Karen M. Fischer is a seismologist who studies the structure and dynamics of Earth's interior. Her work focuses on understanding the lithosphere and asthenosphere, how these layers are created, deform and evolve over time, and their roles in plate tectonics and mantle convection. She and her group analyze and model large datasets of seismic waveforms to measure the structure of the crust and mantle, illuminating present-day and ancient plate boundaries, mantle flow and melting processes.