ENV346H1 Chapter : summary of the plate tectonics chapter
Document Summary
The structure of the inside of the earth remained mystery until very recently. The earth was simply too big to retrieve samples from its core to determine its composition. It was the study of earthquakes that finally revealed how the inside of earth is structured. It was determined that the earth is not of homogenous density and that as you approach the center the density increases; earth is density stratified. The structure was discovered due to the products of earthquakes; primary and. During an earthquake both types of waves are released. Primary or pressure waves (like those when spring is pulled and released) were found to travel faster as they went down and were refracted towards the surface revealing the density stratification of earth. Secondary or shear waves (like those of a shaken rope) were responsible for the discovery of the different states of matter within the earth.
