried out interactively, seeking for best match of orientation of each reflection according to different borehole profiles where the features were seen. The interpretations were built as an add-on to a previous seismic model of the site. The most distinct reflectors were interpreted, compiled to as a part of a terrain model composed of 3D surfaces, and transferred digitally together with other results (3D elements of reflector locations) into Posiva's 3D modeling system. Some of the reflectors have already received direct confirmation from ONKALO observations. (orig.)

Real Time Seismic Prediction while Drilling

Science.gov (United States)

Schilling, F. R.; Bohlen, T.; Edelmann, T.; Kassel, A.; Heim, A.; Gehring, M.; Lüth, S.; Giese, R.; Jaksch, K.; Rechlin, A.; Kopf, M.; Stahlmann, J.; Gattermann, J.; Bruns, B.

2009-12-01

Efficient and safe drilling is a prerequisite to enhance the mobility of people and goods, to improve the traffic as well as utility infrastructure of growing megacities, and to ensure the growing energy demand while building geothermal and in hydroelectric power plants. Construction within the underground is often building within the unknown. An enhanced risk potential for people and the underground building may arise if drilling enters fracture zones, karsts, brittle rocks, mixed solid and soft rocks, caves, or anthropogenic obstacles. Knowing about the material behavior ahead of the drilling allows reducing the risk during drilling and construction operation. In drilling operations direct observations from boreholes can be complemented with geophysical investigations. In this presentation we focus on “real time” seismic prediction while drilling which is seen as a prerequisite while using geophysical methods in modern drilling operations. In solid rocks P- and S-wave velocity, refraction and reflection as well as seismic wave attenuation can be used for the interpretation of structures ahead of the drilling. An Integrated Seismic Imaging System (ISIS) for exploration ahead of a construction is used, where a pneumatic hammer or a magnetostrictive vibration source generate repetitive signals behind the tunneling machine. Tube waves are generated which travel along the tunnel to the working face. There the tube waves are converted to mainly S- but also P-Waves which interact with the formation ahead of the heading face. The reflected or refracted waves travel back to the working front are converted back to tube waves and recorded using three-component geophones which are fit into the tips of anchor rods. In near real time, the ISIS software allows for an integrated 3D imaging and interpretation of the observed data, geological and geotechnical parameters. Fracture zones, heterogeneities, and variations in the rock properties can be revealed during the drilling

Quaternary tectonics from seismic interpretation and its potential relation with deep geothermal fluids in the Marche (Central Italy).

Science.gov (United States)

Chicco, Jessica; Invernizzi, Chiara; Pierantoni, Pietro Paolo; Costa, Mario

2017-04-01

Knowledge of the structural features is fundamental in evaluating geothermal exchange potential and in modelling geothermal systems. In particular, faults and fractures play an important role for the circulation of fluids in the crust, and structural setting can influence groundwater flow, its regime, chemistry and electrical conductivity. In this context, data coming from accurate studies of groundwater physical properties in the Marche region (Central Italy), concerning electrical conductivity above all, revealed some anomalies in several localities that could be ascribed to a strong structural control. Data acquisition and interpretation of some SW-NE seismic reflection profiles crossing the Apennine chain to the Adriatic sea and kindly provided by ENI S.p.A, highlight important deep Plio-Quaternary structures connected with minor surface ones and to hydrogeological conditions. Seismic profiles interpretation allowed to reconstruct the structural setting and to identify the recent evolution of the Apennine Marche sector in more detail with respect to what is already known. In fact, some high angle structures affecting the whole sedimentary sequence and routing at high depth were labelled. These are NW-SE sub-parallel transpressive structures bounded by SW and NE-dipping high-angle reverse faults reaching > 10 km depth (positive flower structures), and probably involving the upper crust basement. Three main alignments were identified from W to the coast line. In some cases, flower nucleation gives rise to the lifting and counter-clockwise rotation of the Pre-Pliocene substratum blocks, with the upwelling and outcropping of Upper Miocene (Messinian) evaporite deposits along the axial zone of the transpressive structural highs. Noting the analyses of groundwater properties coming from wells placed in proximity of these structures or located along the analysed seismic profiles, anomalies in electrical conductivity are relevant. The activity of the deep rooting

Interpretation of a seismic test of the IPIRG2 program

International Nuclear Information System (INIS)

Blay, N.; Gantenbein, F.

1995-01-01

In the framework of the linear and non linear analysis of PWR cracked pipes under seismic loading, the calculations of the 1.2 seismic test of the important IPIRG2 program (International Piping Integrity Research Group) was undertaken. This seismic test was performed on a pipe with a surface crack and loaded by an imposed displacement. A low level and a high level of excitation were applied to the pipe. The calculations are made with a global model including a through wall crack pipe finite element. The modal analysis made for the non-cracked pipe and the real geometrical characteristics gives a first frequency of the pipe with pressure and temperature in good agreement with the test. For the cracked pipe, the first frequency decrease is less than 0.5%. The low level response was calculated with a linear model by modal combination in order to study the importance of the both inertial and differential displacement responses in the total response. For both configurations, non-cracked and cracked, the inertial contribution to the moment at the crack location is approximately equal to 80% of the total moment. For the linear behaviour, the influence of the crack appears weak. The non linear calculations are performed with the equivalent crack previously defined up to penetration. To study the behaviour after penetration, various hypothesis for the crack size are taken. (authors). 3 refs., 6 figs., 4 tabs

List search hardware for interpretive software

CERN Document Server

Altaber, Jacques; Mears, B; Rausch, R

1979-01-01

Interpreted languages, e.g. BASIC, are simple to learn, easy to use, quick to modify and in general 'user-friendly'. However, a critically time consuming process during interpretation is that of list searching. A special microprogrammed device for fast list searching has therefore been developed at the SPS Division of CERN. It uses bit- sliced hardware. Fast algorithms perform search, insert and delete of a six-character name and its value in a list of up to 1000 pairs. The prototype shows retrieval times of the order of 10-30 microseconds. (11 refs).

Software of Seismic Proportions Promotes Enjoyable Learning

Science.gov (United States)

2005-01-01

While working for NASA, Jack Sculley and Terry Brooks had a revelation. They wanted to find a novel and unique way to present the scientific principles of NASA research to the public, so as to not only enlighten, but entertain. Suddenly, their revelation morphed into something even grander. "Why stop at NASA?" they asked themselves. With this thought, Sculley and Brooks left NASA and set out to convey voluminous scientific findings from different organizations in the form of digital, interactive media that would enhance the exploration and adventure interests of people of all ages. Sculley, a former researcher at Ames Research Center, the Jet Propulsion Laboratory (JPL), and Apple, Inc. s and LucasFilm Ltd. s multimedia labs, and Brooks, a former public information officer at JPL and an Emmy award-winning documentary film producer, founded Seismic Entertainment in 1989 to communicate their "edutainment" ideas. The two acknowledge that NASA has provided much of the inspiration and content for Seismic Entertainment over the past decade and a half. Additionally, Sculley s experience as a virtual reality and Mars specialist and Brooks s experience creating NASA public access programs were significant to the San Francisco-based company s success. Its most recent project, "Inside NASA," provides virtual tours of NASA s field centers and allows for a comprehensive focus on the broad range of NASA programs for the benefit of the general public

Seismic performance for vertical geometric irregularity frame structures

Science.gov (United States)

Ismail, R.; Mahmud, N. A.; Ishak, I. S.

2018-04-01

This research highlights the result of vertical geometric irregularity frame structures. The aid of finite element analysis software, LUSAS was used to analyse seismic performance by focusing particularly on type of irregular frame on the differences in height floors and continued in the middle of the building. Malaysia’s building structures were affected once the earthquake took place in the neighbouring country such as Indonesia (Sumatera Island). In Malaysia, concrete is widely used in building construction and limited tension resistance to prevent it. Analysing structural behavior with horizontal and vertical static load is commonly analyses by using the Plane Frame Analysis. The case study of this research is to determine the stress and displacement in the seismic response under this type of irregular frame structures. This study is based on seven-storey building of Clinical Training Centre located in Sungai Buloh, Selayang, Selangor. Since the largest earthquake occurs in Acheh, Indonesia on December 26, 2004, the data was recorded and used in conducting this research. The result of stress and displacement using IMPlus seismic analysis in LUSAS Modeller Software under the seismic response of a formwork frame system states that the building is safe to withstand the ground and in good condition under the variation of seismic performance.

Seismic Broadband Full Waveform Inversion by shot/receiver refocusing

NARCIS (Netherlands)

Haffinger, P.R.

2013-01-01

Full waveform inversion is a tool to obtain high-resolution property models of the subsurface from seismic data. However, the technique is computationally expens- ive and so far no multi-dimensional implementation exists to achieve a resolution that can directly be used for seismic interpretation

Seismic gaps and plate tectonics: seismic potential for major boundaries

Energy Technology Data Exchange (ETDEWEB)

McCann, W R; Nishenko, S P; Sykes, L R; Krause, J

1979-01-01

The theory of plate tectonics provides a basic framework for evaluating the potential for future great earthquakes to occur along major plate boundaries. Along most of the transform and convergent plate boundaries considered in this paper, the majority of seismic slip occurs during large earthquakes, i.e., those of magnitude 7 or greater. The concepts that rupture zones, as delineated by aftershocks, tend to abut rather than overlap, and large events occur in regions with histories of both long-and short-term seismic quiescence are used in this paper to delineate major seismic gaps. The term seismic gap is taken to refer to any region along an active plate boundary that has not experienced a large thrust or strike-slip earthquake for more than 30 years. A region of high seismic potential is a seismic gap that, for historic or tectonic reasons, is considered likely to produce a large shock during the next few decades. The seismic gap technique provides estimates of the location, size of future events and origin time to within a few tens of years at best. The accompanying map summarizes six categories of seismic potential for major plate boundaries in and around the margins of the Pacific Ocean and the Caribbean, South Sandwich and Sunda (Indonesia) regions for the next few decades. These six categories are meant to be interpreted as forecasts of the location and size of future large shocks and should not be considered to be predictions in which a precise estimate of the time of occurrence is specified. The categories of potential assigned here provide a rationale for assigning priorities for instrumentation, for future studies aimed at predicting large earthquakes and for making estimates of tsunami potential.

A single geophone to locate seismic events on Mars

Science.gov (United States)

Roques, Aurélien; Berenguer, Jean-Luc; Bozdag, Ebru

2016-04-01

Knowing the structure of Mars is a key point in understanding the formation of Earth-like planets as plate tectonics and erosion have erased the original suface of the Earth formation. Installing a seismometer on Mars surface makes it possible to identify its structure. An important step in the identification of the structure of a planet is the epicenter's location of a seismic source, typically a meteoric impact or an earthquake. On Earth, the classical way of locating epicenters is triangulation, which requires at least 3 stations. The Mars InSight Project plans to set a single station with 3 components. We propose a software to locate seismic sources on Mars thanks to the 3-components simulated data of an earthquake given by Geoazur (Nice Sophia-Antipolis University, CNRS) researchers. Instrumental response of a sensor is crucial for data interpretation. We study the oscillations of geophone in several situations so as to awaken students to the meaning of damping in second order modeling. In physics, car shock absorbers are often used to illustrate the principle of damping but rarely in practical experiments. We propose the use of a simple seismometer (a string with a mass and a damper) that allows changing several parameters (inductive damping, temperature and pressure) so as to see the effects of these parameters on the impulse response and, in particular, on the damping coefficient. In a second step, we illustrate the effect of damping on a seismogram with the difficulty of identifying and interpreting the different phase arrival times with low damping.

Seismic characteristics of central Brazil crust and upper mantle: A deep seismic refraction study

Science.gov (United States)

Soares, J.E.; Berrocal, J.; Fuck, R.A.; Mooney, W.D.; Ventura, D.B.R.

2006-01-01

A two-dimensional model of the Brazilian central crust and upper mantle was obtained from the traveltime interpretation of deep seismic refraction data from the Porangatu and Cavalcante lines, each approximately 300 km long. When the lines were deployed, they overlapped by 50 km, forming an E-W transect approximately 530 km long across the Tocantins Province and western Sa??o Francisco Craton. The Tocantins Province formed during the Neoproterozoic when the Sa??o Francisco, the Paranapanema, and the Amazon cratons collided, following the subduction of the former Goia??s ocean basin. Average crustal VP and VP/VS ratios, Moho topography, and lateral discontinuities within crustal layers suggest that the crust beneath central Brazil can be associated with major geological domains recognized at the surface. The Moho is an irregular interface, between 36 and 44 km deep, that shows evidences of first-order tectonic structures. The 8.05 and 8.23 km s-1 P wave velocities identify the upper mantle beneath the Porangatu and Cavalcante lines, respectively. The observed seismic features allow for the identification of (1) the crust has largely felsic composition in the studied region, (2) the absence of the mafic-ultramafic root beneath the Goia??s magmatic arc, and (3) block tectonics in the foreland fold-and-thrust belt of the northern Brasi??lia Belt during the Neoproterozoic. Seismic data also suggested that the Bouguer gravimetric discontinuities are mainly compensated by differences in mass distribution within the lithospheric mantle. Finally, the Goia??s-Tocantins seismic belt can be interpreted as a natural seismic alignment related to the Neoproterozoic mantle domain. Copyright 2006 by the American Geophysical Union.

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

7. annual software survey 2009

Energy Technology Data Exchange (ETDEWEB)

Anon.

2009-07-15

This article presented a guide to new software applications designed to facilitate petroleum exploration, drilling and production activities. Oil and gas producers can use the products for a range of functions, including reservoir characterization and accounting. In addition to a description of the software application, this article listed the name of software providers and the new features available in each product. The featured software developed by Calgary-based providers included: OpenInvoice software developed by DO2 Technologies Inc; oil and gas solutions by Energy Navigator; WellSpring planning system by Enersight; Entero MOSAIC and Entero ONE software packages by Entero Corporation; Emission Manager by Envirosoft Corporation; ResSurveil, ResBalance and ResAssist by Epic Consulting Services Ltd.; OMNI 3D, VISTA 2D/3D seismic software by Gedco; geoSCOUT, petroCUBE and gDC by GeoLOGIC Systems Ltd.; IHS AccuMap and PETRA by IHS; WELLFLO, PIPEFLO and FORGAS wellbore solutions by Neotec; AFENexus, FANexus, GeoNexus, JVNexus, PANexus software by Pandell Technology Corporation; Oil and gas solutions by the Risk Advisory division of SAS; Petrel, ECLIPSE, Avocet, Osprey and Merak by Schlumberger Information Solutions; esi.manage and esi.executive by 3esi; and STABView, ROCKSBank by Weatherford Advanced Geotechnology. The featured software developed by Texas-based providers included the HTRI Xchanger Suite by Heat Transfer Research Inc.; the RFID-based asset tracking system by Merrick Systems; oil and gas solutions by Neuralog Inc.; geoscience data programs by OpenSpirit; and oil and gas solutions by Seismic Micro-Technology Inc. The featured software developed by Vancouver-based providers included the oil and gas solutions by Sustainet Software Solutions Inc.

Agile software development and the barriers to transfer of knowledge: An interpretive case study

DEFF Research Database (Denmark)

Heeager, Lise Tordrup; Nielsen, Peter Axel

2013-01-01

Agile practices to systems development are believed to depend largely on the developers’ competences, experience and knowledge and to a lesser degree on formal development processes and methods. In this paper we investigate the knowledge transfer and barriers to the transfer of agile development ...... to explain knowledge transfer and barriers, and (2) specifically explicate potential barriers hindering knowledge transfer of agile practices. This has implications for the implementation of agile development practices.......Agile practices to systems development are believed to depend largely on the developers’ competences, experience and knowledge and to a lesser degree on formal development processes and methods. In this paper we investigate the knowledge transfer and barriers to the transfer of agile development...... practices in an interpretive case study. The case company is a pharmaceutical firm where we studied how they develop software and how they transfer their own experience. Based on the literature we develop an initial framework of barriers to knowledge transfer and apply it to interpret the case study. From...

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

Structure and hydrocarbon potential of the Nuussuaq basin: acquisition and interpretation of high-resolution multichannel seismic data

Energy Technology Data Exchange (ETDEWEB)

Marcussen, C.; Skaarup, N.; Chalmers, J.A.

2002-07-01

Data acquisition of project NuussuaqSeis2000 (GEUS2000G survey) was very successful. Due to very favourable weather and ice conditions, 2743 km of good quality data were acquired, nearly 20% more than originally planned. High concentrations of icebergs prevented acquisition of data in the eastern part of Uummannaq Fjord and east of Svartenhuk Halvoe. Data from project NuussuaqSeis 2000 have therefore considerably increased the seismic coverage in the region. Interpretation of the new data has given information on the size and geometry of the individual fault blocks in areas with Cretaceous sediments. Furthermore the new data confirm that the seeps in the Vaigat region are structurally controlled and mainly occur in the block-faulted area north of the Disko gneiss ridge. Data from the GEUS2000G survey confirm the overall structural interpretation published in Chalmers et al. (1999). The interpretation of the structural style in western Vaigat is confirmed as being substantially correct, although the fault patterns have been shown to be much more complex than realised previously, from either the onshore data or from the single line GGU/95-06. The main area of revision has been in eastern Vaigat, but even there the essentials of the Chalmers et al. (1999) interpretation remain. In the area north of Nuussuaq in Uummannaq Fjord and Illorssuit Sund the fault trend is more N-S than in Vaigat, but also here the complexity in the fault pattern prohibites a correlation for too long distances. The general fault pattern from the structural interpretation of Chalmers et al. (1999) remains valid in this area as well. Some of the data acquired under project NuussuaqSeis2000 are highly relevant for an assessment of the petroleum prospectivity of the Disko-Nuussuaq region, and the data and their interpretation will be included in the next revised GEUS Note to the Bureau of Minerals and Petroleum on this matter. The new data and the interpretations are particularly important for

Modernization of the USGS Hawaiian Volcano Observatory Seismic Processing Infrastructure

Science.gov (United States)

Antolik, L.; Shiro, B.; Friberg, P. A.

2016-12-01

The USGS Hawaiian Volcano Observatory (HVO) operates a Tier 1 Advanced National Seismic System (ANSS) seismic network to monitor, characterize, and report on volcanic and earthquake activity in the State of Hawaii. Upgrades at the observatory since 2009 have improved the digital telemetry network, computing resources, and seismic data processing with the adoption of the ANSS Quake Management System (AQMS) system. HVO aims to build on these efforts by further modernizing its seismic processing infrastructure and strengthen its ability to meet ANSS performance standards. Most notably, this will also allow HVO to support redundant systems, both onsite and offsite, in order to provide better continuity of operation during intermittent power and network outages. We are in the process of implementing a number of upgrades and improvements on HVO's seismic processing infrastructure, including: 1) Virtualization of AQMS physical servers; 2) Migration of server operating systems from Solaris to Linux; 3) Consolidation of AQMS real-time and post-processing services to a single server; 4) Upgrading database from Oracle 10 to Oracle 12; and 5) Upgrading to the latest Earthworm and AQMS software. These improvements will make server administration more efficient, minimize hardware resources required by AQMS, simplify the Oracle replication setup, and provide better integration with HVO's existing state of health monitoring tools and backup system. Ultimately, it will provide HVO with the latest and most secure software available while making the software easier to deploy and support.

Experimental software for modeling and interpreting educational data analysis processes

Directory of Open Access Journals (Sweden)

Natalya V. Zorina

2017-12-01

Full Text Available Problems, tasks and processes of educational data mining are considered in this article. The objective is to create a fundamentally new information system of the University using the results educational data analysis. One of the functions of such a system is knowledge extraction from accumulated in the operation process data. The creation of the national system of this type is an iterative and time-consuming process requiring the preliminary studies and incremental prototyping modules. The novelty of such systems is that there is a lack of those using this methodology of the development, for this purpose a number of experiments was carried out in order to collect data, choose appropriate methods for the study and to interpret them. As a result of the experiment, the authors were available sources available for analysis in the information environment of the home university. The data were taken from the semester performance, obtained from the information system of the training department of the Institute of IT MTU MIREA, the data obtained as a result of the independent work of students and data, using specially designed Google-forms. To automate the collection of information and analysis of educational data, an experimental software package was created. As a methodology for developing the experimental software complex, a decision was made using the methodologies of rational-empirical complexes (REX and single-experimentation program technologies (TPEI. The details of the program implementation of the complex are described in detail, conclusions are given about the availability of the data sources used, and conclusions are drawn about the prospects for further development.

Interpretation of Microseismicity Observed From Surface and Borehole Seismic Arrays During Hydraulic Fracturing in Shale - Bedding Plane Slip Model

Science.gov (United States)

Stanek, F.; Jechumtalova, Z.; Eisner, L.

2017-12-01

We present a geomechanical model explaining microseismicity induced by hydraulic fracturing in shales developed from many datasets acquired with two most common types of seismic monitoring arrays, surface and dual-borehole arrays. The geomechanical model explains the observed source mechanisms and locations of induced events from two stimulated shale reservoirs. We observe shear dip-slip source mechanisms with nodal planes aligned with location trends. We show that such seismicity can be explained as a shearing along bedding planes caused by aseismic opening of vertical hydraulic fractures. The source mechanism inversion was applied only to selected high-quality events with sufficient signal-to-noise ratio. We inverted P- and P- and S-wave arrival amplitudes to full-moment tensor and decomposed it to shear, volumetric and compensated linear vector dipole components. We also tested an effect of noise presented in the data to evaluate reliability of non-shear components. The observed seismicity from both surface and downhole monitoring of shale stimulations is very similar. The locations of induced microseismic events are limited to narrow depth intervals and propagate along distinct trend(s) showing fracture propagation in direction of maximum horizontal stress from injection well(s). The source mechanisms have a small non-shear component which can be partly explained as an effect of noise in the data, i.e. events represent shearing on faults. We observe predominantly dip-slip events with a strike of the steeper (almost vertical) nodal plane parallel to the fracture propagation. Therefore the other possible nodal plane is almost horizontal. The rake angles of the observed mechanisms divide these dip-slips into two groups with opposite polarities. It means that we observe opposite movements on the nearly identically oriented faults. Realizing a typical structural weakness of shale in horizontal planes, we interpret observed microseismicity as a result of shearing

Data processing of natural and induced events recorded at the seismic station Ostrava-Kr¨¢sn¨¦ Pole (OKC)

OpenAIRE

Nov¨¢k Josef; Rušajov¨¢ Jana; Holub Karel; Kejzl¨ªk Jarom¨ªr

2001-01-01

The operation of the seismic station Ostrava-Kr¨¢sn¨¦ Pole (OKC) (¦Õ = 49.8352¡ãN; ¦Ë = 18.1422¡ãE) which is situated at present in an experimental gallery nearby the Ostrava planetarium started in the year 1983 being equiped initially by analogue instrumentation. Modernization of instrumentation at the station was aimed at the installation of a new digital data acquisition system and the respective software packages for data interpretation and transmission.Data acquisition system VISTEC is b...

Artificial neural systems for interpretation and inversion of seismic data

Science.gov (United States)

Calderon-Macias, Carlos

The goal of this work is to investigate the feasibility of using neural network (NN) models for solving geophysical exploration problems. First, a feedforward neural network (FNN) is used to solve inverse problems. The operational characteristics of a FNN are primarily controlled by a set of weights and a nonlinear function that performs a mapping between two sets of data. In a process known as training, the FNN weights are iteratively adjusted to perform the mapping. After training, the computed weights encode important features of the data that enable one pattern to be distinguished from another. Synthetic data computed from an ensemble of earth models and the corresponding models provide the training data. Two training methods are studied: the backpropagation method which is a gradient scheme, and a global optimization method called very fast simulated annealing (VFSA). A trained network is then used to predict models from new data (e.g., data from a new location) in a one-step procedure. The application of this method to the problems of obtaining formation resistivities and layer thicknesses from resistivity sounding data and 1D velocity models from seismic data shows that trained FNNs produce reasonably accurate earth models when observed data are input to the FNNs. In a second application, a FNN is used for automating the NMO correction process of seismic reflection data. The task of the FNN is to map CMP data at control locations along a seismic line into subsurface velocities. The network is trained while the velocity analyses are performed at the control locations. Once trained, the computed weights are used as an operator that acts on the remaining CMP data as a velocity interpolator, resulting in a fast method for NMO correction. The second part of this dissertation describes the application of a Hopfield neural network (HNN) to the problems of deconvolution and multiple attenuation. In these applications, the unknown parameters (reflection coefficients

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.

Seismic, gravimetric and geological interpretation of an Andean transect in Venezuela; Interpretacion sismica, gravimetrica y geologica de un perfil transandino venezolano

Energy Technology Data Exchange (ETDEWEB)

Jacome R, Maria Ines; Audemard, Felipe; Gratero, Victor [Universidad Simon Bolivar, Caracas (Venezuela)

1995-12-31

The combination of seismic, gravimetric and geologic data allowed the construction of a crustal model from the Venezuela Andes. This model is aiming to improve the knowledge from this problematic region. The profile is 160 Km long and it cuts perpendicularly the Andes, across the Soledad, Celoso, Bocono, Virtudes and Gavilan faults. The interpreted reflexions seismic profiles lie both flanks of the Venezuelan Andes. Bouguer anomaly lows do not occurs along the central axis but on the satellite basins located along the Northwestern and Southeastern flanks. The contours tend to group on these flanks reflecting a system related to reverse faults. It was also observed a density contrast separating the Cretaceous-Tertiary from the basement lying at depths greater than 5 Km in the northern Barinas Basin. The same contrast was detected around 10 km along the southern Lake Maracaibo area. The Venezuelan Andes is an asymmetric northern vergent Neogene structure generated under compression, transmitted along basement involved thrusts dipping Southeast. In consequence the tectonic transport is from the Southeast to the Northwest. (author). 7 refs., 5 figs., 2 tabs

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.

Seismic Travel Time Tomography in Modeling Low Velocity Anomalies between the Boreholes

Science.gov (United States)

Octova, A.; Sule, R.

2018-04-01

Travel time cross-hole seismic tomography is applied to describing the structure of the subsurface. The sources are placed at one borehole and some receivers are placed in the others. First arrival travel time data that received by each receiver is used as the input data in seismic tomography method. This research is devided into three steps. The first step is reconstructing the synthetic model based on field parameters. Field parameters are divided into 24 receivers and 45 receivers. The second step is applying inversion process for the field data that consists of five pairs bore holes. The last step is testing quality of tomogram with resolution test. Data processing using FAST software produces an explicit shape and resemble the initial model reconstruction of synthetic model with 45 receivers. The tomography processing in field data indicates cavities in several place between the bore holes. Cavities are identified on BH2A-BH1, BH4A-BH2A and BH4A-BH5 with elongated and rounded structure. In resolution tests using a checker-board, anomalies still can be identified up to 2 meter x 2 meter size. Travel time cross-hole seismic tomography analysis proves this mothod is very good to describing subsurface structure and boundary layer. Size and anomalies position can be recognized and interpreted easily.

Teaching hands-on geophysics: examples from the Rū seismic network in New Zealand

International Nuclear Information System (INIS)

Van Wijk, Kasper; Simpson, Jonathan; Adam, Ludmila

2017-01-01

Education in physics and geosciences can be effectively illustrated by the analysis of earthquakes and the subsequent propagation of seismic waves in the Earth. Educational seismology has matured to a level where both the hard- and software are robust and user friendly. This has resulted in successful implementation of educational networks around the world. Seismic data recorded by students are of such quality that these can be used in classic earthquake location exercises, for example. But even ocean waves weakly coupled into the Earth’s crust can now be recorded on educational seismometers. These signals are not just noise, but form the basis of more recent developments in seismology, such as seismic interferometry, where seismic waves generated by ocean waves—instead of earthquakes—can be used to infer information about the Earth’s interior. Here, we introduce an earthquake location exercise and an analysis of ambient seismic noise, and present examples. Data are provided, and all needed software is freely available. (review)

GeoNetGIS: a Geodetic Network Geographical Information System to manage GPS networks in seismic and volcanic areas

Science.gov (United States)

Cristofoletti, P.; Esposito, A.; Anzidei, M.

2003-04-01

This paper presents the methodologies and issues involved in the use of GIS techniques to manage geodetic information derived from networks in seismic and volcanic areas. Organization and manipulation of different geodetical, geological and seismic database, give us a new challenge in interpretation of information that has several dimensions, including spatial and temporal variations, also the flexibility and brand range of tools available in GeoNetGIS, make it an attractive platform for earthquake risk assessment. During the last decade the use of geodetic networks based on the Global Positioning System, devoted to geophysical applications, especially for crustal deformation monitoring in seismic and volcanic areas, increased dramatically. The large amount of data provided by these networks, combined with different and independent observations, such as epicentre distribution of recent and historical earthquakes, geological and structural data, photo interpretation of aerial and satellite images, can aid for the detection and parameterization of seismogenic sources. In particular we applied our geodetic oriented GIS to a new GPS network recently set up and surveyed in the Central Apennine region: the CA-GeoNet. GeoNetGIS is designed to analyze in three and four dimensions GPS sources and to improve crustal deformation analysis and interpretation related with tectonic structures and seismicity. It manages many database (DBMS) consisting of different classes, such as Geodesy, Topography, Seismicity, Geology, Geography and Raster Images, administrated according to Thematic Layers. GeoNetGIS represents a powerful research tool allowing to join the analysis of all data layers to integrate the different data base which aid for the identification of the activity of known faults or structures and suggesting the new evidences of active tectonics. A new approach to data integration given by GeoNetGIS capabilities, allow us to create and deliver a wide range of maps, digital

Calibration of Seismic Attributes for Reservoir Characterization

Energy Technology Data Exchange (ETDEWEB)

Wayne D. Pennington

2002-09-29

The project, "Calibration of Seismic Attributes for Reservoir Characterization," is now complete. Our original proposed scope of work included detailed analysis of seismic and other data from two to three hydrocarbon fields; we have analyzed data from four fields at this level of detail, two additional fields with less detail, and one other 2D seismic line used for experimentation. We also included time-lapse seismic data with ocean-bottom cable recordings in addition to the originally proposed static field data. A large number of publications and presentations have resulted from this work, inlcuding several that are in final stages of preparation or printing; one of these is a chapter on "Reservoir Geophysics" for the new Petroleum Engineering Handbook from the Society of Petroleum Engineers. Major results from this project include a new approach to evaluating seismic attributes in time-lapse monitoring studies, evaluation of pitfalls in the use of point-based measurements and facies classifications, novel applications of inversion results, improved methods of tying seismic data to the wellbore, and a comparison of methods used to detect pressure compartments. Some of the data sets used are in the public domain, allowing other investigators to test our techniques or to improve upon them using the same data. From the public-domain Stratton data set we have demonstrated that an apparent correlation between attributes derived along 'phantom' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the public-domain Boonsville data set we developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into productive and non-productive subfacies, and we

CALIBRATION OF SEISMIC ATTRIBUTES FOR RESERVOIR CHARACTERIZATION

Energy Technology Data Exchange (ETDEWEB)

Wayne D. Pennington; Horacio Acevedo; Aaron Green; Joshua Haataja; Shawn Len; Anastasia Minaeva; Deyi Xie

2002-10-01

The project, ''Calibration of Seismic Attributes for Reservoir Calibration,'' is now complete. Our original proposed scope of work included detailed analysis of seismic and other data from two to three hydrocarbon fields; we have analyzed data from four fields at this level of detail, two additional fields with less detail, and one other 2D seismic line used for experimentation. We also included time-lapse seismic data with ocean-bottom cable recordings in addition to the originally proposed static field data. A large number of publications and presentations have resulted from this work, including several that are in final stages of preparation or printing; one of these is a chapter on ''Reservoir Geophysics'' for the new Petroleum Engineering Handbook from the Society of Petroleum Engineers. Major results from this project include a new approach to evaluating seismic attributes in time-lapse monitoring studies, evaluation of pitfalls in the use of point-based measurements and facies classifications, novel applications of inversion results, improved methods of tying seismic data to the wellbore, and a comparison of methods used to detect pressure compartments. Some of the data sets used are in the public domain, allowing other investigators to test our techniques or to improve upon them using the same data. From the public-domain Stratton data set we have demonstrated that an apparent correlation between attributes derived along ''phantom'' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the public-domain Boonsville data set we developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into

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.

Improvement of high resolution borehole seismics. Part 1: Development of processing methods for VSP surveys. Part 2: Piezoelectric signal transmitter for seismic measurements

International Nuclear Information System (INIS)

Cosma, C.; Heikkinen, P.; Pekonen, S.

1991-05-01

The purpose of the high resolution borehole seismics project has been to improve the reliability and resolution of seismic methods in the particular environment of nuclear waste repository sites. The results obtained, especially the data processing and interpretation methods developed, are applicable also to other geophysical methods (e.g. Georadar). The goals of the seismic development project have been: the development of processing and interpretation techniques for mapping fractured zones, and the design and construction of a seismic source complying with the requirements of repository site characterization programs. Because these two aspects of the work are very different in nature, we have structured the report as two self contained parts. Part 1 describes the development of interpretive techniques. We have used for demonstrating the effect of different methods a VSP data set collected at the SCV site during Stage 1 of the project. Five techniques have been studied: FK-filtering, three versions of Tau-p filtering and a new technique that we have developed lately, Image Space filtering. Part 2 refers to the construction of the piezoelectric source. Earlier results obtained over short distances with low energy piezoelectric transmitters let us believe that the same principle could be applied for seismic signal transmitters, if solutions for higher energy and lower frequency output were found. The instrument which we have constructed is a cylindrical unit which can be placed in a borehole and is able to produce a radial strain when excited axially. The minimum borehole diameter is 56 mm. (au)

The use of Graphic User Interface for development of a user-friendly CRS-Stack software

Science.gov (United States)

Sule, Rachmat; Prayudhatama, Dythia; Perkasa, Muhammad D.; Hendriyana, Andri; Fatkhan; Sardjito; Adriansyah

2017-04-01

The development of a user-friendly Common Reflection Surface (CRS) Stack software that has been built by implementing Graphical User Interface (GUI) is described in this paper. The original CRS-Stack software developed by WIT Consortium is compiled in the unix/linux environment, which is not a user-friendly software, so that a user must write the commands and parameters manually in a script file. Due to this limitation, the CRS-Stack become a non popular method, although applying this method is actually a promising way in order to obtain better seismic sections, which have better reflector continuity and S/N ratio. After obtaining successful results that have been tested by using several seismic data belong to oil companies in Indonesia, it comes to an idea to develop a user-friendly software in our own laboratory. Graphical User Interface (GUI) is a type of user interface that allows people to interact with computer programs in a better way. Rather than typing commands and module parameters, GUI allows the users to use computer programs in much simple and easy. Thus, GUI can transform the text-based interface into graphical icons and visual indicators. The use of complicated seismic unix shell script can be avoided. The Java Swing GUI library is used to develop this CRS-Stack GUI. Every shell script that represents each seismic process is invoked from Java environment. Besides developing interactive GUI to perform CRS-Stack processing, this CRS-Stack GUI is design to help geophysicists to manage a project with complex seismic processing procedures. The CRS-Stack GUI software is composed by input directory, operators, and output directory, which are defined as a seismic data processing workflow. The CRS-Stack processing workflow involves four steps; i.e. automatic CMP stack, initial CRS-Stack, optimized CRS-Stack, and CRS-Stack Supergather. Those operations are visualized in an informative flowchart with self explanatory system to guide the user inputting the

SUPPRESSING DIFFRACTION EFFECT USING KIRCHHOFF PRE-STACK TIME MIGRATION ON 2D SEISMIC MULTICHANNEL DATA AT FLORES SEA

Directory of Open Access Journals (Sweden)

Tumpal Benhard Nainggolan

2017-07-01

Full Text Available 2D seismic multichannel survey has been carried out by Marine Geological Institute of Indonesia to interpret imaging and sub-surface geological information in the Flores Sea. Seismic data processing starts from pre-processing until migration stage. Migration is an important stage in the seismic processing, because at this stage the effects of diffraction and oblique reflectors caused by fault, salt domes, wedging, etc. will be repositioned to the actual points. One example of diffraction effects can be seen on the seismic section of a conventional stacking that have not migrated, i.e. resulting in an apparent bowtie reflector. Geologists find difficulties in interpreting geological information from diffracted seismic section, so it needs further processing to overcome the effects. By using Kirchhoff method and carried out during the Pre-Stack Time Migration (PSTM, this method turns out to produce migrated seismic section which is much better than conventional stacked one. This is due to the Kirchhoff method suppressed the identified diffraction effects, so that the geologist can interpret geological structure of the resulting migrated seismic section of the Flores Sea.

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).

Modeling the impact of melt on seismic properties during mountain building

Science.gov (United States)

Lee, Amicia L.; Walker, Andrew M.; Lloyd, Geoffrey E.; Torvela, Taija

2017-03-01

Initiation of partial melting in the mid/lower crust causes a decrease in P wave and S wave velocities; recent studies imply that the relationship between these velocities and melt is not simple. We have developed a modeling approach to assess the combined impact of various melt and solid phase properties on seismic velocities and anisotropy. The modeling is based on crystallographic preferred orientation (CPO) data measured from migmatite samples, allowing quantification of the variation of seismic velocities with varying melt volumes, shapes, orientations, and matrix anisotropy. The results show nonlinear behavior of seismic properties as a result of the interaction of all of these physical properties, which in turn depend on lithology, stress regime, strain rate, preexisting rock fabrics, and pressure-temperature conditions. This nonlinear behavior is evident when applied to a suite of samples from a traverse across a migmatitic shear zone in the Seiland Igneous Province, Northern Norway. Critically, changes in solid phase composition and CPO, and melt shape and orientation with respect to the wave propagation direction can result in huge variations in the same seismic property even if the melt fraction remains the same. A comparison with surface wave interpretations from tectonically active regions highlights the issues in current models used to predict melt percentages or partially molten regions. Interpretation of seismic data to infer melt percentages or extent of melting should, therefore, always be underpinned by robust modeling of the underlying geological parameters combined with examination of multiple seismic properties in order to reduce uncertainty of the interpretation.

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)

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

Calibration of Seismic Attributes for Reservoir Characterization

Energy Technology Data Exchange (ETDEWEB)

Pennington, Wayne D.; Acevedo, Horacio; Green, Aaron; Len, Shawn; Minavea, Anastasia; Wood, James; Xie, Deyi

2002-01-29

This project has completed the initially scheduled third year of the contract, and is beginning a fourth year, designed to expand upon the tech transfer aspects of the project. From the Stratton data set, demonstrated that an apparent correlation between attributes derived along `phantom' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the Boonsville data set , developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into productive and non-productive subfacies, and developed a method involving cross-correlation of seismic waveforms to provide a reliable map of the various facies present in the area. The Teal South data set provided a surprising set of data, leading us to develop a pressure-dependent velocity relationship and to conclude that nearby reservoirs are undergoing a pressure drop in response to the production of the main reservoir, implying that oil is being lost through their spill points, never to be produced. The Wamsutter data set led to the use of unconventional attributes including lateral incoherence and horizon-dependent impedance variations to indicate regions of former sand bars and current high pressure, respectively, and to evaluation of various upscaling routines.

Seismic data processing for domestic seismic survey over the continental shelf of Korea using the Geobit

Energy Technology Data Exchange (ETDEWEB)

Oh, Jin Yong [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-12-01

The `Geobit`, a new seismic data processing software introduced by the Korea Institute of Geology, Mining and Materials recently, is the token of the achievement for the development of technology in the oil exploration over the Korean continental shelf. In comparison with the foreign seismic data processing systems previously used in Korea, the Geobit system has some advanced facilities; it provides an interactive mode which makes the seismic processing easier and has the user-friendly programs which allow the construction of a job control file simpler. Most of all, the Geobit can be run with many computer hardware systems, from PC to supercomputer. The current version of the Geobit can take care of the two-dimensional multi-channel seismic data and is open to the public for an education tool and a research purpose. To demonstrate the ability of the Geobit, a multi-channel field data acquired in the domestic continental shelf over the Yellow Sea in 1970 has been selected and processed with standard seismic data processing techniques. In this report, the Geobit job files and the corresponding results for the construction of a stack are provided. (author). 8 refs., 14 figs., 1 tab.

Hawaiian Volcano Observatory seismic data, January to March 2009

Science.gov (United States)

Nakata, Jennifer S.; Okubo, Paul G.

2010-01-01

This U.S. Geological Survey (USGS), Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during January–March 2009. The seismic summary offers earthquake hypocenters without interpretation as a source of preliminary data and is complete in that most data for events of M≥1.5 are included. All latitude and longitude references in this report are stated in Old Hawaiian Datum.

Seismic moment tensor for anisotropic media: implication for Non-double-couple earthquakes

Science.gov (United States)

Cai, X.; Chen, X.; Chen, Y.; Cai, M.

