EOSC114_LA_Reading_Assignment-Fall2023

EOSC 114 Reading Assignment, Fall 2023: Landslides (Important copyright notice 1 ) Student ID:18000729 Introduction The reading for the Landslides Topic is more challenging than any of the previous ones, but this worksheet will guide you carefully through the portions of the article that we are interested in. So – do NOT try to read the whole thing. This is a paper published in Geomorphology in 2010, by M. Jakob and P. Friele “ Frequency and Magnitude of Debris Flows on Cheekye River, British Columbia. ” Our Reading Assignment involves only small portions of this article. It may look difficult, but we will NOT cover everything. Follow instructions carefully and you should find it surprisingly easy to learn plenty from this article! Click here https://go.openathens.net/redirector/ubc.ca?url=https%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii %2FS0169555X09003286 for free access and to download this article from the UBC Library. You will need your CWL. Goals . After completing this assignment, expect to be able to: 1. Recognize the different components of this specialists’ article. 2. Confidently extract the key messages the authors are trying to convey. 3. Identify some of the challenges of, and methods for, making Frequency-Magnitude models of debris flow fans that include several thousands of years of debris flow events. 4. Explain how authors justify which data are more important and which are less important when they make recommendations about safety at this debris flow. Reading this kind of paper . Scientists and engineers develop their own strategies for reading articles. They rarely start at the top and work all the way through to the end. We will use one common strategy, outlined in the following 6 steps: 1. Make sure the purpose of the article is aligned with your needs. 2. Read the Abstract to gain first impressions of the authors’ intentions, their work and results. 3. Read the Introduction to appreciate the context, and then the Conclusion which is usually a summary of work done, results and implications. o At this stage, many readers skim the beginning of each section to gain first impressions about background, methods, results and discussions. o Inspect figures and tables to see what authors consider as most important. 4. Begin working on the details of the paper. We will only ask you to read one small section of the details. 5. Caveats, limitations and needs for further work need to be identified explicitly. Scientific writing is never considered “conclusive”. Authors are expected to draw their conclusions knowing the strengths and limitations of their arguments and recognizing that understanding will always evolve and improve. 6. Revisit sections as needed as you work towards learning what you came for, and understanding what was done, how the authors integrated previous work with their own observations, experiments and analysis, and how they arrived at their conclusions or recommendations. Instructions 1. Today’s Reading Assignment is based on an article-reading strategy. Please follow the worksheet carefully; we will indicate exactly what to read. 2. Review the whole worksheet first, then read and answer questions following instructions. Then submit online. 3. NOTE: A glossary is provided at the end of this worksheet. 4. Ignore older versions of this exercise . This Reading Assignment AND Quiz submission questions may seem similar to earlier versions of EOSC 114 Reading Assignment – but many questions are different. 5. Recall our Class Code of Conduct, and UBC’s rules for academic integrity: https://learningcommons.ubc.ca/academic-integrity/ 1 This Worksheet copyright © 2019, F. Jones, L. Porritt and UBC. All rights reserved. Re-distribution to anyone or the web is against copyright law. See UBC intellectual property rights at https://copyright.ubc.ca/guidelines-and-resources/faq/ Page 1 of 15

Step 1: Why would someone read this article? ● Based purely on the article’s title (no need to read anything else), what is most likely to be a good reason for reading this technical article? ● to learn more about past catastrophes that have occurred along the Cheekye River ● to gain a better understanding of how often debris flows of various sizes have occurred along this River ● to determine how engineers might prevent damage to buildings and property along this River ● to find out what is the most likely cause of debris flows that occur on this River ● to determine the date of the last major debris flow in this area ● This paper has 8 sections. Without reading any of them, which of those listed below appears to be the shortest (have the fewest words), not including figures and tables? ● Introduction ● Chronology of Cheekye River studies ● Debris flow frequency-magnitude determination with dendrochronology ● Magnitude of the garbage dump debris flow ● Volume check using DAN3D ● Frequency-magnitude relationship ● Discussion ● Conclusion Page 2 of 15

