The weight above makes deeper layers of ice thin and flow outwards.
Radioactive elements, either of natural origin or created by nuclear testing, can be used to date the layers of ice.
The Philippines, being a country archipelago of islands and seas, have naturally wonderful beaches, some of which are famous the world over.
Beaches like Puerto Galera, Boracay, and the various beaches in Cebu rake in tourists from around the world all year round because of their pristine and cool blue waters and fine, white-sand shores.
Impurities in the ice provide information on the environment from when they were deposited.
These include soot, ash, and other types of particle from forest fires and volcanoes; isotopes such as beryllium-10 created by cosmic rays; micrometeorites; and pollen.
Some volcanic events that were sufficiently powerful to send material around the globe have left a signature in many different cores that can be used to synchronise their time scales.