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Tectonics of Southeastern Arizona

Description: From abstract: The part of Arizona south and east of Tucson is underlain by a wide assortment of deformed rocks, as well as by some major mineralized districts. A synthesis of the tectonic evolution of the region is offered in this report, which is based on older studies of mining districts and on more recent field studies by students and by the U.S. Geological Survey, augmented by field review and selective remapping of many key areas. Through this synthesis the rocks of the region are seen to have been deformed in response to diverse stresses, at various times, with an increasing degree of structural anisotropy of the rocks through time. Consequently, reactivated faults are common features, and segments of some of these faults record various kinds of movement, thereby providing unusual interpretive difficulties for many of the past local studies.
Date: 1981
Creator: Drewes, Harald D.
Partner: UNT Libraries Government Documents Department

Source Analysis of the Crandall Canyon, Utah, Mine Collapse

Description: Analysis of seismograms from a magnitude 3.9 seismic event on August 6, 2007 in central Utah reveals an anomalous radiation pattern that is contrary to that expected for a tectonic earthquake, and which is dominated by an implosive component. The results show the seismic event is best modeled as a shallow underground collapse. Interestingly, large transverse surface waves require a smaller additional non-collapse source component that represents either faulting in the rocks above the mine workings or deformation of the medium surrounding the mine.
Date: February 28, 2008
Creator: Dreger, D S; Ford, S R & Walter, W R
Partner: UNT Libraries Government Documents Department

Comprehensive study of the seismotectonics of the eastern Aleutian arc and associated volcanic systems. Annual progress report, March 1, 1980-February 28, 1981

Description: Refined hypocenter locations beneath the Shumagin Islands seismic network of the eastern Aleutian arc, Alaska, provide for the first time conclusive evidence for a double-sheeted dipping seismic (Benioff) zone in this arc. This refined seismicity structure was obtained in the arc section centered on the Shumagin seismic gap. A thorough review of three seismic gaps in the eastern Aleutian arc shows a high potential for great earthquakes within the next one to two decades in the Shumagin and Yakataga seismic gaps, and a less certain potential for a large or great earthquake in the possible Unalaska gap. A tilt reversal was geodetically observed to have occurred in 1978/79 in the forearc region of the Shumagin gap and could indicate the onset of a precursory strain relief episode prior to a great quake. A comparative study of the Pavlof volcano seismicity with that of other recently active volcanoes (i.e., Mt. St. Helens) indicates that island-arc (explosive-type) volcanoes respond to small ambient, periodic stress changes (i.e., tides). Stress drop measurements from earthquakes on the main thrust zone indicate high stress drops within the seismic gap regions of the Aleutian arc and low stress drops outside the gap region.
Date: January 1, 1981
Creator: Jacob, K.H.; Davies, J.N. & House, L.
Partner: UNT Libraries Government Documents Department

Quarterly seismic monitoring report 96B

Description: This report summarizes the location, magnitude, and other pertinent information on earthquakes recorded on and near the Hanford Site by Westinghouse Seismic Monitoring during the period encompassing January 1, 1996 to March 31, 1996.
Date: June 12, 1996
Creator: Reidel, S.P.
Partner: UNT Libraries Government Documents Department

BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

Description: The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule. The principal objectives of the project are to develop through basin analysis and modeling the concept that petroleum systems acting in a basin can be identified through basin modeling and to demonstrate that the information and analysis resulting from characterizing and modeling of these petroleum systems in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin can be used in providing a more reliable and advanced approach for targeting stratigraphic traps and specific reservoir facies within a geologic system and in providing a refined assessment of undiscovered and underdeveloped reservoirs and associated oil and gas resources.
Date: February 5, 2004
Creator: Mancini, Ernest A.
Partner: UNT Libraries Government Documents Department

BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

Description: The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule.
Date: September 11, 2003
Creator: Mancini, Ernest A.
Partner: UNT Libraries Government Documents Department

BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

Description: The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule.
Date: November 11, 2003
Creator: Mancini, Ernest A.
Partner: UNT Libraries Government Documents Department

BASIN ANALYSIS OF THE MISSISSIPPI INTERIOR SALT BASIN AND PETROLEUM SYSTEM MODELING OF THE JURASSIC SMACKOVER FORMATION, EASTERN GULF COASTAL PLAIN

