Roman Teisseyre Minoru Takeo Eugeniusz Majewski Earthquake Source Asymmetry, Structural Media and Rotation Effects

Transcription

1 Roman Teisseyre Minoru Takeo Eugeniusz Majewski Earthquake Source Asymmetry, Structural Media and Rotation Effects

2 Roman Teisseyre Minoru Takeo Eugeniusz Majewski (Eds.) Earthquake Source Asymmetry, Structural Media and Rotation Effects With 223 Figures

3 EDITORS: PROFESSOR ROMAN TEISSEYRE ASSOCIATE PROFESSOR EUGENIUSZ MAJEWSKI INSTITUTE OF GEOPHYSICS, POLISH ACADEMY OF SCIENCES UL. KS. JANUSZA WARSAW POLAND PROFESSOR MINORU TAKEO EARTHQUAKE RESEARCH INSTITUTE UNIVERSITY OF TOKYO 1-1 YAYOI 1-CHOME, BUNKYO-KU TOKYO JAPAN ISBN 10 ISBN Springer Berlin Heidelberg New York Springer Berlin Heidelberg New York Library of Congress Control Number: This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable to prosecution under the German Copyright Law. Springer is a part of Springer Science+Business Media springeronline.com Springer-Verlag Berlin Heidelberg 2006 Printed in The Netherlands The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover design: E. Kirchner, Heidelberg Production: A. Oelschläger Typesetting: Camera-ready by the Editors Printed on acid-free paper 30/2132/AO

4 Preface When thinking, at the beginning of the new century, on our horizons in seismology, we might return to the old question related to the seismic rotation effects and waves. Seismology, with its spectacular achievements instrumentation, data processing, seismic tomography and source process theories remains practically confined to linear ideal elasticity (isotropic or anisotropic). Numerous renown seismologists have tried to go beyond this horizon. As concerns rotation waves, such attempts were inspired by numerous macroscopic observations pointing out the rotation effects, often observed on the ground surface. However, this problem has been apparently closed by Mallet in 1862, who gave the following explanation: rotations of a body on the surface are due to a sequence of impacts of different seismic phases emerging under different angles. Later on, in 1937, Imamura underlined an influence of different inertia moments of an inflicted body. Thus, the surface rotation effects rotation of some objects on the ground surface were explained as being caused by the consecutive inclinations and recovery of these objects to the vertical, when hit by the incident seismic body or surface waves. The final position of the object could become slightly twisted in comparison to its former place; the differences between the inertia tensor moments of the object and/or its attachment (as related to friction resistance of binding) to the ground surface play an important role. At that time, seismic observations were not accurate enough to detect any rotation waves; moreover, from the point of view of ideal elasticity such waves shall not be observed at all, because rotation motion, even if generated in a seismic source, shall be immediately attenuated. Of course, there remains the displacement rotation component, which differs from zero for shear motion, but in an ideal isotropic elastic body this component attains very small values. Perhaps some new, but rather isolated, attempts to record the rotation waves were undertaken again in relation to these theoretical predictions. However, most of them failed again because the instrumental tools were not powerful enough. In the second half of last century, we have observed a spectacular development of mechanics of continua including defects, granular structure and other deviations from the ideal linear elasticity. Special interests were

