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The natural environment of Virginia encompasses the physical geography and biology of the U.S. state of Virginia. Virginia has a total area of , including of water, making it the 35th-largest state by area. Forests cover 65% of the state, wetlands and water cover 6% of the land in the state, while 5% of the state is a mixture of commercial, residential, and transitional. Virginia is bordered by Maryland and Washington, D.C. to the north and east; by the Atlantic Ocean to the east; by North Carolina and Tennessee to the south; by Kentucky to the west; and by West Virginia to the north and west. Due to a peculiarity of Virginia 's original charter, its boundary with Maryland and Washington, D.C. does not extend past the low-water mark of the south shore of the Potomac River (unlike many boundaries that split a river down the middle). The southern border is defined as the 36° 30′ parallel north, though surveyor error led to deviations of as much as three arcminutes. The state agencies whose primary focii are on the natural environment of Virginia are the Department of Conservation and Recreation (DCR), and the Department of Environmental Quality (DEQ). ==Physiogeographic regions and geology== Geologically, Virginia is divided into five regions, while the EPA lists seven ecoregions with further precision. From east to west, the regions are as follows: *The Tidewater is a coastal plain between the Atlantic coast and the fall line. It includes the Eastern Shore and major estuaries which enter the Chesapeake Bay. This region corresponds to the EPA's Middle Atlantic Coastal Plain (#63) and Southeastern Plains (#65) regions. : The Chesapeake Bay separates the contiguous portion of the Commonwealth from the two-county peninsula of Virginia's Eastern Shore. The bay was formed following a meteoroid impact crater during the Eocene. Many of Virginia's rivers flow into the Chesapeake Bay, including the Potomac, Rappahannock, James, and York, which create three peninsulas in the bay. *The Piedmont is a series of sedimentary and igneous rock-based foothills east of the mountains which were formed in the Mesozoic. The region, known for its heavy clay soil, includes the Southwest Mountains. This region corresponds to the EPA's Piedmont (#45) and Northern Piedmont (#64) regions. *The Blue Ridge Mountains are a physiographic province of the chain of Appalachian Mountains with the highest points in the state, the tallest being Mount Rogers at . This corresponds to the EPA's Blue Ridge (#66) region. *The Ridge and Valley region is west of the mountains, and includes the Great Appalachian Valley, which includes the Shenandoah Valley. This region corresponds to the EPA's Ridge and Valley (#67) region. The region is carbonate rock based (primarily limestone), and includes Massanutten Mountain. Because of the areas of carbonate rock and resulting karst formations, more than 4,000 caves exist in Virginia, with ten open for tourism. Likewise, another feature that resulted from limestone erosion in the valley region is the Natural Bridge. *The Cumberland Plateau (also called the Appalachian Plateau) and the Cumberland Mountains are in the south-west corner of Virginia, below the Allegheny Plateau. In this region rivers flow northwest, with a dendritic drainage system, into the Ohio River basin. This region corresponds to the EPA's Central Appalachians (#69) region. Coal mining takes place in the three mountainous regions at 40 distinct coal beds near Mesozoic basins. Besides coal, resources such as slate, kyanite, sand, and gravel are mined, with an annual value over $2 billion . Virginia has a low risk on earthquakes, especially in the northern part of the state. The Virginia seismic zone has not had a history of regular earthquake activity. Earthquakes are rarely above 4.5 in magnitude because Virginia is located centrally on the North American Plate, far from plate boundaries. Locations near tectonic plates suffer earthquakes frequently. The largest recorded earthquake, at an estimated 5.9 magnitude, was in 1897 near Blacksburg. The largest since then was in August 2011, when a 5.8 magnitude quake struck near Mineral, Virginia and was felt moderately to strongly throughout the state. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Environment of Virginia」の詳細全文を読む スポンサード リンク
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