Description: Part 2 (Basin Analysis of the Mississippi Interior Salt Basin) objectives are to provide a comprehensive analysis of the Mississippi Interior Salt Basin in Years 2 and 3 of the project and to transfer effectively the research results to producers through workshops and topical reports. Work accomplished so far: (Task 1) Tectonic History--Petroleum traps in the Mississippi Interior Salt Basin have been characterized. (Task 2) Depositional History--The depositional systems for Mesozoic strata in the Mississippi Interior Salt Basin have been identified and characterized. (Task 3) Fluid Flow--Modeling of 1-D burial and thermal history profiles for 48 wells in the Mississippi Interior Salt Basin has been completed. Multidimensional thermal maturity modeling has been initiated. (Task 4) Underdeveloped Plays--Three major exploration plays have been identified. These include the basement ridge play, the regional peripheral fault trend play, and the salt anticline play. (Task 5) Technology Transfer--No work was performed on this task for this quarter. (Task 6) Topical Reports--The topical reports on the tectonic, depositional, burial and thermal histories of the Mississippi Interior Salt Basin have been completed and sent to DOE.
Date: April 9, 1999
Creator: Ernest A,. Mancini
Partner: UNT Libraries Government Documents Department

Geology of the southern Guadalupe Mountains, Texas

Description: From Abstract: "This report deals with an area of 425 square miles in the western part of Texas, immediately south of the New Mexico line. The report describes the geology of the area, that is, the nature of its rocks, tectonics, and surface features, and the evidence that they give as to the evolution of the area through geologic time. Incidental reference is made to the geology of surrounding regions in order to place the area in its environment."
Date: 1948
Creator: King, Philip B.
Partner: UNT Libraries Government Documents Department

High Resolution Velocity Structure in Eastern Turkey

Description: We investigate the crustal and upper mantle structure of eastern Turkey where the Anatolian, Arabian and Eurasian Plates meet and form a complex tectonic structure. The Bitlis suture is a continental collision zone between the Anatolian plateau and the Arabian plate. Broadband data available through the Eastern Turkey Seismic Experiment (ETSE) provided a unique opportunity for studying the high resolution velocity structure. Zor et al. found an average 46 km thick crust in Anatolian plateau using six-layered grid search inversion of the ETSE receiver functions. Receiver functions are sensitive to the velocity contrast of interfaces and the relative travel time of converted and reverberated waves between those interfaces. The interpretation of receiver function alone with many-layered parameterization may result in an apparent depth-velocity tradeoff. In order to improve previous velocity model, we employed the joint inversion method with many layered parameterization of Julia et al. (2000) to the ETSE receiver functions. In this technique, the receiver function and surface-wave observations are combined into a single algebraic equation and each data set is weighted by an estimate of the uncertainty in the observations. We consider azimuthal changes of receiver functions and have stacked them into different groups. We calculated the receiver functions using iterative time-domain deconvolution technique and surface wave group velocity dispersion curves between 10-100 sec. We are making surface wave dispersion measurements at the ETSE stations and have incorporated them into a regional group velocity model. Preliminary results indicate a strong trend in the long period group velocity in the northeast. This indicates slow upper mantle velocities in the region consistent with Pn, Sn and receiver function results. We started with both the 1-D model that is obtained with the 12 tones dam explosion shot data recorded by ETSE network and the existing receiver function inversion results. In fact, ...
Date: September 3, 2004
Creator: Pasyanos, M; Gok, R; Zor, E & Walter, W
Partner: UNT Libraries Government Documents Department

Comprehensive study of the seismotectonics of the Aleutian Arc. Annual progress report, March 1, 1975--February 29, 1976

Description: Seismological and geodetic research performed during the past contract year has increased our understanding of the seismotectonics of the eastern Aleutian Island Arc. While generally aimed at producing a coherent theory for the evaluation of the entire arc, our research has focused on the Shumagin Islands seismic gap, a region within which a major earthquake is expected in the not too distant future. Basic seismological data were collected to investigate certain earthquake prediction techniques.
Date: January 1, 1976
Creator: Davies, J. N.; House, L.; Jacob, K. H.; Bilham, R.; Cormier, V. F. & Kienle, J.
Partner: UNT Libraries Government Documents Department

