Figure 2.04. Incorporated Research Institutions for Seismology (IRIS) Seismic Shadow Zone diagram. Seismic s-waves do not propagate through liquids. This diagram shows seismic s-waves paths (black curved lined) from an earthquake epicenter at the top of the diagram based on where they are observed by seimometers. S-wave data demonstrate that the earth has a solid mantle and a liquid outer core. Click on the image for more s-wave information on the IRIS website.