ALBERT

Description / Table of Contents: Chapter I. Air-Sea Exchange Processes and Flux --- Chemical composition of marine aerosols over the Central North Pacific—Results ftom the 1991 cruise of Hakurei Maru No. 2 / Uematsu, M., Kawamupa, K., Ibusuki, T. and Kimoto, T. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 3-14 --- Estimation of mineral aerosol fluxes to the Pacific by using environmental plutonium as a tracer / Nakanishi, T., Shiba, Y., Muramatsu, M. and Haque, M. A. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 15-30 --- Land-derived lipid class compounds in the deep-sea sediments and marine aerosols from the North Pacific / Kawamura, K. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 31-51 --- Iron and manganese in the atmosphere and oceanic waters / Nakayama, E., Obata, H., Okamura, K., Isshiki, K., Karatani, H. and Kimoto, T. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 53-68 --- Laboratory estimation of CO2 transfer velocity across the air-sea interface / Komom, S., Shimada, T. and Murakami, Y. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 69-81 --- Dissolution of calcareous tests in the ocean and atmospheric carbon dioxide / Nozaki, Y. and Oba, T. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 83-92 --- Calcium carbonate production and carbon dioxide flux on a coral reef, Okinawa / Ohde, S. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 93-98 --- Chapter II. Geochemical Processes in Seawater --- Generations of carbonyl sulfide and hydrogen peroxide in the Seto Inland Sea—Photochemical reactions progressing in the coastal seawater / Fujiwara, K., Takeda, K. and Kumamoto, Y. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 101-127 --- Speciation of organoarsenical compounds in the hydrosphere / Sohrin, Y., Hasegawa, H. and Matsui, M. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 129-138 --- Chemical speciation of selenium in natural waters / Nakaguchi, Y., Koike, Y. and Hiraki, K. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 139-158 --- The concentration distribution and chemical form of arsenic compounds in seawater / Tanaka, S. and Santosa, S. J. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 159-170 --- The rare earth elements and yttrium in the coastal/offshore mixing zone of Tokyo Bay waters and the Kuroshio / Nozaki, Y. and Zhang, J. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 171-184 --- The tetrad effect in seawater; a long dispute and an analytical approach to the confirmation of the effect / Akagi, T. and Masuda, A. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 185-199 --- Detection, characterization and dynamics of dissolved organic ligands in oceanic waters / Tanoue, E. and Midorikawa, T. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 201-224 --- Chapter III. Primary Production and Other Biological Processes --- Nitrate assimilation and new production in open ocean / Kanda, J. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 227-238 --- Primary production and community respiration in the subarctic water of the western North Pacific / Odate, T. and Furuya, K. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 239-253 --- Effects of a seamount on phytoplankton production in the western Pacific Ocean / Furuya, K., Odate, T. and Taguchi, K. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 255-273 --- Marine colloids: Their roles in food webs and biogeochemical fluxes / Nagata, T. and Koike, I. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 275-292 --- Regional and seasonal variations of biomass and bio-mediated materials in the North Pacific Ocean / Yanada, M. and Maita, Y. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 293-306 --- Nitrogen and carbon stable isotopic ecology in the ocean: The transportation of organic materials through the food web / Sugisakj, H. and Tsuda, A. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 307-317 --- The role of carnivorous zooplankton, particularly chaetognaths in ocean flux / Terazaki, M. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 319-330 --- Seasonal changes in deep-sea benthic foraminiferal populations: Results of long-term observations at Sagami Bay, Japan / Kitazato, H. and Ohga, T. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 331-342 --- Chapter IV. Particle Flux and Sediment Geochemistry --- Spatial variation of Al flux in the North Pacific observed with sediment trap / Noriki, S., Iwai, T., Shimamoto, A., Tsunogai, S. and Harada, K. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 345-354 --- Spatial and temporal variation of δ515N in sinking particles in deep waters: Its implication for the origin and transport of particulate organic matter / Nakatsuka, T., Handa, N. and Imaizumi, S. