Slow Movement of Earth under Tropical Rain Forest Conditions

Measurements of soil creep in El Yunque National Forest, Puerto Rico, indicate that the average rates of soil movement are greater than rates in other forested areas and generally are greater than in other locales. Also, the velocity distribution indicates two zones of maximum movement. This phenomenon is not explained by normal creep behavior. For the wet tropics, theory must include the roles of throughflow and the distribution, of plant roots, as well as the interaction between gravity and the individual expansion and contraction of soil particles.