International Association for the Physical Sciences of the Earth's Interior (IASPEI)


S B1: Opening Plenary

S B2: Closing Plenary

S L1: Association Lecture

The Underdetermined Earth Lecturer: B. L. N. Kennett (Second Vice-President)

S L2: Association Lecture

Geoid and Geodynamics: Certainties and Controversies Lecturer: C. Froidevaux (First Vice-President)

S D: Association Barbecue

G JS1: Crustal Deformation Along Plate Boundaries (IAG, IASPEI)

Over the past two decades, space geodesy has "come of age," and has evolved from an experimental discipline to one of the most important tools available to scientists interested in active tectonics. It now permits detailed measurements of tectonic motions over spatial and temporal scales never before accessible to Earth scientists. With the ubiquitous accessibility of inexpensive techniques such as the Global Positioning System (GPS) and with the deployment and operation of precise global international geodetic networks and of dense regional permanent networks, the short-term kinematics of plate boundary deformation zones on continents _ where the rigid plate paradigm is inadequate_can now be elucidated in a global reference frame and compared with long-term geological interpretations. This opens new and exciting possibilities for a new, improved understanding of the geomechanics of these regions. This interdisciplinary symposium invites papers dealing with the geodetic aspects of the problem, including descriptions of novel techniques and special network deployments; with the geophysical aspects, specifically the seismic and volcanic cycles; and with the geodynamical aspects, including in particular rheological and dynamical models of the lithosphere and asthenosphere, as well as fault zone mechanics. Papers dealing with applications of such studies to the characterization and mitigation of natural disasters are especially welcome. Convener: J.-B Minster (IAG/IASPEI), Scripps Institute of Oceanography, University of California at San Diego, Institute of Geophysics and Planetary Science, La Jolla, CA 92093 (USA); tel: 1-619-534-5650; fax: 1-619-534-2902; e-mail:

G JS2: Geodetic, Remote Sensing, and Seismic Methods for Monitoring of Volcanic Activities (IAG, IASPEI, IAVCEI)

In order to study the volcano-mantle dynamics and volcano-climate connections, the monitoring and analysis of both lava-producing and explosive volcanic eruptions and deposits produced by volcanoes are essential. Terrestrial and space geodetic methods, seismic mentods, as well as aircraft and satellite remote sensing techniques are essential tools to collect data for monitoring and analysis and for the development of early warning systems. Within its three sessions, the symposium will concentrate on instrumental and analytical methodologies which help to obtain better understanding of processes before, during, and following volcanic eruptions and are used or proposed for volcano monitoring, volcanic eruption prediction, and early warning systems. Terrestrial and space geodetic techniques for monitoring horizontal and vertical displacements (laser distance measurements, gravity-meter, tiltmeter, GPS Doris, and PRARE space observations) will be covered in Session 1. Airborne and satellite remote sensing methods for acquiring high-resolution multispectral images and the use of radar interferometry from the ERS 1/2 SAR sensors for mapping small-scale topographic changes due to the growth of volcanic domes or the intrusion of magma at shallow depth will be dealt with in Session 2. Seismic methodologies, aimed at revealing the characteristics and origin of volcanic tremors as well as their relationship to volcanic activity and major eruptions will be discussed in Session 3. Automatic event recording, three-component seismometry, broad band seismometry, and special array techniques are considered to be topics of discussion for this session. Lead Convener: C. Reigber (IAG), GeoForschungs Zentrum (GRZ), Department of Kinematics and Dynamics of the Earth, Telegrafenberg A17, D-14473 Potsdam (GERMANY); tel: +49-331-288-1100 or 1114; fax: +49-331-288-1111; e-mail: Co-conveners: A. Hasegawa (JAPAN), A. Linde (USA).

G JS3: Earth Rotation: An Interdisciplinary Approach To Earth System Science (IAG, IAMAS, OCEANS, IASPEI, IAGA, IAHS, SEDI)

The modern approach to understanding Earth rotation irregularities deals with interacting physical constituents as diverse as a liquid, magnetic core, a visco-elastic mantle, and liquid and gaseous external layers, each with internal motions and responding to external forces. The global character of the observational evidence is a major challenge to theoreticians who develop dynamical models of the behavior of each layer. No single theory can explain the complete set of observed irregularities. The monitoring of Earth rotation itself includes the participation of worldwide space geodetic and astronomical programs, leading to intensive international cooperation. The symposium will focus on those aspects of Earth rotation studies that imply, or even create, bridges between scientific disciplines. Lead Convener: M. Feissel (IAG), Observatoire de Paris, Central Bureau, International Earth Rotation Service, 61, Avenue d'Observatoire, F-75014 Paris (FRANCE); tel: +33-1-4051-2226; fax: +33-1-40-51-22-91; e-mail: Co-conveners: D. Cartwright (UK), R. Hide (UK), R. Sabadini (ITALY), J. Wahr (USA), P. Brosche (GERMANY).

GA JS1.02: Relating Geophysical Measurements to Lithospheric Processes Through Continental Drilling (IAGA, IASPEI, ILP)

This symposium focuses on multidisciplinary experiments in the vicinity of and within deep boreholes and laboratory studies of fresh core samples, which can provide insights of local problems useful in a more general understanding of the formation of the continental crust. Lead Convener: Volker Haak, GeoForschungsZentrum Potsdam, Telegrafenberg, D-14407 Potsdam (GERMANY); fax: +49-331-288-1235; e-mail: vhaak@gfz-potsdam. Co-conveners: J. Erzinger (GERMANY), J. Mutter (USA), D. R. Schmitt (CANADA).

GA JS1.05/5.13: Geomagnetic Secular Variation and Core Flow Near the Core-Mantle Boundary (IAGA, IAG, IASPEI, SEDI)

Time variations of the main geomagnetic field on all timescales from very short (magnetic jerks) to secular, especially with interpretations relating to flow near the core-mantle boundary and global studies at all timescales and using other (e. g., astronomical or seismological) data. Lead Convener: G. Hulot, IPGP, Laboratoire de Geomagnetisme et Palaeomagnestisme, CNRS UA279, 4 Place Jussieu, B89 Tour 24, 75252 Paris, Cedex 05 (FRANCE); fax: +33-1-44-27-3373; e-mail: Co-convener: R. A. Langel (USA), D. Crossley (CANADA).

GA JS1.07: Lithospheric Anisotropy Observations and Interpretation (IAGA, IASPEI, ILP)

Contributions are sought from a broad range of topics concerning the electromagnetic and/or seismological identification and characterization of anisotropy. The symposium seeks, in particular, studies that address the relation of anisotrophy to the tectonic history, fabric, and stress regime of the continental lithosphere and to mantle flow in the asthenosphere. Studies may be either regional or global in scope. Laboratory measurements of electrical or seismic anisotropy in rocks of deep origin, as well as theoretical studies of the relation between electrical or seismic properties and the petrology of mantle rocks, are also encouraged. Finally, reports of theoretical advances in the extraction of anisotropic parameters from analysis of various portions of the seismic wavefield (regional phases, teleseisms, surface waves) are welcome. Lead Convener: Marianne Mareschal, Genie Mineral, CP6079, succ Centre Ville, Montreal H3C 3A7 (CANADA); fax: 1-514-340-4191; e-mail: Co-convener: Michael Bostock (CANADA).

