Caves are found around the island, offering spelunkers a glimpse of delicate underground formations.

What geologists call 3D-seismic technology bounces sound waves off underground formations, then uses computers to create three-dimensional pictures.

Spring water must be derived from an underground formation from which water flows naturally to the Earth's surface.

Aquifer - An underground geological formation or group of formations, containing water.

Nuclear logging was initially developed to measure the natural gamma radiation emitted by underground formations.

To minimize pollution, salt water produced by drilling rigs would be pumped back into the underground formations.

They began pumping water into the underground formations in order to force the oil to the surface.

Most underground formations contain water, often salt water, in their pores.

To generate the data, ships bounce sound signals off underground formations.

The CO is then re-injected into an underground formation.