2008-12-01

It is often found that the inversion results of seismic moment tensor from real seismic recorded data show the trace of seismic moment tensor M is not zero, a phenomenon called non-double-couple earthquake sources mechanism. Recently we have derived the analytical expressions of M in transversely isotropic media with the titled axis of symmetry and the results shows even only pure shear-motion of fault can lead to the implosive components determined by several combined anisotropic elastic constants. Many non-double-couple earthquakes from observations often appear in volcanic and geothermal areas (Julian, 1998), where there exist a mount of stress-aligned fluid-saturated parallel vertical micro-cracks identical to transversely isotropic media (Crampin, 2008), this stress-aligned crack will modify the seismic moment tensor. In another word, non-double-couple earthquakes don't mean to have a seismic failure movement perpendicular to the fault plane, while traditional research of seismic moment tensor focus on the case of isotropy, which cannot provide correct interpretation of seismic source mechanism. Reference: Julian, B.R., Miller, A.D. and Foulger, G.R., 1998. Non-double-couple earthquakes,1. Theory, Rev. Geophys., 36, 525¨C549. Crampin,S., Peacock,S., 2008, A review of the current understanding of seismic shear-wave splitting in the Earth's crust and common fallacies in interpretation, wave motion, 45,675-722

Subsurface geology off Bombay with paleoclimatic inferences interpreted from shallow seismic profiles

Digital Repository Service at National Institute of Oceanography (India)

Bhattacharya, G.C.; Almeida, F.; Vora, K.H.; Siddiquie, H.N.

High resolution seismic reflection profiles nearshore areas off Bombay provide information on subsurface geology and permit certain paleoclimatic inferences. Three sedimentary units overlie the acoustic basement: late Pleistocene consolidated...

ESAA environment for seismic activity analysis

International Nuclear Information System (INIS)

Zhang Shuyu; Hao Bailin.

1994-09-01

ESAA is an X-window based, graphical and interactive, software system for analyzing seismic activity, using the earthquake catalogues of a given region as input. Basic design idea and structure of this system, as well as the progress in its implementation are reported. (author). 12 refs

Theoretical models for crustal displacement assessment and monitoring in Vrancea-Focsani seismic zone by integrated remote sensing and local geophysical data for seismic prognosis

International Nuclear Information System (INIS)

Zoran, Maria; Ciobanu, Mircea; Mitrea, Marius Gabriel; Talianu, Camelia; Cotarlan, Costel; Mateciuc, Doru; Radulescu, Florin; Biter Mircea

2002-01-01

The majority of strong Romanian earthquakes has the origin in Vrancea region. Subduction of the Black Sea Sub-Plate under the Pannonian Plate produces faulting processes. Crustal displacement identification and monitoring is very important for a seismically active area like Vrancea-Focsani. Earthquake displacements are very well revealed by satellite remote sensing data. At the same time, geomorphologic analysis of topographic maps is carried out and particularly longitudinal and transverse profiles are constructed, as well as structural-geomorphologic maps. Faults are interpreted by specific features in nature of relief, straightness of line of river beds and their tributaries, exits of springs, etc. Remote sensing analysis and field studies of active faults can provide a geologic history that overcomes many of the shortcomings of instrumental and historic records. Our theoretical models developed in the frame of this project are presented as follows: a) Spectral Mixture Analysis model of geomorphological and topographic characteristics for Vrancea region proposed for satellite images analysis which assumes that the different classes present in a pixel (image unit) contribute independently to its reflectance. Therefore, the reflectance of a pixel at a particular frequency is the sum of the reflectances of the components at that frequency. The same test region in Vrancea area is imaged at several different frequencies (spectral bands), leading to multispectral observations for each pixel. It is useful to merge different satellite data into a hybrid image with high spatial and spectral resolution to create detailed images map of the abundance of various materials within the scene based on material spectral fingerprint. Image fusion produces a high-resolution multispectral image that is then unmixed into high-resolution material maps. b) Model of seismic cross section analysis which is applied in seismic active zones morphology. Since a seismic section can be

Astor Pass Seismic Surveys Preliminary Report

Energy Technology Data Exchange (ETDEWEB)

Louie, John [UNR; Pullammanappallil, Satish [Optim; Faulds, James; Eisses, Amy; Kell, Annie; Frary, Roxanna; Kent, Graham

2011-08-05

In collaboration with the Pyramid Lake Paiute Tribe (PLPT), the University of Nevada, Reno (UNR) and Optim re-processed, or collected and processed, over 24 miles of 2d seismic-reflection data near the northwest corner of Pyramid Lake, Nevada. The network of 2d land surveys achieved a near-3d density at the Astor Pass geothermal prospect that the PLPT drilled during Nov. 2010 to Feb. 2011. The Bureau of Indian Affairs funded additional seismic work around the Lake, and an extensive, detailed single-channel marine survey producing more than 300 miles of section, imaging more than 120 ft below the Lake bottom. Optim’s land data collection utilized multiple heavy vibrators and recorded over 200 channels live, providing a state-of-the-art reflection-refraction data set. After advanced seismic analysis including first-arrival velocity optimization and prestack depth migration, the 2d sections show clear fault-plane reflections, in some areas as deep as 4000 ft, tying to distinct terminations of the mostly volcanic stratigraphy. Some lines achieved velocity control to 3000 ft depth; all lines show reflections and terminations to 5000 ft depth. Three separate sets of normal faults appear in an initial interpretation of fault reflections and stratigraphic terminations, after loading the data into the OpendTect 3d seismic visualization system. Each preliminary fault set includes a continuous trace more than 3000 ft long, and a swarm of short fault strands. The three preliminary normal-fault sets strike northerly with westward dip, northwesterly with northeast dip, and easterly with north dip. An intersection of all three fault systems documented in the seismic sections at the end of Phase I helped to locate the APS-2 and APS-3 slimholes. The seismic sections do not show the faults connected to the Astor Pass tufa spire, suggesting that we have imaged mostly Tertiary-aged faults. We hypothesize that the Recent, active faults that produced the tufa through hotspring

Phase 1 report: the 4D seismic market from 2000 to 2003

International Nuclear Information System (INIS)

Sagary, C.

2004-01-01

This report synthesizes the phase 1 results of the joint industrial project, called ''4D Seismic: Technologies, Economics and Issues''. This project was conducted by IFP between November 2003 and April 2004, in collaboration with Compagnie Generale de Geophysique (CGG) and sponsored by Gaz de France and 4. Wave Imaging. Phase 1 offers an objective view of the 4D seismic market over the period 2000-2003. The market has been assessed from IFP extensive databases, gathering 115 4D projects conducted worldwide and from interviews of seven oil companies, both representing 90% of the activity in time-lapse seismic. This study provides sales estimation and sales/projects breakdown by: in-house/subcontracted activity, geography, onshore/offshore, reservoir rocks and recovery methods, technology/methodology, oil companies and service companies. The market of 4D seismic has been split into 4 segments: acquisition, processing, reservoir studies - feasibility, interpretation and seismic history matching -, borehole seismic (acquisition and processing). In addition, the market of passive seismic monitoring, another technique of seismic reservoir monitoring has also been estimated. The main sources, used to build the IFP databases, were: Worldwide Global E and P Service Reports from IHS Energy, World Geophysical News, an extensive bibliographic study through more than 200 articles, abstracts and summaries, a collaboration with CGG. For all market estimations, numbers computed from IFP databases and from interviews of oil companies were extrapolated from 90% to 100%, to quantify the total 4D activity. The estimations obtained were not rounded in order to preserve trends with a consistent computation from one year to another and from one market segment to another, despite uncertainties of about 10%. Quality controls were performed to validate the final estimations: volumes of 4D seismic data, computed from IFP databases, were checked by comparing processed data with acquired data

Seismic characterisation of subsurface structural features of parts of ...

African Journals Online (AJOL)

A total of thirty-four migrated 2D seismic reflection lines and two composite well logs have been interpreted with a view to unravel the subsurface geological ... The interpretation procedure includes horizon identification, fault mapping, timing of horizons at selected shot points, posting of times, time-depth conversion and ...

Seismic surface wave tomography of waste sites. 1997 annual progress report

International Nuclear Information System (INIS)

Long, T.L.

1997-01-01

'The objective of the Seismic Surface Wave Tomography of Waste Sites is to develop a robust technique for field acquisition and analysis of surface wave data for the interpretation of shallow structures, such as those associated with the burial of wastes. The analysis technique is to be developed and tested on an existing set of seismic data covering the K-901 burial site at the East Tennessee Technology Park. Also, a portable prototype for a field acquisition system will be designed and developed to obtain additional data for analysis and testing of the technique. The K-901 data have been examined and a preliminary Single Valued Decomposition inversion has been obtained. The preliminary data indicates a need for additional seismic data to ground-truth the inversion. The originally proposed gravity data acquisition has been dropped because sufficient gravity data are now available for a preliminary analysis and because the seismic data are considered more critical to the interpretation. The proposed prototype for the portable acquisition and analysis system was developed during the first year and will be used in part of the acquisition of additional seismic data.'

Development of a shelf margin delta due to uplift of Munkagrunnur Ridge at the margin of Faroe-Shetland Basin: a seismic sequence stratigraphic study

DEFF Research Database (Denmark)

Òlavsdóttir, Jana; Boldreel, Lars Ole; Andersen, Moretn S

2010-01-01

During the last decade several 3D digital reflection seismic datasets have been acquired in the Faroese sector of the Faroe-Shetland Basin which allow detailed seismic interpretation and mapping of parts of the area. This study presents mapping and seismic sequence stratigraphic interpretation of...

Going for the play: Structural interpretation in offshore Congo

Energy Technology Data Exchange (ETDEWEB)

Platt, N.; Philip, P. (GECO-PRAKLA Exploration Services, Woking (United Kingdom)); Walter, S. (ARK Geophysics Ltd., Milton Keynes, (United Kingdom))

1993-01-01

Looking for new hydrocarbons in frontier areas, geologists and geophysicists use very trick in the book: plate tectonics, magnetic and gravity data, plain old geological horse sense and lots of seismic data. An interpretation team is followed, as they pick their way through a seismic survey shot in offshore Congo, Africa, searching for those areas (the plays) that show the greatest promise. 17 figs., 9 refs.

Detection of sinkholes or anomalies using full seismic wave fields : phase II.

Science.gov (United States)

2016-08-01

A new 2-D Full Waveform Inversion (FWI) software code was developed to characterize layering and anomalies beneath the ground surface using seismic testing. The software is capable of assessing the shear and compression wave velocities (Vs and Vp) fo...

Preliminary evaluation of the seismic hazard at Cernavoda NPP site

International Nuclear Information System (INIS)

Mingiuc, C.; Serban, V.; Androne, M.

2001-01-01

The probabilistic seismic hazard analysis (PSHA) is a methodology by which one evaluates the probability of exceeding different parameters of the ground motions (the maximum ground acceleration - PGA and the ground response spectrum - SA) as effect of the seismic action, on a given site at a future time moment. Due to the large uncertainties in the geological, geophysical, seismological input data, as well as, in the models utilised, various interpretation schemes are applied in the PSHA analyses. This interpretation schemes lead to opinion discrepancies among specialists which finally lead to disagreements in estimating the values of the seismic design for a given site. In order to re-evaluate the methodology and to improve the PSHA result stability, U.S. Nuclear Regulatory Commission (NRC), U.S. Department of Energy (DOE) and Electric Power Research Institute (EPRI) sponsored a project for defining methodological guides of performing PSHA analyses. The project was implemented by a panel of 7 experts, the Senior Seismic Hazard Analysis Committee - SSHAC. This paper presents a preliminary evaluation of the seismic hazard for the Cernavoda NPP site by application of the methodology mentioned, by taking into account the possible sources which could affect the site (the Vrancea focus, Galati - Tulcea fault, Sabla - Dulovo fault and local earthquakes)

Romanian Data Center: A modern way for seismic monitoring

Science.gov (United States)

Neagoe, Cristian; Marius Manea, Liviu; Ionescu, Constantin

2014-05-01

The main seismic survey of Romania is performed by the National Institute for Earth Physics (NIEP) which operates a real-time digital seismic network. The NIEP real-time network currently consists of 102 stations and two seismic arrays equipped with different high quality digitizers (Kinemetrics K2, Quanterra Q330, Quanterra Q330HR, PS6-26, Basalt), broadband and short period seismometers (CMG3ESP, CMG40T, KS2000, KS54000, KS2000, CMG3T,STS2, SH-1, S13, Mark l4c, Ranger, gs21, Mark l22) and acceleration sensors (Episensor Kinemetrics). The data are transmitted at the National Data Center (NDC) and Eforie Nord (EFOR) Seismic Observatory. EFOR is the back-up for the NDC and also a monitoring center for the Black Sea tsunami events. NIEP is a data acquisition node for the seismic network of Moldova (FDSN code MD) composed of five seismic stations. NIEP has installed in the northern part of Bulgaria eight seismic stations equipped with broadband sensors and Episensors and nine accelerometers (Episensors) installed in nine districts along the Danube River. All the data are acquired at NIEP for Early Warning System and for primary estimation of the earthquake parameters. The real-time acquisition (RT) and data exchange is done by Antelope software and Seedlink (from Seiscomp3). The real-time data communication is ensured by different types of transmission: GPRS, satellite, radio, Internet and a dedicated line provided by a governmental network. For data processing and analysis at the two data centers Antelope 5.2 TM is being used running on 3 workstations: one from a CentOS platform and two on MacOS. Also a Seiscomp3 server stands as back-up for Antelope 5.2 Both acquisition and analysis of seismic data systems produce information about local and global parameters of earthquakes. In addition, Antelope is used for manual processing (event association, calculation of magnitude, creating a database, sending seismic bulletins, calculation of PGA and PGV, etc.), generating

Global seismic inversion as the next standard step in the processing sequence

Energy Technology Data Exchange (ETDEWEB)

Maver, Kim G.; Hansen, Lars S.; Jepsen, Anne-Marie; Rasmussen, Klaus B.

1998-12-31

Seismic inversion of post stack seismic data has until recently been regarded as a reservoir oriented method since the standard inversion techniques rely on extensive well control and a detailed user derived input model. Most seismic inversion techniques further requires a stable wavelet. As a consequence seismic inversion is mainly utilised in mature areas focusing of specific zones only after the seismic data has been interpreted and is well understood. By using an advanced 3-D global technique, seismic inversion is presented as the next standard step in the processing sequence. The technique is robust towards noise within the seismic data, utilizes a time variant wavelet, and derives a low frequency model utilizing the stacking velocities and only limited well control. 4 figs.

Imaging the Crust in the Northern Sector of the 2009 L'Aquila Seismic Sequence through Oil Exploration Data Interpretation

Science.gov (United States)

Grazia Ciaccio, Maria; Improta, Luigi; Patacca, Etta; Scandone, Paolo; Villani, Fabio

2010-05-01

The 2009 L'Aquila seismic sequence activated a complex, about 40 km long, NW-trending and SW-dipping normal fault system, consisting of three main faults arranged in right-lateral en-echelon geometry. While the northern sector of the epicentral area was extensively investigated by oil companies, only a few scattered, poor-quality commercial seismic profiles are available in the central and southern sector. In this study we interpret subsurface commercial data from the northern sector, which is the area where is located the source of the strong Mw5.4 aftershock occurred on the 9th April 2009. Our primary goals are: (1) to define a reliable framework of the upper crust structure, (2) to investigate how the intense aftershock activity, the bulk of which is clustered in the 5-10 km depth range, relates to the Quaternary extensional faults present in the area. The investigated area lies between the western termination of the W-E trending Gran Sasso thrust system to the south, the SW-NE trending Mt. Sibillini thrust front (Ancona-Anzio Line Auctt.) to the north and west, and by the NNW-SSE trending, SW-dipping Mt. Gorzano normal fault to the east. In this area only middle-upper Miocene deposits are exposed (Laga Flysch and underlying Cerrogna Marl), but commercial wells have revealed the presence of a Triassic-Miocene sedimentary succession identical to the well known Umbria-Marche stratigraphic sequence. We have analyzed several confidential seismic reflection profiles, mostly provided by ENI oil company. Seismic lines are tied to two public wells, 5766 m and 2541 m deep. Quality of the reflection imaging is highly variable. A few good quality stack sections contain interpretable signal down to 4.5-5.5 s TWT, corresponding to depths exceeding 10-12 km and thus allowing crustal imaging at seismogenic depths. Key-reflectors for the interpretation correspond to: (1) the top of the Miocene Cerrogna marls, (2) the top of the Upper Albian-Oligocene Scaglia Group, (3) the

Seismic interpretation of the triangle zone at Jumping Pound, Alberta

Energy Technology Data Exchange (ETDEWEB)

Slotboom, R. T. [Amerada Hess Canada Ltd., Calgary, AB (Canada); Lawton, D. C.; Spratt, D. A. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

1996-06-01

The triangle zone at Jumping Point, Alberta was characterized using seismic survey data as a NW-SE-trending antiformal stack of thrust sheets involving Cretaceous rocks that have been wedged into the foreland between two detachments. Three major thrust sheets of Lower and Upper Cretaceous strata have been stacked to form the main extremity of the wedge. The structure is tightly folded at Jumping Point, and broadens northwest along the strike. 13 refs., 8 figs.

4-D seismic in a complex fluvial reservoir: the Snorre feasibility study

NARCIS (Netherlands)

Smith, P.; Berg, J.I.; Eidsvig, S.; Magnus, I.; Verhelst, F.J.P.C.M.G.; Helgesen, J.

2001-01-01

The saga petroleum, discoverer of Snorre Field, describe's how 3-D seismic surveys are used to determine the value of time-lapse seismic data for field management. Careful examination of the repeatability of the time-lapse data sets, before interpretation stark, establishes a framework defining the

Seismic Readings from the Deepest Borehole in the New Madrid Seismic Zone

Energy Technology Data Exchange (ETDEWEB)

Woolery, Edward W [KY Geological Survey, Univ of KY; Wang, Zhenming [KY Geological Survey, Univ of KY; Sturchio, Neil C [Dept of earth and Env. Sciences, Univ of Ill at Chicago

2006-03-01

Since the 1980s, the research associated with the UK network has been primarily strong-motion seismology of engineering interest. Currently the University of Kentucky operates a strong-motion network of nine stations in the New Madrid Seismic Zone. A unique feature of the network is the inclusions of vertical strong-motion arrays, each with one or two downhole accelerometers. The deepest borehole array is 260 m below the surfaces at station VASA in Fulton County, Kentucky. A preliminary surface seismic refraction survey was conducted at the site before drilling the hole at VSAS (Woolery and Wang, 2002). The depth to the Paleozoic bedrock at the site was estimated to be approximately 595 m, and the depth to the first very stiff layer (i.e. Porters Creek Clay) was found to be about 260 m. These depths and stratigraphic interpretation correlated well with a proprietary seismic reflection line and the Ken-Ten Oil Exploration No. 1 Sanger hole (Schwalb, 1969), as well as our experience in the area (Street et al., 1995; Woolery et al., 1999).

Calibration of Seismic Attributes for Reservoir Characterization; ANNUAL

International Nuclear Information System (INIS)

Pennington, Wayne D.; Acevedo, Horacio; Green, Aaron; Len, Shawn; Minavea, Anastasia; Wood, James; Xie, Deyi

2002-01-01

This project has completed the initially scheduled third year of the contract, and is beginning a fourth year, designed to expand upon the tech transfer aspects of the project. From the Stratton data set, demonstrated that an apparent correlation between attributes derived along 'phantom' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the Boonsville data set , developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into productive and non-productive subfacies, and developed a method involving cross-correlation of seismic waveforms to provide a reliable map of the various facies present in the area. The Teal South data set provided a surprising set of data, leading us to develop a pressure-dependent velocity relationship and to conclude that nearby reservoirs are undergoing a pressure drop in response to the production of the main reservoir, implying that oil is being lost through their spill points, never to be produced. The Wamsutter data set led to the use of unconventional attributes including lateral incoherence and horizon-dependent impedance variations to indicate regions of former sand bars and current high pressure, respectively, and to evaluation of various upscaling routines

Seismic characterisation for geothermal energy prospecting

NARCIS (Netherlands)

Huck, A.; Groot, P. de; Simmelink, E.; Vandeweijer, V.P.; Willemsen, A.

2009-01-01

The city of The Hague intends to use geothermal energy to heat approx. 4000 houses in a planned urban development area called The Hague South-West. This paper describes the application of advanced seismic interpretation workflows to help positioning a geothermal doublet consisting of one injector -

Seismic data interpretation for hydrocarbon potential, for Safwa/Sabbar field, East Ghazalat onshore area, Abu Gharadig basin, Western Desert, Egypt

Directory of Open Access Journals (Sweden)

Naser A. Hameed El Redini

2017-12-01

Full Text Available Safwa/Sabbar oil field located in the East Ghazalat Concession in the proven and prolific Abu Gharadig basin, Western Desert, Egypt, and about 250 km to the southwest of Cairo, it’s located in the vicinity of several producing oil fields ranging from small to large size hydrocarbon accumulation, adjacent to the NW-SE trending major Abu Gharadig fault which is throwing to the Southwest.All the geological, “structure and stratigraphic” elements, have been identified after interpreting the recent high quality 3D seismic survey for prospect generation, evaluation and their relation to the hydrocarbon exploration.Synthetic seismograms have been carried out for all available wells to tie horizons to seismic data and to define the lateral variation characters of the beds.The analysis has been done using the suitable seismic attributes to understand the characteristics of different types of the reservoir formations, type of trap system, identify channels and faults, and delineating the stratigraphic plays of good reservoirs such as Eocene Apollonia Limestone, AR “F”, AR “G” members, Upper Bahariya, Jurassic Khatatba Sandstone, upper Safa and Lower Safa Sandstone.The top Cenomanian Bahariya level is the main oil reservoir in the Study area, which consist of Sandstone, Siltstone and Shale, the thickness is varying from 1 to 50 ft along the study area.In addition to Upper-Bahariya there are a good accessibility of hydrocarbon potential within the Jurassic Khatatba Sandstone and the Eocene Apollonia Limestone. More exploring of these reservoirs are important to increase productivity of Oil and/or Gas in the study area.

Combining mineral physics with seismic observations: What can we deduce about the thermochemical structure of the Earth's deep interior?

Science.gov (United States)

Cobden, L. J.

2017-12-01

Mineral physics provides the essential link between seismic observations of the Earth's interior, and laboratory (or computer-simulated) measurements of rock properties. In this presentation I will outline the procedure for quantitative conversion from thermochemical structure to seismic structure (and vice versa) using the latest datasets from seismology and mineralogy. I will show examples of how this method can allow us to infer major chemical and dynamic properties of the deep mantle. I will also indicate where uncertainties and limitations in the data require us to exercise caution, in order not to "over-interpret" seismic observations. Understanding and modelling these uncertainties serves as a useful guide for mineralogists to ascertain which mineral parameters are most useful in seismic interpretation, and enables seismologists to optimise their data assembly and inversions for quantitative interpretations.

Analysis of large concrete storage tank under seismic response

Energy Technology Data Exchange (ETDEWEB)

Le, Jingyuan; Cui, Hongcheng; He, Qiang; Ju, Jinsan [China Agricultural University, Beijing (China); You, Xiaochuan [Tsinghua University, Beijing (China)

2015-01-15

This study adopted the finite element software ABAQUS to trace the dynamic response history of large reinforced concrete storage tank during different seismic excitations. The dynamic characteristics and failure modes of the tank's structure were investigated by considering the rebar's effect. Calculation results show that the large concrete storage tank remains in safe working conditions under a seismic acceleration of 55 cm/s{sup 2}. The joint of the concrete wall and dome begins to crack when seismic acceleration reaches 250 cm/s{sup 2}. As the earthquake continues, cracks spread until the top of the wall completely fails and stops working. The maximum displacement of the concrete tank and seismic acceleration are in proportion. Peak displacement and stress of the tank always appear behind the maximum acceleration.

Maturity of nearby faults influences seismic hazard from hydraulic fracturing

Science.gov (United States)

Kozłowska, Maria; Brudzinski, Michael R.; Friberg, Paul; Skoumal, Robert J.; Baxter, Nicholas D.; Currie, Brian S.

2018-02-01

Understanding the causes of human-induced earthquakes is paramount to reducing societal risk. We investigated five cases of seismicity associated with hydraulic fracturing (HF) in Ohio since 2013 that, because of their isolation from other injection activities, provide an ideal setting for studying the relations between high-pressure injection and earthquakes. Our analysis revealed two distinct groups: (i) deeper earthquakes in the Precambrian basement, with larger magnitudes (M > 2), b-values 1.5, and few post–shut-in earthquakes. Based on geologic history, laboratory experiments, and fault modeling, we interpret the deep seismicity as slip on more mature faults in older crystalline rocks and the shallow seismicity as slip on immature faults in younger sedimentary rocks. This suggests that HF inducing deeper seismicity may pose higher seismic hazards. Wells inducing deeper seismicity produced more water than wells with shallow seismicity, indicating more extensive hydrologic connections outside the target formation, consistent with pore pressure diffusion influencing seismicity. However, for both groups, the 2 to 3 h between onset of HF and seismicity is too short for typical fluid pressure diffusion rates across distances of ˜1 km and argues for poroelastic stress transfer also having a primary influence on seismicity.

Maturity of nearby faults influences seismic hazard from hydraulic fracturing.

Science.gov (United States)

Kozłowska, Maria; Brudzinski, Michael R; Friberg, Paul; Skoumal, Robert J; Baxter, Nicholas D; Currie, Brian S

2018-02-20

Understanding the causes of human-induced earthquakes is paramount to reducing societal risk. We investigated five cases of seismicity associated with hydraulic fracturing (HF) in Ohio since 2013 that, because of their isolation from other injection activities, provide an ideal setting for studying the relations between high-pressure injection and earthquakes. Our analysis revealed two distinct groups: ( i ) deeper earthquakes in the Precambrian basement, with larger magnitudes (M > 2), b-values 1.5, and few post-shut-in earthquakes. Based on geologic history, laboratory experiments, and fault modeling, we interpret the deep seismicity as slip on more mature faults in older crystalline rocks and the shallow seismicity as slip on immature faults in younger sedimentary rocks. This suggests that HF inducing deeper seismicity may pose higher seismic hazards. Wells inducing deeper seismicity produced more water than wells with shallow seismicity, indicating more extensive hydrologic connections outside the target formation, consistent with pore pressure diffusion influencing seismicity. However, for both groups, the 2 to 3 h between onset of HF and seismicity is too short for typical fluid pressure diffusion rates across distances of ∼1 km and argues for poroelastic stress transfer also having a primary influence on seismicity.

ANZA Seismic Network- From Monitoring to Science

Science.gov (United States)

Vernon, F.; Eakin, J.; Martynov, V.; Newman, R.; Offield, G.; Hindley, A.; Astiz, L.

2007-05-01

The ANZA Seismic Network (http:eqinfo.ucsd.edu) utilizes broadband and strong motion sensors with 24-bit dataloggers combined with real-time telemetry to monitor local and regional seismicity in southernmost California. The ANZA network provides real-time data to the IRIS DMC, California Integrated Seismic Network (CISN), other regional networks, and the Advanced National Seismic System (ANSS), in addition to providing near real-time information and monitoring to the greater San Diego community. Twelve high dynamic range broadband and strong motion sensors adjacent to the San Jacinto Fault zone contribute data for earthquake source studies and continue the monitoring of the seismic activity of the San Jacinto fault initiated 24 years ago. Five additional stations are located in the San Diego region with one more station on San Clemente Island. The ANZA network uses the advance wireless networking capabilities of the NSF High Performance Wireless Research and Education Network (http:hpwren.ucsd.edu) to provide the communication infrastructure for the real-time telemetry of Anza seismic stations. The ANZA network uses the Antelope data acquisition software. The combination of high quality hardware, communications, and software allow for an annual network uptime in excess of 99.5% with a median annual station real-time data return rate of 99.3%. Approximately 90,000 events, dominantly local sources but including regional and teleseismic events, comprise the ANZA network waveform database. All waveform data and event data are managed using the Datascope relational database. The ANZA network data has been used in a variety of scientific research including detailed structure of the San Jacinto Fault Zone, earthquake source physics, spatial and temporal studies of aftershocks, array studies of teleseismic body waves, and array studies on the source of microseisms. To augment the location, detection, and high frequency observations of the seismic source spectrum from local

NORTH HILL CREEK 3-D SEISMIC EXPLORATION PROJECT

Energy Technology Data Exchange (ETDEWEB)

Marc T. Eckels; David H. Suek; Denise H. Harrison; Paul J. Harrison

2004-05-06

Wind River Resources Corporation (WRRC) received a DOE grant in support of its proposal to acquire, process and interpret fifteen square miles of high-quality 3-D seismic data on non-allotted trust lands of the Uintah and Ouray (Ute) Indian Reservation, northeastern Utah, in 2000. Subsequent to receiving notice that its proposal would be funded, WRRC was able to add ten square miles of adjacent state and federal mineral acreage underlying tribal surface lands by arrangement with the operator of the Flat Rock Field. The twenty-five square mile 3-D seismic survey was conducted during the fall of 2000. The data were processed through the winter of 2000-2001, and initial interpretation took place during the spring of 2001. The initial interpretation identified multiple attractive drilling prospects, two of which were staked and permitted during the summer of 2001. The two initial wells were drilled in September and October of 2001. A deeper test was drilled in June of 2002. Subsequently a ten-well deep drilling evaluation program was conducted from October of 2002 through March 2004. The present report discusses the background of the project; design and execution of the 3-D seismic survey; processing and interpretation of the data; and drilling, completion and production results of a sample of the wells drilled on the basis of the interpreted survey. Fifteen wells have been drilled to test targets identified on the North Hill Creek 3-D Seismic Survey. None of these wildcat exploratory wells has been a dry hole, and several are among the best gas producers in Utah. The quality of the data produced by this first significant exploratory 3-D survey in the Uinta Basin has encouraged other operators to employ this technology. At least two additional 3-D seismic surveys have been completed in the vicinity of the North Hill Creek Survey, and five additional surveys are being planned for the 2004 field season. This project was successful in finding commercial oil, natural gas

CORSSA: Community Online Resource for Statistical Seismicity Analysis

Science.gov (United States)

Zechar, J. D.; Hardebeck, J. L.; Michael, A. J.; Naylor, M.; Steacy, S.; Wiemer, S.; Zhuang, J.

2011-12-01

Statistical seismology is critical to the understanding of seismicity, the evaluation of proposed earthquake prediction and forecasting methods, and the assessment of seismic hazard. Unfortunately, despite its importance to seismology-especially to those aspects with great impact on public policy-statistical seismology is mostly ignored in the education of seismologists, and there is no central repository for the existing open-source software tools. To remedy these deficiencies, and with the broader goal to enhance the quality of statistical seismology research, we have begun building the Community Online Resource for Statistical Seismicity Analysis (CORSSA, www.corssa.org). We anticipate that the users of CORSSA will range from beginning graduate students to experienced researchers. More than 20 scientists from around the world met for a week in Zurich in May 2010 to kick-start the creation of CORSSA: the format and initial table of contents were defined; a governing structure was organized; and workshop participants began drafting articles. CORSSA materials are organized with respect to six themes, each will contain between four and eight articles. CORSSA now includes seven articles with an additional six in draft form along with forums for discussion, a glossary, and news about upcoming meetings, special issues, and recent papers. Each article is peer-reviewed and presents a balanced discussion, including illustrative examples and code snippets. Topics in the initial set of articles include: introductions to both CORSSA and statistical seismology, basic statistical tests and their role in seismology; understanding seismicity catalogs and their problems; basic techniques for modeling seismicity; and methods for testing earthquake predictability hypotheses. We have also begun curating a collection of statistical seismology software packages.

Seismic data classification and artificial neural networks: can software replace eyeballs?

Science.gov (United States)

Reusch, D. B.; Larson, A. M.

2006-05-01

Modern seismic datasets are providing many new opportunities for furthering our understanding of our planet, ranging from the deep earth to the sub-ice sheet interface. With many geophysical applications, the large volume of these datasets raises issues of manageability in areas such as quality control (QC) and event identification (EI). While not universally true, QC can be a labor intensive, subjective (and thus not entirely reproducible) and uninspiring task when such datasets are involved. The EI process shares many of these drawbacks but has the benefit of (usually) being closer to interesting science-based questions. Here we explore two techniques from the field of artificial neural networks (ANNs) that seek to reduce the time requirements and increase the objectivity of QC and EI on seismic datasets. In particular, we focus on QC of receiver functions from broadband seismic data collected by the 2000-2003 Transantarctic Mountains Seismic Experiment (TAMSEIS). Self-organizing maps (SOMs) enable unsupervised classification of large, complex geophysical data sets (e.g., time series of the atmospheric circulation) into a fixed number of distinct generalized patterns or modes representing the probability distribution function of the input data. These patterns are organized spatially as a two-dimensional grid such that distances represent similarity (adjacent patterns will be most similar). After training, input data are matched to their most similar generalized pattern to produce frequency maps, i.e., what fraction of the data is represented best by each individual SOM pattern. Given a priori information on data quality (from previous manual grading) or event type, a probabilistic classification can be developed that gives a likelihood for each category of interest for each SOM pattern. New data are classified by identifying the closest matching pattern (without retraining) and examining the associated probabilities. Feed-forward ANNs (FFNNs) are a supervised

SIGKit: a New Data-based Software for Learning Introductory Geophysics

Science.gov (United States)

Zhang, Y.; Kruse, S.; George, O.; Esmaeili, S.; Papadimitrios, K. S.; Bank, C. G.; Cadmus, A.; Kenneally, N.; Patton, K.; Brusher, J.

2016-12-01

Students of diverse academic backgrounds take introductory geophysics courses to learn the theory of a variety of measurement and analysis methods with the expectation to be able to apply their basic knowledge to real data. Ideally, such data is collected in field courses and also used in lecture-based courses because they provide a critical context for better learning and understanding of geophysical methods. Each method requires a separate software package for the data processing steps, and the complexity and variety of professional software makes the path through data processing to data interpretation a strenuous learning process for students and a challenging teaching task for instructors. SIGKit (Student Investigation of Geophysics Toolkit) being developed as a collaboration between the University of South Florida, the University of Toronto, and MathWorks intends to address these shortcomings by showing the most essential processing steps and allowing students to visualize the underlying physics of the various methods. It is based on MATLAB software and offered as an easy-to-use graphical user interface and packaged so it can run as an executable in the classroom and the field even on computers without MATLAB licenses. An evaluation of the software based on student feedback from focus-group interviews and think-aloud observations helps drive its development and refinement. The toolkit provides a logical gateway into the more sophisticated and costly software students will encounter later in their training and careers by combining essential visualization, modeling, processing, and analysis steps for seismic, GPR, magnetics, gravity, resistivity, and electromagnetic data.

Insights into crustal structure of the Eastern North American Margin from community multichannel seismic and potential field data

Science.gov (United States)

Davis, J. K.; Becel, A.; Shillington, D. J.; Buck, W. R.

2017-12-01

In the fall of 2014, the R/V Marcus Langseth collected gravity, magnetic, and reflection seismic data as part of the Eastern North American Margin Community Seismic Experiment. The dataset covers a 500 km wide section of the Mid-Atlantic passive margin offshore North Carolina, which formed after the Mesozoic breakup of the supercontinent Pangaea. Using these seismic and potential field data, we present observations and interpretations along two cross margin and one along-margin profiles. Analyses and interpretations are conducted using pre-stack depth migrated reflection seismic profiles in conjunction with forward modeling of shipboard gravity and magnetic anomalies. Preliminary interpretations of the data reveal variations in basement character and structure across the entire transition between continental and oceanic domains. These interpretations help provide insight into the origin and nature of the prominent East Coast and Blake Spur magnetic anomalies, as well as the Inner Magnetic Quiet Zone which occupies the domain between the anomalies. Collectively, these observations can aid in deciphering the rift-to-drift transition during the breakup of North America and West Africa and formation of the Central Atlantic.

3-D seismic velocity and attenuation structures in the geothermal field

Energy Technology Data Exchange (ETDEWEB)

Nugraha, Andri Dian [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Syahputra, Ahmad [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Fatkhan,; Sule, Rachmat [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)

2013-09-09

We conducted delay time tomography to determine 3-D seismic velocity structures (Vp, Vs, and Vp/Vs ratio) using micro-seismic events in the geothermal field. The P-and S-wave arrival times of these micro-seismic events have been used as input for the tomographic inversion. Our preliminary seismic velocity results show that the subsurface condition of geothermal field can be fairly delineated the characteristic of reservoir. We then extended our understanding of the subsurface physical properties through determining of attenuation structures (Qp, Qs, and Qs/Qp ratio) using micro-seismic waveform. We combined seismic velocities and attenuation structures to get much better interpretation of the reservoir characteristic. Our preliminary attanuation structures results show reservoir characterization can be more clearly by using the 3-D attenuation model of Qp, Qs, and Qs/Qp ratio combined with 3-D seismic velocity model of Vp, Vs, and Vp/Vs ratio.

A microseismic workflow for managing induced seismicity risk as CO₂ storage projects

Energy Technology Data Exchange (ETDEWEB)

Matzel, E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Morency, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pyle, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Templeton, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); White, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-10-27

It is well established that fluid injection has the potential to induce earthquakes—from microseismicity to large, damaging events—by altering state-of-stress conditions in the subsurface. While induced seismicity has not been a major operational issue for carbon storage projects to date, a seismicity hazard exists and must be carefully addressed. Two essential components of effective seismic risk management are (1) sensitive microseismic monitoring and (2) robust data interpretation tools. This report describes a novel workflow, based on advanced processing algorithms applied to microseismic data, to help improve management of seismic risk. This workflow has three main goals: (1) to improve the resolution and reliability of passive seismic monitoring, (2) to extract additional, valuable information from continuous waveform data that is often ignored in standard processing, and (3) to minimize the turn-around time between data collection, interpretation, and decision-making. These three objectives can allow for a better-informed and rapid response to changing subsurface conditions.

Seismic Search Engine: A distributed database for mining large scale seismic data

Science.gov (United States)

Liu, Y.; Vaidya, S.; Kuzma, H. A.

2009-12-01

The International Monitoring System (IMS) of the CTBTO collects terabytes worth of seismic measurements from many receiver stations situated around the earth with the goal of detecting underground nuclear testing events and distinguishing them from other benign, but more common events such as earthquakes and mine blasts. The International Data Center (IDC) processes and analyzes these measurements, as they are collected by the IMS, to summarize event detections in daily bulletins. Thereafter, the data measurements are archived into a large format database. Our proposed Seismic Search Engine (SSE) will facilitate a framework for data exploration of the seismic database as well as the development of seismic data mining algorithms. Analogous to GenBank, the annotated genetic sequence database maintained by NIH, through SSE, we intend to provide public access to seismic data and a set of processing and analysis tools, along with community-generated annotations and statistical models to help interpret the data. SSE will implement queries as user-defined functions composed from standard tools and models. Each query is compiled and executed over the database internally before reporting results back to the user. Since queries are expressed with standard tools and models, users can easily reproduce published results within this framework for peer-review and making metric comparisons. As an illustration, an example query is “what are the best receiver stations in East Asia for detecting events in the Middle East?” Evaluating this query involves listing all receiver stations in East Asia, characterizing known seismic events in that region, and constructing a profile for each receiver station to determine how effective its measurements are at predicting each event. The results of this query can be used to help prioritize how data is collected, identify defective instruments, and guide future sensor placements.

A new moonquake catalog from Apollo 17 seismic data I: Lunar Seismic Profiling Experiment: Thermal moonquakes and implications for surface processes

Science.gov (United States)

Weber, R. C.; Dimech, J. L.; Phillips, D.; Molaro, J.; Schmerr, N. C.

2017-12-01

Apollo 17's Lunar Seismic Profiling Experiment's (LSPE) primary objective was to constrain the near-surface velocity structure at the landing site using active sources detected by a 100 m-wide triangular geophone array. The experiment was later operated in "listening mode," and early studies of these data revealed the presence of thermal moonquakes - short-duration seismic events associated with terminator crossings. However, the full data set has never been systematically analyzed for natural seismic signal content. In this study, we analyze 8 months of continuous LSPE data using an automated event detection technique that has previously successfully been applied to the Apollo 16 Passive Seismic Experiment data. We detected 50,000 thermal moonquakes from three distinct event templates, representing impulsive, intermediate, and emergent onset of seismic energy, which we interpret as reflecting their relative distance from the array. Impulsive events occur largely at sunrise, possibly representing the thermal "pinging" of the nearby lunar lander, while emergent events occur at sunset, possibly representing cracking or slumping in more distant surface rocks and regolith. Preliminary application of an iterative event location algorithm to a subset of the impulsive waveforms supports this interpretation. We also perform 3D modeling of the lunar surface to explore the relative contribution of the lander, known rocks and surrounding topography to the thermal state of the regolith in the vicinity of the Apollo 17 landing site over the course of the lunar diurnal cycle. Further development of both this model and the event location algorithm may permit definitive discrimination between different types of local diurnal events e.g. lander noise, thermally-induced rock breakdown, or fault creep on the nearby Lee-Lincoln scarp. These results could place important constraints on both the contribution of seismicity to regolith production, and the age of young lobate scarps.

Determination of bedrock depth at Faculty of Medicine Universitas Sebelas Maret Surakarta by using seismic refraction method

Science.gov (United States)

Pridasiwi, A. T.; Legowo, B.; Koesuma, S.