5 VI concentrated on the micropolar and micromorphic continua. In such elastic continua, the real rotations can be accompanied by another kind of axial motion the twist-bend motion. We must stress that seismologists share different opinions on the nature of rotation waves. Perhaps, still the majority believes that such rotation motions are not related to inner rotations but are directly related to rotation of displacement field which may reach much higher magnitudes in materials with an internal structure than in homogeneous layers; considering damages in the high buildings, there are many examples indicating enormous increase of rotation effects caused by consecutive impacts of seismic body and surface waves. The rotation and twist motions are parts of the microdisplacement motion as related to the tensor of microstrain which appears in the generalized continua. In ideal elasticity, any rotation motion is reduced to the displacement vector rotation components, while the twist motion is related to the non-diagonal strain components. In our Monograph, both approaches are discussed. In the last years, new types of the very sensitive rotation seismographs and the laser/fiber ring interferometers (ring laser gyroscopes and fiber optic gyros), based on the Sagnac principle, opened new abilities of recording techniques. Real media deviate from the ideal elasticity mainly due to defect content and granular structure; such media will be further called the structured continua. At the same time, some theoretical papers have recently appeared pointing out that the values of the displacement rotation components may be much higher than those predicted by the ideal elastic theory. In both cases, anisotropy shall be also included. However, apart of the rotation of displacements, in the structured media there may also appear true rotation motions, as independent deformation features. These rotation motions are part of the deformation and rotation tensors, which includes rotation, twist and compression/dilatation motions; together with the displacement vector, these motions form a complete deformation pattern. The theory of structured continua enhanced our interest in the microdisplacement motions. The microdisplacement fields are produced by the asymmetric pattern of the faulting and friction motions. The slip friction process causes rotation of adjacent grains and any deviations from symmetry lead to a non-zero net rotation motion. Here, we point out the major feature of earthquakes revealed in faulting along the main fault plane. This is the main asymmetry feature of earthquake processes. We may admit that generation of real rotation and twist motions in a source zone is a real fact. However, there remains an open question whether such fields can propa-

6 VII gate far from a source or are quickly attenuated when reaching a more consolidated elastic zone. Probably we should confine our considerations to the near-field effects only. However, we shall again take into account the fact that body and surface seismic waves, when entering a near-surface region, which is characterized by the more complex structure features, may give rise to conjugated microdisplacement motions; hence, rotation and twist waves may again appear due to interaction of the incident seismic waves with the complex features of a near-surface zone. The theories of micropolar and micromorphic media predict some relation between the displacement derivatives and the microdisplacements. Such considerations inspired us to write a comprehension monograph which may open a new insight into seismological observations and studies. We decided that a subject of such a monograph shall be broad, covering many aspects, beginning from the historical observations, through modern sensors detecting different types of seismic motions, to the advanced theories and models giving us a better insight into the complexity pattern of earthquake source processes. Among other things, further studies on soliton solutions for the events generated in a confined source zone may improve the fracture band models, as introduced by some authors participating in the present task. Also, more attention shall be paid to the anisotropy pattern related to the earthquake source zone. At last, we shall turn to questions related to the earthquake engineering problems which may arise even due to small rotation motions; the whole problem started because in many cases some twist deformations have been observed on ground surface. And now we shall also examine whether the true rotation or twist motions, however small, can influence some structures senstive to moment of momentum impact. The book covers, thus, many subjects, enlightened from different points of view, as presented by the individual authors; we tried to collect the individual contributions in such a way as to create a possibly complete coverage of the discussed subjects. At the end of these considerations, it seems suitable to give a very brief outline of the content of the present Monograph. It is divided into the following six parts: Part I. MACROSEISMIC ROTATION EFFECTS AND MICROMOTIONS. We discuss the possible causes of the rotation motions and effects in the Earth s interior and on its surface; also we recall some descriptions of the rotation-like damages caused by the historical earthquakes. Part II. THEORY OF CONTINUA AND FIELDS OF DEFECTS. We present the asymmetric theory of continuous media with defects and anti-