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 355-374 --- 230Th and 231Pa distributions in surface sediments off Enshunada, Japan / Taguchi, K. and Narita, H. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 375-382 --- Remobilization of transition elements in pore water of continental slope sediments / Kato, Y., Tanase, M., Minami, H. and Okabe, S. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 383-405 --- Geochemistry of pore waters from a bathyal Calyptogena community off Hatsushima Island, Sagami Bay, Japan / Masuzawa, T., Nakatsuka, T. and Handa, N. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 407-421 --- Chapter V. Submarine Hydrothermal Processes --- Wide variation of chemical characteristics of submarine hydrothermal fluids due to secondary modification processes after high temperature water-rock interaction: a review / Gamo, T. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 425-451 --- Geochemistry of phase-separated hydrothermal fluids of the North Fiji Basin, Southwest Pacific / Ishibashi, J. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 453-467 --- Chemical modeling of seawater-rock interaction: Effect of rock-type on the fluid chemistry and mineral assemblage / Chiba, H. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 469-486 --- Hydrothermal mineralization in the Mid-Okinawa Trough / Nakashima, K., Sakai, H., Yoshida, H., Chiba, H., Tanaka, Y., Gamo, T., Ishibashi, J. and Tsunogai, U. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 487-508 --- Iron-rich smectite formation in the hydrothermal sediment of Iheya Basin, Okinawa Trough / Masuda, H. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 509-521 --- Formation and alteration of organic compounds in simulated submarine hydrothermal vent environments / Kobayashi, K., Kohara, M., Gamo, T. and Yanagawa, H. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 523-535 --- Localized heat flow anomalies in the middle Okinawa Trough associated with hydrothermal circulation / Kinoshita, M. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 537-559 --- Chapter VI. Modeling and Physical Oceanography --- Material transport models from Tokyo Bay to the Pacific Ocean / Yanagi, T. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 563-574 --- Climate and weather effects on the chlorophyll concentration in the northwestern North Pacific / Sugimoto, T., Tadokoro, K. and Furushima, Y. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 575-592 --- Ecosystem models for the three regional problems in the Northern Pacific / Kishi, M. J. and Kawamiya, M. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 593-611 --- A review on the subtropical mode water of the North Pacific (NPSTMW) / Hanawa, K. and Suga, T. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 613-627 --- Flow distribution at 165°E in the Pacific Ocean / Kawabe, M. and Taira, K. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 629-649 --- Determination of monthly mean sea surface temperature from 1981 to 1990 by the NOAA-AVHRR in the equatorial Pacific / Kishino, M. / Biogeochemical Processes and Ocean Flux in the Western Pacific, / pp. 651-659

Description / Table of Contents: PREFACE Through the last few decades inversion concepts have become an integral past of experimental data interpretation in several branches of science. In numerous cases similar inversion-like techniques were developed independently in separate disciplines, sometimes based on different lines of reasoning, and sometimes not to the same level of sophistication. This fact was realized early in inversion history. In the seventies and eighties "generalized inversion" and "total inversion" became buzz words in Earth Science, and some even saw inversion as the panacea that would eventually raise all experimental science into a common optimal frame. It is true that a broad awareness of the generality of inversion methods is established by now. On the other hand, the volume of experimental data varies greatly among disciplines, as does the degree of nonlinearity and numerical load of forward calculations, the amount and accuracy of a priori information, and the criticality of correct error propagation analysis. Thus, some clear differences in terminology, philosophy and numerical implementation remain, some of them for good reasons, but some of them simply due to tradition and lack of interdisciplinary communication. In a sense the development of inversion methods could be viewed as an evolution process where it is important that "species" can arise and adapt through isolation, but where it is equally important that they compete and mate afterwards through interdisciplinary exchange of ideas. This book was actually initiated as a proceedings volume of the "Interdisciplinary Inversion Conference 1995", held at the University of Aarhus, Denmark. The aim of this conference was to further the