Geography Glossary - H
heartland theory
Sir Halford John Mackinder's theory that Russia is the strategic center of the earth
hemisphere
Half of the earth's surface. There are four hemispheres, Northern and Southern (divided by the equator) and the Eastern and Western (divided by the Prime Meridian and 180¡ã)
humidity
The amount of water vapor in the air
hurricane
A tropical story that contains winds of at least 74 miles per hour (119km/h). Also known as a cyclone in the northern Indian Ocean and a typhoon in the western Pacific Ocean.
hydrologic cycle
The circulation of water between the atmosphere, streams and land, the ocean, and back to the atmosphere.
hydrosphere
The water of the earth
hypocenter
The point under the earth's surface where the energy of an earthquake is first released. The point directly above the hypocenter on the earth's surface is the epicenter