Practical Approaches to USO Costing and Financing

In this paper we set out a holistic approach that incorporates recent developments in assessing the net cost of the USO and presents a robust methodology for practical implementation. We analyse the issues relating to assessing the net costs of the USO with particular focus on the benefits associated with USO and current empirical approaches to calculating the net costs. We then present an overview of approaches that have been applied in various countries and highlight their strengths and shortcomings in light of the necessarily theoretical aspects discussed in the first part of the paper. Finally, we present a practical approach that we believe assesses robustly the net cost of the USO.Regulation, Post, Universal service obligation, Financing

Dupin's indicatrix: a tool for quantifying periclinal folds on maps

The elliptical and hyperbolic outcrop patterns characteristic of periclinal folds can be used to classify structures according to different curvature attributes. Elliptical patterns indicate domal-basinal structures with synclastic curvature, that is, principal curvatures of the same sign. Hyperbolic patterns are diagnostic of anticlastic curvature (saddle-like structures). Such outcrop geometries are geological examples of Dupin’s indicatrix, the geometrical figure obtained by sectioning a curved surface on a plane parallel and almost coincident with the tangent plane. The aspect ratio of Dupin’s indicatrix is theoretically related to the ratio of the principal curvature values for the part of the structure being considered. This new method allows quantitative assessment of structures on maps and on remote sensing images. Illustrations are given from Wyoming, USA, and Yorkshire, England

New method of estimating regional stress orientations: Application to focal mechanism data of recent British earthquakes

It is demonstrated how a recently devised graphical method for estimating palaeostresses from exposed striated fault planes can be adapted for use with earthquake focal mechanism data. Provided the data set includes one or more earthquakes for which the fault plane can be identified, the principal stress directions can be determined more precisely than by using the alternative Right Dihedra method. Using the new so-called Right Trihedra method stress directions are found which are compatible with recent British earthquakes. The method can also be used, in the case of some focal mechanisms, to resolve the ambiguity regarding which focal plane corresponds to the fault plane

Geological folds in three dimensions

The majority of terms that structural geologists use to describe the geometrical features of folds are defined in terms of simple cylindrical fold model. These terms have served well in the past where folds are observed at surface outcrop, and where three-dimensional information is limited. However, new mapping methods, e.g. high precision GPS, seismic and LIDAR deliver more complete 3D data on folded surfaces and reveal that the cylindrical model is an inadequate model of fold geometry. This review examines how existing terms such as the antiform, synform, hinge line and fold inflection line can be re-defined in order to make them useful for describing general non-cylindrical folds

The facing of faults

It is proposed that the usage of the term structural facing be extended to include fault structures. Fault facing is defined as the direction in a fault plane which is at right angles to the trace of the bedding and is directed towards the younger beds. Certain types of faulted structures are found to have diagnostic patterns of facing variation