The earth in macro historical geology homework 1 the earth's crust, lower lithosphere, and asthenosphere are thin in comparison to deeper zones of the earth (mesosphere, outer core and inner core). textbooks commonly exaggerate the outer zone thicknesses, for clarity on page-sized illustrations. using a millimeter ruler and compass with a very fine pencil, draw the whole earth cross section at a scale of 1: 100,000,000 (1cm 1000 km). illustrate the following boundaries exactly to scale, using solid lines to indicate changes in chemistry and dashed lines to indicate changes in mechanical properties, at the depths indicated o. ol 1000 a. oceanic moho at 12 km; b. continental moho at 35 km; c. transition from lithosphere to asthenosphere at 150 km d. bottom of very soft asthenosphere at 350 km e. top of hard mesosphere at 700 km f. top of core mantle boundary at 2900 km 8. h. outer core/ inner core boundary at 5100 km center of earth at 6300 km 160 sm 2.900 km outer 5.155 km 6,371 km