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 What We Do What We Do is the second studio album by jazz group The John Scofield Quartet. It was recorded in May 1992 and released the following year on the Blue Note label. Besides John Scofield on guitar, the quartet features saxophonist Joe Lovano, Bill Stewart on drums and Dennis Irwin on bass, replacing Marc Johnson. Irwin and Scofield (both born in 1951) had already recorded together in the mid-1980s with Bennie Wallace on a track for his album "Sweeping Through the City." Irwin would be the bassist on two more albums by Scofield, "Hand Jive" (1994) and "Groove