competition and mating part of above-mentioned evolution process, and we decided to extend the effect through this publication of 35 selected contributions. The point of departure is a story about geophysics and astronomy, in which the classical methods of Backus and Gilbert from around 1970 have been picked up by helioseismology. Professor Douglas Gough, who is a pioneer in this field, is the right person to tell this success story of interdisciplinary exchange of research experience and techniques [1-31] (numbers refer to pages in this book). Practitioners of helioseismology like to stress the fact that the seismological coverage on the Sun in a sense is much more complete and accurate than it is on Earth. Indeed we witness vigorous developments in the Backus & Gilbert methods (termed MOLA/SOLA in the helioseismology literature) [32-59] driven by this fortunate data situation. Time may have come for geophysicists to look into helioseismology for new ideas. Seismic methods play a key role in the study of the Earth's lithosphere. The contributions in [79 - 130,139 - 150] relate to reflection seismic oil exploration, while methods for exploration of the whole crust and the underlying mantle axe presented in [131 - 138, 151 - 166]. Two contributions [167 - 185] present the application of inversion for the understanding of the origin of petroleum and the prediction of its migration in sedimentary basins. Inversion is applied to hydrogeophysical and environmental problems [186 - 222], where again developments are driven by the advent of new, mainly electromagnetic, experimental techniques. The role of inversion in electromagnetic investigations of the lithosphere/astenosphere system as well as the ionosphere axe exemplified in [223 - 238]. Geodesy has a fine tradition of sophisticated linear inversion of large, accurate sets of potential field data. This leads naturally to the fundamental study of continuous versus discrete inverse formulations found in [262-275]. Applications of inversion to geodetic satellite data are found in [239 - 261]. General mathematical and computational aspects are mainly found in [262 - 336]. Nonlinearity in weakly nonlinear problems may be coped with by careful modification of lineaxized methods [295 - 302]. Strongly nonlinear problems call for Monte Carlo methods, where the cooling scedule in simulated annealing [303 - 311,139 - 150] is critical for convergence to a useful (local) minimum, and the set of consistent models is explored through importance sampling [89 - 90]. The use of prior information, directly or indirectly, is a key issue in most contributions, ranging from Bayesian formulations based a priori covariances e.g. [98 - 112,122 - 130, 254 - 261], over more general but also less tractable prior probability densities [79 - 97], to inclusion of specific prior knowledge of shape [284 - 294, 312 - 319]. Given the differences and similarities in approach, can we benefit from exchange of ideas and experience? In practice ideas and experience seldom jump across discipline boundaries by themselves. Normally one must go and get them the hard way, for instance by reading and understanding papers from disciplines far from the home ground. Look at the journey into the interdisciplinary cross-field of inversion techniques as a demanding safari into an enormous hunting ground. This book is meant to provide a convenient starting point.

Description / Table of Contents: PREFACE In the geologic record, vertical crustal uplift has often resulted in erosional removal of huge thicknesses of sedimentary strata. If the uplift is of a broad regional nature or the uplifted strata remain relatively undeformed and sediments deposited after the uplift are not preserved, the magnitude of uplift and subsequent erosion may be difficult to quantify. This may lead to misinterpretation or omission of chapters of geologic history of a region. Fortunately, a number of indirect methods can be used to infer the thicknesses of missing strata and reconstruct the geologic history. Our book titled "Thick Post-Devonian Sediment Cover Over New York State: Evidence from Fluid-Inclusion, Organic Maturation, Clay Diagenesis and Stable Isotope Studies" uses four techniques of paleotemperature measurements in sedimentary rocks in order to determine burial depths of the existing Paleozoic strata in New York State. Since every technique has its own analytical and interpretative uncertainties, the use of four techniques allowed us to place a better constraint on our results. We show how regionally extensive paleotemperature data can be used to estimate the thicknesses of strata lost from an uplifted sedimentary basin. We also provide a tentative tectonic-, paleogeographic- and depositional history of New York State after the Devonian when the missing strata were deposited...

