Core–mantle boundary Core–mantle boundary The core–mantle boundary (CMB in the parlance of solid earth geophysicists) of the Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core. This boundary is located at approximately 2891 km (1796 mi) depth beneath the Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle and the molten outer core. P-wave velocities are much slower in the outer core than in the deep mantle while S-waves do not exist at all in the liquid portion of
What We Do Is Secret (film) Story". Additional songs used in the film that do not appear on the soundtrack album include: What We Do Is Secret (film) What We Do Is Secret is a 2007 American biographical film about Darby Crash, singer of the late-1970s Los Angeles punk rock band the Germs. Rodger Grossman directed the film and wrote the screenplay, based on a story he had written with Michelle Baer Ghaffari, a friend of Crash's and co-producer of the film. Shane West stars as Crash, while Rick Gonzalez, Bijou Phillips, and Noah Segan respectively portray Germs members Pat Smear, Lorna Doom, and Don Bolles.