2018-03-01

The study of determination of bedrock depth has been done at Faculty of Medicine Sebelas Maret University Surakarta using seismic refraction method. The study was conducted on 3 lines using seismograph PASI type 16S24-P with spread length of 46 meters, interval between geophone 2 meters, 5 shots in each spread. Data processing is done using WinSism11.6 software and intercept time calculation method. Results of seismic data processing obtained 2 dimensions interpretation of 3 layers structure. In the first line, the P wave velocity (600-2000) m/s with the depth of 11 meters, the second line (400-2000) m/s with the depth of 11 meters and the third line (600-2000) m/s with the depth of 7 meters. Based on the P wave velocity that have been correlated with the drill data, the rock lithology of the 3 lines are consist of top soil, sand with silt and clay (massif). It was concluded that bedrock lies at depth 11 meters.

Assessing the cost-effectiveness of seismic risk reduction options in oil industry

International Nuclear Information System (INIS)

Nasserasadi, K.; Ghafory-Ashtiany, M.

2007-01-01

An integrated probabilistic methodology for cost-efficiency estimation of different sort of seismic risk management measures are introduced by adding Cost Benefit Analysis (CBA) module to an integrated seismic risk assessment model. An oil refinery in Iran has been selected for case study and cost-efficiency of software and hardware mitigation measures are evaluated. The results have shown that: (1) software mitigation measures have more benefit than hardware ones, (2) considering indirect loss in CBA lead to more benefit-cost ratio and (3) although increase of discount ratio decreases the benefit-cost ratio, the arrangement of mitigation measures from benefit-cost viewpoint are constant. (authors)

Unified Geophysical Cloud Platform (UGCP) for Seismic Monitoring and other Geophysical Applications.

Science.gov (United States)

Synytsky, R.; Starovoit, Y. O.; Henadiy, S.; Lobzakov, V.; Kolesnikov, L.

2016-12-01

We present Unified Geophysical Cloud Platform (UGCP) or UniGeoCloud as an innovative approach for geophysical data processing in the Cloud environment with the ability to run any type of data processing software in isolated environment within the single Cloud platform. We've developed a simple and quick method of several open-source widely known software seismic packages (SeisComp3, Earthworm, Geotool, MSNoise) installation which does not require knowledge of system administration, configuration, OS compatibility issues etc. and other often annoying details preventing time wasting for system configuration work. Installation process is simplified as "mouse click" on selected software package from the Cloud market place. The main objective of the developed capability was the software tools conception with which users are able to design and install quickly their own highly reliable and highly available virtual IT-infrastructure for the organization of seismic (and in future other geophysical) data processing for either research or monitoring purposes. These tools provide access to any seismic station data available in open IP configuration from the different networks affiliated with different Institutions and Organizations. It allows also setting up your own network as you desire by selecting either regionally deployed stations or the worldwide global network based on stations selection form the global map. The processing software and products and research results could be easily monitored from everywhere using variety of user's devices form desk top computers to IT gadgets. Currents efforts of the development team are directed to achieve Scalability, Reliability and Sustainability (SRS) of proposed solutions allowing any user to run their applications with the confidence of no data loss and no failure of the monitoring or research software components. The system is suitable for quick rollout of NDC-in-Box software package developed for State Signatories and aimed for

Earthquake Monitoring: SeisComp3 at the Swiss National Seismic Network

Science.gov (United States)

Clinton, J. F.; Diehl, T.; Cauzzi, C.; Kaestli, P.

2011-12-01

The Swiss Seismological Service (SED) has an ongoing responsibility to improve the seismicity monitoring capability for Switzerland. This is a crucial issue for a country with low background seismicity but where a large M6+ earthquake is expected in the next decades. With over 30 stations with spacing of ~25km, the SED operates one of the densest broadband networks in the world, which is complimented by ~ 50 realtime strong motion stations. The strong motion network is expected to grow with an additional ~80 stations over the next few years. Furthermore, the backbone of the network is complemented by broadband data from surrounding countries and temporary sub-networks for local monitoring of microseismicity (e.g. at geothermal sites). The variety of seismic monitoring responsibilities as well as the anticipated densifications of our network demands highly flexible processing software. We are transitioning all software to the SeisComP3 (SC3) framework. SC3 is a fully featured automated real-time earthquake monitoring software developed by GeoForschungZentrum Potsdam in collaboration with commercial partner, gempa GmbH. It is in its core open source, and becoming a community standard software for earthquake detection and waveform processing for regional and global networks across the globe. SC3 was originally developed for regional and global rapid monitoring of potentially tsunamagenic earthquakes. In order to fulfill the requirements of a local network recording moderate seismicity, SED has tuned configurations and added several modules. In this contribution, we present our SC3 implementation strategy, focusing on the detection and identification of seismicity on different scales. We operate several parallel processing "pipelines" to detect and locate local, regional and global seismicity. Additional pipelines with lower detection thresholds can be defined to monitor seismicity within dense subnets of the network. To be consistent with existing processing

PH5: HDF5 Based Format for Integrating and Archiving Seismic Data

Science.gov (United States)

Hess, D.; Azevedo, S.; Falco, N.; Beaudoin, B. C.

2017-12-01

PH5 is a seismic data format created by IRIS PASSCAL using HDF5. Building PH5 on HDF5 allows for portability and extensibility on a scale that is unavailable in older seismic data formats. PH5 is designed to evolve to accept new data types as they become available in the future and to operate on a variety of platforms (i.e. Mac, Linux, Windows). Exemplifying PH5's flexibility is the evolution from just handling active source seismic data to now including passive source, onshore-offshore, OBS and mixed source seismic data sets. In PH5, metadata is separated from the time series data and stored in a size and performance efficient manner that also allows for easy user interaction and output of the metadata in a format appropriate for the data set. PH5's full-fledged "Kitchen Software Suite" comprises tools for data ingestion (e.g. RefTek, SEG-Y, SEG-D, SEG-2, MSEED), meta-data management, QC, waveform viewing, and data output. This software suite not only includes command line and GUI tools for interacting with PH5, it is also a comprehensive Python package to support the creation of software tools by the community to further enhance PH5. The PH5 software suite is currently being used in multiple capacities, including in-field for creating archive ready data sets as well as by the IRIS Data Management Center (DMC) to offer an FDSN compliant set of web services for serving PH5 data to the community in a variety of standard data and meta-data formats (i.e. StationXML, QuakeML, EventXML, SAC + Poles and Zeroes, MiniSEED, and SEG-Y) as well as StationTXT and ShotText formats. These web services can be accessed via standard FDSN clients such as ObsPy, irisFetch.m, FetchData, and FetchMetadata. This presentation will highlight and demonstrate the benefits of PH5 as a next generation adaptable and extensible data format for use in both archiving and working with seismic data.

Design and implementation of a unified certification management system based on seismic business

Science.gov (United States)

Tang, Hongliang

2018-04-01

Many business software for seismic systems are based on web pages, users can simply open a browser and enter their IP address. However, how to achieve unified management and security management of many IP addresses, this paper introduces the design concept based on seismic business and builds a unified authentication management system using ASP technology.

Focusing patterns of seismicity with relocation and collapsing

Science.gov (United States)

Li, Ka Lok; Gudmundsson, Ólafur; Tryggvason, Ari; Bödvarsson, Reynir; Brandsdóttir, Bryndís

2016-07-01

Seismicity is generally concentrated on faults or in fault zones of varying, sometimes complex geometry. An earthquake catalog, compiled over time, contains useful information about this geometry, which can help understanding the tectonics of a region. Interpreting the geometrical distribution of events in a catalog is often complicated by the diffuseness of the earthquake locations. Here, we explore a number of strategies to reduce this diffuseness and hence simplify the seismicity pattern of an earthquake catalog. These strategies utilize information about event locations contained in their overall catalog distribution. They apply this distribution as an a priori constraint on relocations of the events, or as an attractor for each individual event in a collapsing scheme, and thereby focus the locations. The latter strategy is not a relocation strategy in a strict sense, although event foci are moved, because the movements are not driven by data misfit. Both strategies simplify the seismicity pattern of the catalog and may help to interpret it. A synthetic example and a real-data example from an aftershock sequence in south west Iceland are presented to demonstrate application of the strategies. Entropy is used to quantify their effect.

Underground gas storage Lobodice geological model development based on 3D seismic interpretation

International Nuclear Information System (INIS)

Kopal, L.

2015-01-01

Aquifer type underground gas storage (UGS) Lobodice was developed in the Central Moravian part of Carpathian foredeep in Czech Republic 50 years ago. In order to improve knowledge about UGS geological structure 3D seismic survey was performed in 2009. Reservoir is rather shallow (400 - 500 m below surface) it is located in complicated locality so limitations for field acquisition phase were abundant. This article describes process work flow from 3D seismic field data acquisition to geological model creation. The outcomes of this work flow define geometry of UGS reservoir, its tectonics, structure spill point, cap rock and sealing features of the structure. Improving of geological knowledge about the reservoir enables less risky new well localization for UGS withdrawal rate increasing. (authors)

SM1.3 Seismic Centers Data Acquisition: an introduction to Antelope, EarthWorm, SeisComP and their usage around the world

Science.gov (United States)

Pesaresi, Damiano; Sleeman, Reinoud

2010-05-01

Many medium to big size seismic data centers around the world are facing the same question: which software to use to acquire seismic data in real-time? A home-made or a commercial one? Both choices have pros and cons. The in-house development of software usually requires an increased investment in human resources rather than a financial investment. However, the advantage of fully accomplishing your own needs could be put in danger when the software engineer quits the job! Commercial software offers the advantage of being maintained, but it may require both a considerable financial investment and training. The main seismic software data acquisition suites available nowadays are the public domain SeisComP and EarthWorm packages and the commercial package Antelope. Nanometrics, Guralp and RefTek also provide seismic data acquisition software, but they are mainly intended for single station/network acquisition. Antelope is a software package for real-time acquisition and processing of seismic network data, with its roots in the academic seismological community. The software is developed by Boulder Real Time Technology (BRTT) and commercialized by Kinemetrics. It is used by IRIS affiliates for off-line data processing and it is the main acquisition tool for the USArray program and data centers in Europe like the ORFEUS Data Center, OGS (Italy), ZAMG (Austria), ARSO (Slovenia) and GFU (Czech Republic). SeisComP was originally developed for the GEOFON global network to provide a system for data acquisition, data exchange (SeedLink protocol) and automatic processing. It has evolved into to a widely distributed, networked seismographic system for data acquisition and real-time data exchange over Internet and is supported by ORFEUS as the standard seismic data acquisition tool in Europe. SeisComP3 is the next generation of the software and was developed for the German Indonesian Tsunami Early Warning System (GITEWS). SeisComP is licensed by GFZ (free of charge) and

2D seismic interpretation and characterization of the Hauterivian-Early Barremian source rock in Al Baraka oil field, Komombo Basin, Upper Egypt

Science.gov (United States)

Ali, Moamen; Darwish, M.; Essa, Mahmoud A.; Abdelhady, A.

2018-03-01

Komombo Basin is located in Upper Egypt about 570 km southeast of Cairo; it is an asymmetrical half graben and the first oil producing basin in Upper Egypt. The Six Hills Formation is of Early Cretaceous age and subdivided into seven members from base to top (A-G); meanwhile the B member is of Hauterivian-Early Barremian and it is the only source rock of Komombo Basin. Therefore, a detailed study of the SR should be carried out, which includes the determination of the main structural elements, thickness, facies distribution and characterization of the B member SR which has not been conducted previously in the study area. Twenty 2D seismic lines were interpreted with three vertical seismic profiles (VSP) to construct the depth structure-tectonic map on the top of the B member and to highlight the major structural elements. The interpretation of depth structure contour map shows two main fault trends directed towards the NW-SE and NE to ENE directions. The NW-SE trend is the dominant one, creating a major half-graben system. Also the depth values range from -8400 ft at the depocenter in the eastern part to -4800 ft at the shoulder of the basin in the northwestern part of the study area. Meanwhile the Isopach contour map of the B member shows a variable thickness ranging between 300 ft to 750 ft. The facies model shows that the B member SR is composed mainly of shale with some sandstone streaks. The B member rock samples were collected from Al Baraka-1 and Al Baraka SE-1 in the eastern part of Komombo Basin. The results indicate that the organic matter content (TOC) has mainly good to very good (1-3.36 wt %), The B member samples have HI values in the range 157-365 (mg HC/g TOC) and dominated by Type II/III kerogen, and is thus considered to be oil-gas prone based on Rock-Eval pyrolysis, Tmax values between 442° and 456° C therefore interpreted to be mature for hydrocarbon generation. Based on the measured vitrinite equivalent reflectance values, the B member SR

Preliminary seismic hazard assessment, shallow seismic refraction and resistivity sounding studies for future urban planning at the Gebel Umm Baraqa area, Egypt

International Nuclear Information System (INIS)

Khalil, Mohamed H; Hanafy, Sherif M; Gamal, Mohamed A

2008-01-01

Gebel Umm Baraqa Fan, west Gulf of Aqaba, Sinai, is one of the most important tourism areas in Egypt. However, it is located on the active Dead Sea-Gulf of Aqaba Levant transform fault system. Geophysical studies, including fresh water aquifer delineation, shallow seismic refraction, soil characterization and preliminary seismic hazard assessment, were conducted to help in future city planning. A total of 11 vertical electrical soundings (1000–3000 m maximum AB/2) and three bore-holes were drilled in the site for the analysis of ground water, total dissolved solids (TDS) and fresh water aquifer properties. The interpretation of the one-dimensional (1D) inversion of the resistivity data delineated the fresh water aquifer and determined its hydro-geologic parameters. Eleven shallow seismic refraction profiles (125 m in length) have been collected and interpreted using the generalized reciprocal method, and the resulting depth–velocity models were verified using an advanced finite difference (FD) technique. Shallow seismic refraction effectively delineates two subsurface layers (VP ∼ 450 m s −1 and VP ∼ 1000 m s −1 ). A preliminary seismic hazard assessment in Umm Baraqa has produced an estimate of the probabilistic peak ground acceleration hazard in the study area. A recent and historical earthquake catalog for the time period 2200 BC to 2006 has been compiled for the area. New accurate seismic source zoning is considered because such details affect the degree of hazard in the city. The estimated amount of PGA reveals values ranging from 250 to 260 cm s −2 in the bedrock of the Umm Baraqa area during a 100 year interval (a suitable time window for buildings). Recommendations as to suitable types of buildings, considering the amount of shaking and the aquifer properties given in this study, are expected to be helpful for the Umm Baraqa area

Technical development of seismic imaging prospecting

International Nuclear Information System (INIS)

Xu Guilai

2006-01-01

Geophysical methods and apparatus for shallow engineering geophysical prospecting and mining related in-roadway geophysical prospecting are important research fields which has been studied for long time, unfortunately, little significant advancement has been made compared with the demand of engineering geology. The seismic imaging method and its corresponding equipment are viewed as the most hopeful choice for 0-50 m depth and are studied in this research systematically. The recording equipment CSA is made and the related in-situ data processing software is also developed. Field application experiment for shallow seismic prospecting has been finished, the results show that the CSA seismic imaging and its application technology are effective and practical for the engineering geophysical prospecting of 0-50 m depth, and can meet the demand of engineering geology investigation. Hence, the geophysical method and equipment, which can meet the demand for 0-50 m depth engineering geology investigation have been formed through this research. (authors)

Seismic anisotropy in deforming salt bodies

Science.gov (United States)

Prasse, P.; Wookey, J. M.; Kendall, J. M.; Dutko, M.

2017-12-01

Salt is often involved in forming hydrocarbon traps. Studying salt dynamics and the deformation processes is important for the exploration industry. We have performed numerical texture simulations of single halite crystals deformed by simple shear and axial extension using the visco-plastic self consistent approach (VPSC). A methodology from subduction studies to estimate strain in a geodynamic simulation is applied to a complex high-resolution salt diapir model. The salt diapir deformation is modelled with the ELFEN software by our industrial partner Rockfield, which is based on a finite-element code. High strain areas at the bottom of the head-like strctures of the salt diapir show high amount of seismic anisotropy due to LPO development of halite crystals. The results demonstrate that a significant degree of seismic anisotropy can be generated, validating the view that this should be accounted for in the treatment of seismic data in, for example, salt diapir settings.

Cluster Computing For Real Time Seismic Array Analysis.

Science.gov (United States)

Martini, M.; Giudicepietro, F.

A seismic array is an instrument composed by a dense distribution of seismic sen- sors that allow to measure the directional properties of the wavefield (slowness or wavenumber vector) radiated by a seismic source. Over the last years arrays have been widely used in different fields of seismological researches. In particular they are applied in the investigation of seismic sources on volcanoes where they can be suc- cessfully used for studying the volcanic microtremor and long period events which are critical for getting information on the volcanic systems evolution. For this reason arrays could be usefully employed for the volcanoes monitoring, however the huge amount of data produced by this type of instruments and the processing techniques which are quite time consuming limited their potentiality for this application. In order to favor a direct application of arrays techniques to continuous volcano monitoring we designed and built a small PC cluster able to near real time computing the kinematics properties of the wavefield (slowness or wavenumber vector) produced by local seis- mic source. The cluster is composed of 8 Intel Pentium-III bi-processors PC working at 550 MHz, and has 4 Gigabytes of RAM memory. It runs under Linux operating system. The developed analysis software package is based on the Multiple SIgnal Classification (MUSIC) algorithm and is written in Fortran. The message-passing part is based upon the LAM programming environment package, an open-source imple- mentation of the Message Passing Interface (MPI). The developed software system includes modules devote to receiving date by internet and graphical applications for the continuous displaying of the processing results. The system has been tested with a data set collected during a seismic experiment conducted on Etna in 1999 when two dense seismic arrays have been deployed on the northeast and the southeast flanks of this volcano. A real time continuous acquisition system has been simulated by

Multivariate Formation Pressure Prediction with Seismic-derived Petrophysical Properties from Prestack AVO inversion and Poststack Seismic Motion Inversion

Science.gov (United States)

Yu, H.; Gu, H.

2017-12-01

A novel multivariate seismic formation pressure prediction methodology is presented, which incorporates high-resolution seismic velocity data from prestack AVO inversion, and petrophysical data (porosity and shale volume) derived from poststack seismic motion inversion. In contrast to traditional seismic formation prediction methods, the proposed methodology is based on a multivariate pressure prediction model and utilizes a trace-by-trace multivariate regression analysis on seismic-derived petrophysical properties to calibrate model parameters in order to make accurate predictions with higher resolution in both vertical and lateral directions. With prestack time migration velocity as initial velocity model, an AVO inversion was first applied to prestack dataset to obtain high-resolution seismic velocity with higher frequency that is to be used as the velocity input for seismic pressure prediction, and the density dataset to calculate accurate Overburden Pressure (OBP). Seismic Motion Inversion (SMI) is an inversion technique based on Markov Chain Monte Carlo simulation. Both structural variability and similarity of seismic waveform are used to incorporate well log data to characterize the variability of the property to be obtained. In this research, porosity and shale volume are first interpreted on well logs, and then combined with poststack seismic data using SMI to build porosity and shale volume datasets for seismic pressure prediction. A multivariate effective stress model is used to convert velocity, porosity and shale volume datasets to effective stress. After a thorough study of the regional stratigraphic and sedimentary characteristics, a regional normally compacted interval model is built, and then the coefficients in the multivariate prediction model are determined in a trace-by-trace multivariate regression analysis on the petrophysical data. The coefficients are used to convert velocity, porosity and shale volume datasets to effective stress and then

Seismicity and crustal structure at the Mendocino triple junction, Northern California

Energy Technology Data Exchange (ETDEWEB)

Dicke, M.

1998-12-01

A high level of seismicity at the Mendocino triple junction in Northern California reflects the complex active tectonics associated with the junction of the Pacific, North America, and Gorda plates. To investigate seismicity patterns and crustal structure, 6193 earthquakes recorded by the Northern California Seismic Network (NCSN) are relocated using a one-dimensional crustal velocity model. A near vertical truncation of the intense seismic activity offshore Cape Mendocino follows the strike of the Mattole Canyon fault and is interpreted to define the Pacific plate boundary. Seismicity along this boundary displays a double seismogenic layer that is attributed to interplate activity with the North America plate and Gorda plate. The interpretation of the shallow seismogenic zone as the North America - Pacific plate boundary implies that the Mendocino triple junction is situated offshore at present. Seismicity patterns and focal mechanisms for events located within the subducting Gorda pl ate are consistent with internal deformation on NE-SW and NW-SE trending rupture planes in response to north-south compression. Seismic sections indicate that the top of the Gorda plate locates at a depth of about 18 Km beneath Cape Mendocino and dips gently east-and southward. Earthquakes that are located in the Wadati-Benioff zone east of 236{sup o}E show a change to an extensional stress regime indicative of a slab pull force. This slab pull force and scattered seismicity within the contractional forearc region of the Cascadia subduction zone suggest that the subducting Gorda plate and the overriding North America plate are strongly coupled. The 1992 Cape Mendocino thrust earthquake is believed to have ruptured a blind thrust fault in the forearc region, suggesting that strain is accumulating that must ultimately be released in a potential M 8+ subduction earthquake.

MULTI-ATTRIBUTE SEISMIC/ROCK PHYSICS APPROACH TO CHARACTERIZING FRACTURED RESERVOIRS

Energy Technology Data Exchange (ETDEWEB)

Gary Mavko

2000-10-01

This project consists of three key interrelated Phases, each focusing on the central issue of imaging and quantifying fractured reservoirs, through improved integration of the principles of rock physics, geology, and seismic wave propagation. This report summarizes the results of Phase I of the project. The key to successful development of low permeability reservoirs lies in reliably characterizing fractures. Fractures play a crucial role in controlling almost all of the fluid transport in tight reservoirs. Current seismic methods to characterize fractures depend on various anisotropic wave propagation signatures that can arise from aligned fractures. We are pursuing an integrated study that relates to high-resolution seismic images of natural fractures to the rock parameters that control the storage and mobility of fluids. Our goal is to go beyond the current state-of-the art to develop and demonstrate next generation methodologies for detecting and quantitatively characterizing fracture zones using seismic measurements. Our study incorporates 3 key elements: (1) Theoretical rock physics studies of the anisotropic viscoelastic signatures of fractured rocks, including up scaling analysis and rock-fluid interactions to define the factors relating fractures in the lab and in the field. (2) Modeling of optimal seismic attributes, including offset and azimuth dependence of travel time, amplitude, impedance and spectral signatures of anisotropic fractured rocks. We will quantify the information content of combinations of seismic attributes, and the impact of multi-attribute analyses in reducing uncertainty in fracture interpretations. (3) Integration and interpretation of seismic, well log, and laboratory data, incorporating field geologic fracture characterization and the theoretical results of items 1 and 2 above. The focal point for this project is the demonstration of these methodologies in the Marathon Oil Company Yates Field in West Texas.

Interpretation of interseismic deformations and the seismic cycle associated with large subduction earthquakes

Science.gov (United States)

Trubienko, Olga; Fleitout, Luce; Garaud, Jean-Didier; Vigny, Christophe

2013-03-01

The deformations of the overriding and subducting plates during the seismic cycle associated with large subduction earthquakes are modelled using 2D and 3D finite element techniques. A particular emphasis is put on the interseismic velocities and on the impact of the rheology of the asthenosphere. The distance over which the seismic cycle perturbs significantly the velocities depends upon the ratio of the viscosity in the asthenosphere to the period of the seismic cycle and can reach several thousand km for rheological parameters deduced from the first years of deformation after the Aceh earthquake. For a same early postseismic velocity, a Burger rheology of the asthenosphere implies a smaller duration of the postseismic phase and thus smaller interseismic velocities than a Maxwell rheology. A low viscosity wedge (LVW) modifies very significantly the predicted horizontal and vertical motions in the near and middle fields. In particular, with a LVW, the peak in vertical velocity at the end of the cycle is predicted to be no longer above the deep end of the locked section of the fault but further away, above the continentward limit of the LVW. The lateral viscosity variations linked to the presence at depth of the subducting slab affect substantially the results. The north-south interseismic compression predicted by this preliminary 2D model over more than 1500 km within the Sunda block is in good agreement with the pre-2004 velocities with respect to South-China inferred from GPS observations in Thailand, Malaysia and Indonesia. In Japan, before the Tohoku earthquake, the eastern part of northern Honshu was subsiding while the western part was uplifting. This transition from subsidence to uplift so far away from the trench is well fitted by the predictions from our models involving a LVW. Most of the results obtained here in a 2D geometry are shown to provide a good estimate of the displacements for fault segments of finite lateral extent, with a 3D spherical

Health software: a new CEI Guide for software management in medical environment.

Science.gov (United States)

Giacomozzi, Claudia; Martelli, Francesco

2016-01-01

The increasing spread of software components in the healthcare context renders explanatory guides relevant and mandatory to interpret laws and standards, and to support safe management of software products in healthcare. In 2012 a working group has been settled for the above purposes at Italian Electrotechnical Committee (CEI), made of experts from Italian National Institute of Health (ISS), representatives of industry, and representatives of the healthcare organizations. As a first outcome of the group activity, Guide CEI 62-237 was published in February 2015. The Guide incorporates an innovative approach based on the proper contextualization of software products, either medical devices or not, to the specific healthcare scenario, and addresses the risk management of IT systems. The Guide provides operators and manufacturers with an interpretative support with many detailed examples to facilitate the proper contextualization and management of health software, in compliance with related European and international regulations and standards.

Design and development of digital seismic amplifier recorder

Energy Technology Data Exchange (ETDEWEB)

Samsidar, Siti Alaa; Afuar, Waldy; Handayani, Gunawan, E-mail: gunawanhandayani@gmail.com [Department of Physics, ITB (Indonesia)

2015-04-16

A digital seismic recording is a recording technique of seismic data in digital systems. This method is more convenient because it is more accurate than other methods of seismic recorders. To improve the quality of the results of seismic measurements, the signal needs to be amplified to obtain better subsurface images. The purpose of this study is to improve the accuracy of measurement by amplifying the input signal. We use seismic sensors/geophones with a frequency of 4.5 Hz. The signal is amplified by means of 12 units of non-inverting amplifier. The non-inverting amplifier using IC 741 with the resistor values 1KΩ and 1MΩ. The amplification results were 1,000 times. The results of signal amplification converted into digital by using the Analog Digital Converter (ADC). Quantitative analysis in this study was performed using the software Lab VIEW 8.6. The Lab VIEW 8.6 program was used to control the ADC. The results of qualitative analysis showed that the seismic conditioning can produce a large output, so that the data obtained is better than conventional data. This application can be used for geophysical methods that have low input voltage such as microtremor application.

Lower bound earthquake magnitude for probabilistic seismic hazard evaluation

International Nuclear Information System (INIS)

McCann, M.W. Jr.; Reed, J.W.

1990-01-01

This paper presents the results of a study that develops an engineering and seismological basis for selecting a lower-bound magnitude (LBM) for use in seismic hazard assessment. As part of a seismic hazard analysis the range of earthquake magnitudes that are included in the assessment of the probability of exceedance of ground motion must be defined. The upper-bound magnitude is established by earth science experts based on their interpretation of the maximum size of earthquakes that can be generated by a seismic source. The lower-bound or smallest earthquake that is considered in the analysis must also be specified. The LBM limits the earthquakes that are considered in assessing the probability that specified ground motion levels are exceeded. In the past there has not been a direct consideration of the appropriate LBM value that should be used in a seismic hazard assessment. This study specifically looks at the selection of a LBM for use in seismic hazard analyses that are input to the evaluation/design of nuclear power plants (NPPs). Topics addressed in the evaluation of a LBM are earthquake experience data at heavy industrial facilities, engineering characteristics of ground motions associated with small-magnitude earthquakes, probabilistic seismic risk assessments (seismic PRAs), and seismic margin evaluations. The results of this study and the recommendations concerning a LBM for use in seismic hazard assessments are discussed. (orig.)

PGS sets sail over the seismic horizon

International Nuclear Information System (INIS)

McBarnet, Andrew.

1997-01-01

A report on the rapid expansion of the Norwegian marine seismic company, Petroleum Geo-Services, is given. The company recently completed another acquisition which should take its value to around three million pounds. This will give it a base in geophysics, floating platform technologies and the appropriate hardware and software systems. (UK)

Seismic stratigraphy of the Heuksan mud belt in the southeastern Yellow Sea, Korea

Science.gov (United States)

Lee, Gwang-Soo; Yoo, Dong Geun; Bae, Sung Ho; Min, Gun-Hong; Kim, Seong-Pil; Choi, Hunsoo

2015-12-01

To establish the seismic stratigraphy of the Heuksan mud belt (HMB) and reconstruct its depositional history, approximately 1,600 km of high-resolution seismic data were newly obtained using chirp acoustic sub-bottom profiler, sparker, and air-gun seismic systems. Based on seismic stratigraphic analysis, the HMB can be divided into three major seismic units (I, II, and III, from top to bottom) and four subunits (II-a, II-b, III-a, and III-b) overlying transgressive sands, pre-last glacial maximum (LGM) deposits, and the acoustic basement. Each unit and subunit show different seismic facies and geometry, being clearly separated from each other by bounding surfaces formed since the LGM. The spatial distribution, thicknesses and volumes of the seismic units were determined and plotted to document the sequential formation of the HMB. The correlation between deep drill core data (HMB-101, HMB-102, HMB-103, YSDP-101, and YSDP-102) and the seismic data suggests that subunits III-b and III-a were formed by the continuous accumulation of fine-grained sediment with partial sandy sediment in an estuarine/deltaic environment during the early to middle transgressive stage, accompanied by landward migration of the shoreline. Subunits II-b and II-a were probably formed by re-deposition of large volumes of sediment eroded from unit III during the middle transgressive to early highstand stage. Unit I is interpreted as the most recent mud deposit representing the highstand systems tract when sea-level rise terminated. The careful definition of seismic units and their interpretation proposed in this study, on the basis of the large and partly new seismic dataset covering the entire HMB together with deep drill core data, have been instrumental in reconstructing the depositional environment and formation mechanisms of the HMB.

Eastern US seismic hazard characterization update

International Nuclear Information System (INIS)

Savy, J.B.; Boissonnade, A.C.; Mensing, R.W.; Short, C.M.

1993-06-01

In January 1989, LLNL published the results of a multi-year project, funded by NRC, on estimating seismic hazard at nuclear plant sites east of the Rockies. The goal of this study was twofold: to develop a good central estimate (median) of the seismic hazard and to characterize the uncertainty in the estimates of this hazard. In 1989, LLNL was asked by DOE to develop site specific estimates of the seismic hazard at the Savannah River Site (SRS) in South Carolina as part of the New Production Reactor (NPR) project. For the purpose of the NPR, a complete review of the methodology and of the data acquisition process was performed. Work done under the NPR project has shown that first order improvement in the estimates of the uncertainty (i.e., lower mean hazard values) could be easily achieved by updating the modeling of the seismicity and ground motion attenuation uncertainty. To this effect, NRC sponsored LLNL to perform a reelicitation to update the seismicity and ground motion experts' inputs and to revise methods to combine seismicity and ground motion inputs in the seismic hazard analysis for nuclear power plant sites east of the Rocky Mountains. The objective of the recent study was to include the first order improvements that reflect the latest knowledge in seismicity and ground motion modeling and produce an update of all the hazard results produced in the 1989 study. In particular, it had been demonstrated that eliciting seismicity information in terms of rates of earthquakes rather than a- and b-values, and changing the elicitation format to a one-on-one interview, improved our ability to express the uncertainty of earthquake rates of occurrence at large magnitudes. Thus, NRC sponsored this update study to refine the model of uncertainty, and to re-elicitate of the experts' interpretations of the zonation and seismicity, as well as to reelicitate the ground motion models, based on current state of knowledge

Seismic monitoring at Deception Island volcano (Antarctica): the 2010-2011 survey

Science.gov (United States)

Martín, R.; Carmona, E.; Almendros, J.; Serrano, I.; Villaseñor, A.; Galeano, J.

2012-04-01

As an example of the recent advances introduced in seismic monitoring of Deception Island volcano (Antarctica) during recent years, we describe the instrumental network deployed during the 2010-2011 survey by the Instituto Andaluz de Geofísica of University of Granada, Spain (IAG-UGR). The period of operation extended from December 19, 2010 to March 5, 2011. We deployed a wireless seismic network composed by four three-component seismic stations. These stations are based on 24-bit SL04 SARA dataloggers sampling at 100 sps. They use a PC with embedded linux and SEISLOG data acquisition software. We use two types of three-component seismometers: short-period Mark L4C with natural frequency of 1 Hz and medium-period Lennartz3D/5s with natural frequency of 0.2 Hz. The network was designed for an optimum spatial coverage of the northern half of Deception, where a magma chamber has been reported. Station locations include the vicinity of the Spanish base "Gabriel de Castilla" (GdC), Obsidianas Beach, a zone near the craters from the 1970 eruptions, and the Chilean Shelter located south of Pendulum Cove. Continuous data from the local seismic network are received in real-time in the base by wifi transmission. We used Ubiquiti Networks Nanostation2 antennas with 2.4 GHz, dual-polarity, 10 dBi gain, and 54 Mbps transmission rate. They have shown a great robustness and speed for real-time applications. To prioritize data acquisition when the battery level is low, we have designed a circuit that allows independent power management for the seismic station and wireless transmission system. The reception antenna located at GdC is connected to a computer running SEISCOMP. This software supports several transmission protocols and manages the visualization and recording of seismic data, including the generation of summary plots to show the seismic activity. These twelve data channels are stored in miniseed format and displayed in real time, which allows for a rapid evaluation of

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

The shallow structure of Solfatara Volcano, Italy, revealed by dense, wide-aperture seismic profiling.

Science.gov (United States)

Bruno, Pier Paolo G; Maraio, Stefano; Festa, Gaetano

2017-12-12

Two active-source, high-resolution seismic profiles were acquired in the Solfatara tuff cone in May and November 2014, with dense, wide-aperture arrays. Common Receiver Surface processing was crucial in improving signal-to-noise ratio and reflector continuity. These surveys provide, for the first time, high-resolution seismic images of the Solfatara crater, depicting a ~400 m deep asymmetrical crater filled by volcanoclastic sediments and rocks and carved within an overall non-reflective pre-eruptive basement showing features consistent with the emplacement of shallow intrusive bodies. Seismic reflection data were interpreted using the trace complex attributes and clearly display several steep and segmented collapse faults, generally having normal kinematics and dipping toward the crater centre. Fault/fracture planes are imaged as sudden amplitude drops that generate narrow low-similarity and high-dip attributes. Uprising fluids degassed by a magmatic source are the most probable cause of the small-scale amplitude reduction. Seismic data also support the interpretation of the shallow structure of the Solfatara crater as a maar. Our results provides a solid framework to constrain the near-surface geological interpretation of such a complex area, which improves our understanding of the temporal changes of the structure in relation with other geophysical and geochemical measurements.

Estimation of seismic attenuation of gas hydrate bearing sediments from multi-channel seismic data: A case study from Krishna-Godavari offshore basin

Digital Repository Service at National Institute of Oceanography (India)

Dewangan, P.; Mandal, R.; Jaiswal, P.; Ramprasad, T.; Sriram, G.

thickness of water column. The estimated effective Q-values, along the inline and crossline seismic profiles, depend on several factors such as gas hydrate, free gas and the complex fault system. The combined interpretation of the quality factor...

The passive seismic aftershock Monitoring system: testing program and preliminary results

International Nuclear Information System (INIS)

Mokhtari, M.

2005-01-01

The paper is dedicated to testing program (phase of the passive seismic aftershock monitoring system with RefTek equipment (Refraction Technology, Inc., USA) for On-Site Inspection purposes that was carried out near Vienna International Centre in 2000. Equipment and applied software are described. Testing results were analyzed; in particular, least needs in maintenance personnel during operation. Development perspectives of passive seismic aftershock monitoring system for On-Site Inspection have been discussed. (author)

Study of iron deposit using seismic refraction and resistivity in Carajás Mineral Province, Brazil

Science.gov (United States)

Nogueira, Pedro Vencovsky; Rocha, Marcelo Peres; Borges, Welitom Rodrigues; Silva, Adalene Moreira; Assis, Luciano Mozer de

2016-10-01

This work comprises the acquisition, processing and interpretation of 2D seismic shallow refraction (P-wave) and resistivity profiles located in the iron ore deposit of N4WS, Carajás Mineral Province (CMP), northern Brazil. The geophysical methods were used to identify the boundaries of the iron ore deposit. Another objective was to evaluate the potentiality of these geophysical methods in that geological context. In order to validate the results, the geophysical lines were located to match a geological borehole line. For the seismic refraction, we used 120 channels, spaced by 10 m, in a line of 1190 m, with seven shot points. The resistivity method used in the acquisition was the electrical resistivity imaging, with pole-pole array, in order to reach greater depths. The resistivity line had a length of 1430 m, with 10 m spacing between electrodes. The seismic results produced a model with two distinct layers. Based on the velocities values, the first layer was interpreted as altered rocks, and the second layer as more preserved rocks. It was not possible to discriminate different lithologies with the seismic method inside each layer. From the resistivity results, a zone of higher resistivity (> 3937 Ω·m) was interpreted as iron ore, and a region of intermediate resistivity (from 816 to 2330 Ω·m) as altered rocks. These two regions represent the first seismic layer. On the second seismic layer, an area with intermediated resistivity values (from 483 to 2330 Ω·m) was interpreted as mafic rocks, and the area with lower resistivity (boreholes and show reasonable correlation, suggesting that the geophysical anomalies correspond to the main variations in composition and physical properties of rocks.

The analysis and interpretation of very-long-period seismic signals on volcanoes

Science.gov (United States)

Sindija, Dinko; Neuberg, Jurgen; Smith, Patrick

2017-04-01

The study of very long period (VLP) seismic signals became possible with the widespread use of broadband instruments. VLP seismic signals are caused by transients of pressure in the volcanic edifice and have periods ranging from several seconds to several minutes. For the VLP events recorded in March 2012 and 2014 at Soufriere Hills Volcano, Montserrat, we model the ground displacement using several source time functions: a step function using Richards growth equation, Küpper wavelet, and a damped sine wave to which an instrument response is then applied. This way we get a synthetic velocity seismogram which is directly comparable to the data. After the full vector field of ground displacement is determined, we model the source mechanism to determine the relationship between the source mechanism and the observed VLP waveforms. Emphasis of the research is on how different VLP waveforms are related to the volcano environment and the instrumentation used and on the processing steps in this low frequency band to get most out of broadband instruments.

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

Seismic activity parameters of the Finnish potential repository sites

International Nuclear Information System (INIS)

Saari, J.

2000-10-01

Posiva Oy has started a project for estimating the possible earthquake induced rock movements on the deposition holes containing canisters of spent nuclear fuel. These estimates will be made for the four investigation sites, Romuvaara, Kivetty, Olkiluoto and Haestholmen. This study deals with the current and future seismicity associated with the above mentioned sites. Seismic belts that participate the seismic behaviour of the studied sites have been identified and the magnitude-frequency distributions of these belts have been estimated. The seismic activity parameters of the sites have been deduced from the characteristics of the seismic belts in order to forecast the seismicity during the next 100,000 years. The report discusses the possible earthquakes induced by future glaciation. The seismic interpretation seems to indicate that the previous postglacial faults in Finnish Lapland have been generated in compressional environment. The orientation of the rather uniform compression has been NW-SE, which coincide with the current stress field. It seems that, although the impact of postglacial crustal rebound must have been significant, the impact of plate tectonics has been dominant. A major assumption of this study has been that future seismicity will generally resemble the current seismicity. However, when the postglacial seismicity is concerned, the magnitude-frequency distribution is likely different and the expected maximum magnitude will be higher. Maximum magnitudes of future postglacial earthquakes have been approximated by strain release examinations. Seismicity has been examined within the framework of the lineament maps, in order to associate the future significant earthquakes with active fault zones in the vicinity of the potential repository sites. (orig.)

The Morávka meteorite fall. 2. Interpretation of infrasonic and seismic data

Czech Academy of Sciences Publication Activity Database

Brown, P. G.; Kalenda, P.; ReVelle, D.O.; Borovička, Jiří

2003-01-01

Roč. 38, č. 7 (2003), s. 989-1003 ISSN 0026-1114 Institutional research plan: CEZ:AV0Z1003909 Keywords : meteors * acustic effects * seismic waves Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.992, year: 2003

High resolution seismic stratigraphy and Mass Transport Deposits of the proximal continental margin, offshore Quarteira, South Portugal: Preliminary Results.

