Preliminary reference earth model

This essential reference for graduate students and researchers provides a unified treatment of earthquakes and faulting as two aspects of brittle tectonics at different timescales. The intimate connection between the two is manifested in their scaling laws and populations, which evolve from fracture growth and interactions between fractures. The connection between faults and the seismicity generated is governed by the rate and state dependent friction laws - producing distinctive seismic styles of faulting and a gamut of earthquake phenomena including aftershocks, afterslip, earthquake triggering, and slow slip events. The third edition of this classic treatise presents a wealth of new topics and new observations. These include slow earthquake phenomena; friction of phyllosilicates, and at high sliding velocities; fault structures; relative roles of strong and seismogenic versus weak and creeping faults; dynamic triggering of earthquakes; oceanic earthquakes; megathrust earthquakes in subduction zones; deep earthquakes; and new observations of earthquake precursory phenomena.

The Mechanics of Earthquakes and Faulting

Stakeholder participation for environmental management: A literature review

Common understanding of the causes of land-use and land-cover change is dominated by simplifications which, in turn, underlie many environment-development policies. This article tracks some of the major myths on driving forces of land-cover change and proposes alternative pathways of change that are better supported by case study evidence. Cases reviewed support the conclusion that neither population nor poverty alone constitute the sole and major underlying causes of land-cover change worldwide. Rather, peoples’ responses to economic opportunities, as mediated by institutional factors, drive land-cover changes. Opportunities and

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The causes of land-use and land-cover change: moving beyond the myths

The nonlinear inverse problem for seismic reflection data is solved in the acoustic approximation. The method is based on the generalized least‐squares criterion, and it can handle errors in the data set and a priori information on the model. Multiply reflected energy is naturally taken into account, as well as refracted energy or surface waves. The inverse problem can be solved using an iterative algorithm which gives, at each iteration, updated values of bulk modulus, density, and time source function. Each step of the iterative algorithm essentially consists of a forward propagation of the actual sources in the current model and a forward propagation (backward in time) of the data residuals. The correlation at each point of the space of the two fields thus obtained yields the corrections of the bulk modulus and density models. This shows, in particular, that the general solution of the inverse problem can be attained by methods strongly related to the methods of migration of unstacked data, and commerc...

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Inversion of seismic reflection data in the acoustic approximation

In the past decade, seismology has matured as a quantitative science through an extensive interplay between theoretical and experimental workers. Several specialized journals have recorded this progress in thousands of pages of research papers, yet such a forum does not bring out key concepts systematically. Because many graduate students have expressed their need for a textbook on this subject and because many methods of seismogram analysis now used almost routinely by small groups of seismologists have never been adequately explained to the wider audience of scientists and engineers who work in the peripheral areas of seismology, we have here attempted to give a unified treatment of those methods of seismology th at are currently used in interpreting actual data. We develop the theory of seismic-wave propagation in realistic Earth models. We study specialized theories of fracture and rupture propagation as models of an earthquake, and we supplement these theoretical subjects with practical descriptions of how seismographs work and how data are analyzed and inverted. Our text is arranged in two volumes. Volume I gives a systematic development of the theory of seismic-wave propagation in classical Earth models, in which material properties vary only with depth. It concludes with a chapter on seismometry. This volume is intended to be used as a textbook in basic courses for advanced students of seismology. Volume II summarizes progress made in the major frontiers of seismology during the past decade. It covers a range of special subjects, including chapters on data analysis and inversion, on successful methods for quantifying wave propagation in media varying laterally (as well as with depth), and on the kinematic and dynamic aspects of motions near a fault plane undergoing rupture. The second volume may be used as a texbook in graduate courses on tectonophysics, earthquake mechanics, inverse problems in geophysics, and geophysical data processing.n

Quantitative seismology : theory and methods

Quantitative Seismology, 2nd Ed.

Do small wars in Africa manifest a 'new barbarism'? What appears as random, anarchic violence is no such thing. The terrifying military methods of of Sierra Leone's soldiers may not fir conventional western models of warfare, but they are rational and effective nonetheless. The war must be understood partly as a 'performance', in which techniques of terror compensate for lack of equipment.BR> PAUL RICHARDS is Professor of Technology and Agrarian Development, Wageningen University Published in association with the International African Institute

Fighting for the Rain Forest: War, Youth and Resources in Sierra Leone

Contrasting the prevailing theories of the evolution of agriculture, the author argues that the practice of smallholding is more efficient and less environmentally degrading than that of industrial agriculture which depends heavily on fossil fuel, chemical fertilizers, pesticides and herbicides. He presents a convincing case for his argument with examples taken from Africa, Asia, Europe and the Americas, and demonstrates that there are fundamental commonalities among smallholder cultures. \"Smallholders, Householders\" is a detailed and innovative analysis of the agricultural efficiency and conservation of resources practiced around the world by smallholders.

Paul Richards

Papers

Quantitative seismology : theory and methods

Quantitative Seismology, 2nd Ed.

Fighting for the Rain Forest: War, Youth and Resources in Sierra Leone

Smallholders, Householders: Farm Families and the Ecology of Intensive Sustainable Agriculture

Indigenous agricultural revolution : ecology and food production in West Africa