7 VIII symmetric strains and stresses (as equivalent to the stress moments and related conservation law for moment of momentum); the included introduction to the soliton physics has a particular meaning for the fracturing processes. Part III. ROTATION MOTIONS, SEISMIC SOURCE MODELS, AND ASYMMETRY OF FRACTURE. We discuss a rotation counterpart in the fracturing process and the related energy release, we approach the problems of complex fracturing and flow phenomena and we face the problems of analysis of the complex seismic motions; further, we present different approaches to fracturing processes and the associated rotation motions in the seismic active regions. Part IV. EFFECTS RELATED TO MEDIUM STRUCTURES AND COMPLEXITY OF WAVE PROPAGATION. We present some new approaches to the complexity of deformations in the structured and micromorphic media; the non-riemannian description of deformations is included. Part V. SEISMIC ROTATIONAL MOTIONS: RECORDING TECHNIQUES AND DATA ANALYSIS. Starting with a historical note, we include the descriptions of some modern measuring systems for rotation, twist and tilt motions, we discuss the gained observations and recordings and we give their tentative analysis. Part VI. ROTATIONS AND ENGINEERING SEISMOLOGY. We end our Monograph with the problems of the earthquake engineering and strong motions which include the rotation and tilt impacts on high buildings. Acknowledgement. I would like to express my great thankfulness to the editors of the camera-ready PDF form of manuscripts, Mrs Anna Dziembowska, Mrs Maria Wernik and their staff, for their devoted and laborious work. Roman Teisseyre

8 IX Contents PART I MACROSEISMIC ROTATION EFFECTS AND MICROMOTIONS Development of Earthquake Rotational Effect Study Jan T. Kozák Sources of Rotation and Twist Motions Roman Teisseyre, Jan T. Kozák Introduction Elements of the Basic Theory Recording the Rotation and Twist Motions Some Examples of Rotation Effects: the Tulbagh Earthquake, South Africa Gerhard Graham, Andrzej Kijko...25 PART II THEORY OF CONTINUA AND FIELDS OF DEFECTS 29 4 Deviations from Symmetry and Elasticity: Asymmetric Continuum Mechanics Roman Teisseyre, Wojciech Boraty ski Introduction Symmetric Stresses: Motion Equations Thermal Deformations The Maxwell and Voigt Kelvin Bodies: Equivalence Theorems Asymmetric Fields Degenerated Asymmetric Continuum Theory Roman Teisseyre, Mariusz Bia ecki, Marek Górski Introduction Transition to Symmetric Tensor of Potentials Special Case Conclusions...53

9 X 6 Continuum with Rotation Nuclei and Defects: Dislocation and Disclination Densities Wojciech Boraty ski, Roman Teisseyre Introduction Defect Density Fields Dislocation Stress Relations Equations of Motion Discussion Towards a Discrete Theory of Defects Mariusz Bia ecki Introduction Towards a Discrete Description Discrete Weingarten Theorem Prospects...74 Appendix: Discrete Integration by Parts Fault Dynamics and Related Radiation Wojciech Boraty ski, Roman Teisseyre Introduction Fault and Related Stresses Evolution Equations for Dislocations and Disclinations Motion Equations: Fault and Radiation Parts Discussion A Review on Friction Panayiotis Varotsos, Mary Lazaridou Introduction Stick-Slip Friction of a Granular System. Hysteresis and Precursors Rock Friction Laboratory Experiments at High Rates of Slip. The Energy Budget for Tectonic Faulting Modern Views on Friction. Theoretical Studies Constitutive Friction Law for the Antisymmetric Stresses Open Questions Soliton Physics Eugeniusz Majewski Introduction The Discovery of Solitary Waves The Korteweg de Vries Equation...115

10 XI 10.4 The Modified Korteweg de Vries Equation The Kadomtsev Petviashvili Equation The Boussinesq Equations The Doubly Dispersive Equations The Nonlinear Schrödinger Equation The Nonlinear Klein Gordon Equation The Sine-Gordon Equation The Inverse Scattering Transform Rotating Solitons Discrete Soliton Systems Conclusions PART III ROTATION MOTIONS, SEISMIC SOURCE MODELS, AND ASYMMETRY OF FRACTURE Rotational Motions Excited by Earthquakes Minoru Takeo Introduction Geometrical Theory of Defects Formulation of Rotational and Translational Motions Due to Earthquakes Possibility of Estimating a Rotational Strain Tensor Due to an Earthquake Conclusions Ground Rotational Motions Recorded in Near-Source Region of Earthquakes Minoru Takeo Introduction Observational System Near-Source Ground Rotational Motions Discussion Fracture-Band Geometry and Rotation Energy Release Roman Teisseyre, Marek Górski, Krzysztof P. Teisseyre Introduction Earthquake Dislocation Theory Earthquake Thermodynamics and Fracture Band Model Elastic Rotation Energy Cross-Band Fracturing Model and Rotation Processes Conclusions...182