Science.gov (United States)

Duarte, Débora; Santos, Joana; Terrinha, Pedro; Brito, Pedro; Noiva, João; Ribeiro, Carlos; Roque, Cristina

2017-04-01

More than 300 nautical miles of multichannel seismic reflection data were acquired in the scope of the ASTARTE project (Assessment Strategy and Risk Reduction for Tsunamis in Europe), off Quarteira, Algarve, South Portugal. The main goal of this very high resolution multichannel seismic survey was to obtain high-resolution images of the sedimentary record to try to discern the existence of high energy events, possibly tsunami backwash deposits associated with large magnitude earthquakes generated at the Africa-Eurasia plate boundary This seismic dataset was processed at the Instituto Português do Mar e da Atmosfera (IPMA), with the SeisSpace PROMAX Seismic Processing software. A tailor-made processing flow was applied, focusing in the removal of the seafloor multiple and in the enhancement of the superficial layers. A sparker source, using with 300 J of energy and a fire rate of 0,5 s was used onboard Xunauta, an 18 m long vessel. The preliminary seismostratigraphic interpretation of the Algarve ASTARTE seismic dataset allowed the identification of a complex sequence seismic units of progradational and agradational bodies as well as Mass Transported Deposits (MTD). The MTD package of sediments has a very complex internal structure, 20m of thickness, is apparently spatially controlled by an escarpment probably associated to past sea level low stands. The MTD covers across an area, approximately parallel to an ancient coastline, with >30 km (length) x 5 km (across). Acknowledgements: This work was developed as part of the project ASTARTE (603839 FP7) supported by the grant agreement No 603839 of the European Union's Seventh. The Instituto Portugues do Mar e da Atmosfera acknowledges support by Landmark Graphics (SeisWorks) via the Landmark University Grant Program.

AECB workshop on seismic hazard assessment in southern Ontario

International Nuclear Information System (INIS)

Stepp, J.C.; Price, R.A.; Coppersmith, K.J.; Klimkiewicz, G.C.; McGuire, R.K.

1995-10-01

The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: (1) The importance of geological and geophysical observations for the determination of seismic sources, (2) Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information, (3) Methods and data which should be used for characterizing the seismicity parameters of seismic sources, and (4) Methods for assessment of vibratory ground motion hazard. The format of each session involved invited presentations of relevant data followed by open presentations by participants, a general discussion focusing on the relevance of the presented information for seismic hazard assessment in southern Ontario, then development of conclusions and recommendations. In the final session, the conclusions and recommendations were summarized and an open discussion was held to develop consensus. This report presents perspective summaries of the workshop technical sessions together with conclusions and recommendations prepared by the session chairs and the general chairman. 2 refs

A seismic fault recognition method based on ant colony optimization

Science.gov (United States)

Chen, Lei; Xiao, Chuangbai; Li, Xueliang; Wang, Zhenli; Huo, Shoudong

2018-05-01

Fault recognition is an important section in seismic interpretation and there are many methods for this technology, but no one can recognize fault exactly enough. For this problem, we proposed a new fault recognition method based on ant colony optimization which can locate fault precisely and extract fault from the seismic section. Firstly, seismic horizons are extracted by the connected component labeling algorithm; secondly, the fault location are decided according to the horizontal endpoints of each horizon; thirdly, the whole seismic section is divided into several rectangular blocks and the top and bottom endpoints of each rectangular block are considered as the nest and food respectively for the ant colony optimization algorithm. Besides that, the positive section is taken as an actual three dimensional terrain by using the seismic amplitude as a height. After that, the optimal route from nest to food calculated by the ant colony in each block is judged as a fault. Finally, extensive comparative tests were performed on the real seismic data. Availability and advancement of the proposed method were validated by the experimental results.

The New Italian Seismic Hazard Model

Science.gov (United States)

Marzocchi, W.; Meletti, C.; Albarello, D.; D'Amico, V.; Luzi, L.; Martinelli, F.; Pace, B.; Pignone, M.; Rovida, A.; Visini, F.

2017-12-01

In 2015 the Seismic Hazard Center (Centro Pericolosità Sismica - CPS) of the National Institute of Geophysics and Volcanology was commissioned of coordinating the national scientific community with the aim to elaborate a new reference seismic hazard model, mainly finalized to the update of seismic code. The CPS designed a roadmap for releasing within three years a significantly renewed PSHA model, with regard both to the updated input elements and to the strategies to be followed. The main requirements of the model were discussed in meetings with the experts on earthquake engineering that then will participate to the revision of the building code. The activities were organized in 6 tasks: program coordination, input data, seismicity models, ground motion predictive equations (GMPEs), computation and rendering, testing. The input data task has been selecting the most updated information about seismicity (historical and instrumental), seismogenic faults, and deformation (both from seismicity and geodetic data). The seismicity models have been elaborating in terms of classic source areas, fault sources and gridded seismicity based on different approaches. The GMPEs task has selected the most recent models accounting for their tectonic suitability and forecasting performance. The testing phase has been planned to design statistical procedures to test with the available data the whole seismic hazard models, and single components such as the seismicity models and the GMPEs. In this talk we show some preliminary results, summarize the overall strategy for building the new Italian PSHA model, and discuss in detail important novelties that we put forward. Specifically, we adopt a new formal probabilistic framework to interpret the outcomes of the model and to test it meaningfully; this requires a proper definition and characterization of both aleatory variability and epistemic uncertainty that we accomplish through an ensemble modeling strategy. We use a weighting scheme

New Version of SeismicHandler (SHX) based on ObsPy

Science.gov (United States)

Stammler, Klaus; Walther, Marcus

2016-04-01

The command line version of SeismicHandler (SH), a scientific analysis tool for seismic waveform data developed around 1990, has been redesigned in the recent years, based on a project funded by the Deutsche Forschungsgemeinschaft (DFG). The aim was to address new data access techniques, simplified metadata handling and a modularized software design. As a result the program was rewritten in Python in its main parts, taking advantage of simplicity of this script language and its variety of well developed software libraries, including ObsPy. SHX provides an easy access to waveforms and metadata via arclink and FDSN webservice protocols, also access to event catalogs is implemented. With single commands whole networks or stations within a certain area may be read in, the metadata are retrieved from the servers and stored in a local database. For data processing the large set of SH commands is available, as well as the SH scripting language. Via this SH language scripts or additional Python modules the command set of SHX is easily extendable. The program is open source, tested on Linux operating systems, documentation and download is found at URL "https://www.seismic-handler.org/".

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.

Seismic Model and Geological Interpretation of the Basement Beneath the Doupovske Hory Volcanic Complex (NW Czech Republic)

Czech Academy of Sciences Publication Activity Database

Valenta, Jan; Brož, Milan; Málek, Jiří; Mlčoch, B.; Rapprich, V.; Skácelová, Z.

2011-01-01

Roč. 59, č. 3 (2011), s. 597-617 ISSN 1895-6572 R&D Projects: GA AV ČR IAA300460602 Institutional research plan: CEZ:AV0Z30460519 Keywords : seismic refraction * seismic tomography * Doupovske Hory Volcanic Complex Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.617, year: 2011

Synchrosqueezing-based Transform and its Application in Seismic Data Analysis

Directory of Open Access Journals (Sweden)

Saman Gholtashi

2015-10-01

Full Text Available Seismic waves are non-stationary due to its propagation through the earth. Time-frequency transforms are suitable tools for analyzing non-stationary seismic signals. Spectral decomposition can reveal the non-stationary characteristics which cannot be easily observed in the time or frequency representation alone. Various types of spectral decomposition methods have been introduced by some researchers. Conventional spectral decompositions have some restrictions such as Heisenberg uncertainty principle and cross-terms which limit their applications in signal analysis. In this paper, synchrosqueezingbased transforms were used to overcome the mentioned restrictions; also, as an application of this new high resolution time-frequency analysis method, it was applied to random noise removal and the detection of low-frequency shadows in seismic data. The efficiency of this method is evaluated by applying it to both synthetic and real seismic data. The results show that the mentioned transform is a proper tool for seismic data processing and interpretation.

Novel seismic instrumentation for nuclear power plants

International Nuclear Information System (INIS)

Bolleter, W.; Savary, C.

1998-01-01

Conforming to the latest issues of the Nuclear Regulatory Commission Regulatory Guide, a novel hardware and software solution for seismic instrumentation is presented. Both instrumentation and PC-based data evaluation software for post-earthquake actions are type-tested and approved by the German TUeV. Reference installations replacing obsolete analog instrumentation were successfully completed and are presented. The instrumentation consists of highly linear, solid-state capacitive accelerometers as well as digital recorders storing the signals from the sensors in situ. These recorders are linked in a star-topology network to a central unit that permanently communicates with them via fiber-optic cable or current-loop links. The central unit is responsible for alerting and synchronizes all recorders which otherwise act autonomously. Data evaluation is handled by a PC-based software package. It includes automatic data evaluation after earthquakes (batch mode), interactive data evaluation software for detailed data analysis, and software tools for remote operation, maintenance and data storage. (author)

Clustering of 2008 West Bohemian seismic swarm mechanisms and its possible interpretation

Czech Academy of Sciences Publication Activity Database

Kolář, Petr; Boušková, Alena

2018-01-01

Roč. 15, č. 1 (2018), s. 27-40 ISSN 1214-9705 R&D Projects: GA ČR(CZ) GA16-03950S Institutional support: RVO:67985530 Keywords : West Bohemian earthquake swarm region * source mechanism * slip distribution * finite seismic source model Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: 1.5. Earth and related environmental sciences Impact factor: 0.699, year: 2016

Seismic Responses of an Added-Story Frame Structure with Viscous Dampers

Directory of Open Access Journals (Sweden)

Xuansheng Cheng

2014-01-01

Full Text Available The damping ratio of an added-story frame structure is established based on complex damping theory to determine the structure seismic response. The viscous dampers are selected and arranged through target function method. A significant damping effect is obtained when a small velocity index is selected. The seismic responses of a five-floor reinforced concrete frame structure with directly added light steel layers and light steel layers with viscous dampers are compared with the finite element software SAP2000. Calculation results show that, after adding the layers, the structure becomes flexible and the shear in the bottom layer decreases. However, the interlaminar shear of the other layers increases. The seismic response of the added layers is very significant and exhibits obvious whiplash effect. The interstory displacement angles of some layers do not meet the requirements. The seismic response of the structure decreases after the adoption of viscous dampers; thereby seismic requirements are satisfied.

Why style matters - uncertainty and structural interpretation in thrust belts.

Science.gov (United States)

Butler, Rob; Bond, Clare; Watkins, Hannah

2016-04-01

Structural complexity together with challenging seismic imaging make for significant uncertainty in developing geometric interpretations of fold and thrust belts. Here we examine these issues and develop more realistic approaches to building interpretations. At all scales, the best tests of the internal consistency of individual interpretations come from structural restoration (section balancing), provided allowance is made for heterogeneity in stratigraphy and strain. However, many existing balancing approaches give misleading perceptions of interpretational risk - both on the scale of individual fold-thrust (trap) structures and in regional cross-sections. At the trap-scale, idealised models are widely cited - fault-bend-fold, fault-propagation folding and trishear. These make entirely arbitrary choices for fault localisation and layer-by-layer deformation: precise relationships between faults and fold geometry are generally invalidated by real-world conditions of stratigraphic variation and distributed strain. Furthermore, subsurface predictions made using these idealisations for hydrocarbon exploration commonly fail the test of drilling. Rarely acknowledged, the geometric reliability of seismic images depends on the assigned seismic velocity model, which in turn relies on geological interpretation. Thus iterative approaches are required between geology and geophysics. The portfolio of commonly cited outcrop analogues is strongly biased to examples that simply conform to idealised models - apparently abnormal structures are rarely described - or even photographed! Insight can come from gravity-driven deep-water fold-belts where part of the spectrum of fold-thrust complexity is resolved through seismic imaging. This imagery shows deformation complexity in fold forelimbs and backlimbs. However, the applicability of these, weakly lithified systems to well-lithified successions (e.g. carbonates) of many foreland thrust belts remains conjectural. Examples of

A basis for standardized seismic design (SSD) for nuclear power plants/critical facilities

International Nuclear Information System (INIS)

O'Hara, T.F.; Jacobson, J.P.; Bellini, F.X.

1991-01-01

US Nuclear Power Plants (NPP's) are designed, engineered and constructed to stringent standards. Their seismic adequacy is assured by compliance with regulatory standards and demonstrated by both probabilistic risk assessments (PRAs) and seismic margin studies. However, present seismic siting criteria requires improvement. Proposed changes to siting criteria discussed here will provide a predictable licensing process and a stable regulatory environment. Two recent state-of-the-art studies evaluate the seismic design for all eastern US (EUS) NPP'S: a Lawrence Livermore National Labs study (LLNL, 1989) funded by the NRC and similar research by the Electric Power Research Institute (EPRI, 1989) supported by the utilities. Both confirm that Appendix A 10CFR Part 100 has not provided consistent seismic design levels for all sites. Standardized Seismic Design (SSD) uses a probabilistic framework to accommodate alternative deterministic interpretations. It uses seismic hazard input from EPRI or LLNL to produce consistent bases for future seismic design. SSD combines deterministic and probabilistic insights to provide a comprehensive approach for determining a future site's acceptable seismic design basis

Making waves in seismic exploration software: Annual report 1998

International Nuclear Information System (INIS)

1999-01-01

GMA International is in the business of developing and supplying geological, geophysical and petrophysical computer-aided exploration software products for use in hydrocarbon exploration and exploitation world-wide. The company is headquartered in Calgary; it also has offices in Houston and London. It has over 5,500 installations and licensing arrangements with over 700 companies in 53 countries. This report details operating results during 1998, which included adding 77 new clients and the sale of over 300 new software licenses to new and existing clients. Consolidated balance sheets provide statements of earning (losses) and retained earnings, and changes in the company's financial position

Continuous recording of seismic signals in Alpine permafrost

Science.gov (United States)

Hausmann, H.; Krainer, K.; Staudinger, M.; Brückl, E.

2009-04-01

Over the past years various geophysical methods were applied to study the internal structure and the temporal variation of permafrost whereof seismic is of importance. For most seismic investigations in Alpine permafrost 24-channel equipment in combination with long data and trigger cables is used. Due to the harsh environment source and geophone layouts are often limited to 2D profiles. With prospect for future 3D-layouts we introduce an alternative of seismic equipment that can be used for several applications in Alpine permafrost. This study is focussed on controlled and natural source seismic experiments in Alpine permafrost using continuous data recording. With recent data from an ongoing project ("Permafrost in Austria") we will highlight the potential of the used seismic equipment for three applications: (a) seismic permafrost mapping of unconsolidated sediments, (b) seismic tomography in rock mass, and (c) passive seismic monitoring of rock falls. Single recording units (REFTEK 130, 6 channels) are used to continuously record the waveforms of both the seismic signals and a trigger signal. The combination of a small number of recording units with different types of geophones or a trigger allow numerous applications in Alpine permafrost with regard to a high efficiency and flexible seismic layouts (2D, 3D, 4D). The efficiency of the light and robust seismic equipment is achieved by the simple acquisition and the flexible and fast deployment of the (omni-directional) geophones. Further advantages are short (data and trigger) cables and the prevention of trigger errors. The processing of the data is aided by 'Seismon' which is an open source software project based on Matlab® and MySQL (see SM1.0). For active-source experiments automatic stacking of the seismic signals is implemented. For passive data a program for automatic detection of events (e.g. rock falls) is available which allows event localization. In summer 2008 the seismic equipment was used for the

Structure of the Wagner Basin in the Northern Gulf of California From Interpretation of Seismic Reflexion Data

Science.gov (United States)

Gonzalez, M.; Aguilar, C.; Martin, A.

2007-05-01

The northern Gulf of California straddles the transition in the style of deformation along the Pacific-North America plate boundary, from distributed deformation in the Upper Delfin and Wagner basins to localized dextral shear along the Cerro Prieto transform fault. Processing and interpretation of industry seismic data adquired by Petroleos Mexicanos (PEMEX) allow us to map the main fault structures and depocenters in the Wagner basin and to unravel the way strain is transferred northward into the Cerro Prieto fault system. Seismic data records from 0.5 to 5 TWTT. Data stacking and time-migration were performed using semblance coefficient method. Subsidence in the Wagner basin is controlled by two large N-S trending sub-parallel faults that intersect the NNW-trending Cerro Prieto transform fault. The Wagner fault bounds the eastern margin of the basin for more than 75 km. This fault dips ~50° to the west (up to 2 seconds) with distinctive reflectors displaced more than 1 km across the fault zone. The strata define a fanning pattern towards the Wagner fault. Northward the Wagner fault intersects the Cerro Prieto fault at 130° on map view and one depocenter of the Wagner basin bends to the NW adjacent to the Cerro Prieto fault zone. The eastern boundary of the modern depocenter is the Consag fault, which extends over 100 km in a N-S direction with an average dip of ~50° (up to 2s) to the east. The northern segment of the Consag fault bends 25° and intersects the Cerro Prieto fault zone at an angle of 110° on map view. The acoustic basement was not imaged in the northwest, but the stratigraphic succession increases its thickness towards the depocenter of the Wagner basin. Another important structure is El Chinero fault, which runs parallel to the Consag fault along 60 km and possibly intersects the Cerro Prieto fault to the north beneath the delta of the Colorado River. El Chinero fault dips at low-angle (~30°) to the east and has a vertical offset of about 0

Integrated geophysical interpretation of the Valhall 4C OBS survey

Energy Technology Data Exchange (ETDEWEB)

Thomsen, Leon A.; Barkved, Olav I; Mueller, Michael C.; Haggard, Bill W.; Kommedal, Jan H.; Rosland, Boerge O.

1998-12-31

This presentation gives a brief classic example of a North Sea reservoir which cannot be imaged by conventional P-wave techniques. In two-dimensional P-wave sections, extending across the crest of the structure, the top of the chalk reservoir is depressed in time, and has low amplitude and coherency so that even its identification is uncertain. The classical interpretation of these effects is that, over geologic time, gas has leaked from the reservoir into the overburden, in the zone above the reservoir. This gas, while present in uneconomic concentrations, has the effect of lowering seismic velocities and increasing seismic attenuation. Efficient methods of seismic surveying were used for oil prediction in the reservoir. 6 refs.

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.

Management of seismic data on network

Energy Technology Data Exchange (ETDEWEB)

Chung, Bu Heung [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-12-01

KIGAM has managed magnetic tapes written in seismic data acquired in Korea offshore and abroad since 1979. For now, it amounts about 13,000 tapes and other documents of seismic data are reserved by KIGAM also. For handling with them, FOX-PRO database management system has been used since 1993. In case of one user, it seems useful and convenient because the program is very easy to use and many well done utility was provided. In contrast with that, it has many problems also. For example, a user who wants to query information of these magnetic tapes must go magnetic tape room where the system is installed and he must know how to use the utilities of the FOX-PRO database management system. For the reason of above, the seismic data processing team attempted to change the FOX-PRO system with other client-server system supports networking on internet. After many testing and considering, they selected like as following hardware and software( System: PC with networking, OS: Linux and Unix, Software: Just Logic/SQL). The main reasons for selecting above system, first, any kinds of personal computer are available and easy to get. Secondly, Linux and Unix OS are good for using network. Especially, Linux is free and easy to get on many internet ftp sites. Lastly Just Logic/SQL is for client-server system, supports Linux OS and the programming style is very similar to C language. The contents of this report are as follows. In chapter 2, the Just Logic/SQL system structure and existing files through the sub-directories are showed and commented. In chapter 3, the statements using in Just Logic/SQL are explained and some examples are showed. In chapter 4, shows two example programs making seismic database including rack list, optical disk table respectively. The rack list table is the database of magnetic tapes managed by KIGAM. The optical disk table is the information record about how many, what tapes are converted to optical disk. (author). 4 tabs.

SIG-VISA: Signal-based Vertically Integrated Seismic Monitoring

Science.gov (United States)

Moore, D.; Mayeda, K. M.; Myers, S. C.; Russell, S.

2013-12-01

Traditional seismic monitoring systems rely on discrete detections produced by station processing software; however, while such detections may constitute a useful summary of station activity, they discard large amounts of information present in the original recorded signal. We present SIG-VISA (Signal-based Vertically Integrated Seismic Analysis), a system for seismic monitoring through Bayesian inference on seismic signals. By directly modeling the recorded signal, our approach incorporates additional information unavailable to detection-based methods, enabling higher sensitivity and more accurate localization using techniques such as waveform matching. SIG-VISA's Bayesian forward model of seismic signal envelopes includes physically-derived models of travel times and source characteristics as well as Gaussian process (kriging) statistical models of signal properties that combine interpolation of historical data with extrapolation of learned physical trends. Applying Bayesian inference, we evaluate the model on earthquakes as well as the 2009 DPRK test event, demonstrating a waveform matching effect as part of the probabilistic inference, along with results on event localization and sensitivity. In particular, we demonstrate increased sensitivity from signal-based modeling, in which the SIGVISA signal model finds statistical evidence for arrivals even at stations for which the IMS station processing failed to register any detection.

Multi-Attribute Seismic/Rock Physics Approach to Characterizing Fractured Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Gary Mavko

2004-11-30

Most current seismic methods to seismically characterize fractures in tight reservoirs depend on a few anisotropic wave propagation signatures that can arise from aligned fractures. While seismic anisotropy can be a powerful fracture diagnostic, a number of situations can lessen its usefulness or introduce interpretation ambiguities. Fortunately, laboratory and theoretical work in rock physics indicates that a much broader spectrum of fracture seismic signatures can occur, including a decrease in P- and S-wave velocities, a change in Poisson's ratio, an increase in velocity dispersion and wave attenuation, as well as well as indirect images of structural features that can control fracture occurrence. The goal of this project was to demonstrate a practical interpretation and integration strategy for detecting and characterizing natural fractures in rocks. The approach was to exploit as many sources of information as possible, and to use the principles of rock physics as the link among seismic, geologic, and log data. Since no single seismic attribute is a reliable fracture indicator in all situations, the focus was to develop a quantitative scheme for integrating the diverse sources of information. The integrated study incorporated three key elements: The first element was establishing prior constraints on fracture occurrence, based on laboratory data, previous field observations, and geologic patterns of fracturing. The geologic aspects include analysis of the stratigraphic, structural, and tectonic environments of the field sites. Field observations and geomechanical analysis indicates that fractures tend to occur in the more brittle facies, for example, in tight sands and carbonates. In contrast, strain in shale is more likely to be accommodated by ductile flow. Hence, prior knowledge of bed thickness and facies architecture, calibrated to outcrops, are powerful constraints on the interpreted fracture distribution. Another important constraint is that

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

E3D, 3-D Elastic Seismic Wave Propagation Code

International Nuclear Information System (INIS)

Larsen, S.; Harris, D.; Schultz, C.; Maddix, D.; Bakowsky, T.; Bent, L.

2004-01-01

1 - Description of program or function: E3D is capable of simulating seismic wave propagation in a 3D heterogeneous earth. Seismic waves are initiated by earthquake, explosive, and/or other sources. These waves propagate through a 3D geologic model, and are simulated as synthetic seismograms or other graphical output. 2 - Methods: The software simulates wave propagation by solving the elasto-dynamic formulation of the full wave equation on a staggered grid. The solution scheme is 4-order accurate in space, 2-order accurate in time

AR2, a novel automatic muscle artifact reduction software method for ictal EEG interpretation: Validation and comparison of performance with commercially available software [version 2; referees: 2 approved

Directory of Open Access Journals (Sweden)

Shennan Aibel Weiss

2017-04-01

Full Text Available Objective: To develop a novel software method (AR2 for reducing muscle contamination of ictal scalp electroencephalogram (EEG, and validate this method on the basis of its performance in comparison to a commercially available software method (AR1 to accurately depict seizure-onset location. Methods: A blinded investigation used 23 EEG recordings of seizures from 8 patients. Each recording was uninterpretable with digital filtering because of muscle artifact and processed using AR1 and AR2 and reviewed by 26 EEG specialists. EEG readers assessed seizure-onset time, lateralization, and region, and specified confidence for each determination. The two methods were validated on the basis of the number of readers able to render assignments, confidence, the intra-class correlation (ICC, and agreement with other clinical findings. Results: Among the 23 seizures, two-thirds of the readers were able to delineate seizure-onset time in 10 of 23 using AR1, and 15 of 23 using AR2 (p<0.01. Fewer readers could lateralize seizure-onset (p<0.05. The confidence measures of the assignments were low (probable-unlikely, but increased using AR2 (p<0.05. The ICC for identifying the time of seizure-onset was 0.15 (95% confidence interval (CI, 0.11-0.18 using AR1 and 0.26 (95% CI 0.21-0.30 using AR2.  The EEG interpretations were often consistent with behavioral, neurophysiological, and neuro-radiological findings, with left sided assignments correct in 95.9% (CI 85.7-98.9%, n=4 of cases using AR2, and 91.9% (77.0-97.5% (n=4 of cases using AR1. Conclusions: EEG artifact reduction methods for localizing seizure-onset does not result in high rates of interpretability, reader confidence, and inter-reader agreement. However, the assignments by groups of readers are often congruent with other clinical data. Utilization of the AR2 software method may improve the validity of ictal EEG artifact reduction.

Rock-physics and seismic-inversion based reservoir characterization of the Haynesville Shale

International Nuclear Information System (INIS)

Jiang, Meijuan; Spikes, Kyle T

2016-01-01

Seismic reservoir characterization of unconventional gas shales is challenging due to their heterogeneity and anisotropy. Rock properties of unconventional gas shales such as porosity, pore-shape distribution, and composition are important for interpreting seismic data amplitude variations in order to locate optimal drilling locations. The presented seismic reservoir characterization procedure applied a grid-search algorithm to estimate the composition, pore-shape distribution, and porosity at the seismic scale from the seismically inverted impedances and a rock-physics model, using the Haynesville Shale as a case study. All the proposed rock properties affected the seismic velocities, and the combined effects of these rock properties on the seismic amplitude were investigated simultaneously. The P- and S-impedances correlated negatively with porosity, and the V _P/V _S correlated positively with clay fraction and negatively with the pore-shape distribution and quartz fraction. The reliability of these estimated rock properties at the seismic scale was verified through comparisons between two sets of elastic properties: one coming from inverted impedances, which were obtained from simultaneous inversion of prestack seismic data, and one derived from these estimated rock properties. The differences between the two sets of elastic properties were less than a few percent, verifying the feasibility of the presented seismic reservoir characterization. (paper)

Making waves in seismic exploration software: Annual report 1998

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-07-01

GMA International is in the business of developing and supplying geological, geophysical and petrophysical computer-aided exploration software products for use in hydrocarbon exploration and exploitation world-wide. The company is headquartered in Calgary; it also has offices in Houston and London. It has over 5,500 installations and licensing arrangements with over 700 companies in 53 countries. This report details operating results during 1998, which included adding 77 new clients and the sale of over 300 new software licenses to new and existing clients. Consolidated balance sheets provide statements of earning (losses) and retained earnings, and changes in the company's financial position.

Making waves in seismic exploration software: Annual report 1998

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-11-01

GMA International is in the business of developing and supplying geological, geophysical and petrophysical computer-aided exploration software products for use in hydrocarbon exploration and exploitation world-wide. The company is headquartered in Calgary; it also has offices in Houston and London. It has over 5,500 installations and licensing arrangements with over 700 companies in 53 countries. This report details operating results during 1998, which included adding 77 new clients and the sale of over 300 new software licenses to new and existing clients. Consolidated balance sheets provide statements of earning (losses) and retained earnings, and changes in the company`s financial position.

New interpretations based on seismic and modelled well data and their implications for the tectonic evolution of the west Greenland continental margin

DEFF Research Database (Denmark)

Mcgregor, E.D.; Nielsen, S.B.; Stephenson, R.A.

Davis Strait is situated between Baffin Island and Greenland and forms part of a sedimentary basin system, linking Labrador Sea and Baffin Bay, developed during Cretaceous and Palaeocene rifting that culminated in a brief period of sea-floor spreading in the late Palaeocene and Eocene. Seismic...... reflection profiles and exploration wells along the Greenland margin of Davis Strait have been analysed in order to elucidate uplift events affecting sedimentary basin development during the Cenozoic with a focus on postulated Neogene (tectonic) uplift affecting the west Greenland continental margin...... tectonic event. An interpretation in which the inferred onshore cooling is related to erosion of pre-existing topography is more consistent with our new results from the offshore region. These results will have important implications for other continental margins developed throughout the Atlantic...

The roles of texture and microstructure for seismic properties and anisotropy of the continental crust

Science.gov (United States)

Almqvist, B. S. G.; Mainprice, D.

2017-12-01

New seismic methods provide images of the continental crust with improved resolution, carrying unique information on the structure and mass transfer regimes within the crust. At the intrinsic scale components contributing to these images are grains and the microfabric, which includes information on grain characteristics. At the extrinsic scale the presence of micro-cracks, fractures and layering are important in controlling seismic velocities. Although the wavelength of a seismic wave is orders of magnitude larger than the intrinsic scale the minerals and microstructures, the interpretations of seismic images are critically dependent on our understanding and quantification of these microscopic constituents. This contribution explores the role of texture and microstructure in governing seismic properties of rocks. We focus on prediction of seismic velocities based on calculations that take into account mineral composition and microfabric of rocks. Emphasis is placed on recent developments in modeling efforts and analytical techniques, which can consider microfabric parameters such as crystallographic preferred orientation (CPO), grain shape, layering and elastic interaction among grains. Static schemes that use Christoffel's equation, and active/dynamic wave propagation methods provide the general techniques to predict seismic velocities. Single crystal elastic constants are essential in predicting seismic properties. However, the database is incomplete considering the variation of crustal mineralogy and lack of data at elevated pressure and temperature conditions occurring in the middle and lower crust. Finally, the method used to measure CPO and microstructure data has an influence on model predictions. Neutron and X-ray goniometry techniques enable investigation of CPO for large sample volumes, but lack other microstructural information. In contrast, electron backscatter diffraction provides data on both CPO and microstructure, but for a relatively small sample

AECB workshop on seismic hazard assessment in Southern Ontario. Recorded proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-31

A workshop on seismic hazard assessment in southern Ontario was conducted on June 19-21, 1995. The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: The importance of geological and geophysical observations for the determination of seismic sources; Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information. Methods and data which should be used for characterizing the seismicity parameters of seismic sources. Methods for assessment of vibratory ground motion hazard. This document presents transcripts from recordings made of the presentations and discussion from the workshop. It will be noted, in some sections of the document, that the record is incomplete. This is due in part to recording equipment malfunction and in part due to the poor quality of recording obtained for certain periods.

AECB workshop on seismic hazard assessment in Southern Ontario. Recorded proceedings

International Nuclear Information System (INIS)

1995-01-01

A workshop on seismic hazard assessment in southern Ontario was conducted on June 19-21, 1995. The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: The importance of geological and geophysical observations for the determination of seismic sources; Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information. Methods and data which should be used for characterizing the seismicity parameters of seismic sources. Methods for assessment of vibratory ground motion hazard. This document presents transcripts from recordings made of the presentations and discussion from the workshop. It will be noted, in some sections of the document, that the record is incomplete. This is due in part to recording equipment malfunction and in part due to the poor quality of recording obtained for certain periods

Attenuation and velocity dispersion in the exploration seismic frequency band

Science.gov (United States)

Sun, Langqiu

In an anelastic medium, seismic waves are distorted by attenuation and velocity dispersion, which depend on petrophysical properties of reservoir rocks. The effective attenuation and velocity dispersion is a combination of intrinsic attenuation and apparent attenuation due to scattering, transmission response, and data acquisition system. Velocity dispersion is usually neglected in seismic data processing partly because of insufficient observations in the exploration seismic frequency band. This thesis investigates the methods of measuring velocity dispersion in the exploration seismic frequency band and interprets the velocity dispersion data in terms of petrophysical properties. Broadband, uncorrelated vibrator data are suitable for measuring velocity dispersion in the exploration seismic frequency band, and a broad bandwidth optimizes the observability of velocity dispersion. Four methods of measuring velocity dispersion in uncorrelated vibrator VSP data are investigated, which are the sliding window crosscorrelation (SWCC) method, the instantaneous phase method, the spectral decomposition method, and the cross spectrum method. Among them, the SWCC method is a new method and has satisfactory robustness, accuracy, and efficiency. Using the SWCC method, velocity dispersion is measured in the uncorrelated vibrator VSP data from three areas with different geological settings, i.e., Mallik gas hydrate zone, McArthur River uranium mines, and Outokumpu crystalline rocks. The observed velocity dispersion is fitted to a straight line with respect to log frequency for a constant (frequency-independent) Q value. This provides an alternative method for calculating Q. A constant Q value does not directly link to petrophysical properties. A modeling study is implemented for the Mallik and McArthur River data to interpret the velocity dispersion observations in terms of petrophysical properties. The detailed multi-parameter petrophysical reservoir models are built according to

Deep structure of the continental margin and basin off Greater Kabylia, Algeria - New insights from wide-angle seismic data modeling and multichannel seismic interpretation

Science.gov (United States)

Aïdi, Chafik; Beslier, Marie-Odile; Yelles-Chaouche, Abdel Karim; Klingelhoefer, Frauke; Bracene, Rabah; Galve, Audrey; Bounif, Abdallah; Schenini, Laure; Hamai, Lamine; Schnurle, Philippe; Djellit, Hamou; Sage, Françoise; Charvis, Philippe; Déverchère, Jacques

2018-03-01

During the Algerian-French SPIRAL survey aimed at investigating the deep structure of the Algerian margin and basin, two coincident wide-angle and reflection seismic profiles were acquired in central Algeria, offshore Greater Kabylia, together with gravimetric, bathymetric and magnetic data. This 260 km-long offshore-onshore profile spans the Balearic basin, the central Algerian margin and the Greater Kabylia block up to the southward limit of the internal zones onshore. Results are obtained from modeling and interpretation of the combined data sets. The Algerian basin offshore Greater Kabylia is floored by a thin oceanic crust ( 4 km) with P-wave velocities ranging between 5.2 and 6.8 km/s. In the northern Hannibal High region, the atypical 3-layer crustal structure is interpreted as volcanic products stacked over a thin crust similar to that bordering the margin and related to Miocene post-accretion volcanism. These results support a two-step back-arc opening of the west-Algerian basin, comprising oceanic crust accretion during the first southward stage, and a magmatic and probably tectonic reworking of this young oceanic basement during the second, westward, opening phase. The structure of the central Algerian margin is that of a narrow ( 70 km), magma-poor rifted margin, with a wider zone of distal thinned continental crust than on the other margin segments. There is no evidence for mantle exhumation in the sharp ocean-continent transition, but transcurrent movements during the second opening phase may have changed its initial geometry. The Plio-Quaternary inversion of the margin related to ongoing convergence between Africa and Eurasia is expressed by a blind thrust system under the margin rising toward the surface at the slope toe, and by an isostatic disequilibrium resulting from opposite flexures of two plates decoupled at the continental slope. This disequilibrium is likely responsible for the peculiar asymmetrical shape of the crustal neck that may thus

Characterization of a complex near-surface structure using well logging and passive seismic measurements

Science.gov (United States)

Benjumea, Beatriz; Macau, Albert; Gabàs, Anna; Figueras, Sara

2016-04-01

We combine geophysical well logging and passive seismic measurements to characterize the near-surface geology of an area located in Hontomin, Burgos (Spain). This area has some near-surface challenges for a geophysical study. The irregular topography is characterized by limestone outcrops and unconsolidated sediments areas. Additionally, the near-surface geology includes an upper layer of pure limestones overlying marly limestones and marls (Upper Cretaceous). These materials lie on top of Low Cretaceous siliciclastic sediments (sandstones, clays, gravels). In any case, a layer with reduced velocity is expected. The geophysical data sets used in this study include sonic and gamma-ray logs at two boreholes and passive seismic measurements: three arrays and 224 seismic stations for applying the horizontal-to-vertical amplitude spectra ratio method (H/V). Well-logging data define two significant changes in the P-wave-velocity log within the Upper Cretaceous layer and one more at the Upper to Lower Cretaceous contact. This technique has also been used for refining the geological interpretation. The passive seismic measurements provide a map of sediment thickness with a maximum of around 40 m and shear-wave velocity profiles from the array technique. A comparison between seismic velocity coming from well logging and array measurements defines the resolution limits of the passive seismic techniques and helps it to be interpreted. This study shows how these low-cost techniques can provide useful information about near-surface complexity that could be used for designing a geophysical field survey or for seismic processing steps such as statics or imaging.

Can Lower Mantle Slab-like Seismic Anomalies be Explained by Thermal Coupling Between the Upper and Lower Mantles?

NARCIS (Netherlands)

Cízková, H. (Hana); Cadek, O.; Berg, A.P. van den; Vlaar, N.J.

1999-01-01

Below subduction zones, high resolution seismic tomographic models resolve fast anomalies that often extend into the deep lower mantle. These anomalies are generally interpreted as slabs penetrating through the 660-km seismic discontinuity, evidence in support of whole-mantle convection. However,

A new tool for rapid and automatic estimation of earthquake source parameters and generation of seismic bulletins

Science.gov (United States)

Zollo, Aldo

2016-04-01

RISS S.r.l. is a Spin-off company recently born from the initiative of the research group constituting the Seismology Laboratory of the Department of Physics of the University of Naples Federico II. RISS is an innovative start-up, based on the decade-long experience in earthquake monitoring systems and seismic data analysis of its members and has the major goal to transform the most recent innovations of the scientific research into technological products and prototypes. With this aim, RISS has recently started the development of a new software, which is an elegant solution to manage and analyse seismic data and to create automatic earthquake bulletins. The software has been initially developed to manage data recorded at the ISNet network (Irpinia Seismic Network), which is a network of seismic stations deployed in Southern Apennines along the active fault system responsible for the 1980, November 23, MS 6.9 Irpinia earthquake. The software, however, is fully exportable and can be used to manage data from different networks, with any kind of station geometry or network configuration and is able to provide reliable estimates of earthquake source parameters, whichever is the background seismicity level of the area of interest. Here we present the real-time automated procedures and the analyses performed by the software package, which is essentially a chain of different modules, each of them aimed at the automatic computation of a specific source parameter. The P-wave arrival times are first detected on the real-time streaming of data and then the software performs the phase association and earthquake binding. As soon as an event is automatically detected by the binder, the earthquake location coordinates and the origin time are rapidly estimated, using a probabilistic, non-linear, exploration algorithm. Then, the software is able to automatically provide three different magnitude estimates. First, the local magnitude (Ml) is computed, using the peak-to-peak amplitude

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.

Building the Community Online Resource for Statistical Seismicity Analysis (CORSSA)

Science.gov (United States)

Michael, A. J.; Wiemer, S.; Zechar, J. D.; Hardebeck, J. L.; Naylor, M.; Zhuang, J.; Steacy, S.; Corssa Executive Committee

2010-12-01

Statistical seismology is critical to the understanding of seismicity, the testing of proposed earthquake prediction and forecasting methods, and the assessment of seismic hazard. Unfortunately, despite its importance to seismology - especially to those aspects with great impact on public policy - statistical seismology is mostly ignored in the education of seismologists, and there is no central repository for the existing open-source software tools. To remedy these deficiencies, and with the broader goal to enhance the quality of statistical seismology research, we have begun building the Community Online Resource for Statistical Seismicity Analysis (CORSSA). CORSSA is a web-based educational platform that is authoritative, up-to-date, prominent, and user-friendly. We anticipate that the users of CORSSA will range from beginning graduate students to experienced researchers. More than 20 scientists from around the world met for a week in Zurich in May 2010 to kick-start the creation of CORSSA: the format and initial table of contents were defined; a governing structure was organized; and workshop participants began drafting articles. CORSSA materials are organized with respect to six themes, each containing between four and eight articles. The CORSSA web page, www.corssa.org, officially unveiled on September 6, 2010, debuts with an initial set of approximately 10 to 15 articles available online for viewing and commenting with additional articles to be added over the coming months. Each article will be peer-reviewed and will present a balanced discussion, including illustrative examples and code snippets. Topics in the initial set of articles will include: introductions to both CORSSA and statistical seismology, basic statistical tests and their role in seismology; understanding seismicity catalogs and their problems; basic techniques for modeling seismicity; and methods for testing earthquake predictability hypotheses. A special article will compare and review

Patterned basal seismicity shows sub-ice stream bedforms

Science.gov (United States)

Barcheck, C. G.; Tulaczyk, S. M.; Schwartz, S. Y.

2017-12-01

Patterns in seismicity emanating from the bottom of fast-moving ice streams and glaciers may indicate localized patches of higher basal resistance— sometimes called 'sticky spots', or otherwise varying basal properties. These seismogenic basal areas resist an unknown portion of the total driving stress of the Whillans Ice Plain (WIP), in West Antarctica, but may play an important role in the WIP stick-slip cycle and ice stream slowdown. To better understand the mechanism and importance of basal seismicity beneath the WIP, we analyze seismic data collected by a small aperture (micro-earthquakes in Dec 2014, and we compare the resulting map of seismicity to ice bottom depth measured by airborne radar. The number of basal earthquakes per area within the network is spatially heterogeneous, but a pattern of two 400m wide streaks of high seismicity rates is evident, with >50-500 earthquakes detected per 50x50m grid cell in 2 weeks. These seismically active streaks are elongated approximately in the ice flow direction with a spacing of 750m. Independent airborne radar measurements of ice bottom depth from Jan 2013 show a low-amplitude ( 5m) undulation in the basal topography superposed on a regional gradient in ice bottom depth. The flow-perpendicular wavelength of these low-amplitude undulations is comparable to the spacing of the high seismicity bands, and the streaks of high seismicity intersect local lows in the undulating basal topography. We interpret these seismic and radar observations as showing seismically active sub-ice stream bedforms that are low amplitude and elongated in the direction of ice flow, comparable to the morphology of mega scale glacial lineations (MSGLs), with high basal seismicity rates observed in the MSGL troughs. These results have implications for understanding the formation mechanism of MSGLS and well as understanding the interplay between basal topographic roughness, spatially varying basal till and hydrologic properties, basal

Seismic site survey investigations in urban environments: The case of the underground metro project in Copenhagen, Denmark.

