The accelerated, and often uncontrolled, growth of the cities has contributed to the ecological transformation of their immediate surroundings. Factors contributing to the urban vulnerability include: lowering or rising of the water table, subsidence, loss of bearing capacity of soil foundations and instability of slopes. Recent catastrophic earthquakes highlight the poor understanding by decision makers of seismic related risk, as well as the tendency of some builders to use the cheapest designs and construction materials to increase short-term economic returns on their investment.

Losses from earthquakes will continue to increase if we do not shift towards proactive solution. Disaster reduction is both an issue for consideration in the sustainable development agenda and a cross-cutting issue relating to the social, economic, environmental and humanitarian sectors. As location is the key factor, which determines the level of risk associated with a hazard, land-use plans and mapping should be used as tools to identify the most suitable usage for vulnerable areas.

requiring the adaptation of probabilistic maps to design ground motions; and (d) the generalization of design parameters to locations where there is little seismic history. Maximum displacements, velocities, and, based on the European Build ing Code EC8, design ground acceleration maps have thus been produced by ZivCic et al. for Slovenia, Marku ic et al. for Croatia, Bus et al. for Hungary, and Radulian et al. for Romania. The last two contributions in the volume are dedicated to studies of local site effects that could affect the microzonation of large urban areas. Moldoveanu et al. employed a technique based on the modal summation and finite dif ferences to calculate the expected ground motion in the capital city of Bucha rest due to large intermediate-depth Vrancea earthquakes. Their results outline that the presence of alluvial sediments and the possible variation of event scenario require the use of all three components of motion for a reliable determination of the seismic input. The study of Marmureanu et al., more limited in scope, offers a laboratory analysis of the attenuation effects for sur face layers. The authors confirm that seismic attenuation in sedimentary layers is a function of the strain levels induced by large earthquakes, and find that the quality factor is nearly constant over a relatively wide frequency range, between 7 and 100 Hz."