Monica Kohler is a research faculty member in the Department of Mechanical and Civil Engineering at the California Institute of Technology. Her research in earthquake engineering and seismology takes advantage of recent rapid technological advances in sensor development to develop new observational techniques for detecting deformation and failure, from inside high-rise buildings to hundreds of kilometers below Earth’s surface. Her research group is driven by a vision of a future in which community-enabled sensing will make it possible to conduct robust, real-time monitoring of vibrations of the coupled ground motion-civil structure system over a city-wide region in order to detect damage and failure events. The overarching goal is to model the 3D structure and dynamic behavior of these systems through analysis of vibration data recorded by dense networks deployed in them. Techniques include tomographic inverse methods and forward dynamic computations applied to observed and simulated datasets comprising earthquake, ambient vibration, pressure wave, and tsunami waveforms. These studies provide frequent reminders of how dense sensor deployments enable the detection and measurement of new, often unanticipated, structural and dynamic behavior.