11 XII 14 Rotation Motions: Recording and Analysis Krzysztof P. Teisseyre, Jerzy Suchcicki Introduction Examples of Records and Their Preliminary Analysis Discussion Glacier Motion: Seismic Events and Rotation/Tilt Phenomena, Marek Górski, Krzysztof P. Teisseyre Introduction Icequakes Ice Vibrations Discussion Rotational Energy and Angular Momentum of Earthquakes Eugeniusz Majewski Introduction Modelling the Rotational Motions Excited in Earthquake Sources as Rolling Motions Rolling in the Earthquake Source as Translation and Rotation Combined The Kinetic Energy of Rolling in the Earthquake Source Modelling Purely Rotational Motions in the Earthquake Source The Torque and Angular Momentum of the Earthquake Source Modelling Rotational Motions in the Earthquake Source as a Turbulence of Grains and Blocks Between Moving Tectonic Plates Conclusions Bend-Rotation Wave as a Mechanism of Macroseismic Effects Vladimir Aksenov Introduction Experimental Data Field Observations Conclusions Solitary Waves in Crustal Faults and their Application to Earthquakes Victor G. Bykov Introduction Observational Evidence...242

12 XIII 18.3 Mathematical Model of Deformation Process Solitary Wave of Fault Activation Evolution of Waves of Fault Activation Effect of Periodical Change of Friction in the Fault Effect of Periodical Change of External Load Conclusions Seismic Rotation Waves: Spin and Twist Solitons Eugeniusz Majewski Introduction Modelling the Rotational Motions Excited in Earthquake Sources Seismic Rotation Waves: PR and SR Waves The Slow Tectonic Rotation Waves Hamilton s Principle A Rock Medium Modelled as a Nonlinear Micropolar Elastic Continuum The Nonlinear Field Equations The Linear Seismic Rotation Waves The Nonlinear Seismic Rotation Waves Dispersion Curves and Rotation Solitons The Seismic Rotation Solitons in the Degenerated Continuum Conclusions Earth Rotation, Elasticity and Geodynamics: Earthquake Wave Rotary Model Alexander V. Vikulin Introduction Hypothesis Stress Field Related to Rotation of Hard Bodies Interaction Between Seismofocal Blocks Chain of Blocks: Application to Pacific Margin Seismic Belt Friction and Irregularities of Block Rotation: Rotation Mechanics of Earthquake Foci Some Consequences Conclusions...286

13 XIV PART IV EFFECTS RELATED TO MEDIUM STRUCTURES AND COMPLEXITY OF WAVE PROPAGATION Seismic Rotation Waves in the Continuum with Nonlinear Microstructure Eugeniusz Majewski Introduction Additivity of Elastic and Self-Parts of Stresses, Microstresses, and Interaction Microforces The Macroscopic and Microscopic Balance Equations The Nonlinear Microstructure Conclusions Tectonic Solitons Propagating Along the Fault Eugeniusz Majewski Introduction Seismic Waves in the Continuum with Dislocations Seismic P waves Splitting the Elastic Distortion Soliton Equation into Seismic and Fault-Related Soliton Equations Seismic S Waves Conclusions Complexity of Rotation Soliton Propagation Eugeniusz Majewski Introduction Preliminary Assumptions Seismic Rotation Solitons Conclusions Micromorphic Continuum with Defects and Taylor Bishop Hill Theory for Polycrystals: Anisotropic Propagation of Seismic Waves and the Golebiewska Gauge Jun Muto, Yusuke Kawada, Hiroyuki Nagahama Introduction Micromorphic Continuum with Defects Taylor Bishop Hill Model Quartz c-axis Preferred Orientation in Quartz Schist Seismic Anisotropy due to LPO in Deformed Rocks Discussion Conclusion...326