Science.gov (United States)

Martínez, K.; Mendoza, J. A.; Colberg-Larsen, J.; Ploug, C.

2009-05-01

Near surface geophysics applications are gaining more widespread use in geotechnical and engineering projects. The development of data acquisition, processing tools and interpretation methods have optimized survey time, reduced logistics costs and increase results reliability of seismic surveys during the last decades. However, the use of wide-scale geophysical methods under urban environments continues to face great challenges due to multiple noise sources and obstacles inherent to cities. A seismic pre-investigation was conducted to investigate the feasibility of using seismic methods to obtain information about the subsurface layer locations and media properties in Copenhagen. Such information is needed for hydrological, geotechnical and groundwater modeling related to the Cityringen underground metro project. The pre-investigation objectives were to validate methods in an urban environment and optimize field survey procedures, processing and interpretation methods in urban settings in the event of further seismic investigations. The geological setting at the survey site is characterized by several interlaced layers of clay, till and sand. These layers are found unevenly distributed throughout the city and present varying thickness, overlaying several different unit types of limestone at shallow depths. Specific results objectives were to map the bedrock surface, ascertain a structural geological framework and investigate bedrock media properties relevant to the construction design. The seismic test consisted of a combined seismic reflection and refraction analyses of a profile line conducted along an approximately 1400 m section in the northern part of Copenhagen, along the projected metro city line. The data acquisition was carried out using a 192 channels array, receiver groups with 5 m spacing and a Vibroseis as a source at 10 m spacing. Complementarily, six vertical seismic profiles (VSP) were performed at boreholes located along the line. The reflection

Foraminiferal and seismic stratigraphy, paleoenvironments and depositional cycles in the Georges Bank Basin

Science.gov (United States)

Poag, C. W.

Biostratigraphic analyses of foraminiferal assemblages sampled from rotary cuttings taken at 10 ft to 90 ft intervals were used with interpretation of seismic sequences to determine the presence of nonconformities and to establish a chronostratigraphic framework for COST G-1 and G-2 wells. The chronostratigraphic sequences were then used to calculate sediment accumulation rates. Lithostratigraphic and chronostratigraphic units were compared with those of the Scotian Basin of Canada, and correlations were established between the COST G-2 and the Shell Mohican L-100 wells. Paleoenvironmental analysis was based on the microfossil record of the G-1 and G-2 wells and on interpretation of seismic facies along USGS multichannel line 19.

Structure of Suasselkä Postglacial Fault in northern Finland obtained by analysis of ambient seismic noise

Science.gov (United States)

Afonin, Nikita; Kozlovskaya, Elena

2016-04-01

Understanding inner structure of seismogenic faults and their ability to reactivate is particularly important in investigating the continental intraplate seismicity regime. In our study we address this problem using analysis of ambient seismic noise recorded by the temporary DAFNE array in northern Fennoscandian Shield. The main purpose of the DAFNE/FINLAND passive seismic array experiment was to characterize the present-day seismicity of the Suasselkä post-glacial fault (SPGF) that was proposed as one potential target for the DAFNE (Drilling Active Faults in Northern Europe) project. The DAFNE/FINLAND array comprised the area of about 20 to 100 km and consisted of 8 short-period and 4 broad-band 3-component autonomous seismic stations installed in the close vicinity of the fault area. The array recorded continuous seismic data during September, 2011-May, 2013. Recordings of the array have being analyzed in order to identify and locate natural earthquakes from the fault area and to discriminate them from the blasts in the Kittilä Gold Mine. As a result, we found several dozens of natural seismic events originating from the fault area, which proves that the fault is still seismically active. In order to study the inner structure of the SPGF we use cross-correlation of ambient seismic noise recorded by the array. Analysis of azimuthal distribution of noise sources demonstrated that that during the time interval under consideration the distribution of noise sources is close to the uniform one. The continuous data were processed in several steps including single station data analysis, instrument response removal and time-domain stacking. The data were used to estimate empirical Green's functions between pairs of stations in the frequency band of 0.1-1 Hz and to calculate correspondent surface wave dispersion curves. After that S-wave velocity models were obtained as a result of dispersion curves inversion using Geopsy software. The results suggest that the area of

Moho Depth and Geometry in the Illinois Basin Region Based on Gravity and Seismic Data from an EarthScope FlexArray Experiment

Science.gov (United States)

Curcio, D. D.; Pavlis, G. L.; Yang, X.; Hamburger, M. W.; Zhang, H.; Ravat, D.

2017-12-01

We present results from a combined analysis of seismic and gravity in the Illinois Basin region that demonstrate the presence of an unusually deep and highly variable Moho discontinuity. We construct a new, high-resolution image of the Earth's crust beneath the Illinois Basin using teleseismic P-wave receiver functions from the EarthScope OIINK (Ozarks, Illinois, INdiana, Kentucky) Flexible Array and the USArray Transportable Array. Our seismic analyses involved data from 143 OIINK stations and 80 USArray stations, using 3D plane-wave migration and common conversion point (CCP) stacking of P-to-S conversion data. Seismic interpretation has been done using the seismic exploration software package Petrel. One of the most surprising results is the anomalous depth of the Moho in this area, ranging from 41 to 63 km, with an average depth of 50 km. This thickened crust is unexpected in the Illinois Basin area, which has not been subject to convergence and mountain building processes in the last 900 Ma. This anomalously thick crust in combination with the minimal topography requires abnormally dense lower crust or unusually light upper mantle in order to retain gravitational equilibrium. Combining gravity modeling with the seismically identified Moho and a ubiquitous lower crustal boundary, we solve for the density variation of the middle and lower crust. We test the hypothesis that the anomalously thick crust and its high lower crustal layer observed in most of the central and southeastern Illinois Basin predates the formation and development of the current Illinois Basin. Post-formation tectonic activity, such as late Precambrian rifting or underplating are inferred to have modified the crustal thickness as well. The combination of high-resolution seismic data analysis and gravity modeling promises to provide additional insight into the geometry and composition of the lower crust in the Illinois Basin area.

A short note on the pressure-depth conversion for geophysical interpretation

DEFF Research Database (Denmark)

Cammarano, Fabio

2013-01-01

to the interpretation of a 2-D thermal structure of the oceanic lithosphere as predicted by a half-space cooling model. The effects are overall small, nevertheless important for interpretation since they are systematic, they have a feedback with thermal interpretation and they can shift the location of predicted...... with this assumption. The corrected pressure profile is obtained by updating the starting one with the inferred density distribution and iterating until convergence (which is attained in few steps). We show two examples. The first is related to the interpretation of average seismic Earth models. The second refers...

Thin-layer effects in glaciological seismic amplitude-versus-angle (AVA analysis: implications for characterising a subglacial till unit, Russell Glacier, West Greenland

Directory of Open Access Journals (Sweden)

A. D. Booth

2012-08-01

Full Text Available Seismic amplitude-versus-angle (AVA methods are a powerful means of quantifying the physical properties of subglacial material, but serious interpretative errors can arise when AVA is measured over a thinly-layered substrate. A substrate layer with a thickness less than 1/4 of the seismic wavelength, λ, is considered "thin", and reflections from its bounding interfaces superpose and appear in seismic data as a single reflection event. AVA interpretation of subglacial till can be vulnerable to such thin-layer effects, since a lodged (non-deforming till can be overlain by a thin (metre-scale cap of dilatant (deforming till. We assess the potential for misinterpretation by simulating seismic data for a stratified subglacial till unit, with an upper dilatant layer between 0.1–5.0 m thick (λ / 120 to > λ / 4, with λ = 12 m. For dilatant layers less than λ / 6 thick, conventional AVA analysis yields acoustic impedance and Poisson's ratio that indicate contradictory water saturation. A thin-layer interpretation strategy is proposed, that accurately characterises the model properties of the till unit. The method is applied to example seismic AVA data from Russell Glacier, West Greenland, in which characteristics of thin-layer responses are evident. A subglacial till deposit is interpreted, having lodged till (acoustic impedance = 4.26±0.59 × 10⁶ kg m⁻² s⁻¹ underlying a water-saturated dilatant till layer (thickness < 2 m, Poisson's ratio ~ 0.5. Since thin-layer considerations offer a greater degree of complexity in an AVA interpretation, and potentially avoid misinterpretations, they are a valuable aspect of quantitative seismic analysis, particularly for characterising till units.

Seismic recording at the Los Medanos area of Southeastern New Mexico, 1974-1975

International Nuclear Information System (INIS)

Sanford, A.R.; Johansen, S.J.; Caravella, F.J.; Ward, R.M.

1976-01-01

The objective has been to determine if low-level seismic activity is occurring at or near the proposed nuclear waste repository in southeastern New Mexico. The research involved installation and maintenance of a continuously recording seismograph at the Los Medanos site and interpretation of the seismic events detected by that station. The following topics are discussed: (1) a description of the seismic instrumentation and its performance; (2) statistics on the local and regional earthquakes detected by the seismograph station at the Los Medanos site; (3) special studies on the seismic events associated with rockfalls at the National Potash Co. Eddy County Mine on July 26, 1972 and November 28, 1974; and (4) improved estimates of recurrence intervals for major earthquakes likely to effect the Los Medanos site

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

Measurement Of Compressional-Wave Seismic Velocities In 29 Wells At The Hanford Site

International Nuclear Information System (INIS)

Peterson, S.W.

2010-01-01

Check shot seismic velocity surveys were collected in 100 B/C, 200 East, 200-PO-1 Operational Unit (OU), and the Gable Gap areas in order to provide time-depth correlation information to aid the interpretation of existing seismic reflection data acquired at the Hanford Site (Figure 1). This report details results from 5 wells surveyed in fiscal year (FY) 2008, 7 wells in FY 2009, and 17 wells in FY 2010 and provides summary compressional-wave seismic velocity information to help guide future seismic survey design as well as improve current interpretations of the seismic data (SSC 1979/1980; SGW-39675; SGW-43746). Augmenting the check shot database are four surveys acquired in 2007 in support of the Bechtel National, Inc. Waste Treatment Plant construction design (PNNL-16559, PNNL-16652), and check shot surveys in three wells to support seismic testing in the 200 West Area (Waddell et al., 1999). Additional sonic logging was conducted during the late 1970s and early 1980s as part of the Basalt Waste Isolation Program (BWIP) (SSC 1979/1980) and check shot/sonic surveys as part of the safety report for the Skagit/Hanford Nuclear project (RDH/10-AMCP-0164). Check shot surveys are used to obtain an in situ measure of compressional-wave seismic velocity for sediment and rock in the vicinity of the well point, and provide the seismic-wave travel time to geologic horizons of interest. The check shot method deploys a downhole seismic receiver (geophone) to record the arrival of seismic waves generated by a source at the ground surface. The travel time of the first arriving seismic-wave is determined and used to create a time-depth function to correlate encountered geologic intervals with the seismic data. This critical tie with the underlying geology improves the interpretation of seismic reflection profile information. Fieldwork for this investigation was conducted by in house staff during the weeks of September 22, 2008 for 5 wells in the 200 East Area (Figure 2); June 1

Automatic classification of endogenous seismic sources within a landslide body using random forest algorithm

Science.gov (United States)

Provost, Floriane; Hibert, Clément; Malet, Jean-Philippe; Stumpf, André; Doubre, Cécile

2016-04-01

Different studies have shown the presence of microseismic activity in soft-rock landslides. The seismic signals exhibit significantly different features in the time and frequency domains which allow their classification and interpretation. Most of the classes could be associated with different mechanisms of deformation occurring within and at the surface (e.g. rockfall, slide-quake, fissure opening, fluid circulation). However, some signals remain not fully understood and some classes contain few examples that prevent any interpretation. To move toward a more complete interpretation of the links between the dynamics of soft-rock landslides and the physical processes controlling their behaviour, a complete catalog of the endogeneous seismicity is needed. We propose a multi-class detection method based on the random forests algorithm to automatically classify the source of seismic signals. Random forests is a supervised machine learning technique that is based on the computation of a large number of decision trees. The multiple decision trees are constructed from training sets including each of the target classes. In the case of seismic signals, these attributes may encompass spectral features but also waveform characteristics, multi-stations observations and other relevant information. The Random Forest classifier is used because it provides state-of-the-art performance when compared with other machine learning techniques (e.g. SVM, Neural Networks) and requires no fine tuning. Furthermore it is relatively fast, robust, easy to parallelize, and inherently suitable for multi-class problems. In this work, we present the first results of the classification method applied to the seismicity recorded at the Super-Sauze landslide between 2013 and 2015. We selected a dozen of seismic signal features that characterize precisely its spectral content (e.g. central frequency, spectrum width, energy in several frequency bands, spectrogram shape, spectrum local and global maxima

Kinematic seismic response of piles in layered soil profile

International Nuclear Information System (INIS)

Ahmad, I.; Khan, A.N.

2006-01-01

This paper is aimed at highlighting the importance of Kinematic Seismic Response of Piles, a phenomenon often ignored in dynamic analysis. A case study is presented where the end bearing pile is embedded in two layer soil system of highly contrasting stiffnesses; a typical case where kinematic loading plays important role. The pile soil system is modeled as continuous system and as discrete parameter system; both are based on BDWF (Beam on Dynamic Winkler Foundation) formulation. For discrete parameter system, a finite element software SAP2000 is used and the modeling technique of kinematic interaction in finite element software is discussed. For pile soil system modeled as continuous system, a general MATLAB code is developed capable of performing elastic site response analysis in two layer soil system, solving differential equation governing kinematic interaction, and giving as output the maximum ground displacement, maximum pile displacement, rotation, moment and shear distribution along pile length. The paper concludes that kinematic seismic actions must be evaluated particularly at the interface of soil layers of significantly differing soil stiffnesses. (author)

Modernization of the Caltech/USGS Southern California Seismic Network

Science.gov (United States)

Bhadha, R.; Devora, A.; Hauksson, E.; Johnson, D.; Thomas, V.; Watkins, M.; Yip, R.; Yu, E.; Given, D.; Cone, G.; Koesterer, C.

2009-12-01

performance and metadata availability. We will improve existing software to facilitate the update of metadata, and to improve the interoperability between SeisNetWatch and our database of metadata. The improved software will also be made available to other regional networks as part of the CISN software distribution. These upgrades, will greatly improve the robustness of the SCSN, and facilitate higher quality and more reliable earthquake monitoring than was available before in southern California. The modernized SCSN will contribute to more coordinated search and rescue as well as economic resilience following a major earthquake by providing accurate earthquake information, and thus facilitate rapid deployment of field crews and rapid business resumption. Further, advances in seismological research will be facilitated by the high quality seismic data that will be collected in one of the most seismically active areas in the contiguous US.

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.

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.

Enhanced seismic criteria for piping

International Nuclear Information System (INIS)

Touboul, F. . E-mail francoise.touboul@cea.fr; Blay, N.; Sollogoub, P.; Chapuliot, S.

2006-01-01

In situ or laboratory experiments have shown that piping systems exhibit satisfactory seismic behavior. Seismic motion is not severe enough to significantly damage piping systems unless large differential motions of anchorage are imposed. Nevertheless, present design criteria for piping are very severe and require a large number of supports, which creates overly rigid piping systems. CEA, in collaboration with EDF, FRAMATOME and IRSN, has launched a large R and D program on enhanced design methods which will be less severe, but still conservative, and compatible with defect justification during operation. This paper presents the background of the R and D work on this matter, and CEA proposed equations. Our approach is based on the difference between the real behavior (or the best estimated computed one) with the one supposed by codified methods. Codified criteria are applied on an elastically calculated behavior that can be significantly different from the real one: the effect of plasticity may be very meaningful, even with low incursion in the plastic domain. Moreover, and particularly in piping systems, the elastic follow-up effect affects stress distribution for both seismic and thermal loads. For seismic load, we have proposed to modify the elastic moment limitation, based on the interpretation of experimental results on piping systems. The methods have been validated on more industrial cases, and some of the consequences of the changes have been studied: modification of the drawings and of the number of supports, global displacements, forces in the supports, stability of potential defects, etc. The basic aim of the studies undertaken is to make a decision on the stress classification problem, one that is not limited to seismic induced stresses, and to propose simplified methods for its solution

SplitRacer - a new Semi-Automatic Tool to Quantify And Interpret Teleseismic Shear-Wave Splitting

Science.gov (United States)

Reiss, M. C.; Rumpker, G.

2017-12-01

We have developed a semi-automatic, MATLAB-based GUI to combine standard seismological tasks such as the analysis and interpretation of teleseismic shear-wave splitting. Shear-wave splitting analysis is widely used to infer seismic anisotropy, which can be interpreted in terms of lattice-preferred orientation of mantle minerals, shape-preferred orientation caused by fluid-filled cracks or alternating layers. Seismic anisotropy provides a unique link between directly observable surface structures and the more elusive dynamic processes in the mantle below. Thus, resolving the seismic anisotropy of the lithosphere/asthenosphere is of particular importance for geodynamic modeling and interpretations. The increasing number of seismic stations from temporary experiments and permanent installations creates a new basis for comprehensive studies of seismic anisotropy world-wide. However, the increasingly large data sets pose new challenges for the rapid and reliably analysis of teleseismic waveforms and for the interpretation of the measurements. Well-established routines and programs are available but are often impractical for analyzing large data sets from hundreds of stations. Additionally, shear wave splitting results are seldom evaluated using the same well-defined quality criteria which may complicate comparison with results from different studies. SplitRacer has been designed to overcome these challenges by incorporation of the following processing steps: i) downloading of waveform data from multiple stations in mseed-format using FDSNWS tools; ii) automated initial screening and categorizing of XKS-waveforms using a pre-set SNR-threshold; iii) particle-motion analysis of selected phases at longer periods to detect and correct for sensor misalignment; iv) splitting analysis of selected phases based on transverse-energy minimization for multiple, randomly-selected, relevant time windows; v) one and two-layer joint-splitting analysis for all phases at one station by

Data quality control and tools in passive seismic experiments exemplified on the Czech broadband seismic pool MOBNET in the AlpArray collaborative project

Science.gov (United States)

Vecsey, Luděk; Plomerová, Jaroslava; Jedlička, Petr; Munzarová, Helena; Babuška, Vladislav; AlpArray Working Group

2017-12-01

This paper focuses on major issues related to the data reliability and network performance of 20 broadband (BB) stations of the Czech (CZ) MOBNET (MOBile NETwork) seismic pool within the AlpArray seismic experiments. Currently used high-resolution seismological applications require high-quality data recorded for a sufficiently long time interval at seismological observatories and during the entire time of operation of the temporary stations. In this paper we present new hardware and software tools we have been developing during the last two decades while analysing data from several international passive experiments. The new tools help to assure the high-quality standard of broadband seismic data and eliminate potential errors before supplying data to seismological centres. Special attention is paid to crucial issues like the detection of sensor misorientation, timing problems, interchange of record components and/or their polarity reversal, sensor mass centring, or anomalous channel amplitudes due to, for example, imperfect gain. Thorough data quality control should represent an integral constituent of seismic data recording, preprocessing, and archiving, especially for data from temporary stations in passive seismic experiments. Large international seismic experiments require enormous efforts from scientists from different countries and institutions to gather hundreds of stations to be deployed in the field during a limited time period. In this paper, we demonstrate the beneficial effects of the procedures we have developed for acquiring a reliable large set of high-quality data from each group participating in field experiments. The presented tools can be applied manually or automatically on data from any seismic network.

Neural net generated seismic facies map and attribute facies map

International Nuclear Information System (INIS)

Addy, S.K.; Neri, P.

1998-01-01

The usefulness of 'seismic facies maps' in the analysis of an Upper Wilcox channel system in a 3-D survey shot by CGG in 1995 in Lavaca county in south Texas was discussed. A neural net-generated seismic facies map is a quick hydrocarbon exploration tool that can be applied regionally as well as on a prospect scale. The new technology is used to classify a constant interval parallel to a horizon in a 3-D seismic volume based on the shape of the wiggle traces using a neural network technology. The tool makes it possible to interpret sedimentary features of a petroleum deposit. The same technology can be used in regional mapping by making 'attribute facies maps' in which various forms of amplitude attributes, phase attributes or frequency attributes can be used

Characterizing Geological Facies using Seismic Waveform Classification in Sarawak Basin

Science.gov (United States)

Zahraa, Afiqah; Zailani, Ahmad; Prasad Ghosh, Deva

2017-10-01

Numerous effort have been made to build relationship between geology and geophysics using different techniques throughout the years. The integration of these two most important data in oil and gas industry can be used to reduce uncertainty in exploration and production especially for reservoir productivity enhancement and stratigraphic identification. This paper is focusing on seismic waveform classification to different classes using neural network and to link them according to the geological facies which are established using the knowledge on lithology and log motif of well data. Seismic inversion is used as the input for the neural network to act as the direct lithology indicator reducing dependency on well calibration. The interpretation of seismic facies classification map provides a better understanding towards the lithology distribution, depositional environment and help to identify significant reservoir rock

Geophysical outlook. Part 8. Interactive interpretation comes of age

Energy Technology Data Exchange (ETDEWEB)

Nelson, H.R. Jr.

1982-05-01

Computer-aided analysis is the obvious solution to handling the large volumes of geophysical data being generated by today's explorationists. When coupled with new developments in display devices, computer technology is particularly relevant to interactive interpretation of seismic data, particularly for mapping, three-dimensional graphics, and color-coding purpposes.

Seismic reservoir characterization: how can multicomponent data help?

International Nuclear Information System (INIS)

Li, Xiang-Yang; Zhang, Yong-Gang

2011-01-01

This paper discusses the concepts of multicomponent seismology and how it can be applied to characterize hydrocarbon reservoirs, illustrated using a 3D three-component real-data example from southwest China. Hydrocarbon reservoirs formed from subtle lithological changes, such as stratigraphic traps, may be delineated from changes in P- and S-wave velocities and impedances, whilst hydrocarbon reservoirs containing aligned fractures are anisotropic. Examination of the resultant split shear waves can give us a better definition of their internal structures. Furthermore, frequency-dependent variations in seismic attributes derived from multicomponent data can provide us with vital information about fluid type and distribution. Current practice and various examples have demonstrated the undoubted potential of multicomponent seismic in reservoir characterization. Despite all this, there are still substantial challenges ahead. In particular, the improvement and interpretation of converted-wave imaging are major hurdles that need to be overcome before multicomponent seismic becomes a mainstream technology

Seismic reservoir characterization: how can multicomponent data help?

Science.gov (United States)

Li, Xiang-Yang; Zhang, Yong-Gang

2011-06-01

This paper discusses the concepts of multicomponent seismology and how it can be applied to characterize hydrocarbon reservoirs, illustrated using a 3D three-component real-data example from southwest China. Hydrocarbon reservoirs formed from subtle lithological changes, such as stratigraphic traps, may be delineated from changes in P- and S-wave velocities and impedances, whilst hydrocarbon reservoirs containing aligned fractures are anisotropic. Examination of the resultant split shear waves can give us a better definition of their internal structures. Furthermore, frequency-dependent variations in seismic attributes derived from multicomponent data can provide us with vital information about fluid type and distribution. Current practice and various examples have demonstrated the undoubted potential of multicomponent seismic in reservoir characterization. Despite all this, there are still substantial challenges ahead. In particular, the improvement and interpretation of converted-wave imaging are major hurdles that need to be overcome before multicomponent seismic becomes a mainstream technology.

Harmonizing seismic hazard assessments for nuclear power plants

International Nuclear Information System (INIS)

Mallard, D.J.

1993-01-01

Even a cursory comparison between maps of global seismicity and NPP earthquake design levels reveals many inconsistencies. While, in part, this situation reflects the evolution in understanding of seismic hazards, mismatches can also be due to ongoing differences in the way the hazards are assessed and in local regulatory requirements. So far, formal international consensus has only been able to encompass broad principles, such as those recently recommended by the International Atomic Energy Agency, and even these can raise many technical issues, particularly relating to zones of diffuse seismicity. In the future, greater harmonisation in hazard assessments and, to some extent, in earthquake design levels could emerge through the more widespread use of probabilistic methods. International collaborative ventures and joint projects will be important for resolving anomalies in the existing databases and their interpretations, and for acquiring new data, but to achieve their ideal objectives, they will need to proceed in clearly defined stages. (author)

Seismic security assessment of earth and rockfill dams located in epicentral regions

Energy Technology Data Exchange (ETDEWEB)

Oldecop, L.; Zabala, F.; Rodari, R. [San Juan National Univ., San Juan (Argentina). Instituto de Invest. Antisismicas

2004-07-01

The seismic safety of dams is of great interest to the midwest region of Argentina, the most seismically active area in the country. This paper examines factors controlling the design of dams subjected to earthquake action, criteria for safety verification and the analysis tools currently available. Data of dams, active faults and epicenters of historic earthquakes in the region were provided. Paleoseismicity research was suggested as an important area of research, potentially enhancing an understanding of a region's seismic activity. It was concluded that analysis tools currently used in engineering include simple models offering advantages in reliability and ease of result interpretation, but have shortcomings in their applicability. Care must be taken in the validation and interpretation of these models, particularly when the behaviour of a dam includes complex phenomena. More sophisticated analysis tools currently available are difficult to apply, largely due to the complexity of algorithms in the models. It was also concluded that in order to overcome difficulties in both simple and complex models, predictions should be contrasted with real behaviour data. Data from measurement of seismic behaviour is still relatively scarce, presenting an obstacle towards the further use of more sophisticated analysis tools, as they are not as yet tested against measurements and observations of real cases. 15 refs., 2 tabs., 11 figs.

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

. Three groups of reflections are observed. A sub.horizontal set that is interpreted to originate from greenstone lenses; a moderately dipping one consisting of two sub.groups, one dipping to the NNW and the other to the SSE; and a steeply dipping one that strikes at 50-70 deg and dips at 70-80 deg to the SE. Reflections from the two latter groups probably originate from fracture zones. The last group being responsible for the highly fractured zone between 1550 m and 1700 m. Reflections from the first sub.horizontal group and the NNW dipping sub.group are also observed on the surface seismic with the same general strike and dips. However, the estimated dips on the surface seismic are consistently lower. This may be explained by the VSP imaging the local reflector dip, while the surface seismic images the more larger scale regional dip. Dips and depth estimates to reflectors are generally known to an accuracy of better than ± 5% on both surface seismic and VSP data if its strike is known and it is planar. A special high resolution VSP survey was run in the cased part of the hole down to 200 m to image a clear 45 deg N dipping reflector on the surface seismic that intersects the borehole at the bottom of the casing at 200 m depth. This reflector generates PP and PS reflections and misinterpretation of the data can easily be done if the PS conversion is not taken into account

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

. Three groups of reflections are observed. A sub.horizontal set that is interpreted to originate from greenstone lenses; a moderately dipping one consisting of two sub.groups, one dipping to the NNW and the other to the SSE; and a steeply dipping one that strikes at 50-70 deg and dips at 70-80 deg to the SE. Reflections from the two latter groups probably originate from fracture zones. The last group being responsible for the highly fractured zone between 1550 m and 1700 m. Reflections from the first sub.horizontal group and the NNW dipping sub.group are also observed on the surface seismic with the same general strike and dips. However, the estimated dips on the surface seismic are consistently lower. This may be explained by the VSP imaging the local reflector dip, while the surface seismic images the more larger scale regional dip. Dips and depth estimates to reflectors are generally known to an accuracy of better than {+-} 5% on both surface seismic and VSP data if its strike is known and it is planar. A special high resolution VSP survey was run in the cased part of the hole down to 200 m to image a clear 45 deg N dipping reflector on the surface seismic that intersects the borehole at the bottom of the casing at 200 m depth. This reflector generates PP and PS reflections and misinterpretation of the data can easily be done if the PS conversion is not taken into account.

Seismic Performance of a Corroded Reinforce Concrete Frame Structure Using Pushover Method

Directory of Open Access Journals (Sweden)

Meng Zhang

2018-01-01

Full Text Available SAP2000 software was used to build the finite element model of a six-storey-three-span reinforced concrete (RC frame structure. The numerical simulation of the seismic performance of the RC frame structure incorporating different levels of rebar corrosion was conducted using pushover analysis method. The degradation characteristics of the seismic performance of the corroded structure under severe earthquake were also analyzed. The results show that the seismic performance of the RC frame decreased significantly due to corrosion of the longitudinal rebars. And the interstory drift ratios increase dramatically with the increasing of the corrosion rate. At the same time, the formation and development of plastic hinges (beam hinges or column hinges will accelerate, which leads to a more aggravated deformation of the structure under rare earthquake action, resulting in a negative effect to the seismic bearing capacity of the structure.

Probabilistic seismic hazard assessment of southern part of Ghana

Science.gov (United States)

Ahulu, Sylvanus T.; Danuor, Sylvester Kojo; Asiedu, Daniel K.

2018-05-01

This paper presents a seismic hazard map for the southern part of Ghana prepared using the probabilistic approach, and seismic hazard assessment results for six cities. The seismic hazard map was prepared for 10% probability of exceedance for peak ground acceleration in 50 years. The input parameters used for the computations of hazard were obtained using data from a catalogue that was compiled and homogenised to moment magnitude (Mw). The catalogue covered a period of over a century (1615-2009). The hazard assessment is based on the Poisson model for earthquake occurrence, and hence, dependent events were identified and removed from the catalogue. The following attenuation relations were adopted and used in this study—Allen (for south and eastern Australia), Silva et al. (for Central and eastern North America), Campbell and Bozorgnia (for worldwide active-shallow-crust regions) and Chiou and Youngs (for worldwide active-shallow-crust regions). Logic-tree formalism was used to account for possible uncertainties associated with the attenuation relationships. OpenQuake software package was used for the hazard calculation. The highest level of seismic hazard is found in the Accra and Tema seismic zones, with estimated peak ground acceleration close to 0.2 g. The level of the seismic hazard in the southern part of Ghana diminishes with distance away from the Accra/Tema region to a value of 0.05 g at a distance of about 140 km.

Probabilistic seismic hazard assessment of southern part of Ghana

Science.gov (United States)

Ahulu, Sylvanus T.; Danuor, Sylvester Kojo; Asiedu, Daniel K.

2017-12-01

This paper presents a seismic hazard map for the southern part of Ghana prepared using the probabilistic approach, and seismic hazard assessment results for six cities. The seismic hazard map was prepared for 10% probability of exceedance for peak ground acceleration in 50 years. The input parameters used for the computations of hazard were obtained using data from a catalogue that was compiled and homogenised to moment magnitude (Mw). The catalogue covered a period of over a century (1615-2009). The hazard assessment is based on the Poisson model for earthquake occurrence, and hence, dependent events were identified and removed from the catalogue. The following attenuation relations were adopted and used in this study—Allen (for south and eastern Australia), Silva et al. (for Central and eastern North America), Campbell and Bozorgnia (for worldwide active-shallow-crust regions) and Chiou and Youngs (for worldwide active-shallow-crust regions). Logic-tree formalism was used to account for possible uncertainties associated with the attenuation relationships. OpenQuake software package was used for the hazard calculation. The highest level of seismic hazard is found in the Accra and Tema seismic zones, with estimated peak ground acceleration close to 0.2 g. The level of the seismic hazard in the southern part of Ghana diminishes with distance away from the Accra/Tema region to a value of 0.05 g at a distance of about 140 km.

Effect of fuel assembly when changing from AFA 2G to AFA 3G on seismic loads of reactor internal

International Nuclear Information System (INIS)

Liu Wenjin; Zeng Zhongxiu; Ye Xianhui; Wu Wanjun

2013-01-01

Nonlinear seismic model for reactor with fuel assemblies of AFA 2G and AFA 3G is established. Using ANSYS software, seismic nonlinear time -history analysis is completed and the effects on seismic loads of reactor system are obtained. The result shows that when the fuel assembly changing from AFA 2G to AFA 3G, it is necessary to reevaluate the fuel assembly itself, but not the reactor internal. (authors)

New developments in seismic surveillance of nuclear power plants

International Nuclear Information System (INIS)

Anesa, Franco; Vavassori, Maurizio; Casirati, Mario

1988-01-01

In the present article, new trends and development of ISMES techniques and methods relating to the seismic surveillance of nuclear power plants, are described. The experience gained in this field is described, and particular attention is paid to the new trend in surveys and instrumentation design criteria (from both the hardware and software point of view). (author)

New developments in seismic surveillance of nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Anesa, Franco; Vavassori, Maurizio [Instrumentation and Systems Department, ISMES, Bergamo (Italy); Casirati, Mario [Dynamic Department, ISMES, Bergamo (Italy)

1988-07-01

In the present article, new trends and development of ISMES techniques and methods relating to the seismic surveillance of nuclear power plants, are described. The experience gained in this field is described, and particular attention is paid to the new trend in surveys and instrumentation design criteria (from both the hardware and software point of view). (author)

A method to establish seismic noise baselines for automated station assessment

Science.gov (United States)

McNamara, D.E.; Hutt, C.R.; Gee, L.S.; Benz, H.M.; Buland, R.P.

2009-01-01

We present a method for quantifying station noise baselines and characterizing the spectral shape of out-of-nominal noise sources. Our intent is to automate this method in order to ensure that only the highest-quality data are used in rapid earthquake products at NEIC. In addition, the station noise baselines provide a valuable tool to support the quality control of GSN and ANSS backbone data and metadata. The procedures addressed here are currently in development at the NEIC, and work is underway to understand how quickly changes from nominal can be observed and used within the NEIC processing framework. The spectral methods and software used to compute station baselines and described herein (PQLX) can be useful to both permanent and portable seismic stations operators. Applications include: general seismic station and data quality control (QC), evaluation of instrument responses, assessment of near real-time communication system performance, characterization of site cultural noise conditions, and evaluation of sensor vault design, as well as assessment of gross network capabilities (McNamara et al. 2005). Future PQLX development plans include incorporating station baselines for automated QC methods and automating station status report generation and notification based on user-defined QC parameters. The PQLX software is available through the USGS (http://earthquake. usgs.gov/research/software/pqlx.php) and IRIS (http://www.iris.edu/software/ pqlx/).

Drill bit seismic, vertical seismic profiling, and seismic depth imaging to aid drilling decisions in the Tho Tinh structure, Nam Con Son basin, Vietnam

Energy Technology Data Exchange (ETDEWEB)

Borland, W; Hayashida, N; Kusaka, H; Leaney, W; Nakanishi, S

1996-10-01

This paper reviews the problem of overpressure, a common reason for acquiring look-ahead VSPs, and the seismic trace inversion problem, a fundamental issue in look-ahead prediction. The essential components of intermediate VSPs were examined from acquisition through processing to inversion, and recently acquired real data were provided, which were indicative of the advances being made toward developing an exclusive high resolution VSP service. A simple interpretation method and an end product of predicted mud weight versus depth were also presented, which were obtained from the inverted acoustic impedance and empirical relations. Of paramount importance in predicting the depth to a target was the velocity function used below the intermediate TD. The use of empirical or assumed density functions was an obvious weak link in the procedure. The advent of real-time time-depth measurements from drill bit seismic allowed a continuously updated predicted target depth below the present bit depth. 8 refs., 7 figs.

Seismic, petrological and geodynamical constraints on thermal and compositional structure of the upper mantle: global thermochemical models

DEFF Research Database (Denmark)

Cammarano, Fabio; Tackley, Paul J.; Boschi, Lapo

2011-01-01

Mapping the thermal and compositional structure of the upper mantle requires a combined interpretation of geophysical and petrological observations. Based on current knowledge of material properties, we interpret available global seismic models for temperature assuming end-member compositional...... structures. In particular, we test the effects of modelling a depleted lithosphere, which accounts for petrological constraints on continents. Differences between seismicmodels translate into large temperature and density variations, respectively, up to 400K and 0.06 g cm-3 at 150 km depth. Introducing...... lateral compositional variations does not change significantly the thermal interpretation of seismic models, but gives a more realistic density structure. Modelling a petrological lithosphere gives cratonic temperatures at 150 km depth that are only 100 K hotter than those obtained assuming pyrolite...

Rock property estimates using multiple seismic attributes and neural networks; Pegasus Field, West Texas

Energy Technology Data Exchange (ETDEWEB)

Schuelke, J.S.; Quirein, J.A.; Sarg, J.F.

1998-12-31

This case study shows the benefit of using multiple seismic trace attributes and the pattern recognition capabilities of neural networks to predict reservoir architecture and porosity distribution in the Pegasus Field, West Texas. The study used the power of neural networks to integrate geologic, borehole and seismic data. Illustrated are the improvements between the new neural network approach and the more traditional method of seismic trace inversion for porosity estimation. Comprehensive statistical methods and interpretational/subjective measures are used in the prediction of porosity from seismic attributes. A 3-D volume of seismic derived porosity estimates for the Devonian reservoir provide a very detailed estimate of porosity, both spatially and vertically, for the field. The additional reservoir porosity detail provided, between the well control, allows for optimal placement of horizontal wells and improved field development. 6 refs., 2 figs.

The Social Dynamics of Software Development

NARCIS (Netherlands)

Heiskanen, A.; Newman, M.; Simila, J.

2000-01-01

A variety of experiences in software development processes between a public sector organisation and several software vendors over a decade-long period are described and interpreted. Three information systems histories are presented as case examples and their analysis is based on detailed insider

Semi-automatic mapping for identifying complex geobodies in seismic images

Science.gov (United States)

Domínguez-C, Raymundo; Romero-Salcedo, Manuel; Velasquillo-Martínez, Luis G.; Shemeretov, Leonid

2017-03-01

Seismic images are composed of positive and negative seismic wave traces with different amplitudes (Robein 2010 Seismic Imaging: A Review of the Techniques, their Principles, Merits and Limitations (Houten: EAGE)). The association of these amplitudes together with a color palette forms complex visual patterns. The color intensity of such patterns is directly related to impedance contrasts: the higher the contrast, the higher the color intensity. Generally speaking, low impedance contrasts are depicted with low tone colors, creating zones with different patterns whose features are not evident for a 3D automated mapping option available on commercial software. In this work, a workflow for a semi-automatic mapping of seismic images focused on those areas with low-intensity colored zones that may be associated with geobodies of petroleum interest is proposed. The CIE L*A*B* color space was used to perform the seismic image processing, which helped find small but significant differences between pixel tones. This process generated binary masks that bound color regions to low-intensity colors. The three-dimensional-mask projection allowed the construction of 3D structures for such zones (geobodies). The proposed method was applied to a set of digital images from a seismic cube and tested on four representative study cases. The obtained results are encouraging because interesting geobodies are obtained with a minimum of information.

Seismic properties of fluid bearing formations in magmatic geothermal systems: can we directly detect geothermal activity with seismic methods?

Science.gov (United States)

Grab, Melchior; Scott, Samuel; Quintal, Beatriz; Caspari, Eva; Maurer, Hansruedi; Greenhalgh, Stewart

2016-04-01

Seismic methods are amongst the most common techniques to explore the earth's subsurface. Seismic properties such as velocities, impedance contrasts and attenuation enable the characterization of the rocks in a geothermal system. The most important goal of geothermal exploration, however, is to describe the enthalpy state of the pore fluids, which act as the main transport medium for the geothermal heat, and to detect permeable structures such as fracture networks, which control the movement of these pore fluids in the subsurface. Since the quantities measured with seismic methods are only indirectly related with the fluid state and the rock permeability, the interpretation of seismic datasets is difficult and usually delivers ambiguous results. To help overcome this problem, we use a numerical modeling tool that quantifies the seismic properties of fractured rock formations that are typically found in magmatic geothermal systems. We incorporate the physics of the pore fluids, ranging from the liquid to the boiling and ultimately vapor state. Furthermore, we consider the hydromechanics of permeable structures at different scales from small cooling joints to large caldera faults as are known to be present in volcanic systems. Our modeling techniques simulate oscillatory compressibility and shear tests and yield the P- and S-wave velocities and attenuation factors of fluid saturated fractured rock volumes. To apply this modeling technique to realistic scenarios, numerous input parameters need to be indentified. The properties of the rock matrix and individual fractures were derived from extensive literature research including a large number of laboratory-based studies. The geometries of fracture networks were provided by structural geologists from their published studies of outcrops. Finally, the physical properties of the pore fluid, ranging from those at ambient pressures and temperatures up to the supercritical conditions, were taken from the fluid physics

Seismic isolation - efficient procedure for seismic response assessement

International Nuclear Information System (INIS)

Zamfir, M. A.; Androne, M.

