Earthquake data provided courtesy University of Utah. Yellowstone is one of the most seismically active areas in the United States. Approximately 1,000 to 3,000 earthquakes occur each year in the Yellowstone area; most are not felt. They result from the enormous number of faults associated with the volcano.
What are the effects of environmental pressure on natural selection? A: Environmental pressure is another term for natural selection, a process that encourages some genes to survive because they are conducive to the environment while others die. This process slowly causes a distinct species to evolve over time. Continue Reading.
The vertical pressure gradient always indicates a decrease in pressure with altitude, but the rate of pressure decrease (gradient) varies directly with changes in air density with altitude. Below 10,000 feet altitude, pressure decreases approximately 1 inch of mercury per 1,000 feet in the standard atmosphere.herefore, a pressure gradient exists in the horizontal (along the surface) as well as the vertical plane (with altitude) in the atmosphere. HORIZONTAL PRESSURE GRADIENT. The horizontal pressure gradient is steep or strong when the isobars determining the pressure system (fig.