A good aquifer is one that carries a large amount of water and recharges quickly. Some aquifers are even under pressure so that little if any work is required to bring water to the surface. An aquifer is any body of groundwater into which a well can be dug.Know More
Aquifers are buried porous rocks or masses of unconsolidated material, such as gravel, sand or silt, that are saturated with water. When one digs into such a rock or mass of material, water seeps into the hole, forming a well. When the layer of water-bearing material has porous materials above or beneath it, it's not under much pressure, and energy must be used to obtain the water. In artesian wells, however, the layer of water-bearing material is sandwiched between non-permeable materials, such as granite or clay. In these cases, the water is under pressure.
Aquifers have limited supplies of water and rely on precipitation to be refilled. Different aquifers refill at different rates depending on the amount of precipitation and the nature of the overlying materials. Human overuse of aquifers can deplete them or, in the case of coastal aquifers, cause saltwater to seep in, rendering them unusable for drinking or agriculture.Learn more about Layers of the Earth
An unconfined aquifer is a source of underground water that seeps through a permeable layer of dirt or sand directly to the ground surface above. Since the pressure of such aquifers is equal to or less than atmospheric pressure, drilling may not result in increased water levels in the area.Full Answer >
Containing everything from the ocean basins to continents, the crust is the outermost layer of the Earth. Overall, the crust makes up very little of the Earth's mass, so the other layers, which are the mantle, outer core and inner core, are much thicker.Full Answer >
The asthenosphere is a layer of the Earth's interior that includes part of the lower crust and part of the mantle. The upper boundary of the asthenosphere is roughly 50 miles below the ground's surface. Its lower boundary, however, is inconsistent and depends primarily on temperature. Experts at the United States Geological Survey estimate its average thickness as 112 miles.Full Answer >
Earth's core has two parts, a solid iron inner core and a molten outer core, which is composed of a nickel-iron alloy. The outer core begins about 1,800 miles under the crust.Full Answer >