Surviving Tsunamis on the Oregon Coast

Transcription

1 Slide 1 Surviving Tsunamis on the Oregon Coast Coastal Engineers Think Inside the Box This talk generally covers civil engineering, coastal engineering, and how engineers work within limitations to create innovation solutions to challenges Slide 2 Part 1 Tsunami and Research at the NEES Tsunami Facility Slide 3 What is a Tsunami? Means Harbor Wave in Japanese It a sudden and dramatic rise in sea level, resulting in a very fast and damaging flood. This diagram shows how a tsunami inundates an area. Understanding the extent of the inundation is critical to developing solutions to reduce loss of life and property. Credit: USGS

2 Slide 4 Tsunami Before and After Community in Japan before (above) and after(below) the Feb 2011 tsunami This slide shows an area in Japan during and after the tsunami. The area had most of its buildings wiped out, except the one with blue roof in the middle. It s possible this one was built from concrete or is more sturdy because of other design considerations. Credit: Dailymail.com Slide 5 Stages of a Tsunami Generation Propagation Inundation Tsunami s have three stages: Generation, Propagation and Inundation. The next slides will review this. Credit:NOAA How are tsunamis created? How do they move through the ocean? Credit: EPA What happens when they hit land? Slide 6 How are Tsunamis Generated? Ask students if they know how tsunamis are generated.

3 Slide 7 How are Tsunamis Generated? Subduction Zone Earthquakes Landslides Volcanoes Glaciers The four basic types of tsunami generation. All generation types cause a massive displacement of water. Subduction Zone Earthquakes, generally create the large waves we see propagate across the ocean. Examples of this generation are the 2004 Indian Ocean Tsunami and the Japan Tsunami of Landslides, Volcanoes, and Glaciers generally do not create large ocean sized waves, but can cause very large run-up locally when geographic features are present. Lituya Bay, Alaska is a good example of a landside generated tsunami. Meteor/Asteroid impact could also generate a tsunami, BUT it is highly unlikely. Slide 8 Tsunami Generation Subduction Zone Earthquakes (video click on the image) Illustration of Tsunami Generation by Subduction Zone (USGS) This video shows how a subduction zone earthquake create a tsunami. It is a slightly erroneous video as it make it as appear that tsunamis occur at a point, whereas in fact a long section of the fault line ruptures. For example the Japan tsunami fault line was over 300 miles long.

4 Slide 9 Tsunamis Generation Landslides Volcanoes Glaciers Lituya Bay 1958 in Alaska source This slide illustrates the effect of a landslide generated tsunami. Note the over 500 M (1500 foot) run-up or inundation caused by this landslide. It is the highest run up in recorded history. However, because it was a landslide generated tsunami it did not propagate across the ocean. Slide 10 Tsunamis Generation Landslides Volcanoes Glaciers This is an image of a landsidegenerated tsunami. Aysen in Chile in 2007 source: Fritz Slide 11 Click on arrow above Tsunami Propagation (video) (NOAA Center for Tsunami Research) This video with very good narration (make sure you have sound on), shows the propagation, across the ocean of the Japan 2011 Tsunami. Notice how fast the wave moves across the ocean, how it effects all of the pacific, how it impacts Oregon and how complicated the wave is once it has propagated across the ocean. The narration will point most of this out, but after the video is over it could be beneficial to point these things our to students.

5 Slide 12 Tsunami Inundation Large amount of water floods into a land area usually above sea level this is measured in feet (or meters) above sea level Credit: Dan Cox Tsunami Inundation is a process by which the displaced water moves over land normally above sea level. Basically there is a very rapid, temporary sea level rise and fall. There are typically 3-4 waves during one tsunami event. Typically the second or third wave has the highest run-up. Run-up refers to the amount of height above sea level the water reaches. This photo of the wave lab at Oregon State University shows tsunami inundation of about 30 feet above sea level in one of our models (this is a 1:50 scale model of Seaside, Oregon). Slide 13 Tsunamis in Oregon 1 in 7 chance in the next 50 years 30 min Cascadia Subduction Zone The Cascadia Subduction Zone runs from Northern California to British Columbia. It is where the Juan de Fuca (continental plate) meets the Pacific plate (oceanic plate). We know from seafloor coring evidence that the Cascadia Subduction Zone has a major earthquake and tsunami every years, most frequently rupturing every 300 years. The last earthquake and tsunami happened in It is about miles off the Oregon Coast, and scientists estimate that there is a 1 in 7 chance of a 9M earthquake and a tsunami in the next 50 years, and there is a 1 in 3 chance of a 8M earthquake in the next 50 years. After the earthquake, the first wave will take about 30 minutes to reach the coast. The average expected inundation height is 50 feet above sea level.

