Sinkholes occur when an underground void collapses, bringing the layers of earth and rock above it down with the collapse. The surface above the sinkhole suddenly drops, plunging anything in the area into a deep hole in ... More »

Anxiety can cause the sensation of shaking or trembling, according to the American Psychiatric Association. This is especially true in the case of panic disorder, which is characterized by overwhelming physical and emoti... More »

The inside of a volcano has one or more vents through which gas and lava flow during eruptions. Below the vent is the magma, which is the molten rock that flows upward due to the divergence or convergence of tectonic pla... More »

Sinkholes form when water erodes the supporting bedrock away. They are more common in areas where carbonates, including dolomite and gypsum, formed as water evaporated to create bedrock. More »

Sinkholes are depressions or holes that form on the Earth's surface when the ground below erodes away. Sinkholes often indicate the presence of tunnels or caverns below the ground. More » Science Earth Science Erosion & Weathering

The Qattara Depression in Egypt is the largest sinkhole in the world, at approximately 80 kilometers long and 120 kilometers wide. It is a desert sinkhole, and it was created naturally over millennia by the strong winds ... More » Science Earth Science Erosion & Weathering

Cliffs collapse for a number of reasons, one of the most common being the effects of weathering, but there other factors as well, such as water crashing against the cliff face, what the cliff is made out of and the clima... More »