GA JS1.08: Geophysical Signatures of Modern and Ancient Continental Margins (IAGA, IASPEI, ILP)

This symposium focuses on modern and ancient continental margins using a spectrum of techniques (seismology, electromagnetic induction, palaeomagnetism, geodesy, geochemistry, geology, etc), with emphasis on the synergistic value of multiple approaches to a problem. Lead Convener: John R. Booker, Geophysics AK50, University of Washington, Seattle, WA 98195 (USA); fax: 1-206-543-0489; e-mail: Co-convener: M. Christina Pomposiello (ARGENTINA).

GA JS5.18: Architecture of the Continents_Interpretation of Their Main Structural Elements From Magnetic Anomalies and Other

This symposium examines the latest achievements in magnetometry used for study of the deep structure of large-scale geological features such as global orogenic belts_the Urals, for example_within continents, including data analysis, integration with other geophysical data, geophysical and geological modelling. Lead Convener: V. Shapiro, Institute of Geophysics, Amundsen str 100, Ekaterinberg 620219 (RUSSIA). Co-conveners: J. Broome (CANADA), L. Antoine (SOUTH AFRICA).

M JS14: Climatic Variability and Forcing over the Past Millennium (IAMAS, IAVCEI, IASPEI, OCEANS)

This joint symposium invites presentations describing the climate of the past millennium, including its natural variations and changes induced by natural forcing and by human activities. The symposium will cover the means and techniques for reconstruction of the climate and climate forcings over this period, the spatial and temporal patterns of the climate and its variations, the explanations for and causes of these variations, the extent to which natural and human influences can be distinguished over the past two centuries, and the implications of these findings for distinguishing anthropogenic and natural changes in climate in the future. Session themes are planned to include: methods for reconstructing climate, high-resolution records of volcanism and other forcing factors, the Medieval Climate Optimum, the Little Ice Age, the Industrial Period, and the implications of past climate relationships for the future climate. Lead Convener: Michael MacCracken, Office of the U.S. Global Change Research Project, c/o National Science Foundation 300 D Street, S.W., Suite 840, Washington, DC 20024 (USA); tel: 1- 202-651-8240; fax: 1-202-554-6715; e-mail: Co-conveners: C. Folland (UK), P. D. Jones (UK), H. Pollack (USA), A. Robock (USA), S. Self (USA),
U. Mikolajewicz (GERMANY), G. Zielinski (USA).

PS JS4: Tsunami Disaster Reduction (OCEANS, IASPEI)

This symposium, which is also the Tsunami Commission's 17th International Tsunami Symposim, will focus on research that leads to disaster reduction. The themes of the symposium are (1) historical and contemporary observations of tsunamis; (2) physical processes of tsunami evolution; and (3) hazard reduction through assessment techniques and warning systems. All interested scientists are invited to contribute. Lead Convener: Eddie N. Bernard, Director, Pacific Marine Environment Laboratory, NOAA/PMEL Bin C 15700 - Bldg. 3, 7600 Sand Point Way NE, Seattle, WA 98115-0070, (USA); tel: 1-206-526-6800; fax: 1-206-526-6815;
e-mail: Co-conveners: Gerassimos A. Papadopoulos (GREECE), Nobuo Shuto (JAPAN), Stefano Tinti (ITALY).

S JS1: Earthquake Generation Processes_Environmental Aspects and Physical Modelling (IASPEI, IAVCEI)

Earthquake generation processes should eventually be described quantitatively in terms of basic equations, which include a fault constitutive law under realistic environmental conditions. Laboratory-based constitutive laws have been proposed, and quantitative description of the entire processes of tectonic stress accumulation, quasi-static rupture nucleation, and subsequent dynamic rupture propagation based on physical principles is in sight. Quantification may be complicated by the mechanical and chemical interaction of fluids with country rock. This research trend should be encouraged because of its great potential for understanding earthquake generation and its consequences for earthquake prediction. The interdisciplinary nature of the subject and the complexity of the problems necessitate the integrated cooperation and discussion of scientists in relevant fields such as seismology, volcanology, geology, and rock physics. We invite contributions on any aspect of earthquake generation, including but not limited to those noted above. Lead Convener: M. Matsu'ura, Department of Earth and Planetary Physics, University of Tokyo, 2-11-16 Bunkyo-ku, Tokyo 113 (JAPAN); tel: +81-3-3812-2111 (x4318); fax: +81-3-3818-3247; e-mail: Co-conveners: T. Lewis (CANADA), C. J. Marone (USA), S. McNutt (USA), M. Takeo (JAPAN).

S JS2: Physical and Chemical Evolution of the Earth (IASPEI, IAVCEI)

This symposium focuses on the physical and chemical processes which occur within the evolving Earth. We seek observational laboratory and theoretical papers bearing on early Earth formation. Topics of interest include magma oceans, primitive atmospheres, core-mantle separation, the effects of heavy bombardment and giant impact, formation and evolution of the atmosphere and ocean, and initial komatiite magmatism. Post-Hadean differentiation processes (including, for example, crust formation, growth of the inner core and putative core-mantle boundary interactions), as well as small- and large-scale fractionation phenomena and related phase diagrams, and physical and chemical properties of minerals are of interest. Papers are requested on the relation of these processes to the present geodynamic picture of the Earth. Also, papers are invited which consider how some of these processes have led to irreversible differentiation (e. g., formation of the continental crust and inner core growth), while others (e. g., development of mantle plume, ocean island, and MORB and volcanic arc rocks from recycled oceanic lithosphere) may be regenerative in nature. Lead Convener: T. J. Ahrens, Seismological Laboratory 252-21, California Institute of Technology, Pasadena, CA 91125 (USA); tel: 1-818-395-6906; fax: 1-818-564-0715 (568 0935); telex: 675425 Caltech PSD; e-mail: Co-conveners: P. Gillet (FRANCE), W. McDonough (AUSTRALIA), E. Ohtani (JAPAN).

S JS3: Long-Term Seafloor Observations and Networks (IASPEI, IAG, IAGA, OCEANS, ION)

The observation network of global processes is currently nonuniform and undersampled. Establishing long-term seafloor stations to cover 70% of the Earth's surface, hosting most of the active plate boundaries and hot spots, is the key to bringing about a breakthrough in understanding the dynamic Earth. Careful planning and experiments, taking an interdisciplinary approach through international coordination utilizing available resources such as ODP drilled holes and submarine cables, could accelerate such efforts. Scientific objectives and the technological feasibility of establishing deep sea floor stations to observe geophysical or geochemical parameters ranging from ocean to core processes are to be discussed in light of experimental and theoretical studies. Lead Convener: K. Suyehiro, Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano-ku. Tokyo 164 (JAPAN); tel: +81-3-5351-6439; fax: +81-3-5351-6438; e-mail: Co-conveners: J.-P. Montagner (France), J. Orcutt (USA), A. Chave (USA), A. Schultz (UK), F. Spiess (USA).

