T2-2023

GEOL 3010: Environmental Geology Name: Kevin Hoffman Fall 2023 TEST 2 Multiple Choice. (2 points each) 1. What is the main cause of soil degradation in the United States? a. overgrazing b. agriculture c. industrialization d. wind e. deforestation 2. On average , how many years does it take to form 1 millimeter of soil? a. 5-10 years b. 10-100 years c. 100-200 years d. 200-400 years e. > 400 years 3. __________ is a soil resource that is rich in Aluminum (Al): a. aridosols b. bauxite c. peat d. topsoil e. caliche 4. Which involves changes in evapotranspiration, runoff, and sediment yield similar to those produced when forested lands are clear-cut for timber? a. conversion of forest to agricultural fields b. conversion of agricultural fields to urbanized areas 5. Which soil particles play an important part in binding and storing minerals and soil nutrients? a. sand b. hummus c. silt d. clay f. caliche 6. Which soil particles are being preferentially lost from fields during wind erosion? a. sand b. hummus c. silt d. clay f. caliche 7. Which factor(s) below are not influential in soil formation? a. time b. climate c. your birthday d. slope e. plants 8. What mechanical weathering process involves the breaking loose of concentric slabs of rocks as erosion removes the overlying material? a. frost wedging b. exfoliation c. thermal expansion d. root wedging 9. Which is NOT an important aspect of the classification of mass downslope movements of geologic materials? a. The nature of materials moving b. The mechanism that triggered movement c. The velocity of motion d. The type of motion 10. _________ refers to the downhill movement of weakly to moderately cohesive surface soils are accompanied by internal deformation of the moving material. a. flowage b. subsidence c. sliding d. falling e. creeping 11. __________ refers to a relatively intact block/slab of bedrock or very cohesive soil moves down slope along a fracture, bedding plane, or other well-defined slip surface. a. flowage b. subsidence c. sliding d. falling e. creeping 12. __________ refers to a detached bedrock blocks freely drop, bounce, and roll downhill; blocks accumulate as a debris slope at the base of a steep bedrock slope or cliff. a. flowage b. subsidence c. sliding d. falling e. creeping 13. Which two statements concerning the 1995 LaConchita, CA slide are reasonably correct and consistent with our knowledge of this landslide? a. This was a large, complex landslide; rotational block slumps in the upper part graded into earth flows at the toe or down slope portion of the slide. b. Local oversteepening was caused by stream erosion of the concave lower portion of the slope. Clear-cutting of old-growth forest reduced the resisting forces on the slope and increased the driving forces. c. The slide broke away from the crest of an old sea cliff that had been free of slope failures for the past 40,000 years. d. Water infiltrating from heavy rains and irrigation lowered the shear strength of portions of the slope-forming material. 14. Active faults are those that have moved: a. within the past 10 million years b. within the past 1 million years c. within the past 100,000 years d. within the past 10,00 years 15. At which plate boundary type do shallow, moderate, and deep foci earthquakes occur? a. convergent only b. convergent & divergent c. convergent & transform d. divergent & transform 16. What foundation material produces the most amplification of ground shaking during an earthquake? a. unfractured igneous rock b. well-cemented sandstone c. water-saturated sand, slit, and clay d. well-compacted, dry soil and colluvium

