Valley

A valley is a low area between two mountains or hills that typically has a stream or river running through it.  It is usually V-shaped, with steep sides and a flat bottom. Valleys are formed by erosion from flowing water or by movements of the earth’s crust.  They can be long or short and can vary in size and depth. Valleys are important in terms of geology, ecology, and human settlement.

Valley Glacier

A valley glacier is a long, narrow glacier that forms in a valley or a mountainous area.  It is formed by the accumulation of snow and ice that moves slowly down the valley due to gravity.  Valley glaciers erode the landscape, creating U-shaped valleys and leaving behind moraines and other glacial features.  They can have a significant impact on the environment, as they can alter the course of rivers and affect the distribution of water resources.

Vaporization

Vaporization is the process of converting a liquid or solid substance into a gas or vapor.  This can happen through heating or evaporation.  The most common example of vaporization is water turning into steam.  Vaporization can occur at any temperature, but it is more rapid at higher temperatures.  It is an important process in the water cycle, as it allows water to be transported from the surface to the atmosphere.

Variable Scale Map

A variable scale map is a map that uses different scales in different parts of the map.  This is done to provide a more accurate representation of the features in the map.  For example, a variable scale map of a mountainous area might have a larger scale in the mountains and a smaller scale in the surrounding areas.  This allows the map to show more detail in the mountainous areas while still providing an overview of the surrounding terrain. Variable scale maps are used in a variety of fields, including geography, geology, and cartography.

Variogram

A variogram is a tool used in geostatistics to study the spatial structure of a variable.  It is a mathematical function that describes the correlation between pairs of points in a spatial dataset.  The variogram is used to analyze the degree of similarity between points at different distances and to estimate the range of spatial dependence of the variable being studied.  The variogram is an important tool in many fields, including hydrology, geology, and ecology.

Vector Data

Vector data is a type of geospatial data that represents geographic features using points, lines, and polygons.  It is a format that uses mathematical equations to describe the location and shape of features on the Earth’s surface.  Vector data is used to represent physical features such as rivers, roads, and buildings, as well as abstract features such as political boundaries and demographic data.  Vector data is used in many fields, including cartography, urban planning, and environmental science.

Vegetation

Vegetation refers to the plant life that exists in a particular area . It can include trees, shrubs, grasses, and other plants. Vegetation is an important component of many ecosystems, providing food and shelter for animals, contributing to the water cycle, and playing a role in carbon storage and climate regulation.  Vegetation is also important for human communities, providing food, medicine, and other resources.

Velocity

Velocity is a measure of the speed and direction of an object.  In physical geography, velocity is used to describe the movement of fluids such as water and air. For example, the velocity of a river can be used to estimate the rate at which sediment is transported downstream.  Velocity is also an important component of many climate models, as it affects the movement of air masses and the distribution of heat and moisture around the Earth.  Velocity is typically measured in meters per second or kilometers per hour.

Vent

A vent is an opening in the Earth’s surface that allows gases, ash, and other materials to escape from a volcano.  Vents can be found on the summit or on the flanks of a volcano and can vary in size and shape.  Some vents are active and constantly emit gases and ash, while others are dormant or inactive. Vents are an important feature of volcanic systems and are used by scientists to monitor and predict volcanic activity.

Vernal Equinox

The vernal equinox is one of two points in the Earth’s orbit where the tilt of the Earth’s axis is perpendicular to the plane of its orbit around the sun.  It occurs in March in the Northern Hemisphere and September in the Southern Hemisphere.  At the vernal equinox, day and night are approximately equal in length, and the sun rises due east and sets due west.  The vernal equinox marks the beginning of spring in the Northern Hemisphere and autumn in the Southern Hemisphere.

Vertical Exaggeration

Vertical exaggeration is a technique used in cartography to increase the vertical scale of a map.  It is used to emphasize the elevation differences in a particular area, such as a mountain range or a valley.  Vertical exaggeration is achieved by increasing the vertical scale of a map while maintaining the horizontal scale.  This can be done by increasing the vertical scale of the contour lines or by using shading or color to highlight the relief of the terrain.

Vertical Interval

A vertical interval is the difference in elevation between two contour lines on a topographic map.  It represents the change in elevation over a particular distance and is used to calculate the slope of the terrain.  The vertical interval is typically listed on the map legend and varies depending on the scale of the map.  A smaller vertical interval indicates a steeper slope, while a larger vertical interval indicates a gentler slope.  The vertical interval is an important component of topographic maps and is used to analyze and understand the terrain.

