To secure that impact arises as one longed for goal in all the projects from investigation or action. It must consider that the effort to reach this goal can take to the institutions to the adoption of hasty measures or cosmetic solutions. It is urgent the agreement of ideas, a of integral studies and multidisciplinary that by means of a globalizante vision, integrated from the beginning, allows the development of studies, appropriate investigations and solutions (the UNDERGROUND SHOCKS: 1897). The accomplishment of studies of reduction of natural disasters must be avoided that motivated by an anxiety of knowledge on one of the factors is specific, are developed separately and with methodologies that take to fragmented results, whose application or success can be taken as effective or suitable for one it disciplines but it does not stop a goal of reduction of disasters. The social impact secured by the projects of reduction of the sequels of disasters and the boarding of the subject that occurs in its methodologies, is one of the factors of greater discussion at present. During a long lapse, the physical point of view has been the determinant to mark to the footpath of the actions of prevention and preparation for disasters, to which a strongly determinist characteristic has been printed them: it has been created a scope of investigation and study in which social sciences would behind schedule seem to have arrived; Lavell says (1993): from the point of view of social sciences (agricultural economy, sociology, geography, anthropology, social, administration, political science, right ecology, etc.) does not exist any institution with consolidated research programs and continuous, while very limited number of native, individual investigators, they have penetrated in this subject (DURN: 1994). All the projects of study must be justified on the base of a vulnerable population to which has been called the social antecedent.