17. Which manmade coastal structures are designed to keep tidal inlets from shifting location or filling with sand? a. groins b. jetties c. breakwaters d. seawalls 18. Which two statements concerning tsunamis are true? a. They travel as deep water waves at speeds greater than surface, seismic waves but slower than S waves. b. Wave heights increase and wavelengths decrease as they enter shallower water. c. They are started by fault-induced, horizontal shifts in flat area of the seafloor; the fault movements suddenly propel great masses of water in opposite directions. d. In the open ocean, wavelengths are many kilometers; wave heights are a few feet. 19. Each integer on the logarithmic Richter scale represents a __________ increase in amplitude, and a __________ increase in energy released. a. linear, exponential b. ten-fold, thirty-fold c. one hundred-fold, thousand-fold c. small, large 20. How does shaking ground cause soft sediment to liquefy? a. It breaks the sediment particles into smaller pieces. b. It evaporates water in the pores of the sediment. c. It melts the sediment. d. It causes sand grains to lose contact with one another and be temporarily suspended. 21. The diagram below shows a simple, deep-water wave. Directly on the diagram, show and label the following characteristic dimensions and features of the wave. (10 points) a. crest b. trough c. wavelength d. wave height e. wave base Short and Long Answers. 22. How are water and seismic waves similar? How are they different? (6 points) Water and seismic waves share some similarities, but they also have distinct differences. Both types of waves are forms of energy that propagate through a medium. They both exhibit wave-like behavior, such as reflection, refraction, and diffraction. Additionally, both water and seismic waves can cause disturbances and transmit energy over long distances. However, there are notable differences between water and seismic waves. Water waves are mechanical waves that travel through water, whereas seismic waves are elastic waves that travel through the Earth's crust. Water waves are created by wind, tides, or the movement of objects on the water's surface, while seismic waves are generated by earthquakes, volcanic activity, or human activities like explosions. In terms of motion, water waves move in a circular or elliptical motion, with the water particles oscillating perpendicular to the direction of wave propagation. On the other hand, seismic waves can

O= organic material/ humus A= rich in organic material/ topsoil B= accumulation zone/subsoil C= Weathered sediment with little organic material/ parent rock R= parent sediment that hasn’t been weathered / bedrock 26. Can an earthquake rank low on the Mercalli intensity scale but high on the Richter magnitude scale ? Explain. (5 points) An earthquake can rank low on the Mercalli intensity scale but high on the Richter magnitude scale. The Richter scale measures the energy released by by an earthquake at its source and it’s a single value that doesn’t depend on where the measurement was made. The Mercalli intensity scale measures the intensity of the earthquake by observing its effect on people, the environment, and the earth’s surface. So, if an earthquake occurs in a remote or uninhabited area, it could have a high Richter magnitude due to the large amount of energy released, but a low Mercalli intensity because there are few or no observed effects. 27. What are the pros and cons of beach nourishment versus seawall construction in combatting coastal erosion? (5 points) The pros and cons of beach nourishment versus seawall construction in combatting coastal erosion are that the beach nourishment pros are that it protects the structure, widens the beach, creates a safer environment, and protects the ecosystem. The cons of beach nourishment are that it is a temporary solution that will not permanently reduce the risk of erosion. It also depends on the location and the amount of submerged sand that that available. The pros and cons of the seawall, one of the pros is that it’s a long-term solution because the seawall offers a long-term solution to shoreline erosion. The con of the seawall is it has a high maintenance cost due to the abuse that the seawall takes over the years people have to go out and check if the wall is stable and has no wear and tear on it. Both methods have their advantages and disadvantages, and the choice between them often depends on the specific circumstances.

28. What is terracing and how does it help to mitigate soil erosion and mass wasting? (5 points) Terracing is an erosion Best Management Practice (BMP) that involves constructing ridges and channels across a slope. Terracing helps to mitigate soil erosion and mass wasting by reducing runoff velocity, preventing soil erosion, and supporting vegetation growth. Terracing can create conditions that are conducive to the growth of vegetation. Plants and trees stabilize the soil and protect it from erosion. Terracing also reduces the speed at which water moves down a slope and its constructed ridges and channels help to prevent soil from being eroded by the forces of water . Source: https://www.deseret.com/utah/2023/5/18/23728577/record-snow-pack-wet-soils-landslides-utah-geological-survey 29. The picture above shows a mass wasting event that occurred in a Morgan, UT, in April 2023. What class of mass wasting is this? What led you to this classification? What factors do you think triggered the event? What could be done to mitigate the impact of mass wasting at this site? (10 points) EXTRA CREDIT. (up to 10 points) (1) What is the term used to describe a rapid outburst of water from a melting glacier? You must spell it correctly! (2.5 points) The term used to describe a rapid outburst of water from a melting glacier is called a jökulhlaup. (2) What is the role of pore fluid pressure in human induced seismic events? (5 points) Pore fluid pressure plays a significant role in human induced seismic events. When fluid, such as water or oil, is injected into the subsurface, it can increase the pore fluid pressure in the rocks. This