An isotope is one of two or more species of atoms of a chemical element with the same atomic number (same number or protons in the nucleus) and position in the periodic table and nearly identical chemical behavior but with different atomic masses and physical properties. Every chemical element has one or more isotopes.
A landslide is the movement of rock, debris or earth down a slope. They result from the failure of the materials which make up the hill slope and are driven by the force of gravity. Landslides are known also as landslips, slumps or slope failure.
Landslides occur when gravity overcomes the force of friction. Several common causes of landslides are: 1  Water: Perhaps the most common trigger of a landslide, water reduces the friction between the bedrock and the overlying sediment, and gravity sends the debris sliding downhill. 2  In sand and clay soils, a small amount of water may increase stability.