● the past 5 years ● the past 120 years ● the past several thousand years ● the past 11,700 years ● the past 2.58 million years ● since the origin of the Cheekye River Step 3: The Introduction including Figure 1, and the Conclusion. The conclusion is challenging but we will guide your thinking. Just read it through once and we’ll consider details shortly. ● The Cheekye River fan is currently undeveloped due to prior consulting (not “scientific” ) reports that were published in which 5 decades? ● 1940s ● 1950s ● 1960s ● 1970s ● 1980s ● 1990s ● 2000s ● 2010s ● Based on the short introduction, what will be the main purpose of this article? ● to describe debris flow modelling and risk analysis that is based on existing F-M models ● to discuss implications of the existing F-M relationships on quantitative debris-flow risk assessment ● to summarize prior work in order to start building a useful F-M model ● to describe recent studies by the authors that result in a useful F-M model Page 4 of 15

● to combine both prior work and recent studies to build a useful F-M model ● Use the scale on the map in Figure 1 and a ruler or piece of paper to measure the following straight-line distances. NOTE: If you don’t know how you could do an online search for “measure distance on a map” or check out https://www.youtube.com/watch?v=V3QxrX0MYu4 or https://www.wikihow.com/Measure-a-Straight-Line-Distance-Using-a-Topo-Map ● How far in kilometres (km) “as the crow flies” (a straight line by air) is the point where the Cheekye and Cheakamus Rivers meet from the letter “V” of West Vancouver? (Answer using numbers only, for example, 8.3; no words.) 48.8 ● How far in kilometres (km) “as the crow flies” (a straight line by air) is Mt Garibaldi from Squamish? (Answer using numbers only, for example, 8.3; no words.) 22.5 ● In the Conclusion, read only the last 2 paragraphs starting at “Quantitative risk assessments (QRAs) …” From the second-to-last paragraph of the conclusion, which is the most general, overarching conclusion for those learning more about how to carry out development on debris flow fan? ● Decisions about building on debris flow fans must be based on details about how often and how big flow events are likely to be over wide time ranges. ● QRAs cannot be completed without predicting the flow behaviour using runout modelling. ● This paper is only one part of a more comprehensive study. ● The 10,000-year event described by earlier researchers could be mitigated if appropriate methods and sufficient funds are available. ● Development decisions can be based purely on theoretical quantitative risk assessments. ● From the final paragraph of the Conclusion, the author’s main take-home message is that: ● It would be too expensive to prevent the largest possible event from damaging property or lives. ● Even the smaller estimated size of a 10,000-year event is so large that it would be too expensive to mitigate potentially disastrous effects on development in the area. ● Dams and barriers would have to be built to protect developments regardless of whether older or more recent estimates of frequency and magnitude are used in QRAs. ● Unlike previous estimates, the largest expected flow event can in fact be mitigated, making development feasible. ● Any one of four improvements would be sufficient on its own, to mitigate the worst-case 10,000-year event. Step 4: Details within the paper At this stage you should have a good feeling about the authors’ intentions and outcomes. Now we can consider some of the details. Read the first 4 paragraphs ONLY of Section 3, “ Debris flow frequency-magnitude determination with dendrochronology ”. Figure 4 is also part of this section. NOTE: Details of the equation called the “ Flow Superelevation formula ” are not important, HOWEVER, notice how it can provide values for an important parameter, flow velocity if other parameters can be obtained or estimated. Page 5 of 15