2016-01-01

The aim of this analysis is to reduce the dynamic response of a structure. The seismic isolation solution must take into consideration the specific site ground motion. In this paper will be presented results obtained by applying the seismic isolation method. Based on the obtained results, important conclusions can be outlined: the seismic isolation device has the ability to reduce seismic acceleration of the seismic isolated structure to values that no longer present a danger to people and environment; the seismic isolation solution is limiting devices deformations to safety values for ensuring structural integrity and stability of the entire system; the effective seismic energy dissipation and with no side effects both for the seismic isolated building and for the devices used, and the return to the initial position before earthquake occurence are obtained with acceptable permanent displacement. (authors)

A New Seismic Hazard Model for Mainland China

Science.gov (United States)

Rong, Y.; Xu, X.; Chen, G.; Cheng, J.; Magistrale, H.; Shen, Z. K.

2017-12-01

We are developing a new seismic hazard model for Mainland China by integrating historical earthquake catalogs, geological faults, geodetic GPS data, and geology maps. To build the model, we construct an Mw-based homogeneous historical earthquake catalog spanning from 780 B.C. to present, create fault models from active fault data, and derive a strain rate model based on the most complete GPS measurements and a new strain derivation algorithm. We divide China and the surrounding regions into about 20 large seismic source zones. For each zone, a tapered Gutenberg-Richter (TGR) magnitude-frequency distribution is used to model the seismic activity rates. The a- and b-values of the TGR distribution are calculated using observed earthquake data, while the corner magnitude is constrained independently using the seismic moment rate inferred from the geodetically-based strain rate model. Small and medium sized earthquakes are distributed within the source zones following the location and magnitude patterns of historical earthquakes. Some of the larger earthquakes are distributed onto active faults, based on their geological characteristics such as slip rate, fault length, down-dip width, and various paleoseismic data. The remaining larger earthquakes are then placed into the background. A new set of magnitude-rupture scaling relationships is developed based on earthquake data from China and vicinity. We evaluate and select appropriate ground motion prediction equations by comparing them with observed ground motion data and performing residual analysis. To implement the modeling workflow, we develop a tool that builds upon the functionalities of GEM's Hazard Modeler's Toolkit. The GEM OpenQuake software is used to calculate seismic hazard at various ground motion periods and various return periods. To account for site amplification, we construct a site condition map based on geology. The resulting new seismic hazard maps can be used for seismic risk analysis and management.

Constraints on the thermal and compositional nature of the Earth's mantle inferred from joint inversion of compressional and shear seismic waves and mineral physics data

DEFF Research Database (Denmark)

Tesoniero, Andrea

and by uncertainties in the sensitivity of seismic velocities to these parameters. The combination of seismic observations and information from mineral physics can help overcoming the limited resolution of the seismic data and obtaining an insight into the physical state of the Earth. This Ph.D. project summarizes......- and shear-velocity model has been delivered. The interpretation of the new model gives an insight into lateral compositional variations within the continental lithosphere and upper mantle, as well as a new interpretation of the thermo-chemical state of the lower mantle. Two manuscripts have been prepared...

Instrument Correction and Dynamic Site Profile Validation at the Central United States Seismic Observatory, New Madrid Seismic Zone

Science.gov (United States)

Brengman, C.; Woolery, E. W.; Wang, Z.; Carpenter, S.

2016-12-01

The Central United States Seismic Observatory (CUSSO) is a vertical seismic array located in southwestern Kentucky within the New Madrid seismic zone. It is intended to describe the effects of local geology, including thick sediment overburden, on seismic-wave propagation, particularly strong-motion. The three-borehole array at CUSSO is composed of seismic sensors placed on the surface, and in the bedrock at various depths within the 585 m thick sediment overburden. The array's deep borehole provided a unique opportunity in the northern Mississippi embayment for the direct geological description and geophysical measurement of the complete late Cretaceous-Quaternary sediment column. A seven layer, intra-sediment velocity model is interpreted from the complex, inhomogeneous stratigraphy. The S- and P-wave sediment velocities range between 160 and 875 m/s and between 1000 and 2300 m/s, respectively, with bedrock velocities of 1452 and 3775 m/s, respectively. Cross-correlation and direct comparisons were used to filter out the instrument response and determine the instrument orientation, making CUSSO data ready for analysis, and making CUSSO a viable calibration site for other free-field sensors in the area. The corrected bedrock motions were numerically propagated through the CUSSO soil profile (transfer function) and compared, in terms of both peak acceleration and amplitude spectra, to the recorded surface observations. Initial observations reveal a complex spectral mix of amplification and de-amplification across the array, indicating the site effect in this deep sediment setting is not simply generated by the shallowest layers.

CORSSA: The Community Online Resource for Statistical Seismicity Analysis

Science.gov (United States)

Michael, Andrew J.; Wiemer, Stefan

2010-01-01

Statistical seismology is the application of rigorous statistical methods to earthquake science with the goal of improving our knowledge of how the earth works. Within statistical seismology there is a strong emphasis on the analysis of seismicity data in order to improve our scientific understanding of earthquakes and to improve the evaluation and testing of earthquake forecasts, earthquake early warning, and seismic hazards assessments. Given the societal importance of these applications, statistical seismology must be done well. Unfortunately, a lack of educational resources and available software tools make it difficult for students and new practitioners to learn about this discipline. The goal of the Community Online Resource for Statistical Seismicity Analysis (CORSSA) is to promote excellence in statistical seismology by providing the knowledge and resources necessary to understand and implement the best practices, so that the reader can apply these methods to their own research. This introduction describes the motivation for and vision of CORRSA. It also describes its structure and contents.

Preliminary stratigraphic and hydrogeologic cross sections and seismic profile of the Floridan aquifer system of Broward County, Florida

Science.gov (United States)

Reese, Ronald S.; Cunningham, Kevin J.

2013-01-01

To help water-resource managers evaluate the Floridan aquifer system (FAS) as an alternative water supply, the U.S. Geological Survey initiated a study, in cooperation with the Broward County Environmental Protection and Growth Management Department, to refine the hydrogeologic framework of the FAS in the eastern part of Broward County. This report presents three preliminary cross sections illustrating stratigraphy and hydrogeology in eastern Broward County as well as an interpreted seismic profile along one of the cross sections. Marker horizons were identified using borehole geophysical data and were initially used to perform well-to-well correlation. Core sample data were integrated with the borehole geophysical data to support stratigraphic and hydrogeologic interpretations of marker horizons. Stratigraphic and hydrogeologic units were correlated across the county using borehole geophysical data from multiple wells. Seismic-reflection data were collected along the Hillsboro Canal. Borehole geophysical data were used to identify and correlate hydrogeologic units in the seismic-reflection profile. Faults and collapse structures that intersect hydrogeologic units were also identified in the seismic profile. The information provided in the cross sections and the seismic profile is preliminary and subject to revision.

Seismic wavefield modeling based on time-domain symplectic and Fourier finite-difference method

Science.gov (United States)

Fang, Gang; Ba, Jing; Liu, Xin-xin; Zhu, Kun; Liu, Guo-Chang

2017-06-01

Seismic wavefield modeling is important for improving seismic data processing and interpretation. Calculations of wavefield propagation are sometimes not stable when forward modeling of seismic wave uses large time steps for long times. Based on the Hamiltonian expression of the acoustic wave equation, we propose a structure-preserving method for seismic wavefield modeling by applying the symplectic finite-difference method on time grids and the Fourier finite-difference method on space grids to solve the acoustic wave equation. The proposed method is called the symplectic Fourier finite-difference (symplectic FFD) method, and offers high computational accuracy and improves the computational stability. Using acoustic approximation, we extend the method to anisotropic media. We discuss the calculations in the symplectic FFD method for seismic wavefield modeling of isotropic and anisotropic media, and use the BP salt model and BP TTI model to test the proposed method. The numerical examples suggest that the proposed method can be used in seismic modeling of strongly variable velocities, offering high computational accuracy and low numerical dispersion. The symplectic FFD method overcomes the residual qSV wave of seismic modeling in anisotropic media and maintains the stability of the wavefield propagation for large time steps.

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

Peak Ground Velocities for Seismic Events at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

K. Coppersmith; R. Quittmeyer

2005-01-01

This report describes a scientific analysis to bound credible horizontal peak ground velocities (PGV) for the repository waste emplacement level at Yucca Mountain. Results are presented as a probability distribution for horizontal PGV to represent uncertainties in the analysis. The analysis also combines the bound to horizontal PGV with results of ground motion site-response modeling (BSC 2004 [DIRS 170027]) to develop a composite hazard curve for horizontal PGV at the waste emplacement level. This result provides input to an abstraction of seismic consequences (BSC 2004 [DIRS 169183]). The seismic consequence abstraction, in turn, defines the input data and computational algorithms for the seismic scenario class of the total system performance assessment (TSPA). Planning for the analysis is documented in Technical Work Plan TWP-MGR-GS-000001 (BSC 2004 [DIRS 171850]). The bound on horizontal PGV at the repository waste emplacement level developed in this analysis complements ground motions developed on the basis of PSHA results. In the PSHA, ground motion experts characterized the epistemic uncertainty and aleatory variability in their ground motion interpretations. To characterize the aleatory variability they used unbounded lognormal distributions. As a consequence of these characterizations, as seismic hazard calculations are extended to lower and lower annual frequencies of being exceeded, the ground motion level increases without bound, eventually reaching levels that are not credible (Corradini 2003 [DIRS 171191]). To provide credible seismic inputs for TSPA, in accordance with 10 Code of Federal Regulations (CFR) 63.102(j) [DIRS 156605], this complementary analysis is carried out to determine reasonable bounding values of horizontal PGV at the waste emplacement level for annual frequencies of exceedance as low as 10 -8 . For each realization of the TSPA seismic scenario, the results of this analysis provide a constraint on the values sampled from the

Rippability Assessment of Weathered Sedimentary Rock Mass using Seismic Refraction Methods

Science.gov (United States)

Ismail, M. A. M.; Kumar, N. S.; Abidin, M. H. Z.; Madun, A.

2018-04-01

Rippability or ease of excavation in sedimentary rocks is a significant aspect of the preliminary work of any civil engineering project. Rippability assessment was performed in this study to select an available ripping machine to rip off earth materials using the seismic velocity chart provided by Caterpillar. The research area is located at the proposed construction site for the development of a water reservoir and related infrastructure in Kampus Pauh Putra, Universiti Malaysia Perlis. The research was aimed at obtaining seismic velocity, P-wave (Vp) using a seismic refraction method to produce a 2D tomography model. A 2D seismic model was used to delineate the layers into the velocity profile. The conventional geotechnical method of using a borehole was integrated with the seismic velocity method to provide appropriate correlation. The correlated data can be used to categorize machineries for excavation activities based on the available systematic analysis procedure to predict rock rippability. The seismic velocity profile obtained was used to interpret rock layers within the ranges labelled as rippable, marginal, and non-rippable. Based on the seismic velocity method the site can be classified into loose sand stone to moderately weathered rock. Laboratory test results shows that the site’s rock material falls between low strength and high strength. Results suggest that Caterpillar’s smallest ripper, namely, D8R, can successfully excavate materials based on the test results integration from seismic velocity method and laboratory test.

2-D traveltime and waveform inversion for improved seismic imaging: Naga Thrust and Fold Belt, India

Science.gov (United States)

Jaiswal, Priyank; Zelt, Colin A.; Bally, Albert W.; Dasgupta, Rahul

2008-05-01

Exploration along the Naga Thrust and Fold Belt in the Assam province of Northeast India encounters geological as well as logistic challenges. Drilling for hydrocarbons, traditionally guided by surface manifestations of the Naga thrust fault, faces additional challenges in the northeast where the thrust fault gradually deepens leaving subtle surface expressions. In such an area, multichannel 2-D seismic data were collected along a line perpendicular to the trend of the thrust belt. The data have a moderate signal-to-noise ratio and suffer from ground roll and other acquisition-related noise. In addition to data quality, the complex geology of the thrust belt limits the ability of conventional seismic processing to yield a reliable velocity model which in turn leads to poor subsurface image. In this paper, we demonstrate the application of traveltime and waveform inversion as supplements to conventional seismic imaging and interpretation processes. Both traveltime and waveform inversion utilize the first arrivals that are typically discarded during conventional seismic processing. As a first step, a smooth velocity model with long wavelength characteristics of the subsurface is estimated through inversion of the first-arrival traveltimes. This velocity model is then used to obtain a Kirchhoff pre-stack depth-migrated image which in turn is used for the interpretation of the fault. Waveform inversion is applied to the central part of the seismic line to a depth of ~1 km where the quality of the migrated image is poor. Waveform inversion is performed in the frequency domain over a series of iterations, proceeding from low to high frequency (11-19 Hz) using the velocity model from traveltime inversion as the starting model. In the end, the pre-stack depth-migrated image and the waveform inversion model are jointly interpreted. This study demonstrates that a combination of traveltime and waveform inversion with Kirchhoff pre-stack depth migration is a promising approach

Space and Missile Systems Center Standard: Software Development

Science.gov (United States)

2015-01-16

waterfall development lifecycle models . Source: Adapted from (IEEE 610.12) See (IEEE 1074) for more information. Software ...spiral, and waterfall lifecycle models .) 2. The developer shall record the selected software development lifecycle model (s) in the Software ...through i.e., waterfall , lifecycle model , the following requirements apply with the interpretation that the software is developed as a single build.

Study of seismic events in the Central Part of East European Platform

Science.gov (United States)

Gorbunova, Ella; Sanina, Irina; Ivanchenko, Galina; Nesterkina, Margarita; Konstantinovskaya, Natalya

2015-04-01

A measurement system for location seismic events in the Central Part of East European Platform is situated within the Mikhnevo Geophysical Observatory of the RAS Institute of Geospheres Dynamics and consists of 12 seismic stations. One vertical station is located in the center of the group in a shaft tunnel. The other stations are located on the periphery in three concentric circles and are almost equally spaced with regard to the terrain to ensure full azimuth coverage to the maximum extent possible. The unique array identifies events with a magnitude up to 3 at the distances until 1000 km within the Central Part of East European platform. Most of the events recorded by the Mikhnevo array at a distance of 60-500 km are man-made events represented by explosions in quarries during the development of mineral deposits. Long-term seismic records of explosions in quarries have been processed for the period from 2004 to 2014 to generate a database containing standard waveforms for each quarry. Some events of unknown origin appear in the records for this period; these do not correspond to the identified seismic forms for explosions in known quarries. Epicenter coordinates for these events do not match the coordinates of the known quarries. A cosmotectonic map of the Central Part of East European Platform was compiled during the studies using the LESSA software package (Lineament Extraction and Stripe Statistical Analysis) and data on the deep crustal structure, which made it possible to define the morphostructural plan and evaluate the geodynamic conditions in the area. The deep basement structure through the sedimentary cover is expressed in the surface texture of the area under study. The region's neotectonics is closely related to the history of deep structures, in particular, aulacogens extending in different directions, which may show in the contemporary morphostructural plan, mainly as inversion and partially inherited forms. Out of events of unknown nature

Three-component seismic data in thin interbedded reservoir exploration

Science.gov (United States)

Zhang, Li-Yan; Wang, Yan-Chun; Pei, Jiang-Yun

2015-03-01

We present the first successful application of three-component seismic data to thin interbedded reservoir characterization in the Daqing placanticline of the LMD oilfield. The oilfield has reached the final high water cut stage and the principal problem is how to recognize the boundaries of sand layers that are thicker than 2 m. Conventional interpretation of single PP-wave seismic data results in multiple solutions, whereas the introduction of PS-wave enhances the reliability of interpretation. We analyze the gas reservoir characteristics by joint PP- and PS-waves, and use the amplitude and frequency decomposition attributes to delineate the gas reservoir boundaries because of the minimal effect of fluids on S-wave. We perform joint inversion of PP- and PS-waves to obtain V P/ V S, λρ, and µ ρ and map the lithology changes by using density, λρ, and µ ρ. The 3D-3C attribute λρ slices describe the sand layers distribution, while considering the well log data, and point to favorable region for tapping the remaining oil.

Seismicity Pattern and Fault Structure in the Central Himalaya Seismic Gap Using Precise Earthquake Hypocenters and their Source Parameters

Science.gov (United States)

Mendoza, M.; Ghosh, A.; Rai, S. S.

2017-12-01

The devastation brought on by the Mw 7.8 Gorkha earthquake in Nepal on 25 April 2015, reconditioned people to the high earthquake risk along the Himalayan arc. It is therefore imperative to learn from the Gorkha earthquake, and gain a better understanding of the state of stress in this fault regime, in order to identify areas that could produce the next devastating earthquake. Here, we focus on what is known as the "central Himalaya seismic gap". It is located in Uttarakhand, India, west of Nepal, where a large (> Mw 7.0) earthquake has not occurred for over the past 200 years [Rajendran, C.P., & Rajendran, K., 2005]. This 500 - 800 km long along-strike seismic gap has been poorly studied, mainly due to the lack of modern and dense instrumentation. It is especially concerning since it surrounds densely populated cities, such as New Delhi. In this study, we analyze a rich seismic dataset from a dense network consisting of 50 broadband stations, that operated between 2005 and 2012. We use the STA/LTA filter technique to detect earthquake phases, and the latest tools contributed to the Antelope software environment, to develop a large and robust earthquake catalog containing thousands of precise hypocentral locations, magnitudes, and focal mechanisms. By refining those locations in HypoDD [Waldhauser & Ellsworth, 2000] to form a tighter cluster of events using relative relocation, we can potentially illustrate fault structures in this region with high resolution. Additionally, using ZMAP [Weimer, S., 2001], we perform a variety of statistical analyses to understand the variability and nature of seismicity occurring in the region. Generating a large and consistent earthquake catalog not only brings to light the physical processes controlling the earthquake cycle in an Himalayan seismogenic zone, it also illustrates how stresses are building up along the décollment and the faults that stem from it. With this new catalog, we aim to reveal fault structure, study

Improving fault image by determination of optimum seismic survey parameters using ray-based modeling

Science.gov (United States)

Saffarzadeh, Sadegh; Javaherian, Abdolrahim; Hasani, Hossein; Talebi, Mohammad Ali

2018-06-01

In complex structures such as faults, salt domes and reefs, specifying the survey parameters is more challenging and critical owing to the complicated wave field behavior involved in such structures. In the petroleum industry, detecting faults has become crucial for reservoir potential where faults can act as traps for hydrocarbon. In this regard, seismic survey modeling is employed to construct a model close to the real structure, and obtain very realistic synthetic seismic data. Seismic modeling software, the velocity model and parameters pre-determined by conventional methods enable a seismic survey designer to run a shot-by-shot virtual survey operation. A reliable velocity model of structures can be constructed by integrating the 2D seismic data, geological reports and the well information. The effects of various survey designs can be investigated by the analysis of illumination maps and flower plots. Also, seismic processing of the synthetic data output can describe the target image using different survey parameters. Therefore, seismic modeling is one of the most economical ways to establish and test the optimum acquisition parameters to obtain the best image when dealing with complex geological structures. The primary objective of this study is to design a proper 3D seismic survey orientation to achieve fault zone structures through ray-tracing seismic modeling. The results prove that a seismic survey designer can enhance the image of fault planes in a seismic section by utilizing the proposed modeling and processing approach.

Residence time distribution software analysis. User's manual

International Nuclear Information System (INIS)

1996-01-01

Radiotracer applications cover a wide range of industrial activities in chemical and metallurgical processes, water treatment, mineral processing, environmental protection and civil engineering. Experiment design, data acquisition, treatment and interpretation are the basic elements of tracer methodology. The application of radiotracers to determine impulse response as RTD as well as the technical conditions for conducting experiments in industry and in the environment create a need for data processing using special software. Important progress has been made during recent years in the preparation of software programs for data treatment and interpretation. The software package developed for industrial process analysis and diagnosis by the stimulus-response methods contains all the methods for data processing for radiotracer experiments

Advanced Seismic Data Analysis Program (The Hot Pot Project), DOE Award: DE-EE0002839, Phase 1 Report

Energy Technology Data Exchange (ETDEWEB)

Oski Energy, LLC,

2013-03-28

A five-line (23 mile) reflection- seismic survey was conducted at the Hot Pot geothermal prospect area in north-central Nevada under the USDOE (United States Department of Energy) Geothermal Technologies Program. The project objective was to utilize innovative seismic data processing, integrated with existing geological, geophysical and geochemical information, to identify high-potential drilling targets and to reduce drilling risk. Data acquisition and interpretation took place between October 2010 and April 2011. The first round of data processing resulted in large areas of relatively poor data, and obvious reflectors known from existing subsurface information either did not appear on the seismic profiles or appeared at the wrong depth. To resolve these issues, the velocity model was adjusted to include geologic input, and the lines were reprocessed. The resulting products were significantly improved, and additional detail was recovered within the high-velocity and in part acoustically isotropic basement. Features visible on the improved seismic images include interpreted low angle thrust faults within the Paleozoic Valmy Formation, which potentially are reactivated in the current stress field. Intermediate-depth wells are currently targeted to test these features. The seismic images also suggest the existence of Paleogene sedimentary and volcanic rocks which potentially may function as a near- surface reservoir, charged by deeper structures in Paleozoic rocks.

Homogenization of Electromagnetic and Seismic Wavefields for Joint Inverse Modeling

Science.gov (United States)

Newman, G. A.; Commer, M.; Petrov, P.; Um, E. S.

2011-12-01

A significant obstacle in developing a robust joint imaging technology exploiting seismic and electromagnetic (EM) wave fields is the resolution at which these different geophysical measurements sense the subsurface. Imaging of seismic reflection data is an order of magnitude finer in resolution and scale compared to images produced with EM data. A consistent joint image of the subsurface geophysical attributes (velocity, electrical conductivity) requires/demands the different geophysical data types be similar in their resolution of the subsurface. The superior resolution of seismic data results from the fact that the energy propagates as a wave, while propagation of EM energy is diffusive and attenuates with distance. On the other hand, the complexity of the seismic wave field can be a significant problem due to high reflectivity of the subsurface and the generation of multiple scattering events. While seismic wave fields have been very useful in mapping the subsurface for energy resources, too much scattering and too many reflections can lead to difficulties in imaging and interpreting seismic data. To overcome these obstacles a formulation for joint imaging of seismic and EM wave fields is introduced, where each data type is matched in resolution. In order to accomplish this, seismic data are first transformed into the Laplace-Fourier Domain, which changes the modeling of the seismic wave field from wave propagation to diffusion. Though high frequency information (reflectivity) is lost with this transformation, several benefits follow: (1) seismic and EM data can be easily matched in resolution, governed by the same physics of diffusion, (2) standard least squares inversion works well with diffusive type problems including both transformed seismic and EM, (3) joint imaging of seismic and EM data may produce better starting velocity models critical for successful reverse time migration or full waveform imaging of seismic data (non transformed) and (4

Ifuzzer : An evolutionary interpreter fuzzer using genetic programming

NARCIS (Netherlands)

Veggalam, Spandan; Rawat, Sanjay; Haller, Istvan; Bos, Herbert

We present an automated evolutionary fuzzing technique to find bugs in JavaScript interpreters. Fuzzing is an automated black box testing technique used for finding security vulnerabilities in the software by providing random data as input. However, in the case of an interpreter, fuzzing is

PRISM Software: Processing and Review Interface for Strong‐Motion Data

Science.gov (United States)

Jones, Jeanne M.; Kalkan, Erol; Stephens, Christopher D.; Ng, Peter

2017-01-01

A continually increasing number of high‐quality digital strong‐motion records from stations of the National Strong Motion Project (NSMP) of the U.S. Geological Survey, as well as data from regional seismic networks within the United States, calls for automated processing of strong‐motion records with human review limited to selected significant or flagged records. The NSMP has developed the Processing and Review Interface for Strong Motion data (PRISM) software to meet this need. In combination with the Advanced National Seismic System Quake Monitoring System (AQMS), PRISM automates the processing of strong‐motion records. When used without AQMS, PRISM provides batch‐processing capabilities. The PRISM software is platform independent (coded in Java), open source, and does not depend on any closed‐source or proprietary software. The software consists of two major components: a record processing engine composed of modules for each processing step, and a review tool, which is a graphical user interface for manual review, edit, and processing. To facilitate use by non‐NSMP earthquake engineers and scientists, PRISM (both its processing engine and review tool) is easy to install and run as a stand‐alone system on common operating systems such as Linux, OS X, and Windows. PRISM was designed to be flexible and extensible to accommodate implementation of new processing techniques. All the computing features have been thoroughly tested.

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

Recent developments in seismic analysis in the code Aster

International Nuclear Information System (INIS)

Guihot, P.; Devesa, G.; Dumond, A.; Panet, M.; Waeckel, F.

1996-01-01

Progress in the field of seismic qualification and design methods made these last few years allows physical phenomena actually in play to be better considered, while cutting down the conservatism associated with some simplified design methods. So following the change in methods and developing the most advantageous ones among them contributes to the process of the seismic margins assessment and the preparation of new design tools for future series. In this paper, the main developments and improvements in methods which have been made these last two years in the Code Aster, in order to improve seismic calculation methods and seismic margin assessment are presented. The first development relates to making the MISS3D soil structure interaction code available, thanks to an interface made with the Code Aster. The second relates to the possibility of making modal basis time calculations on multi-supported structures by considering local non linearities like impact, friction or squeeze fluid forces. Recent developments in random dynamics and postprocessing devoted to earthquake designs are then mentioned. Three applications of these developments are then ut forward. The first application relates to a test case for soil structure interaction design using MISS3D-Aster coupling. The second is a test case for a multi-supported structure. The last application, more for manufacturing, refers to seismic qualification of Main Live Steam stop valves. First results of the independent validation of the Code Aster seismic design functionalities, which provide and improve the quality of software, are also recalled. (authors)

PARTOS - Passive and Active Ray TOmography Software: description and preliminary analysis using TOMO-ETNA experiment’s dataset

Directory of Open Access Journals (Sweden)

Alejandro Díaz-Moreno

2016-09-01

Full Text Available In this manuscript we present the new friendly seismic tomography software based on joint inversion of active and passive seismic sources called PARTOS (Passive Active Ray TOmography Software. This code has been developed on the base of two well-known widely used tomographic algorithms (LOTOS and ATOM-3D, providing a robust set of algorithms. The dataset used to set and test the program has been provided by TOMO-ETNA experiment. TOMO-ETNA database is a large, high-quality dataset that includes active and passive seismic sources recorded during a period of 4 months in 2014. We performed a series of synthetic tests in order to estimate the resolution and robustness of the solutions. Real data inversion has been carried out using 3 different subsets: i active data; ii passive data; and iii joint dataset. Active database is composed by a total of 16,950 air-gun shots during 1 month and passive database includes 452 local and regional earthquakes recorded during 4 months. This large dataset provides a high ray density within the study region. The combination of active and passive seismic data, together with the high quality of the database, permits to obtain a new tomographic approach of the region under study never done before. An additional user-guide of PARTOS software is provided in order to facilitate the implementation for new users.

A repeatable seismic source for tomography at volcanoes

Directory of Open Access Journals (Sweden)

A. Ratdomopurbo

1999-06-01

Full Text Available One major problem associated with the interpretation of seismic signals on active volcanoes is the lack of knowledge about the internal structure of the volcano. Assuming a 1D or a homogeneous instead of a 3D velocity structure leads to an erroneous localization of seismic events. In order to derive a high resolution 3D velocity model ofMt. Merapi (Java a seismic tomography experiment using active sources is planned as a part of the MERAPI (Mechanism Evaluation, Risk Assessment and Prediction Improvement project. During a pre-site survey in August 1996 we tested a seismic source consisting of a 2.5 l airgun shot in water basins that were constructed in different flanks of the volcano. This special source, which in our case can be fired every two minutes, produces a repeatable, identical source signal. Using this source the number of receiver locations is not limited by the number of seismometers. The seismometers can be moved to various receiver locations while the source reproduces the same source signal. Additionally, at each receiver location we are able to record the identical source signal several times so that the disadvantage of the lower energy compared to an explosion source can be reduced by skipping disturbed signals and stacking several recordings.

Analysis and Interpretation of Avo Data in Buit-North Prospect of the Niger Delta Slope

International Nuclear Information System (INIS)

Oladapo, M.I.; Ojo, J. S.; Adetola, B.A.

2003-01-01

A qualitative analysis and interpretation of Amplitude Variations with Offset (AVO) data from Buit-North prospect in the Niger Delta Slope has been undertaken. Four horizons evaluated are AA (1900mm), BB (2345m), CC (2500m) and DD (2935). The work involved the comparison of AVO analysis of Buit-I well log and those of 3-D Pre-Stack Time Migrated (PSTM) seismic data acquired from the study area. Acoustic Impedance-Depth trend generated from Buit-1 Well demonstrates that AVO interpretation at depths between 2650m and .3300m (points of polynomial fit convergence) may be subdued due to nera zero impedance contrasts at contacts. Monte-Carlo models generated for the horizons using parameters measured from Buit. Zoeppritz (AVO) curves and seismic attributes crossplots were generated for all the horizons. AA horizon exhibit classes II and IV (falling AVO) while horizon BB reveal class III (classical bright spot) gas sand. Horizon CC exhibit class II (near zero impedance) gas sand while the seismic attributes crossplots show no distinct anomalous plots. The AVO response curves displayed at the upper level of horizon DD is characteristic of class IV response with the lower level exhibiting class II attribute. The seismic attributes crossplots for DD show plots on quandrants II, III and IV thus confirmation AVO analysis complexity within that depth window. Quantitative analysis and interpretation of AVO data is demonstrated in this study as a valuable emerging technology for appraising deep-water prospects for the delineation of probable hydrocarbon zones for further studies

PyBus -- A Python Software Bus

OpenAIRE

Lavrijsen, W

2005-01-01

A software bus, just like its hardware equivalent, allows for the discovery, installation, configuration, loading, unloading, and run-time replacement of software components, as well as channeling of inter-component communication. Python, a popular open-source programming language, encourages a modular design on software written in it, but it offers little or no component functionality. However, the language and its interpreter provide sufficient hooks to implement a thin, integral layer...

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.)

Passive Seismic for Hydrocarbon Indicator : Between Expectation and Reality

Science.gov (United States)

Pandito, Riky H. B.

2018-03-01

In between 5 – 10 years, in our country, passive seismic method became more popular to finding hydrocarbon. Low price, nondestructive acquisition and easy to mobilization is the best reason for choose the method. But in the other part, some people are pessimistically to deal with the result. Instrument specification, data condition and processing methods is several points which influence characteristic and interpretation passive seismic result. In 2010 one prospect in East Java Basin has been measurement constist of 112 objective points and several calibration points. Data measurement results indicate a positive response. Furthermore, in 2013 exploration drliing conducted on the prospect. Drill steam test showes 22 MMCFD in objective zone, upper – late oligocene. In 2015, remeasurement taken in objective area and show consistent responses with previous measurement. Passive seismic is unique method, sometimes will have difference results on dry, gas and oil area, in field production and also temporary suspend area with hidrocarbon content.

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.

Peru Subduction Zone Seismic Experiment (PeruSZE): Preliminary Results From a Seismic Network Between Mollendo and Lake Titicaca, Peru.

Science.gov (United States)

Guy, R.; Stubailo, I.; Skinner, S.; Phillips, K.; Foote, E.; Lukac, M.; Aguilar, V.; Tavera, H.; Audin, L.; Husker, A.; Clayton, R.; Davis, P. M.

2008-12-01

This work describes preliminary results from a 50 station broadband seismic network recently installed from the coast to the high Andes in Peru. UCLA's Center for Embedded Network Sensing (CENS) and Caltech's Tectonic Observatory are collaborating with the IRD (French L'Institut de Recherche pour le Developpement) and the Institute of Geophysics, in Lima Peru in a broadband seismic experiment that will study the transition from steep to shallow slab subduction. The currently installed line has stations located above the steep subduction zone at a spacing of about 6 km. In 2009 we plan to install a line of 50 stations north from this line along the crest of the Andes, crossing the transition from steep to shallow subduction. A further line from the end of that line back to the coast, completing a U shaped array, is in the planning phase. The network is wirelessly linked using multi-hop network software designed by computer scientists in CENS in which data is transmitted from station to station, and collected at Internet drops, from where it is transmitted over the Internet to CENS each night. The instrument installation in Peru is almost finished and we have been receiving data daily from 10 stations (out of total 50) since June 2008. The rest are recording on-site while the RF network is being completed. The software system provides dynamic link quality based routing, reliable data delivery, and a disruption tolerant shell interface for managing the system from UCLA without the need to travel to Peru. The near real-time data delivery also allows immediate detection of any problems at the sites. We are building a seismic data and GPS quality control toolset that would greatly minimize the station's downtime by alerting the users of any possible problems.

Rock mass seismic imaging around the ONKALO tunnel, Olkiluoto 2007

International Nuclear Information System (INIS)

Cosma, C.; Cozma, M.; Balu, L.; Enescu, N.

2008-11-01

Posiva Oy prepares for disposal of spent nuclear fuel in bedrock focusing in Olkiluoto, Eurajoki. This is in accordance of the application filed in 1999, the Decision-in-Principle of the State Council in 2000, and ratification by the Parliament in 2001. Vibrometric Oy has performed a tunnel seismic survey in ONKALO access tunnel on a 100 m line in December 2007. Tunnel length (chainage) was 1720 - 1820 m (vertical depth 170 - 180 m). Measurement applied 120 source positions at 1 m spacing, and on the both ends at 4 m spacing. Electromechanical Vibsist-20 tool was used as the source. Hammer produced 15.36 s sweeps. Signal was recorded with 2-component geophone assemblies, installed in 400 mm long, 45 mm drillholes in the tunnel wall. Sweeps were recorded with Summit II seismograph and decoded to seismic traces. Also percussion drill rig, which is used in drilling the blasting holes in tunnel excavation, was tested from a 100-m distance as a seismic source. Signal is equally good as from actual seismic source, and may be applied later on for production. Obtained seismic results were processed with tomographic reconstruction of the first arrivals to P and S wave refraction tomograms, and to tomograms of Young's modulus and Shear Modulus. The obtained values correspond the typical levels known from Olkiluoto. There are indications of lower velocity near tunnel wall, but resolution is not adequate for further interpretation. Some variation of velocity is detected in the rock mass. Seismic data was also processed with normal reflection profile interpretation and migrated. As a result there was obtained reflection images to a 100-m distance from the tunnel. Several reflecting events were observed in the rock mass. Features making an angle of 30 deg or more with tunnel axis can be imaged from distances of tens of metres. Vertical fractures perpendicular to tunnel can be imaged only near the tunnel. Gently dipping features can be imaged below and above. Images are 2D, i

CARES (Computer Analysis for Rapid Evaluation of Structures) Version 1.0, seismic module

International Nuclear Information System (INIS)

Xu, J.; Philippacopoulas, A.J.; Miller, C.A.; Costantino, C.J.

1990-07-01

During FY's 1988 and 1989, Brookhaven National Laboratory (BNL) developed the CARES system (Computer Analysis for Rapid Evaluation of Structures) for the US Nuclear Regulatory Commission (NRC). CARES is a PC software system which has been designed to perform structural response computations similar to those encountered in licensing reviews of nuclear power plant structures. The documentation of the Seismic Module of CARES consists of three volumes. This report is Volume 2 of the three volume documentation of the Seismic Module of CARES and represents the User's Manual. 14 refs

Automatic detection of karstic sinkholes in seismic 3D images using circular Hough transform

International Nuclear Information System (INIS)

Parchkoohi, Mostafa Heydari; Farajkhah, Nasser Keshavarz; Delshad, Meysam Salimi

2015-01-01

More than 30% of hydrocarbon reservoirs are reported in carbonates that mostly include evidence of fractures and karstification. Generally, the detection of karstic sinkholes prognosticate good quality hydrocarbon reservoirs where looser sediments fill the holes penetrating hard limestone and the overburden pressure on infill sediments is mostly tolerated by their sturdier surrounding structure. They are also useful for the detection of erosional surfaces in seismic stratigraphic studies and imply possible relative sea level fall at the time of establishment. Karstic sinkholes are identified straightforwardly by using seismic geometric attributes (e.g. coherency, curvature) in which lateral variations are much more emphasized with respect to the original 3D seismic image. Then, seismic interpreters rely on their visual skills and experience in detecting roughly round objects in seismic attribute maps. In this paper, we introduce an image processing workflow to enhance selective edges in seismic attribute volumes stemming from karstic sinkholes and finally locate them in a high quality 3D seismic image by using circular Hough transform. Afterwards, we present a case study from an on-shore oilfield in southwest Iran, in which the proposed algorithm is applied and karstic sinkholes are traced. (paper)

A new system for seismic yield estimation of underground explosions

International Nuclear Information System (INIS)

Murphy, J.R.

1991-01-01

Research conducted over the past decade has led to the development of a number of innovative procedures for estimating the yields of underground nuclear explosions based on systematic analyses of digital seismic data recorded from these tests. In addition, a wide variety of new data regarding the geophysical environments at Soviet test locations have now become available as a result of the Joint Verification Experiment (JVE) and associated data exchanges. The system described in this paper represents an attempt to integrate all these new capabilities and data into a comprehensive operational prototype which can be used to obtain optimum seismic estimates of explosion yield together with quantitative measures of the uncertainty in those estimates. The implementation of this system has involved a wide variety of technical tasks, including the development of a comprehensive seismic database and related database access software, formulation of a graphical test site information interface for accessing available information on explosion source conditions, design of an interactive seismic analyst station for use in processing the observed data to extract the required magnitude measures and the incorporation of formal statistical analysis modules for use in yield estimation and assessment

Seismic evidence of Messinian salt in opposite margins of West Mediterranean

Science.gov (United States)

Mocnik, Arianna; Camerlenghi, Angelo; Del Ben, Anna; Geletti, Riccardo; Wardell, Nigel; Zgur, Fabrizio

2015-04-01

The post drift Messinian Salinity Crisis (MSC) affected the whole Mediterranean basin, with deposition of evaporitic sequences in the deep basins, in the lower continental slopes, and in several shallower marginal basins; usually, in the continental margins, the MSC originated noticeable erosional truncations that locally cause important hiatuses in the pre-Messinian sequences, covered by the Plio-Quaternary sediments. In this work we focus on the MSC seismic signature of two new seismic datasets acquired in 2010 (West Sardinia offshore) and in 2012 (within the Eurofleet project SALTFLU in the South Balearic continental margin and the northern Algero abyssal plain). The "Messinian trilogy" recognized in the West-Mediterranean abyssal plain, is characterized by different seismic facies: the Lower evaporite Unit (LU), the salt Mobile Unit (MU) and the Upper evaporite mainly gypsiferous Unit (UU). Both seismic datasets show the presence of the Messinian trilogy also if the LU is not always clearly interpretable due to the strong seismic signal absorption by the halite layers; the salt thickness of the MU is similar in both the basins as also the thickness and stratigraphy of the UU. The Upper Unit (UU) is made up of a well reflecting package of about 10 reflectors, partially deformed by salt tectonic and characterized by a thin transparent layer that we interpreted as salt sequence inner the shallower part of the UU. Below the stratified UU, the MU exhibits a transparent layer in the deep basin and also on the foot of the slope, where a negative reflector, related to the high interval velocity of salt, marks its base. The halokinetic processes are not homogeneously distributed in the region, forming a great number of diapirs on the foot of the slope (due to the pression of the slided sediments) and giant domes toward the deep basin (due to the higher thickness of the Plio-quaternary sediments). This distribution seems to be related to the amount of salt and of the

Probing the internal structure of the asteriod Didymoon with a passive seismic investigation

Science.gov (United States)

Murdoch, N.; Hempel, S.; Pou, L.; Cadu, A.; Garcia, R. F.; Mimoun, D.; Margerin, L.; Karatekin, O.

2017-09-01

Understanding the internal structure of an asteroid has important implications for interpreting its evolutionary history, for understanding its continuing geological evolution, and also for asteroid deflection and in-situ space resource utilisation. Given the strong evidence that asteroids are seismically active, an in-situ passive seismic experiment could provide information about the asteroid surface and interior properties. Here, we discuss the natural seismic activity that may be present on Didymoon, the secondary component of asteroid (65803) Didymos. Our analysis of the tidal stresses in Didymoon shows that tidal quakes are likely to occur if the secondary has an eccentric orbit. Failure occurs most easily at the asteroid poles and close to the surface for both homogeneous and layered internal structures. Simulations of seismic wave propagation in Didymoon show that the seismic moment of even small meteoroid impacts can generate clearly observable body and surface waves if the asteroid's internal structure is homogeneous. The presence of a regolith layer over a consolidated core can result in the seismic energy becoming trapped in the regolith due to the strong impedance contrast at the regolith-core boundary. The inclusion of macro-porosity (voids) further complexifies the wavefield due to increased scattering. The most prominent seismic waves are always found to be those traveling along the surface of the asteroid and those focusing in the antipodal point of the seismic source. We find also that the waveforms and ground acceleration spectra allow discrimination between the different internal structure models. Although the science return of a passive seismic experiment would be enhanced by having multiple seismic stations, one single seismic station can already vastly improve our knowledge about the seismic environment and sub-surface structure of an asteroid. We describe several seismic measurement techniques that could be applied in order to study the

The role of GIS in urban seismic risk studies: application to the city of Almería (southern Spain)

Science.gov (United States)

Rivas-Medina, A.; Gaspar-Escribano, J. M.; Benito, B.; Bernabé, M. A.