Description / Table of Contents: PREFACE In recent years, there has been increasing interest from geoscientists in potassic igneous rocks. Academic geoscientists have been interested in their petrogenesis and their potential value in defining the tectonic setting of the terranes into which they were intruded, and exploration geoscientists have become increasingly interested in the association of these rocks with major epithermal gold and porphyry gold-copper deposits. Despite this current interest, there is no comprehensive textbook that deals with these aspects of potassic igneous rocks. This book redresses this situation by elucidating the characteristic features of potassic (high-K) igneous rocks, erecting a hierarchical scheme that allows interpretation of their tectonic setting using whole-rock geochemistry, and investigating their associations with a variety of gold and copper-gold deposits, worldwide. About twothirds of the book is based on a PhD thesis by Dr Daniel MOiler which was produced at the Key Centre for Strategic Mineral Deposits within the Department of Geology and Geophysics at The University of Western Australia under the supervision of Professor David Groves, the late Dr Nick Rock, Professor Eugen Stumpfl, Dr Wayne Taylor, and Dr Brendon Griffin. The remainder of the book was compiled from the literature using the collective experience of the two authors. The book is dedicated to the memory of Dr Rock who initiated the research project but died before its completion...

Description / Table of Contents: PREFACE The four-year period of activity of the Groupement de Recherche 942 (GDR) of the Centre National de la Recherche Scientifique (CNRS) came to an end in December 1993. This GDR was a scientific association grouping research teams from the academic sphere -- i.e. the Unités de Recherches Associées 723 & 724 of the CNRS as well as the Universities of Orléans and Paris-Sud -- and from the industrial world: Elf-Aquitaine Production, TOTAL and the Institut Français du Pétrole (IFP). The aim of the GDR was to understand the processes and the causes of organic carbon fossilization in sediments, especially when they can be modified by environmental conditions such as climate, eustatism, productivity etc., factors which can alko interact. This goal implies the simultaneous study of ancient geological formations (hydrocarbon source rocks from the famous Kimmeridge Clay Formation) and recent Quaternary sediments (the Lac du Bouchet or lake Bouchet maar, Massif Central, France). In the latter case, we benefit from a fine-scale stratigraphical framework as well as a reliable reconstruction of the local and regional environment. This volume is a collection of papers representing oral presentations given on December 7, 1993, at the Société Géologique de France in Paris, during the final meeting of the GDR. These articles thus report the latest developments of the studies carried out under the GDR. However, this is not the first publication of our results, which can be found in the papers referred to in each article. The Kimmeridge Clay Formation was previously studied in 1987, by the Yorkim Group from IFP, Elf-Aquitaine and the British Geological Survey, on the basis of a series of wells drilled across the Cleveland Basin of Yorkshire. In each well, the distribution with depth of the total organic content is cyclic. We have compared some of the organic cycles from two wells (Matron and Ebberston) based on mineralogy, organic and inorganic geochemistry and petrography, at a high resolution scale (centimetric). The main conclusion of this work is that the driving force for organic matter accumulation in the studied cycles was organic phytoplankton productivity. Oxygenation conditions seem to have played a secondary role as a positive feedback action enhancing organic matter storage. Lac du Bouchet is located on the Devès volcanic plateau, 15 km SW of Le Puy en Velay, at an altitude of 1205 m. The depth of the water column is 28 m. The lake has a subcircular shape (1 km in diameter) and a very restricted watershed. This site is exceptionally suitable for research on climate variations and palaeomagnetic field modifications (Euromaars EC Program). The GDR focused on sedimentary organic matter and its relationship to inorganic phases. An important result is that organic matter appears to be a good indicator of palaeoenvironmental reconstructions for over 350 000 years. In addition, the study of early diagenetic reactions in surficial sediments (porewater and solid phase) allows the specification of the processes of organic matter degradation and storage in such an oligothrophic lake.

Description / Table of Contents: PREFACE The sedimentology of Chalk describes processes that caused the rhythmic vertical variation in grain size, structures and authigenic mineral concentrations in Late Cretaceous and Early Tertiary, subtropical, shallow marine, fine-grained, detrital bioclastic carbonates of northwest Europe. In particular, attention is paid to the sedimentology of the Tuffaceous Chalk of Maaslricht (The Netherlands), a coarsegrained variety of Chalk that resembles the Chalk (coccolithic mudstones) as well as modern shallow marine carbonate sands. Numerical models are presented that enable the simulation of the genesis of flint nodule layers, hardgrounds and complex wavy bedded sequences, such as the K/T boundary sequence of Stevns Klint (Denmark). The aim of this book is to show how depositional and early diagenetic features, which are observed in small-scale Chalk outcrops, can be used to reconstruct the large-scale dynamics of the northwest European continent during the Late Cretaceous and Early Tertiary...

