CE 70 Midterm Engineering Geology (Fall 2020) PDF

11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Midterm Due Oct 16, 2020 at 2am Points 101 Questions 45 Available Oct 15, 2020 at 2pm - Oct 16, 2020 at 2am about 12 hours Time Limit 80 Minutes Instructions Please remember tha...

11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Midterm Due Oct 16, 2020 at 2am Points 101 Questions 45 Available Oct 15, 2020 at 2pm - Oct 16, 2020 at 2am about 12 hours Time Limit 80 Minutes Instructions Please remember that once you start you cannot stop and return to the test. You have exactly 80 minutes to complete the test, unless you were granted and exception by the University. You can upload a picture of your hand written answer for some of the essay questions, but it should not be necessary. Each question has only one correct answer. In case of a problem with the site crashing or your internet crashing, e-mail us at your earliest opportunity. I will monitor my e-mail from 2 pm on, but will not hold office hours. This quiz was locked Oct 16, 2020 at 2am. Attempt History Attempt Time Score LATEST Attempt 1 80 minutes 95 out of 101 Score for this quiz: 95 out of 101 Submitted Oct 15, 2020 at 8:51pm This attempt took 80 minutes. Question 1 1 / 1 pts UC Berkeley Honor Code: As a member of the UC Berkeley community, I act with honesty, integrity, and respect for others. Expectations include: I alone am taking exams with the notes and references allowed and https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 1/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) my calculator. I will not use any external devices, such as phones, tablets, or computers, browse or use online sources of information during the entire period exams are available for students to take. I will not take photos, or otherwise make copies of exam questions to share with others. The consequences for academic dishonesty include: I understand that violating the honor code will result in a grade of “F” for the course. I understand that violating the honor code will result in my referral to the Student Conduct Office for further disciplinary action. Correct! I agree Question 2 2 / 2 pts Plate tectonics is helpful in explaining: the distribution of active volcanoes around the earth the movement of lithospheric plates Correct! all of the statements are correct the formation of oceanic trenches Question 3 2 / 2 pts Active volcanos are not common along https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 2/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Correct! transform plate boundaries any of these applies subduction zones hot spots Question 4 2 / 2 pts Convergent plate boundaries are characterized by large earthquakes Correct! large earthquakes and explosive volcanic activity large earthquakes and mafic volcanic activity felsic volcanic activity Question 5 2 / 2 pts Island arcs form as a result of oceanic volcanism Correct! oceanic subduction mid-ocean ridge volcanism transform offset of an mid-ocean ridge https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 3/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Question 6 2 / 2 pts Why are continental crust rocks lighter than oceanic crust rocks? they have a higher porosity Correct! they contain more Si and Al, K, & Na they contain less Si they do not contain Fe and Mg Question 7 2 / 2 pts The Bowen’s reaction series describes crystallization of granite composition of igneous rocks partial melting of silicate minerals Correct! sequence of crystallization of silicate minerals from magma Question 8 2 / 2 pts Cleavage of minerals, such as micas, is reflection of their streak https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 4/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Correct! crystal structure hardness stiffness Question 9 2 / 2 pts Scratching a glass plate is an easy way to identify fluorite gypsum Correct! quartz pyrite Question 10 2 / 2 pts A dark colored, coarse grained intrusive rock is probably a gabbro none of these are correct if it has less than 10% Quartz Correct! if it does not contain any quartz if it has more than 10% Quartz https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 5/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Question 11 2 / 2 pts The mineralogy of granite corresponds to the following extrusive rock andesite basalt dacite Correct! rhyolite Question 12 2 / 2 pts Which hazard is not likely to be associated with an eruption of Mt. Rainier of Mt. Pinotubo? Correct! tsunami eruption of hot gases pyroclastic flows lava flows Question 13 2 / 2 pts Volcanic activity may have associated emissions of CO2 which is a denser than air poison https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 6/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Correct! denser than air and an asphyxiant denser than air and flammable denser than air and explosive Question 14 2 / 2 pts Lahar is Correct! a hot mixture of water and pyroclastic material a welded ash deposit close to the volcano a superheated pyroclastic flow a massive of volcanic rockslide caused by a volcanic eruption Question 15 2 / 2 pts The rate of chemical weathering of silicate minerals decreases as a function of their hardness as the amount of Fe and Mg increases as their crystallization temperature increases Correct! as the number of bonds between the silica tetrahedra increases https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 7/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Question 16 2 / 2 pts As granitic rocks are exhumed by erosion and exposed on ground surface, they develop Correct! exfoliation joints many types of fractures tectonic joints and fractures random jointing Question 17 2 / 2 pts Acid mine drainage is caused by carbonate dissolution and reaction with pyrite carbonic acid and oxidation of iron Correct! sulfuric acid formed by the oxidation of pyrite none of these Question 18 2 / 2 pts Chemical weathering of orthoclase produces the following Correct! K+ in solution, dissolved silica and clay https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 8/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) hematite and dissolved silica Ca+2 , Na+ and silica in solution and clay all of these Question 19 2 / 2 pts Saprolite is a residual soil formed in warm humid climate transported soil deposited in a warm humid climate Correct! deeply weathered, decomposed rock showing the features of the parent rock a term describing the leached zone in a soil profile Question 20 2 / 2 pts Which of the following is a clastic sedimentary rock? bauxite limestone Correct! claystone laterite https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 9/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Question 21 2 / 2 pts The strongest cementing agent in clastic or detrital sedimentary rocks is Correct! silica feldspar clay calcite Question 22 2 / 2 pts Shale can be differentiated from claystone