For the past four, decades researchers in the field of natural hazards have studied extensively how people “hear” warning messages of potential natural disasters and then, eventually, how they “respond” by way of adopting preparation and mitigation measures. Until the 1980s, a single framework did not exist for understanding risk communication as an integrated process. Much of the early research on risk communication was piecemeal and descriptive, and consisted of exploring the details of communicating risk within the events of a particular disaster. The proliferation of research on risk communication over several decades, though, has resulted in the evolution of a general model of hazards risk commnication. This model presupposes that the process of risk communication is one whereby individuals: (1) hear a warning message; (2) understand its content; (3) internalize or believe the salience of its message; (4) confirm one's interpretation with others; and (5) act or respond to its message. to save one's life and property. This paper applies the risk communication framework and its principles to a case study where probabilities were increased in 1990 of future earthquakes in the San Francisco Bay area. Following the scientific community's announcement, a low-key warning was issued to approximately two million residents through a large-scale information campaign. This study demonstrates that the risk communication model is an invaluable fool for helping us to understand the behavior of individuals who must learn of and act upon warning information that could save their lives and property. Further, researchers are urged to find ways to adapt this risk communication model to other types of natural and human-made hazards.