Description / Table of Contents: PREFACE Seismic imaging is the process through which seismograms recorded on the Earth's surface are mapped into representations of its interior properties. Imaging methods are nowadays applied to a broad range of seismic observations: from nearsurface environmental studies, to oil and gas exploration, even to long-period earthquake seismology. The characteristic length scales of the features imaged by these techniques range over many orders of magnitude. Yet there is a common body of physical theory and mathematical techniques which underlies all these methods. The focus of this book is the imaging of reflection seismic data from controlled sources. At the frequencies typical of such experiments, the Earth is, to a first approximation, a vertically stratified medium. These stratifications have resulted from the slow, constant deposition of sediments, sands, ash, and so on. Due to compaction, erosion, change of sea level, and many other factors, the geologic, and hence elastic, character of these layers varies with depth and age. One has only to look at an exposed sedimentary cross section to be impressed by the fact that these changes can occur over such short distances that the properties themselves are effectively discontinuous relative to the seismic wavelength. These layers can vary in thickness from less than a meter to many hundreds of meters. As a result, when the Earth's surface is excited with some source of seismic energy and the response recorded on seismometers, we will see a complicated zoo of elastic wave types: reflections from the discontinuities in material properties, multiple reflections within the layers, guided waves, interface waves which propagate along the boundary between two different layers, surface waves which are exponentially attenuated with depth, waves which are refracted by continuous changes in material properties, and others. The character of these seismic waves allows seismologists to make inferences about the nature of the subsurface geology. Because of tectonic and other dynamic forces at work in the Earth, this first-order view of the subsurface geology as a layer cake must often be modified to take into account bent and fractured strata. Extreme deformations can occur in processes such as mountain building. Under the influence of great heat and stress, some rocks exhibit a taffy-like consistency and can be bent into exotic shapes without breaking, while others become severely fractured. In marine environments, less dense salt can be overlain by more dense sediments; as the salt rises under its own buoyancy, it pushes the overburden out of the way, severely deforming originally flat layers. Further, even on the relatively localized scale of exploration seismology, there may be significant lateral variations in material properties. For example, if we look at the sediments carried downstream by a river, it isclear that lighter particles will be carried further, while bigger ones will be deposited first; flows near the center of the channel will be faster than the flow on the verge. This gives rise to significant variation is the density and porosity of a given sedimentary formation as a function of just how the sediments were deposited. Taking all these effects into account, seismic waves propagating in the Earth will be refracted, reflected and diffracted. In order to be able to image the Earth, to see through the complicated distorting lens that its heterogeneous subsurface presents to us, in other words, to be able to solve the inverse scattering problem, we need to be able to undo all of these wave propagation effects. In a nutshell, that is the goal of imaging: to transform a suite of seismograms recorded at the surface of the Earth into a depth section, i.e., a spatial image of some property of the Earth (usually wave speed or impedance). There are two main types of spatial variations of the Earth's properties. There are the smooth changes (smooth meaning possessing spatial wavelengths which are long compared to seismic wavelengths) associated with processes such as compaction. These gradual variations cause ray paths to be gently turned or refracted. On the other hand, there are the sharp changes (short spatial wavelength), mostly in the vertical direction, which we associate with changes in lithology and, to a lesser extent, fracturing. These short wavelength features give rise to the reflections and diffractions we see on seismic sections. If the Earth were only smoothly varying, with no discontinuities, then we would not see any events at all in exploration seismology because the distances between the sources and receivers are not often large enough for rays to turn upward and be recorded. This means that to first order, reflection seismology is