by the fact that shale contains more clay Correct! shale has fissility shale is coarser claystone is softer Question 23 2 / 2 pts Silica-alkali reaction in concrete is caused by https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 10/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) halite dissolving and reacting with cement soft limestone reacting with cement pyrite reacting with cement Correct! chert reacting with cement Question 24 2 / 2 pts Which of the following is a foliated metamorphic rock marble Correct! phyllite quartzite greenstone Question 25 2 / 2 pts Which of the following minerals is most likely to cause problems with slope stability if present along foliation planes gypsum feldspar Correct! biotite calcite https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 11/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Question 26 2 / 2 pts The angle of friction for graphite is 15-30 degrees 30-35 degrees Correct! less than 6 degrees 12-20 degrees Question 27 0 / 2 pts Which of these minerals is likely to be most abundant in a sandstone anhydrite orrect Answer quartz ou Answered feldspar pyroxene Question 28 2 / 2 pts Which of these rocks has been subjected to the highest degree of metamorphism https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 12/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) slate biotite schist phyllite Correct! biotite gneiss Question 29 2 / 2 pts Lithification of a sediment involves cementation Correct! all of these consolidation compaction Question 30 2 / 2 pts The direction of flow in an ancient stream be can be determined from angularity of particles shape of particles roundness of particles Correct! none of these https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 13/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Question 31 2 / 2 pts An angular unconformity is a depositional contact of a sedimentary rock with an igneous rock a depositional contact between two rock units where there is a gap in deposition a contact between two rock units Correct! a depositional contact between two rock units of different age that have different orientations Question 32 2 / 2 pts Along which part of a meander would you expect most deposition Correct! on the inside at and around the maximum bend on the inside just below the meander on the outside just below the meander on the outside below the maximum bend Question 33 2 / 2 pts https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 14/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) As sediment is transported downstream, away from its point of origin, the particles become: Correct! all apply smaller and rounder better sorted dominated by minerals resistant to weathering Question 34 2 / 2 pts The lowest elevation to which a stream channel can erode is defined as its Correct! base level profile competence sea level Question 35 2 / 2 pts The absolute age of rocks can be determined from Correct! dating using radioactive elements superposition of adjacent rocks https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 15/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) all of these fossil assemblage Question 36 2 / 2 pts Which radioactive element is best used for dating deposits less than 100,000 years old? RB-87 Correct! C-14 K-40 U-238 Question 37 0 / 2 pts Which property does not affect the angle of repose in talus slope orrect Answer particle density shape of particles size of particles ou Answered frictional property of the particles surface https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 16/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) Question 38 2 / 2 pts The stability of a rock slope increases if normal force decreases Correct! water pressure decreases water pressure increases none of these apply Question 39 2 / 2 pts The most common causes of levee failure are Correct! overtopping and piping erosion and piping piping and slope failures slope failures and overtopping Question 40 2 / 2 pts The probability of a 25-year flood in any given year is: (pls give your answer as a whole # in %) Correct! 4 https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 17/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) orrect Answers 4 (with margin: 0) 0 (with margin: 0) 0.04 (with margin: 0) Question 41 2 / 2 pts The probability of 100-year flood in 30 years is about Correct! 26% Not enough information to answer 36% 3.3% Question 42 4 / 5 pts Describe the main characteristics of karst and give at least two environmental or engineering reasons why recognizing karst features is important. Your Answer: Karst landscapes are characterized by sinkholes, caves, large springs, underground springs, and limestone dissolution. One engineering problem is are sinkholes since they are dangerous to infrastructure as they can randomly occur and cause the ground to collapse. The groundwater is also pumped for a water supply or irrigation. However, they water may become contaminated. https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 18/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) it is the rapid water movement and possibility of easy entry of contaminants Question 43 5 / 5 pts A block weighing 1450 pounds is resting on a slope inclined at 21 degrees. The friction angle between the block and the slope is 30 degrees. a) Compute the static factor of safety against the block sliding. b) Compute the water force necessary to bring the factor of safety to 1.0. Please round your answers to one decimal place, show your basic calculations and units. Your Answer: a) F.S. = tan(30)/tan(21) = 1.5 b) F(resisiting) = F(driving) + V Wcos(21)tan(30) = Wsin(21) + V W = 1450 lb --> V = 261.9 lb Question 44 5 / 5 pts Explain how the shape of a river channel influences the velocity of a stream Your Answer: https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 19/20 11/28/21, 11:22 AM Midterm: Engineering Geology (Fall 2020) A river has a fast flow if it has a small wetted perimeter relative to its cross-sectional area. The wetted perimeter is the water that is in contact with the base of the channel. Water has the some viscosity which causes a stream to lose some energy. Therefore, a stream would be faster if it was more narrow instead of broad. They water is also faster in the interior. Question 45 4 / 5 pts Explain what geologic setting leads to highly explosive volcanism, why, and what is the composition of the magma that is involved. Your Answer: The composition of very explosive magma is felsic. These explosions occur in volcanoes that were formed in subduction zones. As the oceanic plate subducts beneath the continental plate, the subduction also brings sediments and volatiles (seawater) with it, mixing it with the magma. The composition of the magma changes, becoming more felsic and explosive. has high gas content.... Quiz Score: 95 out of 101 https://bcourses.berkeley.edu/courses/1494345/quizzes/2329085 20/20