Caucasus Seismic Information Network: Data and Analysis Final Report

Description: The geology and tectonics of the Caucasus region (Armenia, Azerbaijan, and Georgia) are highly variable. Consequently, generating a structural model and characterizing seismic wave propagation in the region require data from local seismic networks. As of eight years ago, there was only one broadband digital station operating in the region – an IRIS station at Garni, Armenia – and few analog stations. The Caucasus Seismic Information Network (CauSIN) project is part of a nulti-national effort to build a knowledge base of seismicity and tectonics in the region. During this project, three major tasks were completed: 1) collection of seismic data, both in event catalogus and phase arrival time picks; 2) development of a 3-D P-wave velocity model of the region obtained through crustal tomography; 3) advances in geological and tectonic models of the region. The first two tasks are interrelated. A large suite of historical and recent seismic data were collected for the Caucasus. These data were mainly analog prior to 2000, and more recently, in Georgia and Azerbaijan, the data are digital. Based on the most reliable data from regional networks, a crustal model was developed using 3-D tomographic inversion. The results of the inversion are presented, and the supporting seismic data are reported. The third task was carried out on several fronts. Geologically, the goal of obtaining an integrated geological map of the Caucasus on a scale of 1:500,000 was initiated. The map for Georgia has been completed. This map serves as a guide for the final incorporation of the data from Armenia and Azerbaijan. Description of the geological units across borders has been worked out and formation boundaries across borders have been agreed upon. Currently, Armenia and Azerbaijan are working with scientists in Georgia to complete this task. The successful integration of the geologic data also required ...
Date: February 22, 2007
Creator: Martin, Randolph; Krasovec, Mary; Romer, Spring; O'Connor, Timothy; Bombolakis, Emanuel G.; Sun, Youshun et al.
Partner: UNT Libraries Government Documents Department

In situ stress field in the southeastern United States and its implication

Description: Published and unpublished in situ stress measurements and studies of earthquake focal mechanisms in the southeastern United States are reviewed. These data, which provide information on the relative magnitude and orientation of existing stress fields, are analyzed in relation to the geologic characteristics of the Southeast and are compared with data for other areas in the United States. The relation of the stress fields to observed geology and present-day tectonic processes is reviewed. Stress measurements reveal the existence of high horizontal stresses in the Appalachian complex. Different in situ stress states in the Appalachian complex, the Coastal Plain, and the stable interior region indicate different faulting mechanisms. Various techniques for determining in situ stress are consistent. 6 figures, 1 table.
Date: January 1, 1979
Creator: Stephenson, D.E. & Pratt, H.R.
Partner: UNT Libraries Government Documents Department

Tectonics of west central New Mexico and adjacent Arizona: a remote sensing and field study in arid and semi-arid areas

Description: Large-scale fault zones in west-central New Mexico and eastern Arizona were mapped using conventional fieldwork aided by Landsat and Seasat images and high altitude air photos. These faults, which are of post-early Miocene age, trend NE-SW and N-S and extend over 200 km. The fault zones bound very large horst and graben blocks which, although located on the physiographic Colorado Plateau, are characteristic of Basin and Range deformation. Their intersection has been the locus of extensive Cenozoic volcanism. The procedure developed in this project permitted investigation of an area of about 1.8 x 10/sup 5/ km/sup 2/ of arid and semi-arid land whose structures previously were poorly defined.
Date: January 1, 1981
Creator: Baldridge, W.S.; Bartov, Y. & Kron, A.
Partner: UNT Libraries Government Documents Department

Comprehensive study of the seismotectonics of the eastern Aleutian ARC and associated volcanic systems. Annual progress report, March 1, 1981-February 28, 1982

Description: Assessment of the seismic potential for occurrence of great earthquakes in three seismic gaps (Shumagin Islands, Unalaska Island, and Yakataga-Kayak regions) has been completed. In the best-instrumented seismic gap in the Shumagin Islands region, the likelihood for a great earthquake within the next two decades is high. Analysis of earthquake data collected from a telemetered network operated in the Shumagin seismic gap shows near-quiescence in the shallow portion of the main thrust zone. Installation of digital recording equipment at the central station of the Shumagin network, combined with interactive computer analysis at Lamont-Doherty of either digitally recorded or digitized analog seismic data has provided new research possibilities for studying seismic source properties, wave propagation in a laterally heterogeneous velocity structure of the subduction zone, and for seismically screening the root-zone and volcanic pile of Pavlof volcano. High time-resolution data (0.01 sec), and wider frequency band-pass data (0.5 to 30 Hz) are now being collected. Seismic data for two eruptive sequences of Pavlof-volcano have been obtained.
Date: January 1, 1981
Creator: Jacob, K. H.; Hauksson, E. & Sykes, L. R.
Partner: UNT Libraries Government Documents Department

