xShadow zone : The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves. The shadow zone results from S waves being stopped entirely by the liquid core and P waves being b
The Gulf of Mexico: what role will the Mississippi River play in oil washing ashore and into delta wetlands? One of the spill's greatest environmental threats is to Louisiana's wetlands, scientists believe....Read more