S JS4: Patterns in Earth's Structure and Dynamics_Observations, Earth Models, and Laboratory Measurements (IASPEI, IAGA, IAG)

This symposium will discuss electric, elastic, and ametalic properties from the point of view of observations, modelling, and laboratory investigations. Papers which seek to model field observations relevant to Earth's internal physical structure in ways which are also compatible with current laboratory measurements as well as papers which show contradictions between current models, data, and laboratory studies, and which therefore indicate a need for future work are sought. Lead Convener: S. Constable, Institute of Geophysics and Planetary Physics, Scripps Institute of Oceanography, La Jolla, CA 92093-0225 (USA); tel: 1-619-534-2409; fax: 1-619-534-8090; e-mail: Co-conveners: A. G. Duba (USA), I. Jackson (AUSTRALIA), J.-P. Poirier, (FRANCE), T. A. Herring (USA).

S JS5: Structure, Evolution, and Dynamics of the Core-Mantle Boundary Region (IASPEI, IAGA, IAG, SEDI)

The session will focus on new observations, coupled with laboratory and theoretical results bearing on the structure and evolution of the Earth's core-mantle boundary. The objective will be to bring together researchers from a wide variety of disciplines_from seismology, geodesy and geomagnetism to geodynamics, geochemistry and mineral physics_in elucidating what is arguably the most significant geological structure of our planet. Lead Convener: R. Jeanloz, Department of Geology and Geophysics, University of California, Berkeley, CA 94720 (USA); tel: 1-415-642-3993; fax: 1-415-643-9980; telex: 9103667114; e-mail: Co-conveners: B. Buffett (CANADA), K. Whaler (UK).

S JS6: Rock Properties Related To Environmental Concerns (IASPEI, IAHS, SEG)

A knowledge of the properties of rocks is of great importance in the extraction of mineral and fossil resources as well as in the design, monitoring and remediation of nuclear and toxic waste sites. Major projects for the characterization of potential and active nuclear waste sites exist in several countries. Much work on rock and soil properties for the design of these facilities and mine safety has been done and will be the focus of this symposium. The safety of these facilities depends not only on the steady state properties of rocks and soils, but also very importantly on their time dependence and on the processes active within and acting upon these materials. Changes in permeability, elastic properties, electrical properties, corrosion, etc., in response to changes in physical and chemical environments will be presented from field as well as laboratory studies. Lead Convener: G. A. Sobolev, Institute of Physics of the Earth, Russian Academy of Sciences, Molodezhnaya 3, Moscow 117 296 (RUSSIA); tel: +7-095-930-0546; fax: +7-095-930-5509; telex: 411478 SGC SU; e-mail: Co-conveners: S. Ingebritsen (USA), G. Olhoeft (USA), H. Spetzler (USA).

S JS7: Mantle Dynamics and the Geological Record (IASPEI, SEDI, ILP)

Mantle convection leads to strong time-dependent lateral variations in internal temperature and drives horizontal and vertical motions at the Earth's surface; consequently the geological record of mid-plate volcanism, plate motions, and sea level variations provide fundamental constraints on dynamical models. Geodynamicists have begun to exploit these constraints by relating the distribution of past subduction zones to present-day mantle heterogeneity structure and by modelling past plate motions and the inundation of continents (stratigraphy). We encourage abstracts that address the relationship between deep Earth processes and geological processes, including large igneous events, sea level change, epeirogeny, and plate motions. Lead Convener: M. Richards, Department of Geology and Geophysics, University of California, Berkeley, Berkeley, CA 94720 (USA); tel: 1-206-543-6674; fax: 1-206-543-0489; e-mail: Co-conveners: S. Cloetingh (NETHERLANDS), G. Davies (AUSTRALIA), M. Gurnis (USA).

S JS8: Modelling the Earth's Interior (IASPEI, IAVCEI, IAG, SEDI)

This session will focus on current knowledge of the state and dynamical processes of the Earth's interior. The focus will be on the determination of the physical properties, state and composition of the mantle and core, and on the seismological, geomagnetic, geodetic, geochemical, and laboratory data used to infer them, as well as models of dynamical processes such as the geomagnetic field and flow in the mantle and core that relate observations to the state of the interior. Lead Convener: R. O'Connell, Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138 (USA); tel: 1-617-495-2532; fax: 1-617-495-8839; e-mail: Co-conveners: G. Masters (USA), M. Brown (USA), V. Dehant (BELGIUM).

S JW1: Geophysical Networks Possibilities for and Problems With Co-Location of Instruments (IASPEI, IAGA, IAG)

The study of potential fields, seismicity, and deformation can be significantly enhanced with standardized observational networks. With the development of digital recording and storage, the rapid growth in global communication systems, and an improving political climate, it is now possible to record and access data from unattended sensors from many previously inaccessible regions of the Earth. Global and regional networks of geophysical instruments for observations in fields such as seismology, geodesy, and geomagnetism are being established or expanded by research and monitoring organizations in many countries. Because of the high costs of establishing and servicing remote sites, there are significant logistical advantages in the co-location of sensors, possibly with common data recording and access. There are difficulties, however, in finding sites that satisfy the sometimes diverse requirements for different types of observation, coordinating siting plans, and establishing arrangements for long-term support and maintenance. This workshop will review the status of global and regional networks in a variety of geophysical disciplines, consider the opportunities for the development of coordinated programs, and explore the scientific insights that might develop from integrated observations. Lead Convener: D. W. Simpson, Incorporated Research Institute for Seismology, 1616 N. Fort Myer Drive, Suite 1050, Arlington, VA 22209 (USA); tel: 1-703-524-6222; fax: 1-703-527-7256; telex: 7400457 IRIS UC; e-mail: Co-conveners: G. Beulter (SWITZERLAND), G. Boedecker (GERMANY), D. Kerridge (UK), G. Roult (FRANCE).

S JW2: Geophysical Data Challenges in the 21st Century (IASPEI, IAG, IAGA, CODATA, WDC)

This workshop will focus on the changing requirements of the research community for access to geophysical data in the next century. The workshop will discuss both new scientific programs that will be dependent on data availability, and the impact of new data technology on these programs. Important aspects of this new technology are likely to involve high band-width networks, distributed data archive and dissemination facilities, sophisticated network search and retrieval systems, parallel processor computing facilities, and innovative ways to provide data to non-technical users. These will be accompanied by software developments such as hierarchical data systems, artificial intelligence and neural networks, the use of geographic information systems, and advances in optical character recognition methods. This workshop will provide a forum for interactions between research geophysicists and the computer scientists who will design the data systems of the future. Lead Convener: M. A. Chinnery, National Geophysical Data Center,National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80303 (USA); tel: 1-303-497-6215; fax: 1-303-497-6513; telex: 592811 NOAA MASC BDR; e-mail: Co-conveners: G. A. Sobolev (RUSSIA), C. C. Tscherning (DENMARK).

