Analysis And Inversion Methods For Crustal Deformation Data

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 175. A Continental Plate Boundary offers in one place the most comprehensive, up-to-date knowledge for researchers and students to learn about the tectonics and plate dynamics of the Pacific-Australian continental plate boundary in South Island and about the application of modern geological and geophysical methods. It examines what happens when convergence and translation occur at a plate boundary by Describing the geological and geophysical signature of a continental transform fault; Identifying the diverse vertical and lateral patterns of deformation at the plate boundary; Assessing an apparent seismicity gap on the plate boundary fault and fast-moving plate motions; Comparing this plate boundary to other global convergent continental strike-slip plate boundaries; Documenting the utility of the double-sided, onshore-offshore seismic method for exploration of a narrow continental island; and Providing additional papers presenting previously unpublished results. This volume will prove invaluable for seismologists, tectonophysicists, geodesists and potential-field geophysicists, geologists, geodynamicists, and students of the deformation of tectonic plates.

Earthquake and Volcano Deformation is the first textbook to present the mechanical models of earthquake and volcanic processes, emphasizing earth-surface deformations that can be compared with observations from Global Positioning System (GPS) receivers, Interferometric Radar (InSAR), and borehole strain- and tiltmeters. Paul Segall provides the physical and mathematical fundamentals for the models used to interpret deformation measurements near active faults and volcanic centers. Segall highlights analytical methods of continuum mechanics applied to problems of active crustal deformation. Topics include elastic dislocation theory in homogeneous and layered half-spaces, crack models of faults and planar intrusions, elastic fields due to pressurized spherical and ellipsoidal magma chambers, time-dependent deformation resulting from faulting in an elastic layer overlying a viscoelastic half-space and related earthquake cycle models, poroelastic effects due to faulting and magma chamber inflation in a fluid-saturated crust, and the effects of gravity on deformation. He also explains changes in the gravitational field due to faulting and magmatic intrusion, effects of irregular surface topography and earth curvature, and modern concepts in rate- and state-dependent fault friction. This textbook presents sample calculations and compares model predictions against field data from seismic and volcanic settings from around the world. Earthquake and Volcano Deformation requires working knowledge of stress and strain, and advanced calculus. It is appropriate for advanced undergraduates and graduate students in geophysics, geology, and engineering. Professors: A supplementary Instructor's Manual is available for this book. It is restricted to teachers using the text in courses. For information on how to obtain a copy, refer to: http://press.princeton.edu/class_use/solutions.html

In both our past work and the work in progress we focused on understanding the physics and statistical patterns in earthquake faults and fault systems. Our approach had three key aspects. The first was to look for patterns of seismic activity in earthquake fault systems. The second was to understand the physics of a sequence of models for faults and fault systems that are increasingly more realistic. The third key element was to connect the two previous approaches by investigating specific properties found in models to see if they are indeed properties of real faults. A specific example of how this approach works can be seen in the following: In the papers discussed below, we demonstrated that the cellular automation (CA) versions of the slider block models with long range stress transfer are ergodic and could be described by a Boltzmann-Gibbs distribution in the meanfield limit. The ergodicity follows from the fact that the long range stress transfer makes the model meanfield. The meanfield nature of the CA models, generated by long range stress transfer, also allows a description of the CA models by a Langevin equation. The Langevin equation indicates that evolution of seismicity in the model over relatively short times is linear in time. This appears to be consistent with the success of a forecasting algorithm we have developed that is based on a linear evolution of seismicity patterns. This algorithm has had considerable success in that the regions of the Southern California fault system which have been predicted to have a higher probability of an event greater than magnitude 5 have consistently been the sites where such events occur. These two results have led to the question as to whether the Southern California fault system is ergodic and can be described by a Langevin equation like the model. To answer this question we ran a series of tests for ergodicity very much like the ones run on the models. Our results, which have been accepted for publication in Physical Review Letters (Tiampo et al., in press), demonstrate that the Southern California system is ergodic in the same way that is seen in the models. These results will be discussed in more detail below. However, the point that needs to be emphasized is that it was the combination of model investigation via theory and simulation coupled with assimilation and classification of real data and applying the methods of statistical mechanics to real fault systems that led to both a successful forecasting algorithm and a deeper understanding of the nature of earthquake fault systems. This paper describes in some detail the results obtained in the previous funding period. We present these in three groups. (A) Investigation of statistical physics models and applications. (B) Earthquake fault systems and Greens functions for complex sources and (C) Space time patterns, data analysis and forecasting.

This book takes an in depth look at a novel methodology for analyzing Global Positioning System (GPS) data to obtain the highest possible resolution surface imaging of tectonic deformation sources without prescribing the nature of either the sources or the subsurface medium. GPS methods are widely used to track the surface expression of crustal deformation at tectonic plate boundaries, and are typically expressed in terms of velocity fields or strain rate fields. Vertical derivatives of horizontal stress (VDoHS) rates at the Earth’s surface can also be derived from GPS velocities, and VDoHS rates provide much higher resolution information about subsurface deformation sources than velocities or strain rates. In particular, VDoHS rates allow for high precision estimates of fault dips, slip rates and locking depths, as well as objective characterization of previously unknown (or hidden) tectonic deformation zones.

Inverse Problems are found in many areas of engineering mechanics and there are many successful applications e.g. in non-destructive testing and characterization of material properties by ultrasonic or X-ray techniques, thermography, etc. Generally speaking, inverse problems are concerned with the determination of the input and the characteristics of a system, given certain aspects of its output. Mathematically, such problems are ill-posed and have to be overcome through development of new computational schemes, regularization techniques, objective functionals, and experimental procedures. This volume contains a selection of peer-reviewed papers presented at the International Symposium on Inverse Problems in Engineering Mechanics (ISIP2001), held in February of 2001 in Nagano, Japan, where recent development in inverse problems in engineering mechanics and related topics were discussed. The following general areas in inverse problems in engineering mechanics were the subjects of the ISIP2001: mathematical and computational aspects of inverse problems, parameter or system identification, shape determination, sensitivity analysis, optimization, material property characterization, ultrasonic non-destructive testing, elastodynamic inverse problems, thermal inverse problems, and other engineering applications. These papers can provide a state-of-the-art review of the research on inverse problems in engineering mechanics.