Skip to main content

2000 | Buch

Faulting in Brittle Rocks

An Introduction to the Mechanics of Tectonic Faults

verfasst von: Professor Dr. Georg Mandl

Verlag: Springer Berlin Heidelberg

insite
SUCHEN

Über dieses Buch

This book provides an introduction into the mechanics of faulting in the brittle crust of the Earth. It developed from my annual two-semester course on tectono­ mechanics for graduate students of engineering geology and of rock engineering at the Technical University of Graz (Austria). In this course, it is not my task to present a broad exposition and geometrical description of geological structures, but rather to focus on the mechanical processes that produce the structures. Although this was also the aim of my former book "Mechanics of Tectonic Faulting - Models and Basic Concepts" (1988, Elsevier), henceforth referred to as MTF, the present book is different in organisation and content, in order to meet the requirements of the courses and to include more recent developments. Instead of following the traditional subdivision into extensional, compressional and strike-slip faulting, the presentation focuses on mechanical aspects of tectonic faulting that are common to various, or even all types of tectonic faults in the brittle regime. In this way, geometrically disparate or dissimilar fault structures may be revealed as closely related by the underlying mechanical process, and complex structures may be better understood. It may be useful to indicate how the chapters in the book are organised. The first three chapters are an introduction to rock mechanics, tailored to applications in geology. It also presents the extremely useful graphical method of Mohr's stress circle, which is freely used throughout the book to keep the mathematics to an absolute minimum.

Inhaltsverzeichnis

Frontmatter
1. Stress and Strain in Rocks
Abstract
A rock mass is primarily deformed by its weight and by the mechanical interaction with adjacent materials. In quantifying these interactions and in tracing their deformational effects into the interior of a rock body, one has to rely on the basic concepts of stress and strain. The elements of these concepts will be dealt with in this opening chapter. Special attention will be paid to the adaptations of the stress concept that become necessary when dealing with fluid-filled porous rocks.
Georg Mandl
2. The Stress Circle
Abstract
O. Mohr’s stress circle diagram is an extremely useful geometrical representation of the state of stress at a point. It is particularly convenient in problems of plane deformation, since the state of stress may then be visualized by a single stress circle.
Georg Mandl
3. The Brittle Regime
Abstract
In any deformational process stresses and strains are intimately related. This chapter introduces, in a somewhat elementary way, the relationship between stresses and strains in the deformation of rocks in the brittle’ upper crust of the Earth.
Georg Mandl
4. The Coulomb — Mohr Theory of Faulting
Abstract
Faults are shear failures in the Earth’s crust, many mechanical aspects of which can be dealt with by Coulomb — Mohr’s theory of brittle shear failure in a regime of compressive effective stresses.
Georg Mandl
5. Poro — Thermo — Elasticity of Rocks
Abstract
Small elastic strains precede the formation of tensile fractures and the inelastic straining that leads to the formation of faults and folds in the brittle crust. Small elastic strains also occur in the propagation of acoustic waves, in earthquakes, in erosive unloading of rocks, during changes in pore pressure and temperature, and during the geometrical adjustment of sliding fault blocks.
Georg Mandl
6. Fault Structures
Abstract
In this central chapter Coulomb-Mohr’s theory of faulting is applied to:
1)
normal and thrust faulting in rocks composed of layers differing in strength, rheology and pore pressure;
 
2)
the mechanical causes of listric faulting in various geological settings (sediment slopes, ice loads, substratal flow, thrusting and rifting, subsiding basement blocks, compaction, etc.);
 
3)
the role of antithetic faults and continuous ‘double-shearing’ in adjusting sliding rock masses to changes in shape or position of the sliding path;
 
4)
the ‘bookshelf’ operation of parallel antithetic faults in accommodating tectonic (quasi-) simple shearing;
 
5)
providing a mechanical explanation of the paradoxical stress orientation along the San Andreas fault, California.
 
Georg Mandl
7. Slip, Reactivation and Termination of Faults
Abstract
In this chapter we explore in detail the displacement on faults:
  • Section 7.1 surveys the parameters that affect the displacement distribution on a fault, and presents the Walsh—Watterson model of the growth and displacement distribution of ‘blind’ faults.
  • Section 7.2 examines how the near-tip stresses determine the modes of fault propagation and termination.
  • Section 7.3 derives the formula for the maximum resolved shear stress on a fault, and the conditions for fault reactivation and inversion in Andersonian stress regimes with arbitrarily oriented horizontal principal stresses.
  • Section 7.4 deals with the compressive inversion of ‘weak’ normal faults, and the role which ‘hardened’ faults may play during the contractive inversion of a basin.
  • Section 7.5 compares the tectono-mechanical geneses of shear joints and faults.
Georg Mandl
8. Parallel Faults
Abstract
In various tectonic environments, shearing and crustal extension or shortening have been accommodated by arrays of parallel faults, frequently arranged en échelon. In this chapter we use model experiments and mechanical theory to investigate the tectono-mechanical conditions that control the development of these fault patterns.
Georg Mandl
9. Modelling of Faulting Scaling Problems
Abstract
In preceding chapters we have freely used experimental results to complement mechanical analyses of fault structures. In this final chapter we examine the similarity of fault structures and the conditions (scaling rules) that should be fulfilled by the experimental set-up to ensure a one-to-one correspondence between the states of brittle deformation in the model and in the natural system (prototype).
Georg Mandl
Backmatter
Metadaten
Titel
Faulting in Brittle Rocks
verfasst von
Professor Dr. Georg Mandl
Copyright-Jahr
2000
Verlag
Springer Berlin Heidelberg
Electronic ISBN
978-3-662-04262-5
Print ISBN
978-3-642-08570-3
DOI
https://doi.org/10.1007/978-3-662-04262-5