V JS1: Mid-Tertiary To Recent Geodynamic Evolution of the Andean Region (IAVCEI, IASPEI, IGCP, ILP)

The aim of the symposium is to integrate geophysical, geochemical, and tectonic data to evaluate the mid-Tertiary to recent evolution of the Andean subduction zone. The symposium will include both overview presentations on the entire Andean and surrounding oceanic plate system, and specific presentations with emphasis on large-scale regional problems. Examples of possible specific topics include Chile ridge-trench collision, aseismic ridge collision, relation of downgoing and overriding plates, character of the continental lithosphere, seismic characteristics of the downgoing plate, relation between magmatism and the downgoing plate magmatic evolution, plateau uplift, and dynamics of shallow subduction zones. Lead Convener: Suzanne Kay, Department of Geological Sciences, Cornell University, Ithaca, NY 14853 (USA); tel: 1-607-255-4701; fax: 1-607-254-4780; e-mail: Co-conveners: Bryan Isacks (USA), Paul Silver (USA).

V JS2: Subduction Zone Processes At 25-200 Kilometers Depth_The Subducting Slab, Mantle Wedge, and the Slab-Mantle Interface (IAVCEI, IASPEI, ILP)

This symposium features field, petrologic, experimental, geophysical, and geochemical constraints on subduction-zone processes that occur beneath volcanic arcs and forearc regions. Symposium presentations are invited that cover a broad range of topics, including thermal and geochemical evolution, dynamics, hydrology, mineralogy, and rheology of the subducting slab, overlying mantle wedge, and slab-mantle interface, directed toward a better understanding of such processes as arc magma genesis, crust-mantle recycling, and intermediate-depth earthquakes. Lead Convener: Simon M. Peacock, Department of Geology, Arizona State University, Tempe, AZ 85287-1404 (USA); tel: +61-02-965-1733; fax: 1-602-965-8102; e-mail: Co-conveners: Gray E. Bebout (USA), Craig Manning (USA).

V JS4: Geochemical and Geophysical Signatures of Mantle Plumes (IAVCEI, IASPEI, IAG, SEDI)

Mantle plumes are fundamental features of mantle dynamics, but they remain poorly understood. This symposium will integrate geochemical and geophysical observations, laboratory and numerical experiments, and theoretical considerations to address some of the more fundamental questions regarding mantle plumes: From what depth do plumes arise? Do they come from both the 670-km discontinuity and core-mantle boundary or just one of these? What is the ultimate source of material in plumes and how do plumes acquire their unique geochemical signatures? What role do mantle plumes play in heat transport, mantle convection, plate motions? What can mantle plumes tell us about the chemical and physical properties of the deep mantle? How has the plume flux varied with time over the history of the Earth? Are there relationships between the geochemical and geophysical properties of mantle plumes? Lead Convener: W. M. White, Department of Geological Science, Cornell University, Ithaca, NY 14853 (USA);
tel: 1-607-255-7466; fax: 1-607-254-4780; e-mail: Co-conveners: L. Fleitout (IASPEI), B. Hager (USA), L. Kellogg (USA).

V JW1: Electromagnetic Effects of Earthquakes and Volcanoes (IAVCEI, IASPEI)

Changes in electromagnetic fields during earthquakes and volcanic eruptions have clearly been observed during the past few decades. More importantly, some of the more recent observations suggest that electromagnetic effects also occur prior to these catastrophic events and, if a causal relationship can be demonstrated consistent with reasonable physical processes in the crust during these times, they might be used to anticipate these events. In this session, we wish to identify (1) new observations of electromagnetic fields and ionospheric disturbances during earthquakes and volcanic eruptions; (2) experiments that have been or might be done to test causality, or the lack thereof, between electromagnetic fields and earthquakes or volcanic eruption; (3) physical mechanisms for the generation of the electromagnetic fields under various boundary conditions that might explain these data, and how these various mechanisms might be independently identified with other geophysical or geochemical data; and (4) coupling mechanisms that could transform electromagnetic fields generated at the source of earthquake and volcanic activity into larger-scale electromagnetic disturbances. Lead Convener: Malcolm Johnston, USGS, MS 977, 345 Middlefield Road, Menlo Park, CA 94025 (USA); tel: 1-415-329-4812; fax: 1-415-329-5163; e-mail: Co-conveners: M. Gokhberg (RUSSIA), M. Parrot (FRANCE), Y. Fujinawa (JAPAN).

S 1: Seismicity Induced By Petroleum, Mining, and Geothermal Activities (IASPEI, SEG)

It is well established that mining and fluid extraction or migration are often accompanied by the occurrence of small earthquakes. The seismic events induced by these activities lie at the intermediate scale of sizes, between events of plate tectonics and those of laboratory experiments (acoustic emissions). In many cases, the causative relationship between resource extraction and the induced earthquakes is unknown. Increased sensitivity to environmental effects of resource production makes it imperative that these earthquakes be better understood. In recent years, much has been accomplished to expand our understanding of the causes and effects of this seismicity. Sophisticated seismic instrumentation has been developed and installed during the last decade in numerous underground sites, and high-quality full waveform data spanning more than eight magnitude units is now available. Detailed characterization of rock mass properties by tomographic imaging, attenuation measurements, stress modelling, and geological mapping have helped to improve our understanding of the rock masses and the relation between the seismicity and local conditions. It is expected that seismological analyses will benefit from structural geology and geomechanical modelling designed to answer fundamental questions about the accumulation and release of the strain energy in the crust, the mechanics of the earthquake source, the relationship between microseismicity and major events, the practical relationship between induced seismicity and geological structures that control the resource occurrence and extraction, and the relationships between source parameters and damage. This session will bring together scientists and engineers to discuss the latest advances in this field and to propose further studies and future strategies. Lead Convener: M. Fehler,Los Alamos National Laboratory, Los Alamos, NM 87545 (USA); tel: 1-505-667-1925; fax: 1-505-667-8487; e-mail: Co-convener: C. Trifu (CANADA).

S 2: Earthquake Prediction

Contributions concerning all aspects of earthquake prediction will be accepted. The symposium will include not only research papers but also introductions of national programs for earthquake prediction, including strategy and prospects. Methodology for short-term prediction, long-term prediction/forecasting, and evaluation of earthquake potential are of interest. It is important to exchange information on precursors to earthquakes in different places with different tectonic circumstances. Also, algorithms to monitor the seismic regime by many parameters will be discussed. Statistical methods are essential to assess the significance of precursory phenomena, that is, to test discrimination methods of precursory phenomena, and to test the statistical significance such as "probability gain", "probability of successful prediction" and "rate of predicted earthquakes to all earthquakes" in a space-time domain under consideration. Physical models of the source process that explain precursory phenomena to earthquakes are important items as basic research. Technological developments such as deep borehole instruments and GPS technique are also of interest. A special session will be set at the end of the symposium, focusing on major issues, which will be proposed by conveners, speakers, and attending scientists to the Sub-Commission on Earthquake Prediction. Lead Convener: K. Hamada, National Research Institute for Earth Science and Disaster Prevention, Tennodai 3-1, Tsukuba-shi 305 (JAPAN); tel: +81-298-51-1611; fax: +81-298-51-5658 (1622); e-mail: Co-convener: A. Lindh (USA).

