This dissertation theorizes how natural hazards interact with historically-situated institutional and cultural context in shaping the political significance of events. Employing interpretive and comparative methods, I analyze historical media and government records to study seismically-triggered viaduct collapses in the 1989 Loma Prieta Earthquake (U.S.) and the 1995 Great Hanshin Earthquake (Japan). Part One of the dissertation examines the causes of these collapses: in contrast to existing scholarship on technical disaster, I find that these disasters cannot be ascribed to organizationally-embedded cognitive error or positive asymmetry. Rather, the disasters were conditioned by macro-level political economic factors which constrained organizational decision-making—a finding that leads me to develop the concept of the political accident. Part Two examines the political consequences of these collapses, with anti-viaduct campaigns forming in Oakland and San Francisco and successfully removing these unpopular structures from their host communities. By contrast, a similar campaign did not mobilize after a major viaduct collapse in Japan. I theorize that materiality primarily explains this stark difference in outcomes: while material conditions (i.e., the interaction of geological forces with the built environment) enabled successful anti-viaduct campaigns in the U.S., these same conditions constrained contentious political action in Japan due to their physical extremity.This research has implications for our theoretical understanding of the event as a phenomenon, which is implicitly important yet undertheorized in contemporary cultural research. Theorists to date have focused on how agentic social actors orchestrate and react to events, and craft, interpret, and contest associated meanings, but have yet adequately to consider how non-agentic materiality shapes events. My research contributes to this ongoing dialogue—not only by underscoring the social role of materiality in post-disaster contexts, but by identifying specific cultural and political processes and conditions through which non-agentic material impacts event outcomes.