Seismic Risk and Engineering Decisions attempts to bridge the gap in decision making between earthquake characteristics and structural behavior. The book begins by providing the background on earthquake generation and characteristics. It reviews the present state of matters in seismicity assessment and treats uncertainties explicitly. The impact of earthquakes on large bodies of water and structures is also discussed. These discussions set the stage for the final part of the book, which deals with the principles and implications of seismic design decision analysis. The book also delves into the selection of instruments for seismological research and engineering applications, with emphasis on widely used conventional seismological equipment. This book is intended to help experienced consulting engineers in assessing seismic risk and making rational decisions when locating and designing important engineering works and when drafting building codes and land use regulations. It will also provide advanced students of engineering with bases for benefiting from his future experience.