S 3: Continental Evolution Revealed in Geophysical Transects (IASPEI, ILP)

In the past 10 years, much scientific attention has focussed on the evolution of the continental lithosphere and its margins. Significant progress in these studies has come from integrated geological/geophysical transects that have been undertaken across major geological structures and even across whole continents. These long-range transects have spanned lithosphere of all ages, from Archean to Tertiary, and thus provide a view of secular changes in lithospheric evolution. Tectonic settings that have been investigated include stable platforms and shields, ancient and modern collision zones and rifts, and passive and active continental margins. This symposium will focus on the evolution of the continental lithosphere and its margins as revealed by long-range geophysical transects together with complementary geological information. The processes to be addressed include the formation and stabilization of Precambrian crust, mountain building and oregenic collapse, rifting and lithospheric extension, and the evolution of continental margins. Lead Convener: W. D. Mooney, U. S. Geological Survey, Mail Stop 977, 345 Middlefield Road, Menlo Park, CA 94025 (USA); tel: 1-415-329-4764; fax: 1-415-329-5163; e-mail: Co-conveners: R. Clowes (CANADA), H-J. Goetze (GERMANY), S. Mueller (SWITZERLAND), N. Pavlenkova (RUSSIA).

S 4: Origin and Evolution of Sedimentary Basins_Tectonothermal, Geochemical, and Hydrological Aspects (IASPEI, ILP, SEG)

Sedimentary basins provide most of the world's current energy consumption, and in addition to fossil energy resources, they contain significant reserves of freshwater, geothermal fluids, and some types of mineral deposits. The physical and chemical characteristics of the sediments and pore fluids vary greatly due to sedimentation and tectonic history and to basal heat flow variations. Secondary processes such as diagenesis, sediment-water interactions, maturation of organic matter, and fluid flow modify these characteristics. Papers solicited for this session are encouraged on multidisciplinary studies of basin evolution, particularly those quantifying or modelling the physical and chemical processes occurring within the sediments. Lead Convener: R. Allis, Institute of Geological and Nuclear Sciences, P. O; Box 30368, Lower Hutt (NEW ZEALAND); tel: +64-4-569-9059; fax: +64-4-569-5016; e-mail: Co-conveners: C. Beaumont (CANADA), C. Clauser (GERMANY), S. Cloetingh (NETHERLANDS).

S 5: Ground Motion Analysis From Recent Strong-Motion Data

The aim of the session will be to determine what lessons can be learned from recent strong-motion records. Topics to be considered include implications from recorded motions for spectral attenuation models, long-period characteristics, site effects, near-source effects, scaling relations between weak motions and strong motions, and uncertainties in the estimation of ground motions. Lead Convener: Li-li Xie, Institute of Engineering Mechanics, State Seismological Bureau, 9 Xuefu Road, Harbin 150080 (CHINA); tel: +86-451-66-64756 (61304); fax: +86-451-66-64755. Co-convener: N. A. Abrahamson (USA).

S 6: Quantification of Earthquakes

The deployment and operation of broadband, high dynamic range instruments has led to the accumulation of new and different observations of the earthquake source process. In addition, computer modeling of the complex seismic wave field in conjunction with geophysical inverse methods now allows us to image the earthquake source process in space and time. With the accumulation of more precise estimates of slip and rupture properties for individual earthquakes, it becomes natural to review empirical earthquake parameters, such as magnitudes, and their relationship to more physical ones, such as moment, stress and energy. The symposium will focus on methods and results of quantifying the earthquake process and invites discussion of how traditional and new source parameters can be useful in the characterization of seismic activity on the local, regional, and global scale. Additional topics of interest are innovative uses of current and historical catalogs of earthquake parameters, as well as methods for and results from rapid and real-time earthquake analysis. Lead Convener: G. Ekstrom, Department of Geological Sciences, Harvard University, Hoffman Laboratory, 20 Oxford Street, Cambridge, MA 02138 (USA); tel: 1-617-496-8276; fax: 1-617-495-8839; e-mail: Co-conveners: H. Kawakatsu (JAPAN), S. A. Sipkin (USA).

S 7: Rheology and Lithospheric Deformation (IASPEI, ILP)

The theory of plate tectonics is based on the concept of rigid, non-deformable lithospheric plates "floating" on the underlying inviscid asthenosphere. However, large-scale lithospheric deformation is characteristics, for instance, of many plate boundaries. Therefore understanding the nature of lithosphere deformation in response to plate interactions is essential to go beyond the simplifications of plate tectonics. Two important examples of lithospheric deformation are: (1) convergent continental plate boundaries; and (2) subduction of oceanic lithosphere. Significant deformation is ubiquitous in continental collision zones and is often restricted to narrow structures, especially in the crust. A central question here is therefore the mechanisms of strain localization through rheological weakening. Compared to the continental lithosphere, the nature of deformation of subducted oceanic lithosphere is less constrained, but recent high-resolution seismic tomography, analyses of focal mechanisms of deep earthquakes, combined with mineral physics studies on deep mantle rheology provide useful constraints on the nature of deformation of subducted oceanic lithosphere and its interaction with the less viscous mantle. Papers related to lithosphere deformation and rheology with special emphasis on continental collision zones and subducted oceanic lithosphere are invited for this issue. Papers from various disciplines, including seismology, geodynamical modelling, and laboratory studies, are welcome. Lead Convener: S. Karato, Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455 (USA); tel: 1-612-624-7553; fax: 1-612-625-3819; e-mail: Co-conveners: J. Braun (AUSTRALIA), S. Sobolev (RUSSIA).

S 8: Microearthquakes and Tectonics of the Ocean Bottom

A noticeable increase in ocean bottom seismological observations characterizes the present time. New results have been obtained in different regions of the world's oceans. Reports presenting recent microearthquake or acoustic observations made by ocean-based instruments which relate to natural processes in the solid Earth are invited for this session. Papers leading to tectonic conclusions and seismicity estimates, as well as papers describing novel instruments or techniques, are especially welcome. Lead Convener: H. Shimamura, Laboratory for Ocean Bottom Seismology, Hokkaido University, N-10 W-8, Sapporo 060 (JAPAN); tel: +81-11-726-4766; fax: +81-11-726-7240; telex: 932510 hokusc j; e-mail: Co-conveners: A. Ostrovsky (RUSSIA), R. B. Whitmarsh (UK).

