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Practical 3: Tsunami risk in Indonesia 1 Practical 3: Risk Assessment using Ma

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Practical 3: Tsunami risk in Indonesia 1 Practical 3: Risk Assessment using Map Overlay Summary Title:    Tsunami Risk in Indonesia Objective:   To examine the risk to human life of a hypothetical Tsunami south of the island of Java Lab sessions required: 3 Assessment:    This assignment is worth 20% of the total topic marks Due Date: Midday Tues Oct 14 (if registered in ether the Monday or Tuesday Computer Lab) Midday Fri Oct 17 (if registered in ether the Thursday or Friday Computer Lab) 1.0 Introduction On December 26, 2004 an earthquake of magnitude nine occurred off the coast of Sumatra.    The earthquake resulted in a large Tsunami, which devastated Islands off the east coast of India, as well as Sri Lanka, Sumatra, Thailand and Somalia.  It claimed more than 250,000 human lives in these countries. In Figure 1 the small red dots depict all recorded earthquake epicentres around Indonesia.  The large red dot to the west of Sumatra is the epicenter of the 2004 Tsunami. Figure 1 Location of all recorded earthquake epicentres including the 2004 Tsunami epicentre depicted as a red dot, immediately east of the coast of Sumatra.    This workshop will focus on Java (highlighted in red).Practical 3: Tsunami risk in Indonesia 2 Less well-known is an earthquake of magnitude 7.7 (shown as red in Figure 2) which occurred off the coast of Java in July 2006.   This resulted in a three metre high Tsunami which killed at least 668 people. More than 9,000 people were treated for injuries.  The south coast of Java is more vulnerable than the north and it has been devastated by large Tsunamis many times in the distance past.  The small crosses in Figure 2 show other recorded earth quakes of smaller magnitudes.  Note the prevalence of these off the south cost of Java, and in one particular cluster. In this workshop you will compare a vector overlaying approach with a raster overlaying approach in assessing the risk of two hypothetical levels of a Tsunami off the south coast of Java where tectonic plate movement is most prevalent. You will be using aggregated Regency-level census data.    This has the 2007 population data for Java provided by the Central Bureau of Statistics (2008) from the Republic of Indonesia (see black boundaries showing the level of aggregation in Figure 2).    The total population of Indonesia in 2007 was 225,600,000 while on 2010 it was 237,600,000 Central Bureau of Statistics (2010).  There is no current (2014) data available for this practical. You are also separately provided with population density data in the form of a raster grid from Oak Ridge National Laboratories, Minneapolis (see http://web.ornl.gov/sci/landscan/ for information about how this data is created).  You will also be using elevation data, both in the form of contours and a raster Digital Elevation Model (DEM) is of South-east Asia.  This is a 30” DEM obtained through the ESRI online portal. Figure 2 Earthquake of magnitude 7.7 (shown as red) occurred off the coast of Java in 2006. All other epicentres are shown as crosses. Please read the following four articles (available on FLO) for background information and other methodologies using GIS that have been employed. Some of these articles focus on a finer-scale assessments rather than broad-scale assessments, like you will be undertaking in this workshop.Practical 3: Tsunami risk in Indonesia 3 Papathoma M. and Dominey-Howes D. 2003. Tsunami vulnerability assessment and its implications for coastal hazard analysis and disaster management planning, Gulf of Corinth, Greece Natural Hazards and Earth System Sciences 3: 733–747 Post, J., Zosseder, K., Strunz, G., Birkmann, J., Gebert, N., Setiadi, N., Anwar, H.Z., Harjono, H., Nur, M. & Siagian, T., 2008a, Risk and vulnerability assessment to tsunami and coastal hazards in Indonesia: Conceptual framework and indicator development. Available at: http://www.hydroteam.de/Padang_Post_Zosseder_et%20al.pdf, [viewed 05/04/2014]. Post, J., Muck, M., Zosseder, K., Steinmetz, T., Riedlinger, T., Strunz, G., Mehl, H., Dech, S., Birkmann, J., Gebert, N., Anwar, H. Z., and Harjono, H. 2008b. Tsunami risk assessment for local communities in Indonesia to provide information for early warning and disaster management, International Conference on Tsunami Warning (ICTW), Bali, Indonesia, 12–14 November 2008. Strunz G., Post J., Zosseder K., Wegscheider S., Muck M., Riedlinger J., Mehl H.,   Dech S. 2011. Tsunami risk assessment in Indonesia. Natural Hazards and Earth System Sciences 11: 67–82. 2.0 Methodology Out of a sample of 158 Tsunamis, Post el al (2008a) suggest that more than 60% of all these were found to be less than 100 metres inland and only 20% occurring greater than 1 kilometre inland.  