2013-11-01

This work describes the structure and characteristics of the geographic information system (GIS) developed for the urban seismic risk study of the city of Almería (southern Spain), identifying the stages in which the use of this tool proved to be very beneficial for adopting informed decisions throughout the execution of the work. After the completion of the regional emergency plans for seismic risk in Spain and its subsequent approval by the National Civil Defence Commission, the municipalities that need to develop specific local seismic risk plans have been identified. Hence, the next action is to develop urban seismic risk analyses at a proper scale (Urban Seismic Risk Evaluation - Risk-UR). For this evaluation, different factors influencing seismic risk such as seismic hazard, geotechnical soil characteristics, vulnerability of structures of the region, reparation costs of damaged buildings and exposed population are combined. All these variables are gathered and analysed within a GIS and subsequently used for seismic risk estimation. The GIS constitutes a highly useful working tool because it facilitates data interoperability, making the great volume of information required and the numerous processes that take part in the calculations easier to handle, speeding up the analysis and the interpretation and presentation of the results of the different working phases. The result of this study is based on a great set of variables that provide a comprehensive view of the urban seismic risk, such as the damage distribution of buildings and dwellings of different typologies, the mean damage and the number of uninhabitable buildings for the expected seismic motion, the number of dead and injured at different times of the day, the cost of reconstruction and repair of buildings, among others. These results are intended for interpretation and decision making in emergency management by unspecialised users (Civil Defence technicians and managers).

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

Understanding cyclic seismicity and ground deformation patterns at volcanoes: Intriguing lessons from Tungurahua volcano, Ecuador

Science.gov (United States)

Neuberg, Jürgen W.; Collinson, Amy S. D.; Mothes, Patricia A.; Ruiz, Mario C.; Aguaiza, Santiago

2018-01-01

Cyclic seismicity and ground deformation patterns are observed on many volcanoes worldwide where seismic swarms and the tilt of the volcanic flanks provide sensitive tools to assess the state of volcanic activity. Ground deformation at active volcanoes is often interpreted as pressure changes in a magmatic reservoir, and tilt is simply translated accordingly into inflation and deflation of such a reservoir. Tilt data recorded by an instrument in the summit area of Tungurahua volcano in Ecuador, however, show an intriguing and unexpected behaviour on several occasions: prior to a Vulcanian explosion when a pressurisation of the system would be expected, the tilt signal declines significantly, hence indicating depressurisation. At the same time, seismicity increases drastically. Envisaging that such a pattern could carry the potential to forecast Vulcanian explosions on Tungurahua, we use numerical modelling and reproduce the observed tilt patterns in both space and time. We demonstrate that the tilt signal can be more easily explained as caused by shear stress due to viscous flow resistance, rather than by pressurisation of the magmatic plumbing system. In general, our numerical models prove that if magma shear viscosity and ascent rate are high enough, the resulting shear stress is sufficient to generate a tilt signal as observed on Tungurahua. Furthermore, we address the interdependence of tilt and seismicity through shear stress partitioning and suggest that a joint interpretation of tilt and seismicity can shed new light on the eruption potential of silicic volcanoes.

A progressive methodology for seismic safety evaluation of gravity dams

International Nuclear Information System (INIS)

Ghrib, F.; Leger, P.; Tinawi, R.; Lupien, R.; Veilleux, M.

1995-01-01

A progressive methodology for the seismic safety evaluation of existing concrete gravity dams was described. The methodology was based on five structural analysis levels with increasing complexity to represent inertia forces, dam-foundation and dam-interaction mechanisms, as well as concrete cracking. The five levels were (1) preliminary screening, (2) pseudo-static method, (3) pseudo-dynamic method, (4) linear time history analysis, and (5) non-linear history analysis. The first four levels of analysis were applied for the seismic safety evaluation of Paugan gravity dam (Quebec). Results showed that internal forces from pseudo-dynamic, response spectra and transient finite element analyses could be used to interpret the dynamic stability of dams from familiar strength-based criteria. However, as soon as the base was cracked, the seismically induced forces were modified, and level IV analyses proved more suitable to handle rationally these complexities. 8 refs., 7 figs., 1 tab

Ore prospecting in the Iberian Pyrite Belt using seismic and potential-field data

International Nuclear Information System (INIS)

Carvalho, João; Pinto, Carlos; Sousa, Pedro; Matos, João Xavier

2011-01-01

Ore prospecting using gravimetric and magnetic data has become one of the traditional approaches used in past decades, often complemented with electric and electromagnetic methods. However, due to the problem of non-uniqueness inherent to potential-field modelling, constraints provided by structural methods such as seismic reflection are often used. During the exploration of polymetallic massive sulfide minerals in the Iberian Pyrite Belt, Figueira de Cavaleiros sector, located in the Sado Tertiary Basin, several gravimetric and magnetic anomalies were considered to be interesting targets. In order to reduce any ambiguity in the gravimetric modelling and to confirm the geological model of the area, two seismic reflection profiles were acquired. The interpretation of these profiles was assisted by three mechanical boreholes, two of which were located in the research area to make a seismostratigraphic interpretation. Unfortunately, the gravimetric modelling suggests that the anomaly has a lithological and structural origin and is not related to massive sulfides. Nevertheless, a good agreement between the seismic and potential-field data was achieved and new insights into the geological model for the region were obtained from this work, with accurate data about the Tertiary cover and Palaeozoic basement

The seismic project of the National Tsunami Hazard Mitigation Program

Science.gov (United States)

Oppenheimer, D.H.; Bittenbinder, A.N.; Bogaert, B.M.; Buland, R.P.; Dietz, L.D.; Hansen, R.A.; Malone, S.D.; McCreery, C.S.; Sokolowski, T.J.; Whitmore, P.M.; Weaver, C.S.

2005-01-01

In 1997, the Federal Emergency Management Agency (FEMA), National Oceanic and Atmospheric Administration (NOAA), U.S. Geological Survey (USGS), and the five western States of Alaska, California, Hawaii, Oregon, and Washington joined in a partnership called the National Tsunami Hazard Mitigation Program (NTHMP) to enhance the quality and quantity of seismic data provided to the NOAA tsunami warning centers in Alaska and Hawaii. The NTHMP funded a seismic project that now provides the warning centers with real-time seismic data over dedicated communication links and the Internet from regional seismic networks monitoring earthquakes in the five western states, the U.S. National Seismic Network in Colorado, and from domestic and global seismic stations operated by other agencies. The goal of the project is to reduce the time needed to issue a tsunami warning by providing the warning centers with high-dynamic range, broadband waveforms in near real time. An additional goal is to reduce the likelihood of issuing false tsunami warnings by rapidly providing to the warning centers parametric information on earthquakes that could indicate their tsunamigenic potential, such as hypocenters, magnitudes, moment tensors, and shake distribution maps. New or upgraded field instrumentation was installed over a 5-year period at 53 seismic stations in the five western states. Data from these instruments has been integrated into the seismic network utilizing Earthworm software. This network has significantly reduced the time needed to respond to teleseismic and regional earthquakes. Notably, the West Coast/Alaska Tsunami Warning Center responded to the 28 February 2001 Mw 6.8 Nisqually earthquake beneath Olympia, Washington within 2 minutes compared to an average response time of over 10 minutes for the previous 18 years. ?? Springer 2005.

The RING and Seismic Network: Data Acquisition of Co-located Stations

Science.gov (United States)

Falco, L.; Avallone, A.; Cattaneo, M.; Cecere, G.; Cogliano, R.; D'Agostino, N.; D'Ambrosio, C.; D'Anastasio, E.; Selvaggi, G.

2007-12-01

The plate boundary between Africa and Eurasia represents an interesting geodynamical region characterized by a complex pattern of deformation. First-order scientific problems regarding the existence of rigid blocks within the plate boundary, the present-day activity of the Calabrian subduction zone and the modes of release of seismic deformation are still awaiting for a better understanding. To address these issues, the INGV (Istituto Nazionale Geofisica e Vulcanlogia) deployed a permanent, integrated and real-time monitoring GPS network (RING) all over Italy. RING is now constituted by about 120 stations. The CGPS sites, acquiring at 1Hz and 30s sampling rate, are integrated either with broad band or very broad band seismometers and accelerometers for an improved definition of the seismically active regions. Most of the sites are connected to the acquisition centre (located in Rome and duplicated in Grottaminarda) through a satellite system (VSAT), while the remaining sites transmit data by Internet and classical phone connections. The satellite data transmission and the integration with seismic instruments makes this network one of the most innovative CGPS networks in Europe. The heterogeneity of the installed instrumentation, the transmission types and the increasing number of stations needed a central monitoring and acquisition system. A central acquisition system has been developed in Grottaminarda in southern Italy. Regarding the seismic monitoring we chose to use the open source system Earthworm, developed by USGS, with which we store waveforms and implement automatic localization of the seismic events occurring in the area. As most of the GPS sites are acquired by means of Nanometrics satellite technology, we developed a specific software (GpsView), written in Java, to monitor the state of health of those CGPS. This software receives GPS data from NaqsServer (Nanometrics acquisition system) and outputs information about the sites (i.e. approx position

Exploiting IoT Technologies and Open Source Components for Smart Seismic Network Instrumentation

Science.gov (United States)

Germenis, N. G.; Koulamas, C. A.; Foundas, P. N.

2017-12-01

The data collection infrastructure of any seismic network poses a number of requirements and trade-offs related to accuracy, reliability, power autonomy and installation & operational costs. Having the right hardware design at the edge of this infrastructure, embedded software running inside the instruments is the heart of pre-processing and communication services implementation and their integration with the central storage and processing facilities of the seismic network. This work demonstrates the feasibility and benefits of exploiting software components from heterogeneous sources in order to realize a smart seismic data logger, achieving higher reliability, faster integration and less development and testing costs of critical functionality that is in turn responsible for the cost and power efficient operation of the device. The instrument's software builds on top of widely used open source components around the Linux kernel with real-time extensions, the core Debian Linux distribution, the earthworm and seiscomp tooling frameworks, as well as components from the Internet of Things (IoT) world, such as the CoAP and MQTT protocols for the signaling planes, besides the widely used de-facto standards of the application domain at the data plane, such as the SeedLink protocol. By using an innovative integration of features based on lower level GPL components of the seiscomp suite with higher level processing earthworm components, coupled with IoT protocol extensions to the latter, the instrument can implement smart functionality such as network controlled, event triggered data transmission in parallel with edge archiving and on demand, short term historical data retrieval.

Integration of Electrical Resistivity and Seismic Refraction using Combine Inversion for Detecting Material Deposits of Impact Crater at Bukit Bunuh, Lenggong, Perak

Science.gov (United States)

Yusoh, R.; Saad, R.; Saidin, M.; Muhammad, S. B.; Anda, S. T.

2018-04-01

Both electrical resistivity and seismic refraction profiling has become a common method in pre-investigations for visualizing subsurface structure. The encouragement to use these methods is that combined of both methods can decrease the obscure inherent to the distinctive use of these methods. Both method have their individual software packages for data inversion, but potential to combine certain geophysical methods are restricted; however, the research algorithms that have this functionality was exists and are evaluated personally. The interpretation of subsurface were improve by combining inversion data from both method by influence each other models using closure coupling; thus, by implementing both methods to support each other which could improve the subsurface interpretation. These methods were applied on a field dataset from a pre-investigation for archeology in finding the material deposits of impact crater. There were no major changes in the inverted model by combining data inversion for this archetype which probably due to complex geology. The combine data analysis shows the deposit material start from ground surface to 20 meter depth which the class separation clearly separate the deposit material.

Study on structural seismic margin and probabilistic seismic risk. Development of a structural capacity-seismic risk diagram

International Nuclear Information System (INIS)

Nakajima, Masato; Ohtori, Yasuki; Hirata, Kazuta

2010-01-01

Seismic margin is extremely important index and information when we evaluate and account seismic safety of critical structures, systems and components quantitatively. Therefore, it is required that electric power companies evaluate the seismic margin of each plant in back-check of nuclear power plants in Japan. The seismic margin of structures is usually defined as a structural capacity margin corresponding to design earthquake ground motion. However, there is little agreement as to the definition of the seismic margin and we have no knowledge about a relationship between the seismic margin and seismic risk (annual failure probability) which is obtained in PSA (Probabilistic Safety Assessment). The purpose of this report is to discuss a definition of structural seismic margin and to develop a diagram which can identify a relation between seismic margin and seismic risk. The main results of this paper are described as follows: (1) We develop seismic margin which is defined based on the fact that intensity of earthquake ground motion is more appropriate than the conventional definition (i.e., the response-based seismic margin) for the following reasons: -seismic margin based on earthquake ground motion is invariant where different typed structures are considered, -stakeholders can understand the seismic margin based on the earthquake ground motion better than the response-based one. (2) The developed seismic margin-risk diagram facilitates us to judge easily whether we need to perform detailed probabilistic risk analysis or only deterministic analysis, given that the reference risk level although information on the uncertainty parameter beta is not obtained. (3) We have performed numerical simulations based on the developed method for four sites in Japan. The structural capacity-risk diagram differs depending on each location because the diagram is greatly influenced by seismic hazard information for a target site. Furthermore, the required structural capacity

Seismic hydraulic fracture migration originated by successive deep magma pulses: The 2011-2013 seismic series associated to the volcanic activity of El Hierro Island

Science.gov (United States)

Díaz-Moreno, A.; Ibáñez, J. M.; De Angelis, S.; García-Yeguas, A.; Prudencio, J.; Morales, J.; Tuvè, T.; García, L.

2015-11-01

In this manuscript we present a new interpretation of the seismic series that accompanied eruptive activity off the coast of El Hierro, Canary Islands, during 2011-2013. We estimated temporal variations of the Gutenberg-Richter b value throughout the period of analysis, and performed high-precision relocations of the preeruptive and syneruptive seismicity using a realistic 3-D velocity model. Our results suggest that eruptive activity and the accompanying seismicity were caused by repeated injections of magma from the mantle into the lower crust. These magma pulses occurred within a small and well-defined volume resulting in the emplacement of fresh magma along the crust-mantle boundary underneath El Hierro. We analyzed the distribution of earthquake hypocenters in time and space in order to assess seismic diffusivity in the lower crust. Our results suggest that very high earthquake rates underneath El Hierro represent the response of a stable lower crust to stress perturbations with pulsatory character, linked to the injection of magma from the mantle. Magma input from depth caused large stress perturbations to propagate into the lower crust generating energetic seismic swarms. The absence of any preferential alignment in the spatial pattern of seismicity reinforces our hypothesis that stress perturbation and related seismicity, had diffusive character. We conclude that the temporal and spatial evolution of seismicity was neither tracking the path of magma migration nor it defines the boundaries of magma storage volumes such as a midcrustal sill. Our conceptual model considers pulsatory magma injection from the upper mantle and its propagation along the Moho. We suggest, within this framework, that the spatial and temporal distributions of earthquake hypocenters reflect hydraulic fracturing processes associated with stress propagation due to magma movement.

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

Widespread seismicity excitation throughout central Japan following the 2011 M=9.0 Tohoku earthquake and its interpretation by Coulomb stress transfer

Science.gov (United States)

Toda, S.; Stein, R.S.; Lin, J.

2011-01-01

We report on a broad and unprecedented increase in seismicity rate following the M=9.0 Tohoku mainshock for M ≥ 2 earthquakes over inland Japan, parts of the Japan Sea and Izu islands, at distances of up to 425 km from the locus of high (≥15 m) seismic slip on the megathrust. Such an increase was not seen for the 2004 M=9.1 Sumatra or 2010 M=8.8 Chile earthquakes, but they lacked the seismic networks necessary to detect such small events. Here we explore the possibility that the rate changes are the product of static Coulomb stress transfer to small faults. We use the nodal planes of M ≥ 3.5 earthquakes as proxies for such small active faults, and find that of fifteen regions averaging ~80 by 80 km in size, 11 show a positive association between calculated stress changes and the observed seismicity rate change, 3 show a negative correlation, and for one the changes are too small to assess. This work demonstrates that seismicity can turn on in the nominal stress shadow of a mainshock as long as small geometrically diverse active faults exist there, which is likely quite common.

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.

Waste Isolation Pilot Plant (WIPP) site gravity survey and interpretation

International Nuclear Information System (INIS)

Barrows, L.J.; Fett, J.D.

1983-04-01

A portion of the WIPP site has been extensively surveyed with high-precision gravity. The main survey (in T22S, R31E) covered a rectangular area 2 by 4-1/3 mi encompassing all of WIPP site Zone II and part of the disturbed zone to the north of the site. Stations were at 293-ft intervals along 13 north-south lines 880 ft apart. The data are considered accurate to within a few hundredths of a milligal. Long-wavelength gravity anomalies correlate well with seismic time structures on horizons below the Castile Formation. Both the gravity anomalies and the seismic time structures are interpreted as resulting from related density and velocity variations within the Ochoan Series. Shorter wavelength negative gravity anomalies are interpreted as resulting from bulk density alteration in the vicinity of karst conduits. The WIPP gravity survey was unable to resolve low-amplitude, long-wavelength anomalies that should result from the geologic structures within the disturbed zone. It did indicate the degree and character of karst development within the surveyed area

Reanalysis and evaluation of seismic response of reactor building

International Nuclear Information System (INIS)

Li Zhongcheng; Li Zhongxian

2005-01-01

For the Ling Ao phase-I (LA-I) Nuclear Power Plant (NPP), its' seismic analysis of nuclear island was in accordance with the approaches in RCC-G standard for the model M310 in France, in which the Simplified impedance method was employed for the consideration of SSI. Thanks to the rapid progress being made in upgrading the evaluation technology and the capability of data processing systems, methods and software tools for the SSI analysis have experienced significant development all over the world. Focused on the model of reactor building of the LA-I NPP, in this paper the more sophisticated 3D half-space continuum impedance method based on the Green functions is used to analyze the functions of the soil, and then the seismic responses of the coupled SSI system are calculated and compared with the corresponding design values. It demonstrates that the design method provides a set of conservatively safe results. The conclusions from the study are hopefully to provide some important references to the assessment of seismic safety margin for LA-I NPP. (authors)

Interpretation of shallow seismic refraction data using raytracing inversion: A simple example from a groundwater resource study in Pocatello, Idaho

International Nuclear Information System (INIS)

Pelton, J.R.; Dougherty, M.E.; Welhan, J.A.

1994-01-01

Raytracing inversion of seismic refraction data acquired on the northeast side of the Portneuf River valley at the base of Red HIll in Pocatello shows that the thickness of Quaternary and Tertiary sediments above much older quartzite bedrock is 46-53 m. This estimate, which was derived independently of any borehole data, is consistent with the lithologic log of a recently drilled monitoring well (PMW-3) drilled about 1 km northwest of the seismic line. The water table is horizontal at a depth of 22-29 m beneath a gently rising topography (20m/km to the southeast) in the vicinity of the seismic line. The top surface of the quartzite bedrock is either horizontal or dips slightly (1.2 degrees) to the southeast. Unsaturated sediments are characterized by a strong vertical velocity gradient (13-16 s -1 ) probably caused by compaction of the near-surface materials. Seismic P-velocities are estimated as follows: unsaturated sediments (320-780 m/s), saturated sediments (1,670 m/s), and quartzite bedrock (2,950-3,050 m/s). 52 refs

Salton Trough Post-seismic Afterslip, Viscoelastic Response, and Contribution to Regional Hazard

Science.gov (United States)

Parker, J. W.; Donnellan, A.; Lyzenga, G. A.

2012-12-01

The El Mayor-Cucapah M7.2 April 4 2010 earthquake in Baja California may have affected accumulated hazard to Southern California cities due to loading of regional faults including the Elsinore, San Jacinto and southern San Andreas, faults which already have over a century of tectonic loading. We examine changes observed via multiple seismic and geodetic techniques, including micro seismicity and proposed seismicity-based indicators of hazard, high-quality fault models, the Plate Boundary Observatory GNSS array (with 174 stations showing post-seismic transients with greater than 1 mm amplitude), and interferometric radar maps from UAVSAR (aircraft) flights, showing a network of aseismic fault slip events at distances up to 60 km from the end of the surface rupture. Finite element modeling is used to compute the expected coseismic motions at GPS stations with general agreement, including coseismic uplift at sites ~200 km north of the rupture. Postseismic response is also compared, with GNSS and also with the CIG software "RELAX." An initial examination of hazard is made comparing micro seismicity-based metrics, fault models, and changes to coulomb stress on nearby faults using the finite element model. Comparison of seismicity with interferograms and historic earthquakes show aseismic slip occurs on fault segments that have had earthquakes in the last 70 years, while other segments show no slip at the surface but do show high triggered seismicity. UAVSAR-based estimates of fault slip can be incorporated into the finite element model to correct Coloumb stress change.

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

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.

Bayesian Inference for Signal-Based Seismic Monitoring

Science.gov (United States)

Moore, D.

2015-12-01

Traditional seismic monitoring systems rely on discrete detections produced by station processing software, discarding significant information present in the original recorded signal. SIG-VISA (Signal-based Vertically Integrated Seismic Analysis) is a system for global seismic monitoring through Bayesian inference on seismic signals. By modeling signals directly, our forward model is able to incorporate a rich representation of the physics underlying the signal generation process, including source mechanisms, wave propagation, and station response. This allows inference in the model to recover the qualitative behavior of recent geophysical methods including waveform matching and double-differencing, all as part of a unified Bayesian monitoring system that simultaneously detects and locates events from a global network of stations. We demonstrate recent progress in scaling up SIG-VISA to efficiently process the data stream of global signals recorded by the International Monitoring System (IMS), including comparisons against existing processing methods that show increased sensitivity from our signal-based model and in particular the ability to locate events (including aftershock sequences that can tax analyst processing) precisely from waveform correlation effects. We also provide a Bayesian analysis of an alleged low-magnitude event near the DPRK test site in May 2010 [1] [2], investigating whether such an event could plausibly be detected through automated processing in a signal-based monitoring system. [1] Zhang, Miao and Wen, Lianxing. "Seismological Evidence for a Low-Yield Nuclear Test on 12 May 2010 in North Korea". Seismological Research Letters, January/February 2015. [2] Richards, Paul. "A Seismic Event in North Korea on 12 May 2010". CTBTO SnT 2015 oral presentation, video at https://video-archive.ctbto.org/index.php/kmc/preview/partner_id/103/uiconf_id/4421629/entry_id/0_ymmtpps0/delivery/http

Seismic Analysis of a Viscoelastic Damping Isolator

Directory of Open Access Journals (Sweden)

Bo-Wun Huang

2015-01-01

Full Text Available Seismic prevention issues are discussed much more seriously around the world after Fukushima earthquake, Japan, April 2011, especially for those countries which are near the earthquake zone. Approximately 1.8×1012 kilograms of explosive energy will be released from a magnitude 9 earthquake. It destroys most of the unprotected infrastructure within several tens of miles in diameter from the epicenter. People can feel the earthquake even if living hundreds of miles away. This study is a seismic simulation analysis for an innovated and improved design of viscoelastic damping isolator, which can be more effectively applied to earthquake prevention and damage reduction of high-rise buildings, roads, bridges, power generation facilities, and so forth, from earthquake disaster. Solidworks graphic software is used to draw the 3D geometric model of the viscoelastic isolator. The dynamic behavior of the viscoelastic isolator through shock impact of specific earthquake loading, recorded by a seismometer, is obtained via ANSYS finite element package. The amplitude of the isolator is quickly reduced by the viscoelastic material in the device and is shown in a time response diagram. The result of this analysis can be a crucial reference when improving the design of a seismic isolator.

A new seismic station in Romania the Bucovina seismic array

International Nuclear Information System (INIS)

Grigore, Adrian; Grecu, Bogdan; Ionescu, Constantin; Ghica, Daniela; Popa, Mihaela; Rizescu, Mihaela

2002-01-01

Recently, a new seismic monitoring station, the Bucovina Seismic Array, has been established in the northern part of Romania, in a joint effort of the Air Force Technical Applications Center, USA, and the National Institute for Earth Physics, Romania. The array consists of 10 seismic sensors (9 short-period and one broad band) located in boreholes and distributed in a 5 x 5 km area. On July 24, 2002 the official Opening Ceremony of Bucovina Seismic Array took place in the area near the city of Campulung Moldovenesc in the presence of Romanian Prime Minister, Adrian Nastase. Starting with this date, the new seismic monitoring system became fully operational by continuous recording and transmitting data in real-time to the National Data Center of Romania, in Bucharest and to the National Data Center of USA, in Florida. Bucovina Seismic Array, added to the present Seismic Network, will provide much better seismic monitoring coverage of Romania's territory, on-scale recording for weak-to-strong events, and will contribute to advanced seismological studies on seismic hazard and risk, local effects and microzonation, seismic source physics, Earth structure. (authors)

Seismic behaviour of PWR fuel assemblies model and its validation

International Nuclear Information System (INIS)

Queval, J.C.; Gantenbein, F.; Brochard, D.; Benjedidia, A.

1991-01-01

The validity of the models simulating the seismic behaviour of PWR cores can only be exactly demonstrated by seismic testing on groups of fuel assemblies. Shake table seismic tests of rows of assembly mock-ups, conducted by the CEA in conjunction with FRAMATOME, are presented in reference /1/. This paper addresses the initial comparisons between model and test results for a row of five assemblies in air. Two models are used: a model with a single beam per assembly, used regularly in accident analyses, and described in reference /2/, and a more refined 2-beam per assembly model, geared mainly towards interpretation of test results. The 2-beam model is discussed first, together with parametric studies used to characterize it, and the study of the assembly row for a period limited to 2 seconds and for different excitation levels. For the 1-beam model assembly used in applications, the row is studied over the total test time, i.e twenty seconds, which covers the average duration of the core seismic behaviour studies, and for a peak exciting acceleration value at 0.4 g, which corresponds to the SSE level of the reference spectrum

Investigating the Deep Seismic Structure of Volcan de Colima, Mexico

Science.gov (United States)

Gardine, M. D.; Reyes, T. D.; West, M. E.

2006-12-01

We present early-stage results from a novel seismic investigation at Volcan de Colima. The project is a collaboration between the Observatorio Vulcanologico de la Universidad de Colima and the University of Alaska Fairbanks. In January 2006, twenty broadband seismometers were deployed in a wide-aperture array around the volcano as part of the IRIS/PASSCAL-supported Colima Volcano Deep Seismic Experiment (CODEX). They are scheduled to be in the field for eighteen months. Data from the first several months of the deployment have been used to characterize both the regional seismicity and the seismicity of the volcano, as recorded by the temporary array. Colima volcano has an unusually well-distributed suite of earthquakes on the local, regional and teleseismic scale. Data recorded close to the edifice provide an opportunity to explore the daily explosive activity exhibited by the volcano. The diversity of regional and teleseismic earthquake source regions make Colima an ideal place to probe the deep magmatic structure of a prodigous volcanic center. Results will be interpreted in the context of pre-existing petrologic models to address the relative role of crust and mantle in governing the evolution of an andesitic arc volcano.

AECB workshop on seismic hazard assessment in Southern Ontario. Program, list of participants and abstracts

International Nuclear Information System (INIS)

1995-01-01

The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: (1) The importance of geological and geophysical observations for the determination of seismic sources, (2) Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information, (3) Methods and data which should be used for characterizing the seismicity parameters of seismic sources, and (4) Methods for assessment of vibratory ground motion hazard. This document presents a copy of the workshop program, the list of participants and extended abstracts received from speakers. It was distributed to the participants prior to the workshop. The abstracts were intended to provide advance information and to afford some basis for meaningful discussion and exchange of information

AECB workshop on seismic hazard assessment in Southern Ontario. Program, list of participants and abstracts

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-31

The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: (1) The importance of geological and geophysical observations for the determination of seismic sources, (2) Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information, (3) Methods and data which should be used for characterizing the seismicity parameters of seismic sources, and (4) Methods for assessment of vibratory ground motion hazard. This document presents a copy of the workshop program, the list of participants and extended abstracts received from speakers. It was distributed to the participants prior to the workshop. The abstracts were intended to provide advance information and to afford some basis for meaningful discussion and exchange of information.

100 years of seismic research on the Moho

Science.gov (United States)

Prodehl, Claus; Kennett, Brian; Artemieva, Irina M.; Thybo, Hans

2013-12-01

The detection of a seismic boundary, the “Moho”, between the outermost shell of the Earth, the Earth's crust, and the Earth's mantle by A. Mohorovičić was the consequence of increased insight into the propagation of seismic waves caused by earthquakes. This short history of seismic research on the Moho is primarily based on the comprehensive overview of the worldwide history of seismological studies of the Earth's crust using controlled sources from 1850 to 2005, by Prodehl and Mooney (2012). Though the art of applying explosions, so-called “artificial events”, as energy sources for studies of the uppermost crustal layers began in the early 1900s, its effective use for studying the entire crust only began at the end of World War II. From 1945 onwards, controlled-source seismology has been the major approach to study details of the crust and underlying crust-mantle boundary, the Moho. The subsequent description of history of controlled-source crustal seismology and its seminal results is subdivided into separate chapters for each decade, highlighting the major advances achieved during that decade in terms of data acquisition, processing technology, and interpretation methods. Since the late 1980s, passive seismology using distant earthquakes has played an increasingly important role in studies of crustal structure. The receiver function technique exploiting conversions between P and SV waves at discontinuities in seismic wavespeed below a seismic station has been extensively applied to the increasing numbers of permanent and portable broad-band seismic stations across the globe. Receiver function studies supplement controlled source work with improved geographic coverage and now make a significant contribution to knowledge of the nature of the crust and the depth to Moho.

Multiscale seismicity analysis and forecasting: examples from the Western Pacific and Iceland

International Nuclear Information System (INIS)

Eberhard, A. J.

2014-01-01

Seismicity forecasting has three major challenges: (1) the development of models or algorithms to forecast of seismicity, (2) the evaluation and testing of the forecasts and (3) the need for an appropriate software package. The goal of my thesis is to improve seismicity forecasting. I do this by contributing to a solution for all of the three challenges, using data from the West Pacific and from Iceland. The thesis is split into three chapters, each focusing on one of the challenges and each chapter will be (or already is) published in a peer-reviewed scientific journal. This first chapter (chapter 2 in this thesis) is about testing of seismic forecasts. The Collaboratory for the Study of Earthquake Predictability (CSEP, www.cseptesting.org; Jordan, 2006) has been conducting an earthquake forecast experiment in the western Pacific. The data and forecasts of this experiment serve as example for this chapter. For the three participating statistical models, I analyze the first four years of this experiment. I use likelihood-based metrics to evaluate the consistency of the forecasts with the observed target earthquakes, and I apply measures based on Student’s t-test and the Wilcoxon signed-rank test to compare the forecasts. I estimate also the uncertainties of the test results resulting from uncertainties in earthquake location and seismic moment. The estimated uncertainties are relatively small and suggest that the evaluation metrics are relatively robust. In chapter 3 I focus on the forecast itself with an Operational Earthquake Forecasting (OEF) experiment–forecasting seismicity in near real-time–for Iceland. The goal is to estimate the feasibility of OEF with the state-of-the-art models. I use the period between 2007 and 2010 and a sparsely processed catalogue as basis for a retrospective forecasting experiment with next-day forecasts. To better understand the effect of updating cycle on the probability gain I also use scheme in which the forecasts are

Multiscale seismicity analysis and forecasting: examples from the Western Pacific and Iceland

Energy Technology Data Exchange (ETDEWEB)

Eberhard, A. J.

2014-07-01

Seismicity forecasting has three major challenges: (1) the development of models or algorithms to forecast of seismicity, (2) the evaluation and testing of the forecasts and (3) the need for an appropriate software package. The goal of my thesis is to improve seismicity forecasting. I do this by contributing to a solution for all of the three challenges, using data from the West Pacific and from Iceland. The thesis is split into three chapters, each focusing on one of the challenges and each chapter will be (or already is) published in a peer-reviewed scientific journal. This first chapter (chapter 2 in this thesis) is about testing of seismic forecasts. The Collaboratory for the Study of Earthquake Predictability (CSEP, www.cseptesting.org; Jordan, 2006) has been conducting an earthquake forecast experiment in the western Pacific. The data and forecasts of this experiment serve as example for this chapter. For the three participating statistical models, I analyze the first four years of this experiment. I use likelihood-based metrics to evaluate the consistency of the forecasts with the observed target earthquakes, and I apply measures based on Student’s t-test and the Wilcoxon signed-rank test to compare the forecasts. I estimate also the uncertainties of the test results resulting from uncertainties in earthquake location and seismic moment. The estimated uncertainties are relatively small and suggest that the evaluation metrics are relatively robust. In chapter 3 I focus on the forecast itself with an Operational Earthquake Forecasting (OEF) experiment–forecasting seismicity in near real-time–for Iceland. The goal is to estimate the feasibility of OEF with the state-of-the-art models. I use the period between 2007 and 2010 and a sparsely processed catalogue as basis for a retrospective forecasting experiment with next-day forecasts. To better understand the effect of updating cycle on the probability gain I also use scheme in which the forecasts are

Recommendation systems in software engineering

CERN Document Server

Robillard, Martin P; Walker, Robert J; Zimmermann, Thomas

2014-01-01

With the growth of public and private data stores and the emergence of off-the-shelf data-mining technology, recommendation systems have emerged that specifically address the unique challenges of navigating and interpreting software engineering data.This book collects, structures and formalizes knowledge on recommendation systems in software engineering. It adopts a pragmatic approach with an explicit focus on system design, implementation, and evaluation. The book is divided into three parts: "Part I - Techniques" introduces basics for building recommenders in software engineering, including techniques for collecting and processing software engineering data, but also for presenting recommendations to users as part of their workflow.?"Part II - Evaluation" summarizes methods and experimental designs for evaluating recommendations in software engineering.?"Part III - Applications" describes needs, issues and solution concepts involved in entire recommendation systems for specific software engineering tasks, fo...

TkPl_SU: An Open-source Perl Script Builder for Seismic Unix

Science.gov (United States)

Lorenzo, J. M.

2017-12-01

TkPl_SU (beta) is a graphical user interface (GUI) to select parameters for Seismic Unix (SU) modules. Seismic Unix (Stockwell, 1999) is a widely distributed free software package for processing seismic reflection and signal processing. Perl/Tk is a mature, well-documented and free object-oriented graphical user interface for Perl. In a classroom environment, shell scripting of SU modules engages students and helps focus on the theoretical limitations and strengths of signal processing. However, complex interactive processing stages, e.g., selection of optimal stacking velocities, killing bad data traces, or spectral analysis requires advanced flows beyond the scope of introductory classes. In a research setting, special functionality from other free seismic processing software such as SioSeis (UCSD-NSF) can be incorporated readily via an object-oriented style to programming. An object oriented approach is a first step toward efficient extensible programming of multi-step processes, and a simple GUI simplifies parameter selection and decision making. Currently, in TkPl_SU, Perl 5 packages wrap 19 of the most common SU modules that are used in teaching undergraduate and first-year graduate student classes (e.g., filtering, display, velocity analysis and stacking). Perl packages (classes) can advantageously add new functionality around each module and clarify parameter names for easier usage. For example, through the use of methods, packages can isolate the user from repetitive control structures, as well as replace the names of abbreviated parameters with self-describing names. Moose, an extension of the Perl 5 object system, greatly facilitates an object-oriented style. Perl wrappers are self-documenting via Perl programming document markup language.

Hurst analysis of seismicity in Corinth rift and Mygdonia graben (Greece)

International Nuclear Information System (INIS)

Gkarlaouni, Charikleia; Lasocki, Stanislaw; Papadimitriou, Eleftheria; George, Tsaklidis

2017-01-01

Highlights: • Long-term memory properties of seismicity are investigated using R/S analysis. • Small and moderate earthquake interevent times exhibit strong interdependence. • Strong earthquake occurrence indicates a memoryless process. • Seismicity variations in time are associated with Hurst temporal fluctuations. - Abstract: Temporal and spatial analysis of seismicity is performed via the Rescaled Range (R/S) analysis for revealing the hidden characteristics of long memory dependence and clustering between earthquakes. The analysis is applied in two seismogenic units belonging to the extensional Aegean back-arc region, namely the Corinth rift and the Mygdonian graben. The Hurst exponent estimations were used for the interpretation of earthquake collective properties, regarding magnitude, interevent time and interevent epicentral distance for consecutive events. Additional stochastic tools were then engaged for the validation of the results. Τhe analysis outcome is a significant long memory content in the seismic process of both areas, especially for the interevent time of recent micro seismicity and moderate earthquakes in the last decades. This property is not ascertained for the strong (M ≥ 6.0) historical earthquakes indicating that stronger events are rather independent, whereas the weaker ones may be primary carriers of persistence in the seismogenesis process.

Quantifying uncertainties of seismic Bayesian inversion of Northern Great Plains

Science.gov (United States)

Gao, C.; Lekic, V.

2017-12-01

Elastic waves excited by earthquakes are the fundamental observations of the seismological studies. Seismologists measure information such as travel time, amplitude, and polarization to infer the properties of earthquake source, seismic wave propagation, and subsurface structure. Across numerous applications, seismic imaging has been able to take advantage of complimentary seismic observables to constrain profiles and lateral variations of Earth's elastic properties. Moreover, seismic imaging plays a unique role in multidisciplinary studies of geoscience by providing direct constraints on the unreachable interior of the Earth. Accurate quantification of uncertainties of inferences made from seismic observations is of paramount importance for interpreting seismic images and testing geological hypotheses. However, such quantification remains challenging and subjective due to the non-linearity and non-uniqueness of geophysical inverse problem. In this project, we apply a reverse jump Markov chain Monte Carlo (rjMcMC) algorithm for a transdimensional Bayesian inversion of continental lithosphere structure. Such inversion allows us to quantify the uncertainties of inversion results by inverting for an ensemble solution. It also yields an adaptive parameterization that enables simultaneous inversion of different elastic properties without imposing strong prior information on the relationship between them. We present retrieved profiles of shear velocity (Vs) and radial anisotropy in Northern Great Plains using measurements from USArray stations. We use both seismic surface wave dispersion and receiver function data due to their complementary constraints of lithosphere structure. Furthermore, we analyze the uncertainties of both individual and joint inversion of those two data types to quantify the benefit of doing joint inversion. As an application, we infer the variation of Moho depths and crustal layering across the northern Great Plains.

Refraction seismic surveys in the investigation trench TK3 area in Olkiluoto, Eurajoki 2004

Energy Technology Data Exchange (ETDEWEB)

Ihalainen, M. [Suomen Malmi Oy, Espoo (Finland)

2005-03-15

Posiva Oy submitted an application for the Decision in Principle to the Finnish Government in May 1999. A positive decision was made at the end of 2000 by the Government. The Finnish Parliament ratified the Decision in Principle on the final disposal facility for spent nuclear fuel at Olkiluoto, Eurajoki in May 2001. The decision makes it possible for Posiva to focus the confirming bedrock investigations at Olkiluoto, where in the next few years an underground rock characterisation facility, the ONKALO, will be constructed. As a part of the investigations Suomen Malmi Oy (Smoy) conducted refraction seismic surveys at Olkiluoto site in Eurajoki. The work was ordered by Posiva Oy. The field work was carried out during May and June 2004. On five profiles S70-S74 totally 1002.5 m was surveyed. The purpose of the work was to determine the overburden thickness and to study bedrock properties, e.g. eventual fractured zones. The work consisted of staking, levelling, seismic measurements, interpretation and reporting. Fieldwork and interpretation were concluded by May and June 2004. Previously in 2000 and 2002 Smoy has carried out 33.0 km of seismic surveys in the area. (orig.)

CARES (Computer Analysis for Rapid Evaluation of Structures) Version 1.0, seismic module

International Nuclear Information System (INIS)

Xu, J.; Philippacopoulas, A.J.; Miller, C.A.; Costantino, C.J.

1990-07-01

During FY's 1988 and 1989, Brookhaven National Laboratory (BNL) developed the CARES system (Computer Analysis for Rapid Evaluation of Structures) for the US Nuclear Regulatory Commission (NRC). CARES is a PC software system which has been designed to perform structural response computations similar to those encountered in licensing reviews of nuclear power plant structures. The documentation of the Seismic Module of CARES consists of three volumes. This report represents Volume 3 of the volume documentation of the Seismic Module of CARES. It presents three sample problems typically encountered in the Soil-Structure Interaction analyses. 14 refs., 36 figs., 2 tabs

Seismic Facies of Pleistocene–Holocene Channel-fill Deposits in Bawean Island and Adjacent Waters, Southeast Java Sea

Directory of Open Access Journals (Sweden)

Ali Albab

2017-08-01

Full Text Available The late Pleistocene-Holocene stratigraphic architecture of the Bawean Island and surrounding waters, southeast Java Sea has been analyzed by using sparker seismic profiles. Geological interpretation of these seismic profiles revealed the widespread distribution of paleochannels with different shape and size in the present-day Java Sea. Two channel types can be distinguished based on its morphology: U-shaped channels in the western part and V-shaped channels in the eastern part. The stratigraphic successions were grouped into two major seismic units separated by different seismic boundaries. Characters of marine and fluvial deposits were determined based on seismic boundaries and internal reflectors. Three seismic facies can be identified within late Pleistocene – Holocene incised channel fills associated with SB2. The internal structure of incised-channels consist of chaotic reflector at the bottom, covered by parallel–sub parallel and almost reflection-free indicating the homogenous sediment deposited during the succession.

