This is the first textbook to cover all the major aspects of seismic tomography at a level accessible to students. While focusing on applications in solid earth geophysics, the book also includes numerous excursions into helioseismology in order to demonstrate the strong affinity between the two fields. The book presents a comprehensive introduction to seismic tomography including the basic theory of wave propagation, the ray and Born approximations required for interpretation of amplitudes, travel times and phases, eigenvibrations and surface waves, observational methods, model parametrization, finite-frequency methods, inversion, error and resolution analysis, and seismic anisotropy. It presents in-depth consideration of observational aspects of the subject, as well as practical recommendations for implementing numerical models using publicly available software.

A moderately comprehensive reference handbook covering the most important paleontological taxa, terms, concepts, and localities, this book is written primarily for general readers and beginning students in the field. My professional experience lies in technical writing and in teaching literature and history, with a lifelong interest in paleontology inspired by Professor Charles Higgins at UC Davis and by studying the geology collection in UC Berkeley’s beautiful Bacon Hall before it was demolished in 1961. Using the essays of science writers like Loren Eiseley, Stephen Gould, and E.O. Wilson in my composition classes in the 1980s, I made critical thinking and the evolution of life on Earth the center of my teaching. An interesting technical writing project in the early 1990s showed me the lack of a dictionary like this, and I began the groundwork for a good reference work as I directed student research in the history of life in my writing courses. Retiring from teaching in 2014, I have widened my understanding of paleontology with intensive study in the last 5 years. <...>

In preparing this new edition of our Dictionary of Geology and Earth Sciences I have changed the emphasis very slightly by increasing the number of entries for terms that are directly geological. The new title reflects this minor revision. At the same time, however, I have found it necessary to add more entries describing satellite missions and planetary discoveries. I have also added a new Appendix, listing web addresses for all the satellite missions described in dictionary entries.

Inevitably, the dictionary has grown a little longer. That is the way of dictionaries. New terms emerge, but old ones take a long time to die and disappear from the vocabulary. As with the third edition, I have worked alone. I have scrutinized every entry and made many small changes where I thought I could improve the clarity of definitions. If, inadvertently, I have introduced any errors, or failed to spot and remove earlier errors, I have no one to blame but myself. If you find a mistake I will be grateful if you draw it to my attention. You can contact me through my website.

If you are meeting the dictionary for the first time, I hope you find it helpful.

“Prevention is better than cure” has been the leitmotiv of UNESCO, since its creation, in addressing world problems: prevention through education at all levels and in all sectors, the advancement of science and its applications, cultural development and adequate information. Whether in facing wars, conflicts or in coping with hazards, natural and technological in origin, UNESCO has constantly favoured an educational, scientific and cultural approach that sees anticipation as the only possible solution. It is the only possible cost-effective way of dealing with potential risks and disasters. It is of vital importance that the world community takes the long-term view and learns to be proactive rather than reactive.