S 9: Earthquake Hazard Related To Regional and Local Geological Structures (IASPEI, ILP)

This symposium focuses on newer developments in earthquake hazard assessment concepts and procedures. Of particular interest are different regional seismotectonic settings in various azimuths and the effects of surficial geological structures to the reliability of hazard evaluations obtained by present techniques and algorithms, including GIS. Papers on earthquake hazard assessment in regions of rare strong earthquakes in both the inter- and intra-plate environments and on estimation of time-dependent hazard are particularly encouraged. Lead Convener: V. Schenk (IASPEI), Geophysical Institue, Academy of Sciences of Czech Republic, Bocni II, c.p. 1401, 141 31 Praha 4 - Sporilof (CZECH REP); tel: +42-2-6710-3111; fax: +42-2-762-279 or 761-549; telex: 121546 IONP C: e-mail: Co-conveners: R. C. Agrawal (INDIA), D. Giardini (ITALY), A. Shapira (ISRAEL).

S 10: Seismology and Physics of Anisotropic Heterogeneous Media (IASPEI, SEG)

Research in elastic anisotropy has evolved to the point where our current understanding of the Earth has anisotropy in most regions from the shallowest crust to the inner core. Wave propagation in anisotropic media is considerably more complex than that in isotropic media, an obvious example being the propagation of two distinct and often complicated S wave fronts in homogeneous anisotropic material. Despite the complexities of wave propagation in anisotropic media, characteristics of the resulting waveforms can provide valuable insight into the mineralogy, state of stress and deformation, and flow patterns in a variety of tectonic settings. It is the aim of this symposium both to summarize our current understanding of elastic anisotropy and to identify directions of future research, both in global and exploration seismology. The session will be subdivided into three components: (1) theoretical studies of wave propagation in anisotropic media; (2) mechanisms for elastic anisotropy from both experimental and theoretical studies in mineral physics and geodynamics; and (3) the analysis of observational evidence of seismic anisotropy on both global and exploration scales. In addition to regular research papers, each component will have state-of-the-art papers and a poster session, which will enable interactive discussions of research. Lead Convener: J-M. Kendall, Geophysics Section, Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7 (CANADA); tel: 1-416-978-3159; fax: 1-416-978-7606; e-mail: Co-conveners: E. M. Chesnokov (RUSSIA), G. Pratt (UK).

S 11: Real Time Tectonics

This session invites papers on deformation results obtained from geodetic measurements and from earthquake-related strains. Of special interest are papers that address a joint analysis of seismic strains (and/or Quaternary fault slip rate information) and geodetic strains in order to understand the kinematics and dynamics of the deformation in continental lithosphere. The length scales of the deformation that is measured and modeled can range, for example, from the mapping of slip distribution on individual fault rupture zones to the determination of the strain partitioning throughout the width of an entire diffuse plate boundary zone. In this regard we seek an understanding of the nature of strain at plate boundary zones, which is fundamental for the evaluation of seismic hazards. Convener: W. E. Holt, Department of Earth and Space Sciences, SUNY Stony Brook, Stony Brook, NY 11794-2100 (USA); tel: 1-516-632-8216; fax: 1-516-632-8240; e-mail:

S 12: Geophysical Tomography in Complicated Heterogeneous Media (IASPEI, SEG)

This symposium deals with methods of geophysical tomography, not only using seismic waves, but also including electric, gravimetric or magnetic data. Papers are invited on methods of image reconstruction developed in both exploration and global geophysics. New approaches and methods in the following areas are especially interesting for the symposium: tomography of the lithosphere and sediments, specifically oil/gas deposits; nonlinear tomography; waveform tomography; monitoring in space and time; multiwave tomography; scaling of data and model parameters; data and model resolution; reliability estimates of the interpretation; and three-dimensional display of tomographic results. Lead Convener: E. Kissling, Institut fuer Geophysik, ETH-Hoenggerberg, CH-8093 Zurich (SWITZERLAND); tel: +41-1-633-2623; fax: +41-1-633-1065; telex: 823480 eheb ch; e-mail: Co-conveners: L. Lines (CANADA), A. Morelli (ITALY).

S 13: Application of Artificial Intelligence Computing in Geophysics (IASPEI, SEG)

Geophysics has been an interdisciplinary science. New advances in computing science and technology and their application to geophysics have further advanced our science. This symposium invites papers on geophysical applications of artificial intelligence techniques. These computing techniques include, but not limited to, neural networks, fuzzy logic, genetic algorithms and evolutionary programming, knowledge-based systems, and other machine-learning approaches. In the past few years, many successful applications have been developed for seismic and other geophysical data processing and interpretation. Potential applications include nonlinear inversion of geophysical data, pattern matching, and interpretation of large amounts of data in automated operations. Papers are invited on all aspects of artificial intelligence computing techniques, and the focus is on geophysical applications. The purpose of this symposium is to bring together researchers working on related areas for free exchange of results and ideas, and also to develop awareness of the on-going work and its usefulness for further potential applications. Contributed software with example applications will be available for interested investigators. Lead Convener: G. B. Patnaik, Advanced Computing Technologies, P.O. Box 927477, San Diego, CA 92192-7477 (USA); tel: 1-619-535-4840; fax: 1-619-535-4890; e-mail: Co-convener: F. Aminzadeh (USA).

S 14: Advances in Methods and Interpretation of Two-Dimensional and Three-Dimensional Earth Structure_Case Studies, Computational Techniques, Structures (IASPEI, SEG)

Much interpretation in seismology rests on an apparent contradiction. Elastic propagation is best understood and most accurately modelled for media that vary in only one direction, but the goal of seismologists is more commonly the determination and delineation of Earth structures that vary laterally as well as vertically. This symposium aims in part at promoting the exchange of ideas between exploration and global seismologists dealing innovatively with laterally varying Earth structure. Papers which as well as being novel are of interest across the branches of seismology are especially encouraged. Contributions will be welcomed on data processing, interpretation and case histories, all forms of modelling technique, and the basic theory of waves in inhomogeneous media. Papers are encouraged which show the use of waveform and secondary arrival information and the effective exploitation of vector wavefields. Applications can range from the core to the crust, from VSPs to normal modes. Lead Convener: C. Thomson, Department of Geological Sciences, Queen's University, Kingston, Ontario K7L 3N6 (CANADA); tel: 1-613-545-6178 (2597); fax: 1-613-545-6592; e-mail: Co-conveners: D. Miller (USA), M. Weber (GERMANY).

S 15: Dynamics of the Subduction Process

With the dynamics of the subduction process as the governing theme, this symposium aims to address (1) non-stationary aspects of the subduction process and its implications for geodynamic processes associated with subduction; (2) the relationship between subduction and mantle convection; and (3) relationships between seismicity, temperature distribution, rheology, and the stress field in subducting slabs. Contributions are solicited from a wide variety of disciplines that incorporate new information on subduction zones as a complex "geosystem", e. g., results of tomographic and seismicity studies, numerical and experimental dynamical modelling, and rheological and other science-oriented materials, studies relevant for pressures and temperatures in the subducted lithosphere, the transition zone and the uppermost lower mantle. In particular, contributions are welcomed concerning the role of subduction in the relationship between mantle processes and near-surface geological processes. Emphasis will be put on quantitative analyses, at various time scales, in close combination with geological, geophysical, and pertinent geodetic data. Lead Convener: R. Wortel, University of Utrecht, Institute of Earth Sciences, Vening Meinez Lab, Budapestlaan 4, Utrecht 3584 CD (NETHERLANDS); tel: +31-30-535086; e-mail: Co-conveners: R. D. van der Hilst (AUSTRALIA), Y. Fukao (JAPAN).

