Seismic velocity discontinuities beneath the Sierra Nevada, imaged by EarthScope instruments, reveal regions of detaching lower crust beneath the mountain range, demonstrating the complexity of continental lithosphere evolution. (Image updated from original published in H. Gilbert, C. Jones, T. Owens, and G. Zandt, 2007. Imaging Sierra Nevada lithospheric sinking, Eos Transactions, American Geophysical Union, 88(21):225, 229.)