● All 4 parameters ● 3 of the 4 ● 2 of the 4 ● Just 1 of the 4 ● none of the 4 parameters Consider the F-M graph of Figure 8 . There are two relationships shown: (a) total debris flow volume (left axis) versus return period; and (b) peak discharge (right axis) versus return period. The points and lines can be used to consider either relationship because peak discharge is directly related to total debris flow volume. Take care in reading this log-log plot; you must read the values required from the correct axis, so read each question carefully. If needed, please refresh your ability to use logarithm scales by viewing this video: https://bit.ly/2iHOvNd . ● First, which of the following questions about a rainfall-generated debris flow can be answered directly from data given in this graphical frequency magnitude or F-M relationship? Answer: YES , this question CAN be answered from this graph OR NO , This question can NOT be answered from this graph ● YES / NO Assuming a debris flow will occur at a given interval (e.g. 1,000 years), what will its expected peak discharge be? ● YES / NO Assuming a given peak discharge (right axis) of the flow (e.g. 8,000 m 3 /s), when can we expect the next such flow to occur? ● YES / NO Assuming a given volume (left axis) of the flow (e.g. 500,000 m 3 ), how often can it be expected to occur? ● How are rock avalanche-generated debris flows expected to compare to rainfall-generated debris flows? ● Avalanche-generated flows are expected to be larger in volume than rainfall-generated flows. ● Avalanche-generated flows are expected to be smaller in volume than rainfall-generated flows. ● Avalanche-generated flows are expected to be similar in volume to rainfall-generated flows. ● This question cannot be answered using this graph. Now, let’s make some predictions by using this graphical relationship: ● Approximately how often can “V rainfall-generated debris flows” with a volume of 400,000 m 3 be expected to occur? Every 2000 years ● Approximately what volume (left axis) of “Q rainfall-generated debris flows” is expected to occur every 100 years (i.e. with a return period of 100 years)? 60000 m 3 ● Approximately what peak discharge (right axis) of “V rainfall-generated debris flows” is expected to occur every 100 years (i.e. with a return period of 100 years)? 1900 m 3 /s ● Approximately how often can “Q rainfall-generated debris flows” with a peak discharge of 2,000 m 3 /s be expected to occur? Every 50 years Page 7 of 15

Step 5: Assumptions or limitations of the study . NOTE: Recall the outline on page 1 Assumptions and limitations are an important part of any scientific argument. Read just the second paragraph of the Conclusion starting at “ F-M relationships that extend over …. ”. ● Select YES or NO to indicate whether the authors said the following in the 2 nd paragraph of their conclusions. ● YES / NO … climate has not varied so its effects were ignored ● YES / NO … effects of variations in climate and other conditions were likely real, but not incorporated into this study ● YES / NO … vegetation, glacial cover, precipitation and other characteristics have not varied enough to warrant taking such changes into account Page 8 of 15

● YES / NO Assertions and arguments supported by evidence based on observations, measurements or experiments done by the author(s) . ● YES / NO Narrative or personal stories in the portions we read. ● YES / NO Targeted human emotion in the portions we read. ● YES / NO Descriptions of “aesthetic” aspects like scenes, views and impressions in portions we read. ● YES / NO Identified at least some uncertainties, incomplete aspects or needs for further work. As discussed in earlier Reading Assignments, the use of scientific communications requires practice at recognizing claims, arguments and evidence . Evidence involves data, observations or calculations and is distinct from basic facts which are simply “true” without being measured, calculated etc. Some claims or arguments may seem “personal” or “speculative”; these should be recognized as opinions . Finally, methods can be considered as distinct since they involve details about how observations, outcomes or procedures were performed. Should each of the following be considered as evidence , method , opinion or fact ? ● “Wood samples were cut from trees damaged by debris-flow impacts on both sides of Cheekye River” This statement can be most reasonably described as part of: ● a specific observation, data set, measurement or calculated result ● a method (existing or recommended) for carrying out a task or arriving at a result ● an opinion (i.e. an unsupported conjecture, judgement or comment) expressed or quoted by the authors ● a basic fact (not data or result) that does not need to be argued ● “ Planning debris-flow mitigation steps should start with a risk assessment procedure ” This statement can be most reasonably described as part of: ● a specific observation, data set, measurement or calculated result ● a method (existing or recommended) for carrying out a task or arriving at a result ● an opinion (i.e. a conjecture, judgement or comment) expressed or quoted by the authors ● a basic fact (not data or result) that does not need to be argued ● “We consider the 60 years of research near this location to be an impressive body of work.” This statement can be most reasonably described as part of: ● a specific observation, data set, measurement or calculated result ● a method (existing or recommended) for carrying out a task or arriving at a result ● an opinion (i.e. a conjecture, judgement or comment) expressed or quoted by the authors ● a basic fact (not data or result) that does not need to be argued ● “ We believe this area is under-developed” This statement can be most reasonably described as part of: ● a specific observation, data set, measurement or calculated result Page 10 of 15