sensitive primarily to the short spatial wavelength features in the velocity model. We usually assume that we know the smoothly varying part of the velocity model (somehow) and use an imaging algorithm to find the discontinuities. The earliest forms of imaging involved moving, literally migrating, events around seismic time sections by manual or mechanical means. Later, these manual migration methods were replaced by computer-oriented methods which took into account, to varying degrees, the physics of wave propagation and scattering. It is now apparent that all accurate imaging methods can be viewed essentially as linearized inversions of the wave equation, whether in terms of Fourier integral operators or direct gradient-based optimization of a waveform misfit function. The implicit caveat hanging on the word "essentially" in the last sentence is this: people in the exploration community who practice migration are usually not able to obtain or preserve the true amplitudes of the data. As a result, attempts to interpret subtle changes in reflector strength, as opposed to reflector position, usually run afoul of one or more approximations made in the sequence of processing steps that makes up a migration (trace equalization, gaining, deconvolution, etc.) On the other hand, if we had true amplitude data, that is, if the samples recorded on the seismogram really were proportional to the velocity of the piece of Earth to which the geophone were attached, then we could make quantitative statements about how spatial variations in reflector strength are related to changes in geological properties. The distinction here is the distinction between imaging reflectors, on the one hand, and doing a true inverse problem for the subsurface properties on the other. Until quite recently the exploration community was exclusively concerned with the former, and today the word "migration" almost always refers to the imaging problem. The more sophisticated view of imaging as an inverse problem is gradually making its way into the production software of oil and gas exploration companies, since careful treatment of amplitudes is often crucial in making decisions on subtle lithologic plays (amplitude versus offset or AVO) and in resolving the chaotic wave propagation effects of complex structures. When studying migration methods, the student is faced with a bewildering assortment of algorithms, based upon diverse physical approximations. What sort of velocity model can be used: constant wave speed v? v(x), v(x, z), v(x, y, z)? Gentle dips? Steep dips? Shall we attempt to use turning or refracted rays? Take into account mode converted arrivals? 2D (two dimensions)? 3D? Prestack? Poststack? If poststack, how does one effect one-way wave propagation, given that stacking attenuates multiple reflections? What domain shall we use? Time-space? Time-wave number? Frequency-space? Frequency-wave number? Do we want to image the entire dataset or just some part of it? Are we just trying to refine a crude velocity model or are we attempting to resolve an important feature with high resolution? It is possible to imagine imaging algorithms that would work under the most demanding of these assumptions, but they would be highly inefficient when one of the simpler physical models pertains. And since all of these situations arise at one time or another, it is necessary to look at a variety of migration algorithms in daily use. Given the hundreds of papers that have been published in the past 15 years, to do a reasonably comprehensive job of presenting all the different imaging algorithms would require a book many times the length of this one. This was not my goal in any case. I have tried to emphasize the fundamental physical and mathematical ideas of imaging rather than the details of particular applications. I hope that rather than appearing as a disparate bag of tricks, seismic imaging will be seen as a coherent body of knowledge, much as optics is...

Description / Table of Contents: P-wave Velocity Discontinuity in D" Layer beneath Western Pacific with J-Array Records / T. Shibutani, K. Hirahara, and M. Kato / pp. 1-11 --- Formation of Iron Hydrides under the Condition of the Earth's Interior-Implication for the Core Formation Process / T. Yagi / pp. 13-28 --- Computer Simulation of the Structural and Elastic Properties of Iron at Earth's Inner Core Conditions / M. Matsui / pp. 29-34 --- Experimental Study of the Decomposition of Kyanite at High Pressure and High Temperature / T. Irifune, K. Kuroda, T. Minagawa, and M. Unemoto / pp. 35-44 --- Empirical Formulation for the Distribution of Ca2+ between Olivine and Ca-rich Clinopyroxene at 7.5 GPa Pressure / T. Kawasaki / pp. 45-55 --- Rock-Magnetic Study of Sediments: A Brief Review of Bulk Sample Methods / M. Torii / pp. 57-73 --- Intensity of the Geomagnetic Field in Geological Time: A Statistical Study / M. Kono and H. Tanaka / pp. 75-94 --- Strength ol the Magnetic Field in the Earth's Core Estimated from Geomagnetic Field Data / M. Matsushima / pp. 95-104 --- On Truncation Levels in Spherical Harmonic Expansion of Magnetic and Velocity Fields in an MHD Dynamo Model / Y. Tanahashi, Y. Honkura, and M. Matsushima / pp. 105-122 --- Boussinesq Convection in Rotating Spherical Shells ~ A Study on the Equatorial Superrotation / S. Takehiro and Y.