S W1 Seismological Networks for the Next Century

In the near future, rapid evolution in instrumentation and communications technology may greatly improve the science of seismology. Massively dense seismic networks may change the way we understand the crust, lithosphere or mantle. It is time now to start imagining how we want to explore the Earth during the beginning of the next century. This workshop could discuss, among other topics, the following: (1) new seismometers_chemical sensors, light interferometry, nanotechnology; (2) massive instrumentation of the Earth's surface_how many seismometers, fractal networks, funding; and (3) communications_cellular phones, dedicated satellites. To prepare for the workshop, the conveners are requesting reactions to these suggested topics and suggestions for the workshop. Do not hesitate to tell them that you do not like the idea. If general agreement can be reached, participants could plan to have, for the end of the workshop, a document adopted defining the community's goals. Lead Convener: A. Tarantola, Institut de Physique du Globe, 4 place Jussieu, F-75252 Paris Cedez 05 (FRANCE); tel: +33-1-4427-3898; fax: +33-1-4427-4894; e-mail: Co-convener: R. Phinney (USA).

S W2: Thermoelastic Properties of Deep Mantle Phases (IASPEI, SEDI)

New experimental and theoretical techniques have allowed a sharper focus on the subject than has been possible before. The new experimental work on this subject (Stoney Brook, Carnegie Labs., Tokyo) is not in complete agreement, and neither are the newest theories. But the work is booming and there will be lots of surprises by next summer. Lead Convener: O. L. Anderson, Institute of Geophysics and Planetary Physics, 405 Hilgard Avenue, University of California, Los Angeles, Los Angeles, CA 90024-1567 (USA); tel: 1-310-285-2386; fax: 1-310-206-3051. Co-convener: I. Jackson (AUSTRALIA).

S W3: Acquisition and Processing of Deep Crustal Seismic Data (IASPEI, SEG)

The workshop will address advances in data acquisition, processing, and interpretation of crustal reflection data, including wide-angle reflection data and VSPs. New interpretation of crustal structure and the nature of crustal reflectors will be welcomed. Fluids in the crust, crustal velocity profiles and their significance, intracrustal boundaries, sutures, and the Moho are topics of particular interest. Lead Convener: S. Smithson, Department of Geology, University of Wyoming, Laramie, WY 82070 (USA); tel: 1-307-766-5280; fax: 1-307-766-6679; e-mail: Co-conveners: P. Docherty (UK), P. Hubral (GERMANY).

S W4: Reliability of Earthquake Precursors and Prediction

Invited papers longer than 15 minutes will be devoted to assessing the state of the precursors that are on the IASPEI Preliminary List of Significant Precursors, to determine whether they should remain on this list. Precursors and prediction methods using advanced techniques, that are not on the List will also be evaluated for possible inclusion in the List by proponents and critics. Quantitative papers are called for on the usefulness or inadequacy of the following parameters as precursors: foreshocks, swarms, seismic quiescence, and other seismicity patterns; changes of groundwater level, temperature, and chemistry; crustal deformations; and changes of anisotropy and attenuation. Convener: M. Wyss, Geophysical Institute, University of Alaska, Fairbanks, AK 99775-0800 (USA); tel: 1-907-474-5529; fax: 1-907-474-7290; e-mail:

S W5: Recent Devastating Earthquakes

The purpose of this workshop is to review the lessons we have learned from recent devastating earthquakes so that we can use them most effectively in the future. In addition to the traditional efforts for improving building construction, development of sophisticated warning and information systems would be important for preparing for major earthquakes in modern metropolitan areas. Papers on all aspects (seismological, engineering, and social) of recent devastating earthquakes, experiences in hazard mitigation activities, and proposals for future planning are welcome. Convener: H. Kanamori, Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125 (USA); tel: 1-818-395-6914; fax: 1-818-564-0715; e-mail:

S W6: Earthquake Warning Systems_Progress and Results

After nearly 30 years of earthquake prediction research, the ability to predict the time, place, and magnitude of an earthquake accurately for practical use remains elusive [Geller, 1991; U.S. National Research Council, 1991]. However, present technology in seismic instrumentation and telecommunications has advanced to a point that permits the implementation of a system for earthquake warning with a modest funding. Such a system is capable of providing a few seconds to a few tens of seconds of warning before the arrival of strong ground shaking caused by a large earthquake that has just occurred. Such timely information is essential to minimize damage and loss of lives in metropolitan areas. The idea of an earthquake warning system was proposed more than 100 years ago by Cooper [1868] for San Francisco. A modern approach for a seismic computerized alert network was published by Heaton [1985]. For more than 20 years, Japan has benefited from an earthquake warning system on their "bullet" trains [Nakamura and Tucker, 1988], and an intelligent warning system called UrEDAS is being implemented in Japan now [Nakamura, 1988, 1989, 1991]. More recently, an earthquake warning system began operation in Mexico (Espinosa-Aranda et al., 1993), and a similar system is being implemented in Taiwan [Lee, Shin, and Teng, 1993]. The purposes of this workshop are (1) to bring together active workers in these topics to share their experience and results, and (2) to inform interested seismologists how to apply this technology for earthquake hazards reduction. Lead Convener: W. H. K. Lee, U.S. Geological Survey, Mail Stop 977, 345 Middlefield Road, Menlo Park, CA 94025 (USA); tel: 1-415-329-4781; fax: 1-415-329-5163; e-mail: Co-conveners: J. M. Espinosa-Aranda (MEXICO), Y. Nakamura (JAPAN), T. C. Shin (TAIWAN).

S W7: Intra-Continental Earthquakes

The workshop will consider the full range of continental seismotectonic environments, from normally stable plate interiors to plate boundary zones that have high rates of current tectonism. The workshop will be well suited to highlight: (1) characteristics of intra-continental earthquakes, including seismicity, focal mechanism, source parameters, complexity in source process, etc., and their dependency on overall tectonic environment; and (2) recent progress and problems in evaluating the earthquake potential of specific tectonic structures. Papers on entire source regions and on significant individual earthquakes are welcome. Lead Convener: Chen Yun-tai, Institute of Geophysics, State Seismological Bureau, 5 Minzuxueyuan Nanlu, Haidian District, Beijing 100081 (CHINA); tel: +86-1-841-5370; fax: +86-1-841-5372; telex: 221032 IGSSB CN. Co-convener: J. W. Dewey (USA).

S W8: Seismological Data and Practice Into the 21st Century

The practice of seismology is rapidly moving toward the automatic, quasi real-time processing of large volumes of digital waveforms, posing the urgent need to adopt new procedures for routine waveform analysis and parameter extraction. Regional and global networks and international data collection centers are invited to present their present and planned (over the next 5 years) procedures for routine waveform analysis and parameter extraction, with the goal of comparing and disseminating new methodologies. Lead Convener: E. A. Bergman, U.S. Geological Survey, P.O. Box 25046, Mail Stop 967, Denver Federal Center, Denver, CO 80225 (USA); tel: 1-303-273-8421; fax: 1-303-273-8450; telex: 510 6014123 ESL UD; e-mail: Co-convener: D. Giardini (ITALY).