● a method (existing or recommended) for carrying out a task or arriving at a result ● an opinion (i.e. a conjecture, judgement or comment) expressed or quoted by the authors ● a basic fact (not data or result) that does not need to be argued Data used as part of any scientific or engineering study can be acquired in several ways. What kind of data are each of the following? (If you are uncertain, consider who provided or obtained the information, how it was obtained, and the "quality" of the data.) ● Dates of events from historical records ● a quantity or quantities that were collected or measured, often (but not always) with instruments ● information that was observed – i.e. seen or noticed, not measured with instruments ● data that was simulated, modelled or calculated ● information collected from people, archives, records, etc. ● not really data at all ● Volume of a debris flow quoted as “huge” by a news reporter viewing the debris flow from a helicopter ● a quantity or quantities that were collected or measured, often (but not always) with instruments ● information that was observed – i.e. seen or noticed, not measured with instruments ● data that was simulated, modelled or calculated ● information collected from people, archives, records etc. ● not really data at all ● The choices of trees (not the dates) (when identifying or choosing trees for use in dating) ● a quantity or quantities that were collected or measured, often (but not always) with instruments ● information that was observed – i.e. seen or noticed, not measured with instruments ● data that was simulated, modelled or calculated ● information collected from people, archives, records etc. ● not really data at all ● Radiocarbon dates from wood fragments ● a quantity or quantities that were collected or measured, often (but not always) with instruments ● information that was observed – i.e. seen or noticed, not measured with instruments ● data that was simulated, modelled or calculated ● information collected from people, archives, records etc. ● not really data at all Page 11 of 15

● Compare the date of the news item with the first publication date (either online or print) of our journal article. The new article was published 12 years after the technical paper was published. (NOTE: Journal article publication dates are printed at the very top of page 1. Enter numbers only, for example, three and a half years as 3.5.) ● This news item quotes a debris flow volume and return interval for the largest event that can be mitigated with the proposal. Does it look like these two values could be obtained from Figure 8 of the journal article we read? ● This pair of values seems consistent with the F-M relationship of Figure 8 in the article. ● Volume seems to be consistent but return rate is not. ● Return rate seems consistent but volume is not. ● Values quoted in the news item cannot be compared to Figure 8. ● How did the conclusions in the final paragraph of the journal article’s conclusion section compare to mitigation strategy(ies) proposed (not just “considered”) to the city council? The journal article’s conclusion included ______. ● the same strategy(ies) proposed to the city council ● more strategies than were proposed to the city council ● fewer strategies than those proposed to the city council ● none of the strategies proposed to the city council ● How did the interaction between the expert engineer and members of the municipal council affect the decisions that council had to make? The interaction... ● clarified the options, but council still had difficulty reaching consensus ● clarified the options allowing council to arrive at a majority decision ● clarified the options allowing council to arrive at a unanimous decision ● left city councillors confused as to which options to approve ● left city councillors divided as to which proposal would best serve the needs of the community Page 13 of 15

Glossary for the Landslides Reading Assignment Reading 1) Abstract ● dendrochronology . tree-ring counting to determine dates or time spans ● entrainment of saturated sediments. entrainment means “collecting or gathering up” ● F-M model . frequency/magnitude model, or a relationship showing how often events of different strengths occur. Used for all hazards. ● fluidize . make an entity behave like a fluid ● Holocene . the time between 11,700 years ago and now ● hydrological limitations . limits on the situation that are based on water and ground water ● precursor investigations . studies that come before ● predicated . (not the same as predicted!); “based upon” or depends upon ● progressive bulking of in-stream erodible sediments . increasing the amounts of sediments that were in the stream and could be eroded ● proxy data . data that say something indirectly about information that cannot be measured directly ● quasi-homogeneous populations . “quasi” means “partially”; homogeneous means uniform or not mixed ● stratigraphic analysis . analysis of the geological layers to interpret sequences of events ● upstream impoundment . “holding” or “containing” in the area up the stream or river 2) Introduction ● geomorphic evolution . changes over time of the shapes, configurations and contents of geological materials at the surface ● ground penetrating radar . a geophysical technique for identifying variations in subsurface materials by recording the echoes of radio waves that are transmitted into the ground ● quaternary drift deposits . materials that have accumulated during the quaternary period (2.58 Mya to present) Page 14 of 15