This depends largely upon elevation, moreover areas of land within 10 metres elevation of sea level are at the highest risk.   Obviously the depth of the wave will differ according to the ground elevation (Papathoma and Dominey-Howes 2003).  These authors defined different Inundation Depth Zones (IDZ).  They defined a high risk IDZ as ground elevations of between 0 – 2 metres, a medium risk IDZ (ground elevation 2-3 metres), a low risk IDZ (ground elevation 3-4 m) and very low risk IDZ (ground elevation 4 – 5 m). In this workshop you will use high risk IDZ zone for ground elevations of 0-3 metres and a low risk IDZ zone for ground elevations between 3-10 metres.  While these and other authors (i.e. Post et al 2008b; Strunz et al 2011) also considered structurally robust buildings that are above the natural ground level for evacuation purposes, in this workshop we will consider population exposure and risk at a broader- scale. Note: of relevance to this workshop report are the Vector and Raster Analysis Lectures, 8 and 10 respectively. Part I.   Vector Analysis 2.1 Practice dataset – vector map overlay See Practice overlaying instructions.pdf workshop notes for a practice exercise where you will conduct Clip, Union and Intersect polygon overlay operations on a practice dataset for comparison, then you will carry out a series of short calculations on the attributes of the output layers from one of these overlay functions. Here you will calculate the population in each of two flood zones. You will need to report the findings of these operations in the log file of your report.  Please move to this document before continuing.  The log file is to be submitted as a separate .pdf to your main report.  Practical 3: Tsunami risk in Indonesia 4 Practical 3: Tsunami risk in Indonesia 5 2.2 Tsunami dataset Once you have completed 2.1 above, your task now is to use the following two polygon vector layers to calculate the total population of people likely to be affected in the High and Low IDZâ€s.  We also pose the question: How many children under the age of 9 are likely to be affected in each IDZ. The personal geodatabase containing the data you will need can be found in V:CMLSharedGEOG2700Practical 3.  It is called Tsuami.mdb. Open ArcCatalog and copy this across to your own Practical 3 directory on the U: drive. Now open up ArcMap.    In ArcMap add the layers from U:Practical 3Tsuami.mdb.    Please also remember to make U:Practical 3Tsuami.mdb your default geodatabase. Once you add the three layers from your personal geodatabase, use View->Data Frame Properties to check the Coordinate System tab.  The coordinate system of the data frame should be WGS84.   This has been automatically picked up by the data frame from the first of the layers you added.    It can be overridden.    Check the coordinate system in each layer by using the right button over the layer and selecting the Source tab.  They all should be in the same coordinate system.  You will also find when you open the attribute tables of the two polygon layers that the areas and perimeter lengths are again in decimal degrees. Please save your ArcMap project/map document regularly throughout this workshop — ArcMap does often crash when too many processes are left in cache memory that have not been saved. Data familiarization With your right button over the Regencies layer in the Table of Contents (TOC), select Properties and the Symbology tab and then Quantities->Graduated Colours.  Select the value of total_pers (the total population field) and create a thematic map of the population.  Use 10 classes.  Each polygon is called a Regency, which is the census subdivision of a Province.  These figures are in 1000â€s of people.  In other words 0 – 133 means 0 – 113,000 people.   Where are the Regencies in Java which have the highest number of people? The contour layer is a polygon layer showing only two ranges of contours: 0 – 3 metres and 3 – 10 metres above sea level.   Use Symbology this time with Categories and the Contour field to create a thematic map of the contours.   Where are the largest low-lying areas in Java?Practical 3: Tsunami risk in Indonesia 6 The world_earthquakes layer shows the point location of all earthquake epicentres of the world.   By right clicking on the layer name in the TOC and selecting ‘Zoom to layer†you can see the extent of the layer. Using the pull-down menu, choose Selection->Select by attributes and pick the layer called world_earthquakes.    Double click from the list the word “MAGNITUDE” and ensure the expression -MAGNITUDE- > 7 is in the WHERE statement box.  View this spatially and then familiarize yourself with the attribute table attached to this point vector layer.   