S W9: Methodology of Seismic Risk Assessment

This workshop will address the recent methodology applied in seismic risk and in estimates of economic losses expected from future earthquakes in regional, local, and special site (megacity) scales. Special interest will be given to risk theory and practice, to their logistical, physical, and social aspects. Papers comparing different seismic risk techniques and earthquake loss assessments are particularly encouraged. Lead Convener: Chen Yong, State Seismological Bureau, No. 63, Fuxing Avenue, Beijing 100036 (CHINA); tel: +86-1-821-5973; fax: +86-1-821-5973; telex: 716 222351 SSB CN; e-mail: CHENYONG@BEPC2.IHEP.AC.CN. Co-convener: A. Shapira (ISRAEL).

S W10: Exploiting Large Volumes of Digital Waveform Data_Theory and Applications

Owing to the rapidly increasing number of digital seismic stations and to recent developments in computer hardware, the amount of digital seismological data that is available is expanding dramatically. Of the available data, however, only a small fraction is exploited by existing methods of analysis. This symposium is devoted to techniques and case studies that exploit the steadily increasing digital data set for the determination of earth structure. Contributions from diagnostic methods using both seismic waveforms and waveform inversion techniques are welcome. Lead Convener: R. Snieder, Department of Theoretical Geophysics, University of Utrecht, Budapestlaan 4,
P.O. Box 80. 021, 3508 TA Utrecht (NETHERLANDS); tel: +31-30-535087 (575086); fax: +31-30-535030; e-mail: Co-conveners: J. C. VanDecar (USA), H. Benz (USA).

S W11: Deja Q Anelasticity in the Earths Deep Interior (IASPEI, SEDI)

Interest in anelasticity perhaps last peaked in the seismological community in the mid-1970s to reconcile spherically symmetric body waves with normal-mode earth models. Now, with the emergence of the first global-scale images of lateral variations in seismic attenuation across the upper mantle and with greatly improved experimental techniques in measuring anelasticity at seismic periods in the laboratory, the time is ripe for a renewed interest in anelasticity by seismologists, experimental geophysicists, and geodynamicists. The purpose of this session is to bring together seismologists, experimental geophysicists, and geodynamicists to illuminate the state of anelasticity research in each discipline, in the hope of identifying fruitful themes for collaboration and directions for future research. Lead Convener: M. Ritzwoller, Department of Physics, University of Colorado, Campus Box 390, Boulder, CO 80309-0390 (USA); tel: 1-303-492-7075; fax: 1-303-492-7935; e-mail: Co-convener: B. Romanowicz (USA).

S W12G: SHAP_Related Advancement in Techniques and Interpretation in Seismic Hazard Assessment (IASPEI, ILP)

This workshop will address advances that have been made in elements of seismic hazard assessment under the ILP's UN/IDNDR Global Seismic Hazard Assessment Program (GSHAP) that was initiated in 1992, and endorsed as an international demonstration program by the IDNDR. GSHAP has developed guidelines [see Annali di Geofisica, Vol. 36, No. 3-4, 1993] for earthquake catalogues, seismotectonics and earthquake sources, strong seismic ground motion, and seismic hazard computation methodology. Special interest will be given to further development of the GSHAP guidelines and to implementation of the recommended procedures throughout the GSHAP regions. Convener: P. Basham, Geophysics Division, Geological Survey of Canada, 1 Observatory Crescent, Ottawa, Ontario K1A 0Y3 (CANADA); tel: 1-613-995-0904; fax: 1-613-992-8836; telex: 389 0533117 EMAR OTT; e-mail: BASHAM@SEISMO.EMR.CA.

S W13: Improving Regional Cooperation in Observational Seismology

In developing areas there are often serious difficulties in communication among seismologists in different countries. It is in particular in these areas that cooperation can be very beneficial, since individual country networks often are insufficient for doing meaningful processing of the data. Some long-standing organizations exist, such as CERESIS in South America, and regional exchange of bulletins and phase arrival times often takes place. In two areas in particular, Central America and East Africa, seismologists from neighboring countries exchange data and often meet to process their data with a shared processing system. This has resulted in greatly improved earthquake detection and location. Contributions are invited that describe methodologies and results in areas of such regional cooperation, and suggestions are also solicited for further candidate areas, where such cooperation would be beneficial. Lead Convener: J. Havskov, Institute of Solid Earth Physics, University of Bergen, Allegaten 41, N-5007 Bergen (NORWAY); tel: +47-5-213414; fax: +47-5-320009; telex: 856 42877 UBBRB N; e-mail: Co-convener: F. Guendel (COSTA RICA).

S W14: Seismic Noise_Stability and Change in Time and Space

Papers giving the results of the investigation of broadband seismic noise characteristics and their variation in time and space, especially independent of natural and human conditions, are invited. Papers are invited on the results of signal and noise studies aimed at the enhancement of the performance of worldwide networks. Papers with ambient noise measurements for microzonation in its relation to sub-soil characteristics and ground motion site effects are also invited, as are traditional papers on research on the seismic noise related to the frequency range of storm microseisms. Papers on theoretical and numerical modelling of seismic noise fields are also welcome. Lead Convener: A. A. Ostrovsky, Laboratory of Seismic Researches, P. P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Krasikova 23, Moscow 117 218 (RUSSIA); tel: +7-095-124-5996; fax: +7-095-230-2043; telex: 411968 OKEAN SU. Co-conveners: E. Hjortenberg (DENMARK), P. Bormann (GERMANY).

S W15: Statistical Characteristics of Earth Heterogeneity (IASPEI, SEG)

Statistics are a useful method to characterize data where insufficient information is available to model them deterministically or deterministic models become cumbersomely complex. A statistical characterization of a model often gives insight into the general nature of the processes which cause structure in a model and consequently in data. For this session, papers are called for in all fields of geology, seismology, and geophysics which seek to (1) model statistical characteristics of field data in terms of the statistical nature of any physical property of the Earth; (2) study the relations between statistical characteristics of the Earth's heterogeneities and its tectonic and dynamic processes; and (3) study the effects of heterogeneities with different statistical characteristics on wave propagation and geophysical observables. Studies are welcomed on all scales ranging from small-scale crustal heterogeneity as seen in outcrop, well-log, petrophysical, geodynamic, and crustal seismic data (including reflection, refraction, and earthquake experiments), to larger scale regional or global mantle heterogeneity, as inferred from petrophysical, geodynamic, and regional and teleseismic earthquake data. Lead Convener: O. Gudmundsson, Research School of Earth Sciences, Institute of Advanced Studies, The Australian National University, Canberra, ACT 0200 (Australia); fax: +61-6-257-2737; e-mail: Co-conveners: A. Levander (USA), Wu Ru-shan (CHINA).

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IUGG XXI General Assembly