14 XV 25 Seismic Ray Theory for Structural Medium based on Kawaguchi and Finsler Geometry Takahiro Yajima, Hiroyuki Nagahama Introduction Finsler Geometry and Seismic Ray Seismic Finsler Metric and Kawaguchi Space Discussion From Non-Local to Asymmetric Deformation Field Hiroyuki Nagahama, Roman Teisseyre Introduction High-Order Spaces and Non-Locality of Deformation An Interaction Field Between Microscopic and Macroscopic Deformation Fields Asymmetry and Anholonomity of Deformation Discussion Earthquake Hazard in the Valley of Mexico: Entropy, Structure, Complexity Cinna Lomnitz, Heriberta Castaños Introduction Seismology: a Science in Trouble? Disasters in General, and Mexico City in Particular A Higher Level of Description Nonlinearity and Non-Equilibrium Thermodynamics A Theory of Disasters as Unexpected Events Disasters and Society PART V SEISMIC ROTATIONAL MOTIONS: RECORDING TECHNIQUES AND DATA ANALYSIS Note on the Historical Rotation Seismographs Graziano Ferrari Introduction Electrical Seismograph with Sliding Smoked Paper Electrical Seismograph with Sliding Smoked Paper Second Model Ring Laser Gyroscopes as Rotation Sensors for Seismic Wave Studies K. Ulrich Schreiber, Geoffrey E. Stedman, Heiner Igel, Asher Flaws Introduction...377

15 XVI 29.2 Properties of Ring Lasers Detection of Seismic Signals GEOsensor Rotational Motions in Seismology: Theory, Observation, Simulation Alain Cochard, H. Igel, B. Schuberth, W. Suryanto, A. Velikoseltsev, U. Schreiber, J. Wassermann, F. Scherbaum, D. Vollmer Introduction Fundamental Theory Rotational Measurements Observations and Simulations of Rotational Motions Discussion and Conclusions Absolute Rotation Measurement Based on the Sagnac Effect Leszek R. Jaroszewicz, Zbigniew Krajewski, Lech Solarz Introduction Sagnac Effect Optical Gyroscopes as Systems Utilizing the Sagnac Effect Fundamental Measurement Limits Fiber-Optic Rotational Seismometer (FORS) Investigation of the SRE Propagation Velocity Conclusions Design of Rotation Seismometer and Non-Linear Behaviour of Rotation Components of Earthquakes Takeo Moriya, Roman Teisseyre Introduction Design of the Rotation Seismometer Absolute Rotation Component Amplitudes for Earthquakes Observed at Sites of Different Surface Geological Conditions Results and Future Scope Rotation and Twist Motion Recording Couple Pendulum and Rigid Seismometers System Jan Wiszniowski Introduction Behaviour of a Pendulum Seismometer During Measurement of Rotations Static Approach Measurement of Rotations by a Pair of Seismometers Influence of Seismic Waves on Signal...454

16 XVII 33.4 Influence of Small Differences in Channel Responses on Rotation Measurement Dynamic Approach The Pendulum Seismometer for Measurement of Rotations Alone Conclusions Equation of Pendulum Motion Including Rotations and its Implications to the Strong-Ground Motion Vladimir M. Graizer Introduction Theory of the Pendulum Residual Displacements and what can be Done in Absence of Recorded Rotations (Tilts) Numerical Tests of the Effects of Tilt on Computations of Displacement Conclusions Strong Motion Rotation Sensor Ji í Buben, Vladimír Rudajev Introduction Experimental Setup Experimental Records Conclusions High-Resolution Wide-Range Tiltmeter: Observations of Earth Free Oscillations Excited by the 26 December 2004 Sumatra -Andaman Earthquake Marek Kaczorowski Introduction Natural Conditions in the Low Silesian Geophysical Observatory Principle of Operation of the Long Water-Tube Tiltmeter The Hydrodynamic System of the Long Water-Tube Tiltmeter The Optic Module of Interference Gauge of the Water Level Variations Measurements Determination of the Function of Plumb Line Variations Determination of tidal wave coefficients on the basis of the long water-tube measurements Observations of anomalous plumb line variations associated with Earth free oscillations on 26 December Conclusions...516

