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Weathering and Erosion By: Issa Lachica and Kenzie Edens Weathering Weathering is the breaking down of rocks, soils and minerals. There are two important classification of weathering process. Physical and Chemical weathering. Physical weathering involves breakdown of rocks and soils. Chemical weathering involves the direct effect of atmospheric or biological chemicals in the breaking down of rocks,soils and minerals. Erosion Erosion is the process by which soil and rock are removed from the Earth’s surface by natural processes like wind or water flow, and then transported and deposited in other locations. Pictures of different types of weathering This is a picture of cavernous weathering. This is a picture of mechanical weathering. Pictures of weathering and Erosion This is a picture of what weathering looks like. This is what erosion looks like. Causes of weathering and Erosion The Sun’s heat causes surface rocks to expand and fracture, and moisture can evaporate. Rain dissolves atmospheric gases to form acids that add with minerals in surface layers. Water can also freeze at night or in winter, expanding cracks and carrying away smaller rocks and dust. Wind and water also carry small particles that can impact and erode rocks and carry away loose soil. Factors controlling the rate of erosion Soil erosion is a very complicated problem to solve, because there are so many factors include: soil type, rainfall, crops, landscape and farm management. There is an equation to predict the soil loss from fields using this five factors. USGS~ Difference Between Erosion and Weathering Weathering involves two processes that always work in concert to decompose rocks. Both processes occur in place. No movement is involved in weathering. Chemical weathering is a chemical change in at least some of the minerals within a rock. Mechanical weathering is physically breaking rocks into fragments without changing the chemical make up of the minerals within it. As soon as a rock particle moves, we call it erosion or mass wasting. We call it Erosion if the rock particle is moved by some flowing agent such as air, water, or ice. If you cut it short, a particle is loosened, chemically or mechanically, but stays put we call it weathering once the particle moving we call it erosion. Soil Erosion Soil is naturally removed by the action of water or wind. Erosion removes at roughly the same rate soil is formed. During times of erosive rainfall, windstorms, soil may be detached, transported, or deposited. Study of the historic Hopi Buttes Area • Hopi buttes is a volcanic field located in northeastern Arizona. The Volcanic field consists of about 300 maars and diatremes in an area if 965 square miles. • The maars are volcanic cones that form from volcanic explosions near the surface. The diatremes are subsurface pipes that fed maars and were filled by volcanic material at the time of an eruption. Erosion in the Southwest Erosion is carving into the southwest Washington beaches. Erosion rates at Cape shoal water have averaged over 100 feet per year for a century .New erosion hotspots have developed in the past few decades. One erosion hot spot is located at ocean shores, north of the Grays Harbor North Jetty. Coastal erosion prevention One of the most visual reminders of any major hurricane, flood, or storm event causes different changes in the shape of beaches. A visitor o the shore will see that the coastline has retreatedsometimes literally overnightand large amounts of sand disappeared. As shoreline is lost the risk of damage to coastal property increases. First we need to understand and prepare. For us to understand we need to focus on the shores structure. The most recognized shore component, the beach, is a dynamic system and changes all the time. Sand comes and goes, and sand moves. The concern for uncontrolled erosion and economic dynamics of the coast is the sand dune. Wind Erosion Prevention Wind erosion happens when the soil is left unprotected from the strong winds. The loss of top soil lowers the quality of the soil. This makes crops more expensive because it’s harder to grow good crops. Country and city people should both be concerned with wind erosion. Beach Erosion prevention study According to Stephen Leatherman of the national healthy beaches campaign, beach erosion is defined by the actual removal of sand from a beach to deeper water off shore or along shore into inlets, tidal shoals bays. Such erosion can result from any number of factors, including the simple inundation of the land by rising sand levels resulting from melting of the polar ice caps. Geologic Hazards: Landslides Landslides commonly occur in connection with other major natural disasters such as floods, wildfires, earthquakes, and volcanoes. Landslides constitute a major geological hazard because they are wide spread. Landslides are very dangerous and can cause death. Federal Emergency Management Agency (FEMA) landslides and mudflows Landslides occur all over the world caused by a variety of factors including earthquakes, storms, volcanic eruptions, fire and by human modification of land. Landslides can occur quickly often with little notice and the best way to prepare is to stay informed about changes in and around your home that would signal that a landslide is likely to occur. Landslide problems can be caused by land mismanagement particularly in mountains, canyons, and coastal regions. Land-use zoning, professional inspections and proper design can minimize many landslides, mudflow, and debris flow problems The Solution to solve Erosion and Weathering These is some of the ways people try to prevent erosion. Some farmers put ditches around the field to catch the eroded soil. Soil erosions are caused when deforestation is plowed. The roots of trees holds the soil firmly underground to prevent soil erosion. But when people start to chop down trees erosion will follow up. People can prevent erosion by taking proper care of the soil. • These are some of the ways people try to prevent weathering. To prevent weathering problems we need to practice conservation along with agriculture. Using farming methods such as no-till crop rotation, and planting or conserving tree cover near crop lands we can reduce the effect of wind and rain erosion. Bibliography http://www.educatoral.com/weathering_erosion_webques.html www.spindigo.com/doctorluke/.../2_10_soil_erosion_factors.htm http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/c oliseum_maar.html http://www.scientificamerican.com/article.cfm?id=what-causesbeach-erosion http://www.ready.gov/landslides-debris-flows Thanks for watching our presentation!