Underplating of the Hawaiian Swell : evidence from teleseismic receiver functions

Author Posting. © The Authors, 2010. This article is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 183 (2010): 313-329, doi:10.1111/j.1365-246X.2010.04720.x.The Hawaiian Islands are the canonical example of an age-progressive island chain, formed by volcanism long thought to be fed from a hotspot source that is more or less fixed in the mantle. Geophysical data, however, have so far yielded contradictory evidence on subsurface structure. The substantial bathymetric swell is supportive of an anomalously hot upper mantle, yet seafloor heat flow in the region does not appear to be enhanced. The accumulation of magma beneath pre-existing crust (magmatic underplating) has been suggested to add chemical buoyancy to the swell, but to date the presence of underplating has been constrained only by local active-source experiments. In this study, teleseismic receiver functions derived from seismic events recorded during the PLUME project were analysed to obtain a regional map of crustal structure for the Hawaiian Swell. This method yields results that compare favourably with those from previous studies, but permits a much broader view than possible with active-source seismic experiments. Our results indicate that the crustal structure of the Hawaiian Islands is quite complicated and does not conform to the standard model of sills fed from a central source. We find that a shallow P-to-s conversion, previously hypothesized to result from the volcano-sediment interface, corresponds more closely to the boundary between subaerial and subaqueous extrusive material. Correlation between uplifted bathymetry at ocean-bottom-seismometer locations and presence of underplating suggests that much of the Hawaiian Swell is underplated, whereas a lack of underplating beneath the moat surrounding the island of Hawaii suggests that underplated crust outward of the moat has been fed from below by dykes through the lithosphere rather than by sills spreading from the island centre. Local differences in underplating may reflect focusing of magma-filled dykes in response to stress from volcanic loading. Finally, widespread underplating adds chemical buoyancy to the swell, reducing the amplitude of a mantle thermal anomaly needed to match bathymetry and supporting observations of normal heat flow.We are grateful to the Ocean Sciences Division of the U.S. National Science Foundation for their support of this project under grants OCE-0002470, OCE-0002552 and OCE-0002819

Verification of mathematical model in curvilinear motion of the car with AWD system

Abstract In the vehicles development also developed a variety of control systems. However, in their development it is necessary to have a mathematical model of the control object, that is, the vehicle model for the study of electronic control systems. Mathematical modeling is the most effective and promising method of studying the control object behavior. It is possible to carry out vehicle mathematical modeling and its components with sufficient high accuracy and compliance with its real prototype. But there are cases that it is not possible to simulate in detail some phenomena of the control object. In order to verify the accuracy of the compiled model, model verification of the developed vehicle is carried out. The basis used the KIA Sorento. It has AWD based on front wheel drive. This vehicle, equipped with measuring and recording devices, which carried out on the roads of the testing ground (FSUE “NAMI”). The work focuses on modelling the simulation of transmission units in the vehicle. The systems of equations of the engine, gearbox, transfer case, main gears and elastic drive shafts are written. Races on curvilinear trajectories were carried out. It also presents results comparison of the real vehicle movement and the results carried out from modeling in MATLAB&amp;Simulink. The accuracy of the developed mathematical model and admissibility in further application in the development of control systems are proved.</jats:p

Factor analysis of gas wells’ operating parameters

The paper discusses methodological approaches to the use of deterministic factor analysis for identifying the sources of changes in gas wells’ parameters under steadystate gas inflow obeying linear and non-linear filtration laws. Factor analysis methods make it possible to quantify the degree of influence of individual factors on the deviation of the indicator under study. In accordance with the methodology of factor analysis, mathematical models of the factor system were substantiated for linear and non-linear gas filtration, a set of factors of influence was determined, and ready-made solutions for factor analysis of gas wells’ operating parameters were obtained. In the paper, the method of weighted finite differences was substantiated and investigated with the aim of factor analyzing gas wells’ mode of operation and obtaining formulas to calculate the increment in gas production caused by changes in factors. Approbation of working formulas for assessing the degree of influence of factors on either positive or negative deviations in the gas flow rate was carried out with respect to the parameters of the wells of underground gas storages in the cycles of withdrawal and injection. The obtained formulas for factor analysis of gas wells make it possible to quantify the influence of such factors as reservoir and bottomhole pressures, filtration resistance coefficients, on the deviation of gas flow rate. Further ranking of wells by factors constitutes the basis for managing gas withdrawal (injection) processes and for well interventions planning

Component parts of the World Heat Flow Data Collection

Component parts of the World Heat Flow Data Collectio

(Table 1) Results of geothermal measurements in the Black Sea 2000 and 2001 expeditions

According to the World Ocean Program in the northeastern part of the continental slope of the Black Sea geothermal, seismologic and seismic studies were carried out. An analysis of heat flow distribution allowed to distinguish a negative geothermal anomaly near the Dzhubga area, where the Russia-Turkey pipeline was being constructed. During seismological observations (August-September 1999, September 2001) more than 1200 seismic events were recorded. They proved high tectonic activity of the region under study, which stimulates gravitational sediment transport on the continental slope. The seismo-acoustic survey carried out in the area of the geothermal anomaly revealed no reflecting horizons within the sedimentary cover. This may be related to turbidite-landsliding processes. Results of modeling of the heat flow anomaly showed that it had originated approximately 1000 years ago due to a powerful landslide. This also suggests a possibility of an avalanche displacement of sedimentary masses in the area of the pipeline at present

Amphibolites of the metamorphic basement of Wrangel island: age, nature of the protolite and conditions of metamorphism

New data on petrography, geochemistry and geochronology of metamorphic rocks sampled from Neoproterozoic basement of Wrangel Island are presented. Oceanic affinity for mafic rocks underwent greenschist to amphibolite facies conditions (350600C) has been established by geochemical data. Protolith of this rock belongs to products of the evolution of magmatic melts parental for MORB. Protoliths age is 61713 and 69812 Ma was determined by U-Pb isotope dating of Zircons from these rocks (SHRIMP II and La-ICP MS). There are two main stage of metamorphism could be established: Neoproterozoi Early Paleozoi (amphibolite and greenschist facies conditions) and Middle Cretaceous (greenschist facies condition only), Last stage of metamorphism related to Chukcha deformation events accompanied by formation of folded nappes structure and consequent extension. An comparison of studied rocks with samples dredged at Chukcha Borderland evidenced for certain similarity existing between these rock assemblages judging by their petrography and chemistry.</jats:p

Evaluation of the results of exploitation of directional wells in underground gas storage

Abstract The article presents an assessment of the effective use of directional wells as a way to increase the productivity of underground gas storage. It analyzes the solutions to the problem of gas inflow to a horizontal well based on the use of a flat model of filtration flows. Evaluation of the efficiency of operation of directional (horizontal) wells was carried out using the example of the Kushchevsky underground gas storage.</jats:p