17 XVIII 37 Fiber Optic Sensors for Seismic Monitoring William B. Spillman Jr., Dryver R. Huston, Junru Wu Introduction Seismic Monitoring Sensor/Ground Coupling Fiber Optic Sensing Matched Filtering/Antenna Gain Physical Simulation Results Using STM Discussion and Summary PART VI ROTATIONS AND ENGINEERING SEISMOLOGY Deriving Seismic Surface Rotations for Engineering Purposes Zbigniew Zembaty Introduction and Formulation of the Problem Spectral Decomposition of Translational Components of Seismic Ground Motion Rocking from Body Waves Decomposition Rocking from Surface Waves Rocking from Spatial Field of Ground Motion Code Proposals and Approximate Formulae Application Example: A Slender Tower Under Horizontal- Rocking Excitations Summary and Conclusions Effects of Torsional and Rocking Excitations on the Response of Structures Mihailo D. Trifunac Introduction Rotational Strong Ground Motion Recording Rotational Strong Motion Generation of Synthetic Rotational Motions Response of Structures...576

18 XIX Contributors Vladimir AKSENOV Institute of Physics of the Earth, Russian Academy of Sciences Bolshaya Gruzinskaya str., 10, Moscow, Russia. Mariusz BIA ECKI Institute of Geophysics, Polish Academy of Sciences ul. Ksi cia Janusza 64, Warszawa, Poland. Wojciech BORATY SKI Institute of Geophysics, Polish Academy of Sciences ul. Ksi cia Janusza 64, Warszawa, Poland and Faculty of Mathematics and Information Science, Warsaw University of Technology Plac Politechniki 1, Warszawa, Poland. Ji i BUBEN Institute of Rock Structure and Mechanics Academy of Sciences of the Czech Republic V Holešovi kách 41, Praha 8, Czech Republic. Victor G. BYKOV Institute of Tectonics and Geophysics Far East Branch of the Russian Academy of Sciences 65 Kim-Yu-Chen St., Khabarovsk, Russia. Heriberta CASTAÑOS National University of Mexico UNAM, Mexico, DF, Mexico. Alain COCHARD Department of Earth and Environmental Sciences Ludwig-Maximilians-Universität Theresienstr. 41, München, Germany. Asher FLAWS Department für Geo- und Umweltwissenschaften, Sektion Geophysik

19 XX Ludwig-Maximilians-Universität München Theresienstr. 41, München, Germany. Graziano FERRARI SGA Storia Geofisica Ambiente Via del Battiferro 10b Bologna, Italy. Marek GÓRSKI Institute of Geophysics, Polish Academy of Sciences ul. Ksi cia Janusza 64, Warszawa, Poland. Gerhard GRAHAM Council for Geoscience Pretoria 0001, South Africa. Vladimir M. GRAIZER California Geological Survey 801 K Street, MS 12-32, Sacramento, CA, USA. Dryver R. HUSTON Mechanical Engineering, University of Vermont Burlington, VT, USA. Heiner IGEL Department für Geo- und Umweltwissenschaften, Sektion Geophysik Ludwig-Maximilians-Universität München Theresienstr. 41, München, Germany. Leszek R. JAROSZEWICZ Institute of Applied Physics, Military University of Technology ul. Kaliskiego 2, Warszawa, Poland. Marek KACZOROWSKI Space Research Centre, Polish Academy of Sciences ul. Bartycka 18A, Warszawa, Poland. Yusuke KAWADA Department of Geoenvironmental Sciences Graduate School of Sciences, Tohoku University Aoba-ku, Sendai , Japan. Andrzej KIJKO Council for Geoscience Pretoria 0001, South Africa.

