by K. Lambeck, R. Sabadini and E. B08Chi Viscosity is one of the important material properties of the Earth, controlling tectonic and dynamic processes such as mantle convection, isostasy, and glacial rebound. Yet it remains a poorly resolved parameter and basic questions such as whether the planet's response to loading is linear or non-linear, or what are its depth and lateral variations remain uncertain. Part of the answer to such questions lies in laboratory observations of the rheology of terrestrial materials. But the extrapolation of such measurements from the laboratory environment to the geological environment is a hazardous and vexing undertaking, for neither the time scales nor the strain rates characterizing the geological processes can be reproduced in the laboratory. General rules for this extrapolation are that if deformation is observed in the laboratory at a particular temperature, deformation in geological environments will occur at a much reduced temperature, and that if at laboratory strain rates a particular deformation mechanism dominates over all others, the relative importance of possible mechanisms may be quite different at the geologically encountered strain rates. Hence experimental results are little more than guidelines as to how the Earth may respond to forces on long time scales.

The geodynamic evolution of the Mediterranean region has been often described as a puzzling problem' because of the complex space-time distribution of tectonic events. The gathering of new constraining information and frequent changes of data and ideas among the scientists working on this topic seems to be the most suitable approach to the above problem. This volume reports the most significant results of geological, geophysical, seismological, volcanological, paleomagnetic studies and the geodynamic syntheses presented, and discussed. Special attention is devoted to regions, such as the Aegean--Anatolian and central Mediterranean, which played a crucial role in the evolution of the whole Mediterranean area. A considerable improvement in the understanding of the post-Tortonian deformation pattern of the Tyrrhenian--Apennine system has been achieved by recent geological and geophysical investigations. The geodynamic implications of the data presently available might provide important insights into the evolution of continental collision zones, where shortening processes may also involve lateral extrusion of crustal wedges and consumption of continental-like lithosphere. The main uncertainties which still surround the relative motion between Africa and Eurasia in the Mediterranean region are also pointed out. The arguments reported in this volume are mainly addressed to research scientists and advanced students of the earth sciences. (abstract) This volume reports information about the evolutionary history and the present structural-tectonic setting of the Mediterranean region, which has been presented and discussed during a meeting on Recent Evolution and Seismicity of the Mediterranean Region', held in Erice (Italy) in September 1992. Recent results of geological, geophysical, seismological, volcanological and paleomagnetic studies are described. The geodynamic implications of the presently available data set might provide important insights into the evolution of continental collision zones, where shortening processes may also involve lateral extrusion of crustal wedges and consumption of continental-like lithosphere.

The geodynamic evolution of the Mediterranean region has been often described as a puzzling problem' because of the complex space-time distribution of tectonic events. The gathering of new constraining information and frequent changes of data and ideas among the scientists working on this topic seems to be the most suitable approach to the above problem. This volume reports the most significant results of geological, geophysical, seismological, volcanological, paleomagnetic studies and the geodynamic syntheses presented, and discussed. Special attention is devoted to regions, such as the Aegean--Anatolian and central Mediterranean, which played a crucial role in the evolution of the whole Mediterranean area. A considerable improvement in the understanding of the post-Tortonian deformation pattern of the Tyrrhenian--Apennine system has been achieved by recent geological and geophysical investigations. The geodynamic implications of the data presently available might provide important insights into the evolution of continental collision zones, where shortening processes may also involve lateral extrusion of crustal wedges and consumption of continental-like lithosphere. The main uncertainties which still surround the relative motion between Africa and Eurasia in the Mediterranean region are also pointed out. The arguments reported in this volume are mainly addressed to research scientists and advanced students of the earth sciences. (abstract) This volume reports information about the evolutionary history and the present structural-tectonic setting of the Mediterranean region, which has been presented and discussed during a meeting on Recent Evolution and Seismicity of the Mediterranean Region', held in Erice (Italy) in September 1992. Recent results of geological, geophysical, seismological, volcanological and paleomagnetic studies are described. The geodynamic implications of the presently available data set might provide important insights into the evolution of continental collision zones, where shortening processes may also involve lateral extrusion of crustal wedges and consumption of continental-like lithosphere.

by K. Lambeck, R. Sabadini and E. B08Chi Viscosity is one of the important material properties of the Earth, controlling tectonic and dynamic processes such as mantle convection, isostasy, and glacial rebound. Yet it remains a poorly resolved parameter and basic questions such as whether the planet's response to loading is linear or non-linear, or what are its depth and lateral variations remain uncertain. Part of the answer to such questions lies in laboratory observations of the rheology of terrestrial materials. But the extrapolation of such measurements from the laboratory environment to the geological environment is a hazardous and vexing undertaking, for neither the time scales nor the strain rates characterizing the geological processes can be reproduced in the laboratory. General rules for this extrapolation are that if deformation is observed in the laboratory at a particular temperature, deformation in geological environments will occur at a much reduced temperature, and that if at laboratory strain rates a particular deformation mechanism dominates over all others, the relative importance of possible mechanisms may be quite different at the geologically encountered strain rates. Hence experimental results are little more than guidelines as to how the Earth may respond to forces on long time scales.