-Y. Hayashi / pp. 123-156 --- Bubble Convection / K. Iga and R. Kimura / pp. 157-180 --- Simulation of Fluid Flow in the Earth's Outer Core: Application of a Lattice Gas Method / H. Kabayama, Y. Teshima, H. Takayanagi, and Y. Honkura / pp. 181-213 --- Basic Equations for the Evolution of Partially Molten Mantle and Core / Y. Abe / pp. 215-230 --- A Model for the Structural Evolution of the Earth's Core and Its Relation to the Observations / I. Sumita, S. Yoshida, Y. Hamano, and M. Kumazawa / pp. 231-260 --- Evaporation and Condensation Kinetics and Isotopic Mass Fractionations in the Systems Mg-Si-O-H and Fe-S-H in Relation to the Major Element Compositions of the Earth / A. Tsuchiyama and C. Uyeda / pp. 261-275 --- Isotope line Analysis on Primitive Materials Using Ion Microprobe / C. Uyeda and A. Tsuchiyama / pp. 277-285 --- Element Partitioning between MgSiO3 Perovskite, Magma, and Molten Iron: Constraints for the Earliest Processes of the Earth-Moon System / E. Ohtani, H. Yurimoto, T. Segawa, and T. Kato / pp. 287-300 --- Evolution of the Earth's Obliquity and the Role of Core-Mantle Coupling / T. Ito and Y. Hamano / pp. 301-318 --- Core and Deformable Mantle Couplings beneath the Eurasian and the Pacific Plate Boundary / C. Kakuta / pp. 319-330 --- Differences in Morphology and Structure between Hotspot Tracks: Effects of the Lithospheric Age at the Time of Formation / C. Honsho and K. Tamaki / pp. 331-342 --- Noble Gas Constraints on the Plume Sources in the Earth's Deep Interior / I. Kaneoka / pp. 343-355 --- Polynesian Super Plume: A Window down to the Core/Mantle Boundary / Y. Tatsumi and T. Kogiso / pp. 357-367 ---

Description / Table of Contents: DEKORP, the German continental reflection seismic program, was the major focus of deep seismic research in Germany in the 1980s and 1990s. The seismic sections provided fundamental new insight into deep geological structure of the European continent and the dynamics of continental formation. They formed the basis for worldwide comparative studies of orogenic structure. The complicated signature of the reflections from the deep crust indicated that new processing and interpretation techniques must be considered to better image the crystalline crust. Results of these efforts, including pre-stack migration, 3-D imaging, shear waves and seismic anisotropy, are presented in this special volume. In part, the articles open the perspective to new and future research. In part, they document research activity triggered by technical and interpretational questions raised by DEKORP field work and profiling results. Many of the presented methods can find immediate application in industrial seismic prospecting.

Description / Table of Contents: Variations in seismic Q are sensitive to a much greater extent than are seismic velocity variations on factors such as temperature, fluid content, and the movement of solid state defects in the earth. For that reason an understanding of Q and its variation with position in the earth and with time should provide information in earth's tectonic evolution, as well as on aspects of its internal structure. Progress in understanding Q has suffered from difficulty in obtaining reliable amplitude data at global and temporary stations. Moreover, laboratory determinations of Q, until recently, were most often made at frequencies much higher than those measured by seismologists for waves propagating through the earth. Recent advances in seismic station distribution and quality, as well as in methodology at both high and low fequencies, have greatly improved the quality of observational data available to seismologists from global stations. Concurrent advances have been made in measuring Q using laboratory samples at frequencies that pertain to the earth and in theoretical understanding of seismic wave attenuation. Papers of this volume present new information on Q in the earth from several perspectives: methodology, results from global and regional observations of both body and surface waves, laboratory measurements, and theoretical understanding. The editors believe that we have reached a new threshold in Q studies and that advances in data quality and methodology will spur increased interest in this difficult, but interesting field.