This should highlight all earthquakes having a magnitude above level 7, from which you should be able to see in your map the eipicentre south of Java. Find this single record of the earthquake off Java in the attribute table.  It should have “OBJECTID” = 46608 and a “MAGNITUDE” = 7.7 – highlighted in yellow above.    By running your cursor along the bottom of the attribute table you are able to view all records or just your selected records.   Click on ‘show selected records†to constraint your list and find the above named record.  Click this record in the attribute table to highlight it yellow and then right click it and select the option named ‘Zoom to Selectedâ€. This will focus the spatial extent back onto the earth quake epicenter off the coast of Java. After you have finished with selection statements or highlighting various elements, make sure you ‘clear your selection†afterwards using the button found in your attribute table or Tools tool bar.Practical 3: Tsunami risk in Indonesia 7 Next you need to create a field of all children under the age of 9.    This combines two fields in the Regency census data called age_0_4 and age_5_9.  Open the attribute table for Regencies.   Using your right button over the Table Options button, select Add field.  Call the field AGE0_9YRS Now using the Field Calculator (right button over this new fieldâ€s heading), sum the age_0_4 and age_5_9 fields.  Show this as a thematic map. Name the six Regencies in Java which have the highest number of children under nine years old? Name the six Regencies in Java which have the highest number of people?   Use the total_pers field to answer this. Constraining our Regencies data We will confine our analysis to the southern Regencies only.   For the moment, turn off all other layers. To select the southern Regencies you will need to use the manual spatial selection tool   and while holding your keyboard Shift button down, select the following polygons.  The result should look like this: Now export these selected features.   To do this click the right mouse button over the name of this layer in the TOC, select Data->Export Data and save the selected polygons as a separate layer in your personalPractical 3: Tsunami risk in Indonesia 8 geodatabase.  Call it Southern_regencies.  You will need to change the save as type to a ‘File and personal geodatabase feature classâ€.  You will use these polygons in the analysis which follows. For area calculations in the attribute tables that may follow, set your Data Frame coordinate system now to Projected Coordinate Systems->World->Mercator. Before you begin any actual analysis of earthquake impacts on the population, construct a flow chart of the operations you intend to perform to meet the task set above.    Add this flow chart to a Project Planning sub-section of your reportâ€s Methodology section 2.1.  In your own words also describe which overlay function and attribute calculations you intend to use and why. However, do not show details of the ArcGIS dialog box entries and table calculations in your Methodology (or even later in the Results section).    Instead, report these detailed steps in your separate log file.pdf.  Use the Windows Snipping Tool to copy and paste your dialog box entries into the log file. Now begin the analysis, answering the questions throughout and report the results in your Results section.  Be careful how you report your data.  The data you collect in the 10 metre contour polygons is between 3 and 10 metres, not 0 and 10 metres. Your overall two key questions in the report are: How many total persons are affected in the two IDZâ€s? How many children under the age of 9 are affected in the two IDZâ€s Remember these populations are in the 1000â€s   Practical 3: Tsunami risk in Indonesia 9 Part II.  Raster Analysis 2.3  Raster map overlaying There is no practice dataset for this segment of work.    In V: there is a personal geodatabase called raster_analysis.mdb which you need to copy across to your U: drive with ArcCatalog.  In this are two raster grids.  The first (DEM) has the elevation data of Java, the second (Population) has the population estimates of Java in one kilometre raster grids for 2010.  Again, check the documentation about how this was created.  This will be important in your discussion.  These two raster layers have different cell sizes.  Take note of this. You will first need to use the Raster Calculator to create a Boolean (1, 0) raster layer of the High IDZ (=> 3 metre elevations) and separately, the LOW IDZ ( 3 AND =>=> you report the data). These two sets of layers now provide the zoning for you to carry out two Zonal Statistics as Table calculations of what populations fall in each pair of zones. Make sure you do not use the Zonal Statistics function, you need Zonal Statistics as Table to obtain the sum of the population in these zones in a table.   