Physical Geology 101 26 Erosion and Mass Wasting p 402 418 Erosion Where are two U S examples of where shoreline wave erosion is a major concern 1 2 Where is shoreline erosion also a problem at a large lake Weathering involves the breakdown of rock to form loose particles called regolith Any process that involves the movement of this regolith from one location to another and the abrasion of rocks hit by the regolith as it gets transported is termed erosion What 3 natural elements cause erosion 1 2 3 What are the two characteristics of a flowing medium that play an important role in how effectively material gets transported 1 and 2 The resultant types of fluid motion are called and Describe laminar flow Is the flow speed high or low Describe turbulent flow Is the flow speed high or low Is turbulent flow more common in fluids with low or high viscosity So which is more turbulent water flow or wind gusts When pieces of regolith get lifted up off the ground and then bounce it along in small hops and jumps we call this process Mass Wasting What fourth effect may cause a type of erosion called mass wasting What happens during mass wasting 1 Physical Geology 101 The common term used to describe mass wasting is What main factors influence the motion of regolith down a slope 1 2 3 4 5 The susceptibility of loose material to move down a slope is affected by the way the grains of the material are packed together as well as the stickiness of the grains which is called either the or the This stickiness of the grains determines a type of material strength called the What is the definition of this type of strength The steepest angle that a slope can maintain without material tumbling down is called the What is the range for this angle in most types of regolith The steepness of piles of that collect at the bottom of a steep slope is controlled by the angle of repose of the material Upsetting the angle of repose What activity by humans can induce landslide activity Removal of vegetation may induce landslides because roots bind regolith particles together keeping them stable Vegetation can be removed by humans or naturally by How does the addition of water destabilize sediment on a hill This is why landslides are common after What other natural phenomena can induce landslide activity causes collapse of river embankments e g Yungay Peru 1970 25 000 deaths Types of Mass Wasting The three criteria used for classifying the different types of landslides are 2 Physical Geology 101 1 rapid or slow 2 falling sliding or flowing 3 rock soil or debris We can define two categories of mass wasting landslides falling sliding or slumping of otherwise coherent bodies of rock due to sudden failure on a steep slope or cliff fluid like downslope movement of loose regolith What are the different types of mass wasting in each category SLIDES AND FALLS SEDIMENT FLOWS Slides and Falls What is a fall Example of where this is a problem What is a slide What is a slump Example of where slumping is common Sediment Flows A sediment flow that is water saturated is called a A sediment flow that is air saturated is called a Water saturated flows can occur very slowly in areas that typically receive lots of rainfall and may form bulging lobes of migrating regolith on slopes This process is called What is the difference in the sediment size between a mudflow and a debris flow Mudflow 3 Physical Geology 101 Debris flow How fast can a mudflow flow Examples of locations rapidly overwhelmed by mudflows 1 in 1985 lahar induced by a volcanic eruption 2 in 2006 caused by heavy rainfall When a thin layer of water saturated surface material e g soil flows down a slope over a period of days months or years stabilized by a covering of grass the flow is called an A dangerous variety of granular flow in which blocks of regolith race down a slope at speeds of 100s of mph is called a e g Peru 1970 triggered by an earthquake 25 000 deaths in the city of Yungay A slow type of granular flow can cause the imperceptible down slope motion of an entire hillside Objects on the surface eventually lean over e g telephone poles lampposts fences trees FINAL QUESTION What is this slow slope motion called 4