Investigation of rifting processes in the Rio Grande Rift using data from unusually large earthquake swarms

Description: San Acacia Swarm in the Rio Grande Rift. Because the Rio Grande rift is one of the best seismically instrumented rift zones in the world, studying its seismicity provides an exceptional opportunity to explore the active tectonic processes within continental rifts. We have been studying earthquake swarms recorded near Socorro in an effort to link seismicity directly to the rifting process. For FY94, our research has focused on the San Acacia swarm, which occurred 25 km north of Socorro, New Mexico, along the accommodation zone between the Albuquerque-Belen and Socorro basins of the central Rio Grande rift. The swarm commenced on 25 February 1983, had a magnitude 4.2 main shock on 2 March and ended on 17 March, 1983.
Date: December 1, 1995
Creator: Sanford, A.; Balch, R.; House, L. & Hartse, H.
Partner: UNT Libraries Government Documents Department

Numerical and laboratory experiments on the dynamics of plume-ridge interaction. Progress report

Description: Mantle plumes and passive upwelling beneath ridges are the two dominant modes of mantle transport and thermal/chemical fluxing between the Earth`s deep interior and surface. While plumes and ridges independently contribute to crustal accretion, they also interact and the dispersion of plumes within the upper mantle is strongly modulated by mid-ocean ridges. The simplest mode of interaction, with the plume centered on the ridge, has been well documented and modeled. The remaining question is how plumes and ridges interact when the plume is located off-axis; it has been suggested that a pipeline-like flow from the off-axis plume to the ridge axis at the base of the rigid lithosphere may develop. Mid-ocean ridges migrating away from hot mantle plumes can be affected by plume discharges over long times and ridge migration distances. Salient feature of this model is that off-axis plumes communicate with the ridge through a channel resulting from the refraction and dispersion of an axi-symmetric plume conduit along the base of the sloping lithosphere. To test the dynamics of this model, a series of numerical and laboratory dynamic experiments on the problem of a fixed ridge and an off-axis buoyant upwelling were conducted. Results are discussed.
Date: September 1, 1995
Creator: Kincaid, C. & Gable, C.W.
Partner: UNT Libraries Government Documents Department

Fracture characterization and discrimination criteria for karst and tectonic fractures in the Ellenburger Group, West Texas: Implications for reservoir and exploration models

Description: In the Ellenburger Group fractured dolomite reservoirs of West Texas, it is extremely difficult to distinguish between multiple phases of karst-related fracturing, modifications to the karst system during burial, and overprinting tectonic fractures. From the analyses of drill core, the authors developed criteria to distinguish between karst and tectonic fractures. In addition, they have applied these criteria within the context of a detailed diagenetic cement history that allows them to further refine the fracture genesis and chronology. In these analyses, the authors evaluated the relationships between fracture intensity, morphologic attributes, host lithology, fracture cement, and oil-staining. From this analysis, they have been able to characterize variations in Ellenburger tectonic fracture intensity by separating these fractures from karst-related features. In general, the majority of fracturing in the Ellenburger is caused by karst-related fracturing although a considerable percentage is caused by tectonism. These findings underscore the importance of considering the complete geologic evolution of a karst reservoir during exploration and field development programs. The authors have been able to more precisely define the spatial significance of the fracture data sets by use of oriented core from Andector Field. They have also demonstrated the importance of these results for exploration and reservoir development programs in West Texas, and the potential to extrapolate these results around the globe. Given the historic interest in the large hydrocarbon reserves in West Texas carbonate reservoirs, results of this study will have tremendous implications for exploration and production strategies targeting vuggy, fractured carbonate systems not only in West Texas, but throughout the globe.
Date: December 31, 1998
Creator: Hoak, T.E.; Sundberg, K.R.; Deyhim, P. & Ortoleva, P.
Partner: UNT Libraries Government Documents Department

Calculation and interpretation of crustal shortening along the Central Basin Platform, West Texas: A method to calculate basement motion for modeling input