6 Slide 14 Dynamic Tsunami Hazard Map Video courtesy of : Dr. Harry Yeh Oregon State University & Dr. Katada Gunma University, Japan This video is a model of an estimate about what would happen if a tsunami struck Seaside, Oregon today. There are 5000 people represented by the grey dots, which turn blue as the people are preparing to evacuate, and red as they move.. They move at a fast walk pace and disappear off the map when they either reach high ground or are touched by the tsunami. Dots touched by the tsunami are counted as casualties. The casualty counts is in the upper right corner. Time after the earthquake is in the upper left corner.. The yellow dots are Police Cars headed out to tell people to leave the beach. This is based on the Japanese model. Sending the police out to warn people is not the current plan for the Oregon Coast. This is a best case scenario. This is a good slide to discuss modeling as a form of estimating. As researchers develop models they make assumptions because in one model we cannot include all the possible variations. Assumptions are used to simplify the complex problem so that it can be modeled. Those assumptions are used to analyze the results. One good question for the students would be: What do you think would be different in real life? What are some of the assumptions made by the researchers? Common response are: not everyone could walk that fast, some people would run, some people might drive, not everyone will know what to do. Also ask the students how the differences that they are pointing out will affect the total causality count. Finally, point out to students that models are useful to help us

7 understand situations that are difficult to study in real life (i.e. what happens in a tsunami) but to understand the limitations of the results, it is critical to understand the assumptions. Slide 15 Typical waves at Seaside: 6 ft high every 7 sec. Video of waves (wind waves) at Seaside A PHYSICAL Model of Seaside 1:50 scale (somewhat small) You can use the slide to compare what wind waves look like to a tsunami on the next slide Credit: Dan Cox Slide 16 Demonstration of Cascadia subduction zone tsunami Credit: Dan Cox This video shows a tsunami on model of Seaside Oregon. In this model researchers are studying the hydrodynamics or what happens to the water as it interacts with the built world. We refer to building as macroroughness (big things). The 1:50 scale is to small to study the performance of the buildings but we can learn about what happens to the water. We use the data collected in this model to help develop computer models that will predict the forces the tsunami will exert on the structures.

8 Slide 17 Wave Force Potential Numerical Calculations Courtesy of Dr. Patrick Lynett, USC This computer model estimates the forces of the waves. The brighter the colors the higher the force. Researchers used the data from our physical model of Seaside to develop a computer model that estimates the forces of the water, as it flows through the buildings. This information is helpful to engineers as they develop building codes (rules for to designing buildings) in tsunami prone areas. Slide 18 1:6 Scale Residential Building Using the predictions and estimates from the Seaside physical model and the computer model, we can test a larger scale building. Those two models were used develop a prediction of the potential forces and we can use that to see what would happen to a 1:6 scale Courtesy of: Drs. J. Van de Lindt, Colorado State Univ. & R. Gupta, Oregon State University model of a house. As the video shows, wood structures do not perform well against waves. This is important again for designing buildings in tsunami prone areas. Slide 19 Near Prototype Scale Wall This video shows a near 5-foot wave on a near full scale (larger than 1:2) wall. This work allows researchers to focus in on specific forces at specific locations on a structure. Credit: Dan Cox

9 Slide 20 Part 2 Introduction to Civil and Coastal Engineering Slide 21 What is Engineering?? Have students work to brain storm and define engineering. Slide 22 What is Engineering?? Engineering = Math+Science+creativity = problem solving Engineers Design solutions to problems Engineers Innovate (make new things/ solve problems) Engineers work in teams

10 Slide 23 What is Civil Engineering Civil engineering is a discipline that deals with the design, construction, and maintenance of the physical and naturally built environment. (Wikipedia) Slide 24 Civil Engineers work on? Have students list things civil engineers might work on. Source: Jan Drewes Slide 25 Civil Engineers work on? This is a list of some examples Buildings Roads Rivers Sanitation Systems Parks Bridges Towns Dams Subways

11 Slide 26 Safety A major goal of all of civil engineering is to provide safety for the users of the infrastructure. This can mean: Have students brainstorm a list of safety issues civil engineers might be concerned with. Slide 27 Safety Here are some examples A major goal of all of civil engineering is to provide safety for the users of the infrastructure. This can mean: Designing buildings to withstand loads from wind or earthquakes Designing bridges to withstand loading from large heavy trucks or high winds Planning highway/freeway systems to provide adequate evacuation routes Slide 28 Ask student what is it that coastal engineers do? What do coastal engineers work on? As students what this photo might a coastal engineer work on? Coastal Engineering Source:

12 Slide 29 Coastal Engineering The goal of Coastal Engineering is to protect civil infrastructure from coastal processes. Ask students: What are coastal processes? Answer: Coastal process are any sort of natural process that happen on the coast, such wind, waves, storms etc. The next four slides show pictures of coastal process that engineers at OSU study and try to mitigate. Slide 30 Erosion Erosion is happening in many places along the Oregon Coast and can cause houses to wash away, which can be expensive and difficult to fix. Ask the students: What would happen if the road to your school eroded? Source: Armand Thibault Slide 31 Storms can have huge impact on communities. Damaging structures and important infrastructure. Storms Credit: Steve Earley

13 Slide 32 Hurricanes Gilchrist Texas after Hurricane Ike in 2008, (credit: the guardian) Hurricanes are a specific type of large storm with many unique factors that make them more dangerous than storms. They have storm surge, which like a tsunami can flood low lying areas. They have high winds, and driving rain. As the photo shows, they can damage whole communities. Slide 33 This photos show inundation of a tsunami in Japan in Japan March 2011 Tsunami Credit: Kyodo/AP Slide 34 Part 3. Engineering Design Cycle

14 Time Slide 35 Engineers think inside the box and the engineering design cycle How to think and work like an engineer Slide 36 Thinking inside the box Budget Building Code Tsunami forces Engineers have lots of constraints on their design process. Ask students: If you were designing something to protect communities from tsunamis what would your constraints have to be? What factors would you have to consider? Possible answers: money, time, how strong the wave is, how far the wave might come in, how fast the wave might be going. These factors are the constraints. If engineers go outside of the constraints their designs will not work, for example: if a engineer goes over budget then there will not be enough money to complete the project. Constraints are like the sides of a box and good engineer will think to the corner to come-up with innovative and creative solutions.

15 1. Define the problem 1. Define the problem 2. Gather information 2. Gather information 3. Generate multiple solutions 3. Generate multiple solutions 4. Analyze and choose a solution 4. Analyze and choose a solution 5. Implement 5. Implement 6. Evaluate 6. Evaluate Slide 37 The Engineering Design Process 3. Generate 4. Analyze Define 2. Gather 6. Evaluate multiple and choose Implement the problem information solutions a solution Engineers tell us the Engineering Design Process as a method to develop and evolve potential solutions. They use it the same way scientists use the scientific method to do research. In the sand bin activity students should use the Engineering Design Process to develop solutions for saving Legoville Slide 38 Define the Problem Start by defining your problem. Be specific. Make sure everyone on your team agrees with the problem statement The following slides are meant as an introduction to the design cycle using the tsunami sand bin activity as starting point. It might be good to get out a demonstration sand bin and show the students the activity before presenting these slides, or editing them accordingly. Clearly and specifically defining the problem is the first step. Scoping the problem is also important. Slide 39 Gather Information What are the constraints on your design? Write them down Hint: Some constraints include Materials Time Wave Height Budget Think about the constraints within your defined problem. Think about solutions that have already been implemented, will those work for you? Do you need to modify them?

16 1. Define the problem 1. Define the problem 1. Define the problem 2. Gather information 3. Generate multiple solutions 3. Generate multiple solutions 3. Generate multiple solutions 4. Analyze and choose a solution a solution 5. Implement 6. Evaluate Slide 40 Gather Information What does your proposed solution have to do? What forces does it have to resist to stay safe? What kinds of designs are most likely to resist those forces? Slide 41 Generate Multiple Solutions 2. Gather information 4. Analyze and choose 5. Implement 6. Evaluate Brain storm solutions every team member should participate. Decide how you will judge your ideas! What criteria will you use to make a decision on a design? Try different designs, test them in your minitsunami sand bin Record your results Slide 42 Analyze and Choose a Solution 2. Gather information Use the criteria you defined to choose one design 4. Analyze and choose a solution 5. Implement 6. Evaluate Try your solutions in the sand bin. How do you decide which one work best.

17 1. Define the problem 2. Gather information 3. Generate multiple solutions 4. Analyze and choose a solution 5. Implement the solution 6. Evaluate the solution Slide 43 Implement Now the fun starts! Build your chosen design! Record your design performance to report Slide 44 Remember Design is an Iterative Process You can make changes as you go But you have TIME constraints to implement your design! 6. Evaluate 1. Define the problem 5. Implement 2. Gather information 4. Analyze and choose a solution 3. Generate multiple solutions Slide 45 Acknowledgments I would like to thank the following people for their contributions to this presentation Dr. Dan Cox, Oregon State University Deanna Lyons, Oregon State University I would like to thank the following organizations for their fiscal support that made is presentation possible: The National Science Foundation The Network for Earthquake Engineering Simulation Oregon Sea Grant