Short-term destructive events are catalytic and definitive in the evolution of the modern city. As far as the Greek territory is concerned, the destructive events with the Most painful consequences in casualties and damages to the built environment are related to seismic activity. Urban changes after a destructive eventuality are rapid, random, unpredictable. The result of such eventualities is the immediate transformation of areas of the city, in defiance to planning, characterized by the acceleration or abandonment of existent developmental procedures, causing dramatic urban mutations, and unpredictable reactions in the residents themselves. Built environment management in cases of natural disasters is one of the issues subsumed within the field of urban planning. The primary goal of the present paper is an analysis of research methods into the behavior of built environment and its management in cases of earthquake, as well as a consideration of whether an equilibrium can be obtained between the functional needs of the city-expansions, redlesignation of building ratios, institution of new functions of land-with the necessary regulations and prerequisites for the safety of the residential and social whole. According to the research findings, seismic risk management develops along two parallel approaches, that of preventive planning, and that of sustainable development. On the one hand, we are invited to apply a specialized approach to seismic risk within urban space, which places prevention within the framework of sustainable development, and on the other, we face the challenge of formulating preventive planning of risk management. For the above investigation, we use the findings of a pilot urban planning study in the business-historical center of Thessaloniki, which involves the evaluation of planning and architectural facts of the city, in combination with the risk management data analysis. The aforementioned study, incorporated within the domain of the overall planning of the city and having particular sinificance in its saturated urban environment, may become the framework of an urban planning model of facing problems of seismic vulnerability, in the event of a major earthquake. The proposed interventions are part of a wide urban planning spectre which can even include proposals for the revision of existing urban plans, according to the demands of the society. The methodology adopted is endorsed by the planning section of a wider european research program entitled: "An advanced approach to earthquake risk senarids with applications to different European towns", in which M.Alexoudi, S.Argiroudis, A.Anastassiadis (urban plan supervisor), K.Pitilakis (scientific supervisor) participate. In the design of tables and maps there was also the contribution of students, N.Dikas and A.Kiriazis.