Nine-component vertical seismic profiling at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Balch, A.H.; Erdemir, C.; Spengler, R.W.; Hunter, W.C.

1996-01-01

Nine-component vertical seismic profiling has been conducted at the UE-25 UZ No. 16 borehole at Yucca Mountain, Nevada, in support of investigation of the hydrologic significance of fault and fracture systems. A large data set from multi-component sources and receivers allows state-of-the-art advances in processing using polarization filtering and reverse time migration, for enhanced interpretation of geologic features

Shahr-I Sokhta and its Masonry Walls from Structural and Seismicity Standpoint

Directory of Open Access Journals (Sweden)

Masoumi Mohammad Mehdi

2014-12-01

Full Text Available Shahr-I Sokhta, Burned City, located in the south of Zabol, Sistan where founded circa 3200 BCE and some part of the city was burnt. Marvelous finds such as the world's earliest known artificial eyeball, the first animation in the world, the oldest known backgammon, with its dice and so forth all in this city. Their expertise was merely not in handicrafts. In this work provided evidences which Burned City’s walls are highly resistance against seismic loads and has engineering aspects, a wall was simulated by a finite element software and seismically considerations was approve the walls minimal deformation even after circa five thousand years.

Application software profiles 2010

Energy Technology Data Exchange (ETDEWEB)

Anon.

2010-04-15

This article presented information on new software applications designed to facilitate petroleum exploration, drilling and production activities. Computer modelling and analysis enables oil and gas producers to characterize reservoirs, estimate reserves forecast production, plan operations and manage assets. Seven Calgary-based organizations were highlighted along with their sophisticated software tools, the applications and the new features available in each product. The geoSCOUT version 7.7 by GeoLOGIC Systems Ltd. integrates public and proprietary data on wells, well logs, reserves, pipelines, production, ownership and seismic location data. The Value Navigator and AFE Navigator by Energy Navigator provides control over reserves, production and cash flow forecasting. FAST Harmony, FAST Evolution, FAST CBM, FAST FieldNotes, Fast Piper, FAST RTA, FAST VirtuWell and FAST WellTest by Fekete Associates Inc. provide reserve evaluations for reservoir engineering projects and production data analysis. The esi.manage software program by 3esi improves business results for upstream oil and gas companies through enhanced decision making and workforce effectiveness. WELLFLO, PIPEFLO, FORGAS, OLGA, Drillbench, and MEPO wellbore solutions by Neotec provide unique platforms for flow simulation to optimize oil and gas production systems. Petrel, ECLIPSE, Avocet, PipeSim and Merak software tools by Schlumberger Information Solutions are petroleum systems modelling tools for geologic mapping, visualization modelling and reservoir engineering. StudioSL by Streamsim Technologies Inc. is a modelling tool for optimizing flood management. figs.

A story about estimation of a random field of boulders from incomplete seismic measurements

DEFF Research Database (Denmark)

Ditlevsen, Ove Dalager

2005-01-01

deposits along the tunnel line. By use of this important distribution information and of the observed homogeneity of the seismic point source field together with the physical properties of diffraction it became possible to make the wanted prediction. During the excavation the found boulders were counted......This paper reports on the statistical interpretation of seismic diffraction measurements of boulder locations. The measurements are made in a corridor along the planned tunnel line for the later realized bored tunnel through the till deposits under the East Channel of the Great Belt in Denmark...... graphical registrations on seismograms do not make a proper interpretation possible without detailed knowledge about the joint distribution of the primary dimensions of the boulders. Therefore separate measurements were made of the dimensions of boulders deposited visibly on the cliff beaches of the Great...

Local seismic network at the Olkiluoto site. Annual Report for 2007

International Nuclear Information System (INIS)

Saari, J.; Lakio, A.

2008-05-01

In February 2002, Posiva Oy established a local seismic network of six stations on the island of Olkiluoto. Later, in June 2004, the seismic network was expanded with two new seismic stations. At that time started the excavation of the underground characterisation facility (the ONKALO) and the basic operation procedure was changed more suitable for the demands of the new situation. In the beginning of 2006, the target area of the seismic monitoring expanded to semiregional scale. Four new seismic stations started in the beginning of February 2006 and the focus of interpretation was expanded to an area, called the seismic semi-regional area. At the end of 2006, two new borehole geophones were installed in order to improve the sensitivity and the depth resolution of the measurements inside the ONKALO block. The purpose of the microearthquake measurements at Olkiluoto is to improve understanding of the structure, behaviour and long term stability of the bedrock. The studies include both tectonic and excavation-induced microearthquakes. An additional task of monitoring is related to safeguarding of the ONKALO. This report gives the results of microseismic monitoring during the year 2007. Also the changes in the structure and the operation procedure of the network are described. The true orientation of the borehole sensor OL-OS13 was calculated. The correct orientation of triaxial seismometer is essential when the fault plane solution of an earthquake is calculated. The other borehole sensor OL-OS14 was permanently disconnected in October 2007. The network has operated continuously in 2007. Altogether 2207 events have been located in the Olkiluoto area, in reported time period. Altogether 2207 events have been located in 2007. Most of them (1912) are explosions occurred inside the seismic semiregional area and especially inside the ONKALO block (1891 events). The magnitudes of the observed events inside the semi-regional area range from ML = -2.1 to ML = 1.5 (ML

Software process improvement: controlling developers, managers or users?

DEFF Research Database (Denmark)

Nørbjerg, Jacob

1999-01-01

The paper discusses how the latest trend in the management of software development: software process improvement (SPI) may affect user-developer relations. At the outset, SPI concerns the "internal workings" of software organisations, but it may also be interpreted as one way to give the developer...... organisation more control over the development process and the relations with the user organization....

Seismic investigation of an ocean-continent transition zone in the northern South China Sea

Science.gov (United States)

Zhu, J.; Qiu, X.; Xu, H.; Zhan, W.; Sun, Z.

2011-12-01

Rifted continental margins and basins are mainly formed by the lithospheric extension. Thined lithosphere of passive continental margins results in decompression melt of magma and created oceanic crust and thined ocean-continent transition (OCT) zone. Two refraction profiles used ocean bottom seismometers deployed in the broad continental shelf and three multi-channel seismic reflection lines in the northern South China Sea, acquired by the ship "Shiyan 2" of the South China Sea Institute of Oceanology, Chinese Academy of Sciences in 2010, are processed and interpreted in this study. Seismic reflection lines cut through the Dongsha rise, Zhu-1 and Zhu-2 depression within a Tertiary basin, Pear River Mouth basin (called as Zhujiangkou basin). These tectonic features are clear imaged in the seismic reflection records. Numerous normal faults, cutted through the basement and related to the stretch of the northern South China Sea margin, are imaged and interpreted. Reflection characteristics of the ocean-continent transition (OCT) zone are summaried and outlined. The COT zone is mainly divided into the northern syn-rift subsidence zone, central volcano or buried volcano uplift zone and tilt faulted block near the South Chia Sea basin. Compared to the previous seismic reflection data and refraction velocity models, the segmentation range of the OCT zone is outlined, from width of about 225 km in the northeastern South China Sea , of 160 km in the central to of 110 km in the north-central South China Sea. Based on the epicenter distribution of sporadic and large than 6 magnitude earthquakes, it suggests the OCT zone in the northern South China Sea at present is still an active seismic zone.

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

Instantaneous Attributes Applied to Full Waveform Sonic Log and Seismic Data in Integration of Elastic Properties of Shale Gas Formations in Poland

Science.gov (United States)

Wawrzyniak-Guz, Kamila

2018-03-01

Seismic attributes calculated from full waveform sonic log were proposed as a method that may enhance the interpretation the data acquired at log and seismic scales. Though attributes calculated in the study were the mathematical transformations of amplitude, frequency, phase or time of the acoustic full waveforms and seismic traces, they could be related to the geological factors and/or petrophysical properties of rock formations. Attributes calculated from acoustic full waveforms were combined with selected attributes obtained for seismic traces recorded in the vicinity of the borehole and with petrophysical parameters. Such relations may be helpful in elastic and reservoir properties estimation over the area covered by the seismic survey.

SeismicWaveTool: Continuous and discrete wavelet analysis and filtering for multichannel seismic data

Science.gov (United States)

Galiana-Merino, J. J.; Rosa-Herranz, J. L.; Rosa-Cintas, S.; Martinez-Espla, J. J.

2013-01-01

A MATLAB-based computer code has been developed for the simultaneous wavelet analysis and filtering of multichannel seismic data. The considered time-frequency transforms include the continuous wavelet transform, the discrete wavelet transform and the discrete wavelet packet transform. The developed approaches provide a fast and precise time-frequency examination of the seismograms at different frequency bands. Moreover, filtering methods for noise, transients or even baseline removal, are implemented. The primary motivation is to support seismologists with a user-friendly and fast program for the wavelet analysis, providing practical and understandable results. Program summaryProgram title: SeismicWaveTool Catalogue identifier: AENG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 611072 No. of bytes in distributed program, including test data, etc.: 14688355 Distribution format: tar.gz Programming language: MATLAB (MathWorks Inc.) version 7.8.0.347 (R2009a) or higher. Wavelet Toolbox is required. Computer: Developed on a MacBook Pro. Tested on Mac and PC. No computer-specific optimization was performed. Operating system: Any supporting MATLAB (MathWorks Inc.) v7.8.0.347 (R2009a) or higher. Tested on Mac OS X 10.6.8, Windows XP and Vista. Classification: 13. Nature of problem: Numerous research works have developed a great number of free or commercial wavelet based software, which provide specific solutions for the analysis of seismic data. On the other hand, standard toolboxes, packages or libraries, such as the MathWorks' Wavelet Toolbox for MATLAB, offer command line functions and interfaces for the wavelet analysis of one-component signals. Thus, software usually is focused on very specific problems

3D seismic Unterhaching 2009 within hydrothermal exploration and modelling; 3D-Seismik Unterhaching 2009 im Rahmen hydrothermaler Exploration und Modellierung

Energy Technology Data Exchange (ETDEWEB)

Lueschen, Ewald; Dussel, Michael; Thomas, Ruediger; Schulz, Ruediger [Leibniz-Institut fuer Angewandte Geophysik (LIAG), Hannover (Germany)

2011-10-24

Within the exploration of hydrothermal reservoirs, results of 3D reflexion-seismic measurements are presented. These measurements were performed in June / July 2009 according to the vibroseis method on an area of 26.3 square kilometers in the area Unterhaching (Federal Republic of Germany). The 3D seismic survey exhibits much more complex structures than previously known by 2D seismic lines. Subsequent to sinistral transtension (active in the Cretaceous to the Eocene) a short transpression impetus was performed. This is evident from graduated normal faults as well as staggered reverse fault structures and inversion structures in the Upper Jurassic. Top and base of the 600-650 m mighty Malm are well resolved. Brittle fault structures are formed linearly at the top Malm but rounded and chaotic within the Malm. This can be explained by a radical karstification / hydrothermal solution. Several circular structures are interpreted as karstified incursion structures. The seismic facies of the Malm is characterized by a shift from relatively transparent zones, layered fields, scatters and fault zones. This is an expression of smaller and larger reefs, lagoons and reef debris. Reefs are characterized by several seismic attributes. Striking low-velocity zones are oriented along the main fault zones and can be interpreted as zones that are relieved by gap porosity. Azimuth variable processing gives evidence for preferred orientations of fractures on the seismic scale. By means of the 3D seismic diverse geothermal exploration targets can be defined.

Detailed seismic velocity structure of the ultra-slow spread crust at the Mid-Cayman Spreading Center from travel-time tomography and synthetic seismograms

Science.gov (United States)

Harding, J.; Van Avendonk, H. J.; Hayman, N. W.; Grevemeyer, I.; Peirce, C.

2017-12-01

The Mid-Cayman Spreading Center (MCSC), an ultraslow-spreading center in the Caribbean Sea, has formed highly variable oceanic crust. Seafloor dredges have recovered extrusive basalts in the axial deeps as well as gabbro on bathymetric highs and exhumed mantle peridotite along the only 110 km MCSC. Wide-angle refraction data were collected with active-source ocean bottom seismometers in April, 2015, along lines parallel and across the MCSC. Travel-time tomography produces relatively smooth 2-D tomographic models of compressional wave velocity. These velocity models reveal large along- and across-axis variations in seismic velocity, indicating possible changes in crustal thickness, composition, faulting, and magmatism. It is difficult, however, to differentiate between competing interpretations of seismic velocity using these tomographic models alone. For example, in some areas the seismic velocities may be explained by either thin igneous crust or exhumed, serpentinized mantle. Distinguishing between these two interpretations is important as we explore the relationships between magmatism, faulting, and hydrothermal venting at ultraslow-spreading centers. We therefore improved our constraints on the shallow seismic velocity structure of the MCSC by modeling the amplitude of seismic refractions in the wide-angle data set. Synthetic seismograms were calculated with a finite-difference method for a range of models with different vertical velocity gradients. Small-scale features in the velocity models, such as steep velocity gradients and Moho boundaries, were explored systematically to best fit the real data. With this approach, we have improved our understanding of the compressional velocity structure of the MCSC along with the geological interpretations that are consistent with three seismic refraction profiles. Line P01 shows a variation in the thinness of lower seismic velocities along the axis, indicating two segment centers, while across-axis lines P02 and P03

Strategies for Sharing Seismic Data Among Multiple Computer Platforms

Science.gov (United States)

Baker, L. M.; Fletcher, J. B.

2001-12-01

Seismic waveform data is readily available from a variety of sources, but it often comes in a distinct, instrument-specific data format. For example, data may be from portable seismographs, such as those made by Refraction Technology or Kinemetrics, from permanent seismograph arrays, such as the USGS Parkfield Dense Array, from public data centers, such as the IRIS Data Center, or from personal communication with other researchers through e-mail or ftp. A computer must be selected to import the data - usually whichever is the most suitable for reading the originating format. However, the computer best suited for a specific analysis may not be the same. When copies of the data are then made for analysis, a proliferation of copies of the same data results, in possibly incompatible, computer-specific formats. In addition, if an error is detected and corrected in one copy, or some other change is made, all the other copies must be updated to preserve their validity. Keeping track of what data is available, where it is located, and which copy is authoritative requires an effort that is easy to neglect. We solve this problem by importing waveform data to a shared network file server that is accessible to all our computers on our campus LAN. We use a Network Appliance file server running Sun's Network File System (NFS) software. Using an NFS client software package on each analysis computer, waveform data can then be read by our MatLab or Fortran applications without first copying the data. Since there is a single copy of the waveform data in a single location, the NFS file system hierarchy provides an implicit complete waveform data catalog and the single copy is inherently authoritative. Another part of our solution is to convert the original data into a blocked-binary format (known historically as USGS DR100 or VFBB format) that is interpreted by MatLab or Fortran library routines available on each computer so that the idiosyncrasies of each machine are not visible to

Identification of Active Faults by Aerial Photograph Interpretation and Case

Energy Technology Data Exchange (ETDEWEB)

Lee, J.R.; Chang, C.J.; Choi, W.H.; Yun, K.H.; Park, D.H.; Shin, S.H. [Korea Electric Power Research Institute, Taejon (Korea)

2002-07-01

This report is the technical memo of the research project entitled ''Development of Technology of Advanced Seismic Safety Assessment for NPP sites''. The purposes of this report are to describe analysis methods of photographic characteristics related with active faults, to identify active faults by aerial photograph interpretation and to review case studies. (author). 27 refs., 165 figs., 8 tabs.

Seismic Microzonation for Refinement of Seismic Load Parameters

Energy Technology Data Exchange (ETDEWEB)

Savich, A. I.; Bugaevskii, A. G., E-mail: office@geodyn.ru, E-mail: bugaevskiy@geodyn.ru [Center of the Office of Geodynamic Observations in the Power Sector, an affiliate of JSC “Institut Gidroproekt” (Russian Federation)

2016-05-15

Functional dependencies are established for the characteristics of seismic transients recorded at various points of a studied site, which are used to propose a new approach to seismic microzonation (SMZ) that enables the creation of new SMZ maps of strong seismic motion, with due regard for dynamic parameters of recorded transients during weak earthquakes.

The Design of Wireless Data Acquisition and Remote Transmission Interface in Micro-seismic Signals

Directory of Open Access Journals (Sweden)

Huan-Huan BIAN

2014-02-01

Full Text Available The micro-seismic signal acquisition and transmission is an important key part in geological prospecting. This paper describes a bran-new solution of micro-seismic signal acquisition and remote transmission using Zigbee technique and wireless data transmission technique. The hardware such as front-end data acquisition interface made up by Zigbee wireless networking technique, remote data transmission solution composed of general packet radio service (or GPRS for short technique and interface between Zigbee and GPRS is designed in detail. Meanwhile the corresponding software of the system is given out. The solution solves the numerous practical problems nagged by complex and terrible environment faced using micro-seismic prospecting. The experimental results demonstrate that the method using Zigbee wireless network communication technique GPRS wireless packet switching technique is efficient, reliable and flexible.

Seismicity and seismic monitoring in the Asse salt mine

International Nuclear Information System (INIS)

Flach, D.; Gommlich, G.; Hente, B.

1987-01-01

Seismicity analyses are made in order to assess the safety of candidate sites for ultimate disposal of hazardous wastes. The report in hand reviews the seismicity history of the Asse salt mine and presents recent results of a measuring campaign made in the area. The monitoring network installed at the site supplies data and information on the regional seismicity, on seismic amplitudes under ground and above ground, and on microseismic activities. (DG) [de

Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Bjorn N. P. Paulsson

2006-09-30

Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to perform high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology has been hampered by the lack of acquisition technology necessary to record large volumes of high frequency, high signal-to-noise-ratio borehole seismic data. This project took aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array has removed the technical acquisition barrier for recording the data volumes necessary to do high resolution 3D VSP and 3D cross-well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that promise to take the gas industry to the next level in their quest for higher resolution images of deep and complex oil and gas reservoirs. Today only a fraction of the oil or gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of detailed compartmentalization of oil and gas reservoirs. In this project, we developed a 400 level 3C borehole seismic receiver array that allows for economic use of 3D borehole seismic imaging for reservoir characterization and monitoring. This new array has significantly increased the efficiency of recording large data volumes at sufficiently dense spatial sampling to resolve reservoir complexities. The receiver pods have been fabricated and tested to withstand high temperature (200 C/400 F) and high pressure (25,000 psi), so that they can operate in wells up to 7,620 meters (25,000 feet) deep. The receiver array is deployed on standard production or drill tubing. In combination with 3C surface seismic or 3C borehole seismic sources, the 400

Seismic evaluation of existing nuclear power plants

International Nuclear Information System (INIS)

2003-01-01

The IAEA nuclear safety standards publications address the site evaluation and the design of new nuclear power plants (NPPs), including seismic hazard assessment and safe seismic design, at the level of the Safety Requirements as well as at the level of dedicated Safety Guides. It rapidly became apparent that the existing nuclear safety standards documents were not adequate for handling specific issues in the seismic evaluation of existing NPPs, and that a dedicated document was necessary. This is the purpose of this Safety Report, which is written in the spirit of the nuclear safety standards and can be regarded as guidance for the interpretation of their intent. Worldwide experience shows that an assessment of the seismic capacity of an existing operating facility can be prompted for the following: (a) Evidence of a greater seismic hazard at the site than expected before, owing to new or additional data and/or to new methods; (b) Regulatory requirements, such as periodic safety reviews, to ensure that the plant has adequate margins for seismic loads; (c) Lack of anti-seismic design or poor anti-seismic design; (d) New technical finding such as vulnerability of some structures (masonry walls) or equipment (relays), other feedback and new experience from real earthquakes. Post-construction evaluation programmes evaluate the current capability of the plant to withstand the seismic concern and identify any necessary upgrades or changes in operating procedures. Seismic qualification is distinguished from seismic evaluation primarily in that seismic qualification is intended to be performed at the design stage of a plant, whereas seismic evaluation is intended to be applied after a plant has been constructed. Although some guidelines do exist for the evaluation of existing NPPs, these are not established at the level of a regulatory guide or its equivalent. Nevertheless, a number of existing NPPs throughout the world have been and are being subjected to review of their

German seismic regulations

International Nuclear Information System (INIS)

Danisch, Ruediger

2002-01-01

Rules and regulations for seismic design in Germany cover the following: seismic design of conventional buildings; and seismic design of nuclear facilities. Safety criteria for NPPs, accident guidelines, and guidelines for PWRs as well as safety standards are cited. Safety standards concerned with NPPs seismic design include basic principles, soil analysis, design of building structures, design of mechanical and electrical components, seismic instrumentation, and measures to be undertaken after the earthquake

Establishing seismic design criteria to achieve an acceptable seismic margin

International Nuclear Information System (INIS)

Kennedy, R.P.

1997-01-01

In order to develop a risk based seismic design criteria the following four issues must be addressed: (1) What target annual probability of seismic induced unacceptable performance is acceptable? (2). What minimum seismic margin is acceptable? (3) Given the decisions made under Issues 1 and 2, at what annual frequency of exceedance should the Safe Shutdown Earthquake ground motion be defined? (4) What seismic design criteria should be established to reasonably achieve the seismic margin defined under Issue 2? The first issue is purely a policy decision and is not addressed in this paper. Each of the other three issues are addressed. Issues 2 and 3 are integrally tied together so that a very large number of possible combinations of responses to these two issues can be used to achieve the target goal defined under Issue 1. Section 2 lays out a combined approach to these two issues and presents three potentially attractive combined resolutions of these two issues which reasonably achieves the target goal. The remainder of the paper discusses an approach which can be used to develop seismic design criteria aimed at achieving the desired seismic margin defined in resolution of Issue 2. Suggestions for revising existing seismic design criteria to more consistently achieve the desired seismic margin are presented

Seismic capacity of a reinforced concrete frame structure without seismic detailing and limited ductility seismic design in moderate seismicity

International Nuclear Information System (INIS)

Kim, J. K.; Kim, I. H.

1999-01-01

A four-story reinforced concrete frame building model is designed for the gravity loads only. Static nonlinear pushover analyses are performed in two orthogonal horizontal directions. The overall capacity curves are converted into ADRS spectra and compared with demand spectra. At several points the deformed shape, moment and shear distribution are calculated. Based on these results limited ductility seismic design concept is proposed as an alternative seismic design approach in moderate seismicity resign

Integral Analysis of Seismic Refraction and Ambient Vibration Survey for Subsurface Profile Evaluation

Science.gov (United States)

Hazreek, Z. A. M.; Kamarudin, A. F.; Rosli, S.; Fauziah, A.; Akmal, M. A. K.; Aziman, M.; Azhar, A. T. S.; Ashraf, M. I. M.; Shaylinda, M. Z. N.; Rais, Y.; Ishak, M. F.; Alel, M. N. A.

2018-04-01

Geotechnical site investigation as known as subsurface profile evaluation is the process of subsurface layer characteristics determination which finally used for design and construction phase. Traditionally, site investigation was performed using drilling technique thus suffers from several limitation due to cost, time, data coverage and sustainability. In order to overcome those problems, this study adopted surface techniques using seismic refraction and ambient vibration method for subsurface profile depth evaluation. Seismic refraction data acquisition and processing was performed using ABEM Terraloc and OPTIM software respectively. Meanwhile ambient vibration data acquisition and processing was performed using CityShark II, Lennartz and GEOPSY software respectively. It was found that studied area consist of two layers representing overburden and bedrock geomaterials based on p-wave velocity value (vp = 300 – 2500 m/s and vp > 2500 m/s) and natural frequency value (Fo = 3.37 – 3.90 Hz) analyzed. Further analysis found that both methods show some good similarity in term of depth and thickness with percentage accuracy at 60 – 97%. Consequently, this study has demonstrated that the application of seismic refractin and ambient vibration method was applicable in subsurface profile depth and thickness estimation. Moreover, surface technique which consider as non-destructive method adopted in this study was able to compliment conventional drilling method in term of cost, time, data coverage and environmental sustainaibility.

Upside to downsizing : Acceleware's graphic processor technology propels seismic data processing revolution

Energy Technology Data Exchange (ETDEWEB)

Smith, M.

2009-11-15

Accelware has developed a graphic processor technology (GPU) that is transforming the petroleum industry. The benefits of the technology are its small-footprint, low-wattage, and high speed. The software brings supercomputing speed to the desktop by leveraging the massive parallel processing capacity to the very latest in GPU technology. This article discussed the GPU technology and its emergence as a powerful supercomputing tool. Accelware's partnering with California-based NVIDIA was also outlined. The advantages of the technology were also discussed including its smaller footprint. Accelware's hardware takes up a fraction of the space and uses up to 70 per cent less power than a traditional central processing unit. By combining Accelware's core knowledge in making complex algorithms run in parallel with an in-house team of seismic industry experts, the company provides software solutions for seismic data processors that access the massively parallel processing capabilities of GPUs. 1 fig.

Burar seismic station: evaluation of seismic performance

International Nuclear Information System (INIS)

Ghica, Daniela; Popa, Mihaela

2005-01-01

A new seismic monitoring system, the Bucovina Seismic Array (BURAR), has been established since July 2002, in the Northern part of Romania, in a joint effort of the Air Force Technical Applications Center, USA, and the National Institute for Earth Physics (NIEP), Romania. The small-aperture array consists of 10 seismic sensors (9 vertical short-period and one three-component broad band) located in boreholes and distributed in a 5 x 5 km 2 area. At present, the seismic data are continuously recorded by the BURAR and transmitted in real-time to the Romanian National Data Center in Bucharest and National Data Center of the USA, in Florida. Based on the BURAR seismic information gathered at the National Data Center, NIEP (ROM N DC), in the August 2002 - December 2004 time interval, analysis and statistical assessments were performed. Following the preliminary processing of the data, several observations on the global performance of the BURAR system were emphasized. Data investigation showed an excellent efficiency of the BURAR system particularly in detecting teleseismic and regional events. Also, a statistical analysis for the BURAR detection capability of the local Vrancea events was performed in terms of depth and magnitude for the year 2004. The high signal detection capability of the BURAR resulted, generally, in improving the location solutions for the Vrancea seismic events. The location solution accuracy is enhanced when adding BURAR recordings, especially in the case of low magnitude events (recorded by few stations). The location accuracy is increased, both in terms of constraining hypocenter depth and epicentral coordinates. Our analysis certifies the importance of the BURAR system in NIEP efforts to elaborate seismic bulletins. Furthermore, the specific procedures for array data processing (beam forming, f-k analysis) increase significantly the signal-to-noise ratio by summing up the coherent signals from the array components, and ensure a better accuracy

Aim and points of this workshop: The 2. Workshop on Seismic Observation in Deep Borehole (SODB) and its Applications

International Nuclear Information System (INIS)

Sugiyama, Yuichi

2014-01-01

The achievements of the first WS and the aim of the Second WS were explained. The purposes of this Second WS were: to re-recognize the significance of seismic ground motion evaluation based on newly added deep borehole seismic observation in addition to existing borehole investigation, geological surveys, and geophysical exploration; to acknowledge deep borehole seismic observation and geophysical exploration (hardware) as well as the site characteristic evaluation method (software) required for seismic ground motion evaluation; and to consolidate opinions on multi-purpose application of observation technology and data as well as acknowledge issues to be addressed and technological problems. The final goals of this WS were to clarify items and issues that present challenges for the future based on the discussions in this WS. (author)

Seismic hazard estimation based on the distributed seismicity in northern China

Science.gov (United States)

Yang, Yong; Shi, Bao-Ping; Sun, Liang

2008-03-01

In this paper, we have proposed an alternative seismic hazard modeling by using distributed seismicites. The distributed seismicity model does not need delineation of seismic source zones, and simplify the methodology of probabilistic seismic hazard analysis. Based on the devastating earthquake catalogue, we established three seismicity model, derived the distribution of a-value in northern China by using Gaussian smoothing function, and calculated peak ground acceleration distributions for this area with 2%, 5% and 10% probability of exceedance in a 50-year period by using three attenuation models, respectively. In general, the peak ground motion distribution patterns are consistent with current seismic hazard map of China, but in some specific seismic zones which include Shanxi Province and Shijiazhuang areas, our results indicated a little bit higher peak ground motions and zonation characters which are in agreement with seismicity distribution patterns in these areas. The hazard curves have been developed for Beijing, Tianjin, Taiyuan, Tangshan, and Ji’nan, the metropolitan cities in the northern China. The results showed that Tangshan, Taiyuan, Beijing has a higher seismic hazard than that of other cities mentioned above.

Time-lapse seismic - repeatability versus usefulness and 2D versus 3D

Science.gov (United States)

Landro, M.

2017-12-01

Time-lapse seismic has developed rapidly over the past decades, especially for monitoring of oil and gas reservoirs and subsurface storage of CO2. I will review and discuss some of the critical enabling factors for the commercial success of this technology. It was early realized that how well we are able to repeat our seismic experiment is crucial. However, it is always a question of detectability versus repeatability. For marine seismic, there are several factors limiting the repeatability: Weather conditions, positioning of sources and receivers and so on. I will discuss recent improvements in both acquisition and processing methods over the last decade. It is well known that repeated 3D seismic data is the most accurate tool for reservoir monitoring purposes. However, several examples show that 2D seismic data may be used for monitoring purposes despite lower repeatability. I will use examples from an underground blow out in the North Sea, and repeated 2D seismic lines acquired before and after the Tohoku earthquake in 2011 to illustrate this. A major challenge when using repeated 2D seismic for subsurface monitoring purposes is the lack of 3D calibration points and significantly less amount of data. For marine seismic acquisition, feathering issues and crossline dip effects become more critical compared to 3D seismic acquisition. Furthermore, the uncertainties arising from a non-ideal 2D seismic acquisition are hard to assess, since the 3D subsurface geometry has not been mapped. One way to shed more light on this challenge is to use 3D time lapse seismic modeling testing various crossline dips or geometries. Other ways are to use alternative data sources, such as bathymetry, time lapse gravity or electromagnetic data. The end result for all time-lapse monitoring projects is an interpretation associated with uncertainties, and for the 2D case these uncertainties are often large. The purpose of this talk is to discuss how to reduces and control these

Seismic and mechanical anisotropy and the past and present deformation of the Australian lithosphere

NARCIS (Netherlands)

Simons, Frederik J.; Hilst, R.D. van der

2003-01-01

We interpret the three-dimensional seismic wave-speed structure of the Australian upper mantle by comparing its azimuthal anisotropy to estimates of past and present lithospheric deformation. We infer the fossil strain field from the orientation of gravity anomalies relative to topography,

Simulating Seismic Wave Propagation in Viscoelastic Media with an Irregular Free Surface

Science.gov (United States)

Liu, Xiaobo; Chen, Jingyi; Zhao, Zhencong; Lan, Haiqiang; Liu, Fuping

2018-05-01

In seismic numerical simulations of wave propagation, it is very important for us to consider surface topography and attenuation, which both have large effects (e.g., wave diffractions, conversion, amplitude/phase change) on seismic imaging and inversion. An irregular free surface provides significant information for interpreting the characteristics of seismic wave propagation in areas with rugged or rapidly varying topography, and viscoelastic media are a better representation of the earth's properties than acoustic/elastic media. In this study, we develop an approach for seismic wavefield simulation in 2D viscoelastic isotropic media with an irregular free surface. Based on the boundary-conforming grid method, the 2D time-domain second-order viscoelastic isotropic equations and irregular free surface boundary conditions are transferred from a Cartesian coordinate system to a curvilinear coordinate system. Finite difference operators with second-order accuracy are applied to discretize the viscoelastic wave equations and the irregular free surface in the curvilinear coordinate system. In addition, we select the convolutional perfectly matched layer boundary condition in order to effectively suppress artificial reflections from the edges of the model. The snapshot and seismogram results from numerical tests show that our algorithm successfully simulates seismic wavefields (e.g., P-wave, Rayleigh wave and converted waves) in viscoelastic isotropic media with an irregular free surface.

Influence of seismic diffraction for high-resolution imaging: applications in offshore Malaysia

Science.gov (United States)

Bashir, Yasir; Ghosh, Deva Prasad; Sum, Chow Weng

2018-04-01

Small-scale geological discontinuities are not easy to detect and image in seismic data, as these features represent themselves as diffracted rather than reflected waves. However, the combined reflected and diffracted image contains full wave information and is of great value to an interpreter, for instance enabling the identification of faults, fractures, and surfaces in built-up carbonate. Although diffraction imaging has a resolution below the typical seismic wavelength, if the wavelength is much smaller than the width of the discontinuity then interference effects can be ignored, as they would not play a role in generating the seismic diffractions. In this paper, by means of synthetic examples and real data, the potential of diffraction separation for high-resolution seismic imaging is revealed and choosing the best method for preserving diffraction are discussed. We illustrate the accuracy of separating diffractions using the plane-wave destruction (PWD) and dip frequency filtering (DFF) techniques on data from the Sarawak Basin, a carbonate field. PWD is able to preserve the diffraction more intelligently than DFF, which is proven in the results by the model and real data. The final results illustrate the effectiveness of diffraction separation and possible imaging for high-resolution seismic data of small but significant geological features.

Bridges Dynamic Parameters Identification Based On Experimental and Numerical Method Comparison in Regard with Traffic Seismicity

Science.gov (United States)

Krkošková, Katarína; Papán, Daniel; Papánová, Zuzana

2017-10-01

The technical seismicity negatively affects the environment, buildings and structures. Technical seismicity means seismic shakes caused by force impulse, random process and unnatural origin. The vibration influence on buildings is evaluated in the Eurocode 8 in Slovak Republic, however, the Slovak Technical Standard STN 73 0036 includes solution of the technical seismicity. This standard also classes bridges into the group of structures that are significant in light of the technical seismicity - the group “U”. Using the case studies analysis by FEM simulation and comparison is necessary because of brief norm evaluation of this issue. In this article, determinate dynamic parameters by experimental measuring and numerical method on two real bridges are compared. First bridge, (D201 - 00) is Scaffold Bridge on the road I/11 leading to the city of Čadca and is situated in the city of Žilina. It is eleven - span concrete road bridge. The railway is the obstacle, which this bridge spans. Second bridge (M5973 Brodno) is situated in the part of Žilina City on the road of I/11. It is concrete three - span road bridge built as box girder. The computing part includes 3D computational models of the bridges. First bridge (D201 - 00) was modelled in the software of IDA Nexis as the slab - wall model. The model outputs are natural frequencies and natural vibration modes. Second bridge (M5973 Brodno) was modelled in the software of VisualFEA. The technical seismicity corresponds with the force impulse, which was put into this model. The model outputs are vibration displacements, velocities and accelerations. The aim of the experiments was measuring of the vibration acceleration time record of bridges, and there was need to systematic placement of accelerometers. The vibration acceleration time record is important during the under - bridge train crossing, about the first bridge (D201 - 00) and the vibration acceleration time domain is important during deducing the force

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

Seismic attributes characterization for Albian reservoirs in shallow Santos Basin

Energy Technology Data Exchange (ETDEWEB)

Vincentelli, Maria Gabriela C.; Barbosa, Mauro [HRT Petroleum, Rio de Janeiro, RJ (Brazil)

2008-07-01

The Santos basin southwest area is characterized by gas production, but it shows an exploratory problem due to the lack of good reservoirs facies. The main reservoirs are the Albian calcarenites, which show low porosities values (about 2%) in the northwest portion of the study area. From wire log analysis, it was interpreted that the porosity values can reach 15% at the south-west portion, both in the Caravela, Cavalo Marinho and Tubarao oil/gas fields and in the neighborhood of these fields. In order to find the best places to drill exploration wells at Shallow Santos, it is recommended to apply analyses of seismic attributes including: main average amplitude, energy, RMS, main amplitude, etc. Once the application of this methodology is restricted to 3D seismic data, in this study, a pseudo-3D seismic volume was built from 9,635 km of seismic lines, and 13 wells were used for reservoir facies control. As a result, the presence of good facies reservoirs in this area of the basin is restricted to trends with a NE-SW direction, and their presence is not only associated with the structural highs, this fact explains the dry wells over rollover structures. (author)

Progressive Seismic Failure, Seismic Gap, and Great Seismic Risk across the Densely Populated North China Basin

Science.gov (United States)

Yin, A.; Yu, X.; Shen, Z.

2014-12-01

Although the seismically active North China basin has the most complete written records of pre-instrumentation earthquakes in the world, this information has not been fully utilized for assessing potential earthquake hazards of this densely populated region that hosts ~200 million people. In this study, we use the historical records to document the earthquake migration pattern and the existence of a 180-km seismic gap along the 600-km long right-slip Tangshan-Hejian-Cixian (THC) fault zone that cuts across the North China basin. The newly recognized seismic gap, which is centered at Tianjin with a population of 11 million people and ~120 km from Beijing (22 million people) and Tangshan (7 million people), has not been ruptured in the past 1000 years by M≥6 earthquakes. The seismic migration pattern in the past millennium suggests that the epicenters of major earthquakes have shifted towards this seismic gap along the THC fault, which implies that the 180- km gap could be the site of the next great earthquake with M≈7.6 if it is ruptured by a single event. Alternatively, the seismic gap may be explained by aseismic creeping or seismic strain transfer between active faults.

Time-Independent Annual Seismic Rates, Based on Faults and Smoothed Seismicity, Computed for Seismic Hazard Assessment in Italy

Science.gov (United States)

Murru, M.; Falcone, G.; Taroni, M.; Console, R.

2017-12-01

In 2015 the Italian Department of Civil Protection, started a project for upgrading the official Italian seismic hazard map (MPS04) inviting the Italian scientific community to participate in a joint effort for its realization. We participated providing spatially variable time-independent (Poisson) long-term annual occurrence rates of seismic events on the entire Italian territory, considering cells of 0.1°x0.1° from M4.5 up to M8.1 for magnitude bin of 0.1 units. Our final model was composed by two different models, merged in one ensemble model, each one with the same weight: the first one was realized by a smoothed seismicity approach, the second one using the seismogenic faults. The spatial smoothed seismicity was obtained using the smoothing method introduced by Frankel (1995) applied to the historical and instrumental seismicity. In this approach we adopted a tapered Gutenberg-Richter relation with a b-value fixed to 1 and a corner magnitude estimated with the bigger events in the catalogs. For each seismogenic fault provided by the Database of the Individual Seismogenic Sources (DISS), we computed the annual rate (for each cells of 0.1°x0.1°) for magnitude bin of 0.1 units, assuming that the seismic moments of the earthquakes generated by each fault are distributed according to the same tapered Gutenberg-Richter relation of the smoothed seismicity model. The annual rate for the final model was determined in the following way: if the cell falls within one of the seismic sources, we merge the respective value of rate determined by the seismic moments of the earthquakes generated by each fault and the value of the smoothed seismicity model with the same weight; if instead the cells fall outside of any seismic source we considered the rate obtained from the spatial smoothed seismicity. Here we present the final results of our study to be used for the new Italian seismic hazard map.

Instantaneous Attributes Applied to Full Waveform Sonic Log and Seismic Data in Integration of Elastic Properties of Shale Gas Formations in Poland

Directory of Open Access Journals (Sweden)

Wawrzyniak-Guz Kamila

2018-01-01

Full Text Available Seismic attributes calculated from full waveform sonic log were proposed as a method that may enhance the interpretation the data acquired at log and seismic scales. Though attributes calculated in the study were the mathematical transformations of amplitude, frequency, phase or time of the acoustic full waveforms and seismic traces, they could be related to the geological factors and/or petrophysical properties of rock formations. Attributes calculated from acoustic full waveforms were combined with selected attributes obtained for seismic traces recorded in the vicinity of the borehole and with petrophysical parameters. Such relations may be helpful in elastic and reservoir properties estimation over the area covered by the seismic survey.

CARES (Computer Analysis for Rapid Evaluation of Structures) Version 1.0, seismic module

International Nuclear Information System (INIS)

Xu, J.; Philippacopoulas, A.J.; Miller, C.A.; Costantino, C.J.

1990-07-01

During FY's 1988 and 1989, Brookhaven National Laboratory (BNL) developed the CARES system (Computer Analysis for Rapid Evaluation of Structures) for the US Nuclear Regulatory Commission (NRC). CARES is a PC software system which has been designed to perform structural response computations similar to those encountered in licencing reviews of nuclear power plant structures. The docomentation of the Seismic Module of CARES consists of three volumes. This report represents Volume 1 of the three volume documentation of the Seismic Module of CARES. It concentrates on the theoretical basis of the system and presents modeling assumptions and limitations as well as solution schemes and algorithms of CARES. 31 refs., 6 figs