Vesicular Texture

Vesicular texture is a geological term used to describe a type of rock texture that contains vesicles, or small cavities, formed by gas bubbles during the solidification of molten lava.  These cavities can range in size from microscopic to several centimeters and are often filled with minerals such as quartz or calcite.  Vesicular texture is commonly found in volcanic rocks and is used by geologists to study the processes that occur during volcanic eruptions.

Vesuvius

Vesuvius is a stratovolcano located in southern Italy near the city of Naples.  It is one of the most famous and dangerous volcanoes in the world, having erupted many times throughout history, including the infamous eruption in 79 AD that destroyed the Roman cities of Pompeii and Herculaneum. Vesuvius is still active and closely monitored by scientists, who use a variety of techniques to study its behavior and predict potential eruptions.

Vibration

Vibration is a type of mechanical motion that occurs when an object moves back and forth or up and down around a fixed point.  In physical geography, vibration is often used to describe the movement of particles in a medium, such as air or water, in response to energy sources such as earthquakes or wind. Vibration can also occur in the solid Earth as a result of tectonic activity or human activities such as blasting or construction.

Vicinity Map

A vicinity map is a type of map that shows the location of a particular area in relation to its surrounding environment.  It is often used in conjunction with larger scale maps to provide context and help users understand the spatial relationships between different features.  Vicinity maps can also be used to show the location of a particular point of interest, such as a building or landmark, within a larger geographic area.  They are commonly used in urban planning, tourism, and transportation planning.

Viewshed

A viewshed is a term used in geography and landscape architecture to describe the area of land that is visible from a particular point.  It is typically used to assess the visual impact of development or other land use changes on the surrounding environment.  A viewshed analysis can be conducted using Geographic Information Systems (GIS) software, which allows users to create 3D models of the landscape and analyze the visibility of different features from a given viewpoint.  The results of a viewshed analysis can be used to inform land use planning and environmental management decisions.

Viscosity

Viscosity is a measure of a fluid’s resistance to flow.  It is determined by the internal friction between the molecules of the fluid and is dependent on factors such as temperature, pressure, and the chemical composition of the fluid.  In physical geography, viscosity is often used to describe the behavior of fluids such as magma or water.  Viscous fluids flow more slowly than less viscous fluids and can exhibit unique properties such as convection or turbulence.  The study of viscosity is an important component of physical geography and is used by scientists to understand a wide range of natural processes, from the movement of glaciers to the behavior of the Earth’s mantle.

Volatile

Volatile refers to substances that are easily transformed into gas or vapor at relatively low temperatures.  In physical geography, volatile substances are often associated with geothermal activity and volcanic eruptions.  Gases such as sulfur dioxide and carbon dioxide are examples of volatile substances that can be emitted during volcanic activity.

Volcanic Ash

Volcanic ash is a type of pyroclastic material that is ejected from a volcanic eruption.  It is made up of small, angular particles that can range in size from less than a millimeter to several centimeters.  Volcanic ash is composed of various minerals, including silica, which can make it hazardous to human health when inhaled.  It can also have a significant impact on the environment, including soil fertility and water quality.

Volcanic Rock

Volcanic rock is rock that has been formed through volcanic activity. It is typically formed from the solidification of magma or lava, and can take a variety of forms depending on the nature of the eruption.  Basalt and pumice are two common types of volcanic rock, but there are many other varieties as well.

Volcanism

Volcanism refers to the process of volcanic activity, including the eruption of magma and the formation of volcanic rock.  Volcanism is a key driver of physical geography, and has played a significant role in shaping the Earth’s surface and atmosphere over millions of years.  It can also have significant impacts on human populations, including the destruction of property and loss of life.  Understanding the nature and behavior of volcanism is an important component of physical geography, and is studied by scientists around the world.

Volcano

A volcano is a geological landform that forms when molten rock, ash, and gas escape from the Earth’s crust.  Volcanoes can take many forms, from small cones to massive calderas, and can be found on land or in the ocean.  Volcanic eruptions can have significant impacts on human populations, including the destruction of property and loss of life.

Volume

Volume refers to the amount of space occupied by an object or substance.  In physical geography, volume is often used to describe the size or amount of a particular feature or substance.  For example, the volume of water in a lake, the volume of air in the atmosphere, or the volume of sediment in a river.

Volumetric Strain

Volumetric strain refers to the change in volume of a substance or material in response to stress or deformation. In physical geography, volumetric strain can be used to understand the behavior of rocks and other geological materials.  When rocks are subjected to stress, they can deform or change shape, which can result in changes in their volume.  By measuring volumetric strain, scientists can gain insights into the behavior of rocks under different conditions, which can help to improve our understanding of geological processes such as earthquakes and mountain building.