20 XXI Jan T. KOZÁK Geophysical Institute, Academy of Sciences of the Czech Republic Prague 4 Sporilov, Bo ni, Czech Republic. Zbigniew KRAJEWSKI Institute of Applied Physics, Military University of Technology ul. Kaliskiego 2, Warszawa, Poland. Mary LAZARIDOU Solid Earth Physics Institute, Department of Physics, University of Athens Panepistimiopolis, Zografos , Athens, Greece. Cinna LOMNITZ National University of Mexico, UNAM Mexico, DF, Mexico. Eugeniusz MAJEWSKI Institute of Geophysics, Polish Academy of Sciences ul. Ksi cia Janusza 64, Warszawa, Poland. Takeo MORIYA Graduates School of Science, Hokkaido University. Jun MUTO Department of Geoenvironmental Sciences Graduate School of Sciences, Tohoku University Aoba-ku, Sendai , Japan. Hiroyuki NAGAHAMA Department of Geoenvironmental Sciences Graduate School of Sciences, Tohoku University Aoba-ku, Sendai , Japan. Vladimir RUDAJEV Institute of Rock Structure and Mechanics Academy of Sciences of the Czech Republic V Holešovi kách 41, Praha 8, Czech Republic. F. SCHERBAUM Institut für Geowissenschaften, Universität Potsdam Karl-Liebknecht-Str. 24/25, Golm, Germany. K. Ulrich SCHREIBER Forschungseinrichtung Satellitengeodäsie der TU- München Arcisstr. 21, München, Germany.

21 XXII B. SCHUBERTH Department of Earth and Environmental Sciences Ludwig-Maximilians-Universität Theresienstr. 41, München, Germany. Lech SOLARZ Institute of Applied Physics, Military University of Technology ul. Kaliskiego 2, Warszawa, Poland. William B. SPILLMAN Jr. Physics Department, University of Vermont Burlington, VT, USA. Geoffrey E. STEDMAN Department of Physics and Astronomy, University of Canterbury Private Bag 4800, New Zealand. Jerzy SUCHCICKI Institute of Geophysics, Polish Academy of Sciences ul. Ksi cia Janusza 64, Warszawa, Poland. W. SURYANTO Department of Earth and Environmental Sciences Ludwig-Maximilians-Universität Theresienstr. 41, München, Germany. Minoru TAKEO Earthquake Research Institute, University of Tokyo Zip , Yayoi, Bunkyo-ku, Tokyo, Japan. Krzysztof P. TEISSEYRE Institute of Geophysics, Polish Academy of Sciences ul. Ksi cia Janusza 64, Warszawa, Poland. Roman TEISSEYRE Institute of Geophysics, Polish Academy of Sciences ul. Ksi cia Janusza 64, Warszawa, Poland. Mihailo D. TRIFUNAC Department of Civil Engineering, University of Southern California Los Angeles, CA , USA.

22 XXIII Panayiotis VAROTSOS Solid Earth Physics Institute, Department of Physics, University of Athens Panepistimiopolis, Zografos , Athens, Greece. A. VELIKOSELTSEV Forschungseinrichtung Satellitengeodäsie Technical University of Munich, Fundamentalstation Wettzell Sackenriederstr. 25, D Kötzting, Germany. Alexander V. VIKULIN Institute of Volcanology and Seismology Far East Department of Russian Academy of Sciences Piip Ave. 9, Petropavlovsk-Kamchatsky, , Russia. D. VOLLMER Institut für Geowissenschaften, Universität Potsdam Karl-Liebknecht-Str. 24/25, Golm, Germany. J. WASSERMANN Department of Earth and Environmental Sciences Ludwig-Maximilians-Universität Theresienstr. 41, München, Germany. Jan WISZNIOWSKI Institute of Geophysics, Polish Academy of Sciences ul. Ksi cia Janusza 64, Warszawa, Poland. Junru WU Physics Department, University of Vermont Burlington, VT, USA. Takahiro YAJIMA Department of Geoenvironmental Sciences, Graduate School of Science Tohoku University, Aoba-ku, Sendai , Japan. Zbigniew ZEMBATY Faculty of Civil Engineering, Technical University of Opole ul. Miko ajczyka 5, Opole, Poland.