Volcanic activity has shaped the land in many parts of the Southwestern U.S. When lava, ash, or other volcanic materials erupt r
epeatedly in the same area, A. all the materials flow away from the area. B. the elevation of the area usually increases. C. all the materials become metamorphic rocks. D. the elevation of the area usually decreases.
The Southwestern part of the U.S. is characterized by the presence of large mountains, canyons, plateaus, and some plain areas. These features are basically controlled by the continuous volcanic activity that is caused due to the sharing of a convergent boundary and transform boundary between the Pacific Plate and the North American Plate.
The eruption of volcano often releases a significant amount of harmful gases and other particles such as ashes, lava. Pyroclastic materials also erupt. These materials erupted for a long time in the geological past, which were solidified and formed a huge mass of rocks. Due to this continuous eruption and deposition of materials from the past, it gradually leads to an increase in the elevation of the nearby area. This is how volcanic activities configures the land areas.