See below, but before hitting the OK button, click the Environments button. Once you have hit the Environments button, you now need to constrain the calculation to the southern Regencies.  To be consistent you will use the Southern_regencies layer you created as a mask.  This will mask out all raster cells outside of these areas.  To do this, first click the heading called Raster Analysis and then select the Southern_regencies vector layer. Also make sure the cell size is the same as the Population raster grid to ensure the most precision in the results.Practical 3: Tsunami risk in Indonesia 10 Now hit OK on both dialog boxes.  A table will now appear in your TOC.  Open this up and observe the Sum value for the row of the IDZ zone where Value = 1.  In other words, values = 1 in each of your IDZâ€s represent True to your Raster Calculation, while values = 0 represent False.   You need to record the True Sum of the population each time. Comparing the 2010 data with 2007 data. To make the 2007 impact estimates more comparable with the 2010 estimates, use a multiplication factor of 1.58599.  This is multiplied by any of your 2007 estimates to approximate the populations in 2010.    The figure is based on the US Census Bureauâ€s International statistics (see www.censuz.gov). Here they estimated the population growth rate of Indonesia as a whole in 2005 was 1.3 per annum, while the population growth rate in 2014 is likely to be 1.0 per annum.  Over the three years between 2007 and 2010, using these figures one can estimate it as 1.1998 (2008) * 1.1665 (2009) * 1.1332 (2009) = 1.58599. In your report Methods section, construct a flow chart of the raster operations you performed. Issues to bear in mind Unlike the vector analysis, you will only be able to assess the impact to the total population in each IDZ because this data has not been divided into age classes. How do these results compare with the vector results? Practical 3: Tsunami risk in Indonesia 11 3.0 Discussion In order to be able to discuss your results you will need to become familiar with the limitations of the data you have been provided.  Please read the documentation associated with each dataset. In your discussion, first summarize your key findings (from key questions, raster and vector).  Then discuss why these results differ between the two methods.   In this section think about the time the data were recorded, the coarse adjustment, scale and accuracy.  Also look up the definition and issues associated with the Modifiable Areal Unit Problem (MAUP) from the literature. Finish by summarizing the limitations of the method and how these could be improved.  Use the references provided (and any others you find) to help you discuss the limitations. 4.0 Assessment a. Your main report must be presented clearly and succinctly with the rigid structure of Abstract, Contents, Introduction, Methods, Results and ‘Discussion and Summaryâ€.  You will also need a References section in the Harvard format. (10 marks) b. Be sure to connect your Introduction, Methods section and Discussion and Summary sections well to the literature.  A good reference list using published papers rather than just Web sources will be highly regarded.  Relate relevant literature principally to the GIS methodology but general statements about Tsunami risk in this region should also be backed up with sources. (20 marks) c. After you present your key findings in the Discussion and Summary section, you should then list Assumptions made.  Limitations follow this along with Future Recommendations (in terms of method improvement). (20 marks) d. You must also supply an A4 map layout, included as an Appendix, with information of your choice to help present and explain your results.  Refer to the Appendix in your main report.  In other words, use the layout to point the reader to key findings in the results and discussion sections. (10 marks) e. You must also submit a log file as a separate .pdf.  The required contents of this are discussed above.  The format of these files is your choice.  But this needs to be an effective future reference for you to use, would you need to use these functions again.  So try to add any tips and traps you encountered when carrying out these operations and include these in this document. (10 marks) Practical 3: Tsunami risk in Indonesia 12 f. Spelling, good sentence structure and grammar (15 marks) g. Correct results and the questions are addressed. (15 marks) Total Marks:  100 References (other than provided) Central Bureau of Statistics. 2010.   Results of Population Census 2010: Data Aggregated by Provence. Badan Pusat Statistik.The post Practical 3: Tsunami risk in Indonesia 1 Practical 3: Risk Assessment using Ma appeared first on Lion Essays. “Looking for a Similar Assignment? 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