Description: The analysis carried out in the Chemical Interaction of Rocks and Fluids Basin (CIRFB) model describes the chemical and physical evolution of the entire system. One aspect of this is the deformation of the rocks, and its treatment with a rigorous flow and rheological model. This type of analysis depends on knowing the state of the model domain`s boundaries as functions of time. In the Andrews and Ector County areas of the Central Basin Platform of West Texas, the authors calculate this shortening with a simple interpretation of the basic motion and a restoration of the Ellenburger formation. Despite its simplicity, this calculation reveals two distinct periods of shortening/extension, a relatively uniform directionality to all the deformation, and the localization of deformation effects to the immediate vicinities of the major faults in the area. Conclusions are drawn regarding the appropriate expressions of these boundary conditions in the CIRFB model and possible implications for exploration.
Date: December 31, 1998
Creator: Hoak, T. E.; Sundberg, K. R. & Ortoleva, P.
Partner: UNT Libraries Government Documents Department

Investigation of rifting processes in the Rio Grande Rift using data from an unusually large earthquake swarm. Final report, October 1, 1992--September 30, 1993

Description: Because the Rio Grande Rift is one of the best seismically instrumented rift zones in the world, studying its seismicity provides an exceptional opportunity to elucidate the active tectonic processes within continental rifts. Beginning on 29 November 1989, a 15 square km region near Bernardo, NM, produced the strongest and longest lasting sequence of earthquakes in the rift in 54 years. Our research focuses on the Bernardo swarm which occurred 40 km north of Socorro, New Mexico in the axial region of the central Rio Grande rift. Important characteristics concerning hypocenters, fault mechanisms, and seismogenic zones are discussed.
Date: March 1, 1995
Creator: Sanford, A.; Balch, R.; Hartse, H. & House, L.
Partner: UNT Libraries Government Documents Department

Hanford quarterly seismic report - 97C seismicity on and near the Hanford Site, Pasco Basin, Washington. Quarterly report, April 1, 1997--June 30, 1997

Description: Hanford Seismic Monitoring provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network (HSN) for the U.S. Department of Energy and contractors. The staff also locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site. The data are compiled, archived, and published for use by the Hanford Site for activities ranging from waste management, Natural Phenomena Hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of an earthquake on the Hanford Site. The HSN and the Eastern Washington Regional Network (EWRN) consist of 41 individual sensor sites and 15 radio relay sites maintained by the Seismic Monitoring staff. Most stations and five relay sites are solar powered. The operational rate for the second quarter of FY97 for stations in the HSN was 100% and for stations of the EWRN was 99.99%. For fiscal year (FY) 1997 third quarter (97C), the acquisition computer triggered 183. Of these triggers twenty one were local earthquakes: sixteen in the Columbus River Basalt Group, one in the pre-basalt sediments, and four in the crystalline basement. The geologic and tectonic environments are discussed in the report.
Date: August 1, 1997
Creator: Hartshorn, D.C.; Reidel, S.P. & Rohay, A.C.
Partner: UNT Libraries Government Documents Department

Late miocene/pliocene origin of the inverted metamorphism of the Central Himalaya

Description: The spatial association of intracontinental thrusting and inverted metamorphism, recognized in the Himalaya more than a century ago, has inspired continuing efforts to identify their causal relationship. Perhaps the best known sequence of inverted metamorphism is that found immediately beneath the Himalayan Main Central Thrust (MCT), generally thought to have been active during the Early Miocene. It has been widely assumed that the pattern of inverted metamorphism also developed at that time. Using a new approach, in situ Th-Pb dating of monazite included in garnet, we have discovered that the peak metamorphic recrystallization recorded in the footwall of the MCT fault occurred at ca. 5 Ma. The apparent inverted metamorphism resulted from activation of a broad shear zone beneath the MCT zone which juxtaposed two right-way-up metamorphic sequences. Recognition of this remarkably youthful phase of metamorphism resolves outstanding problems in Himalayan tectonics, such as why the MCT (and not the more recently initiated thrusts) marks the break in slope of the present day mountain range, and transcends others, such as the need for exceptional conditions to explain Himalayan anatexis.
Date: January 1, 1997
Creator: Harrison, T.M.; Ryerson, F.J.; LeFort, P. & Yin, A. Lovera, O.M.
Partner: UNT Libraries Government Documents Department