1. Hazards Planning and Risk Management Tsunami Inundation Mapping
Lecture No. 24
Tsunami Inundation Mapping
Fall 2016
US – Pakistan Center for Advanced Studies in Water

2. Learning Objective
To demonstrate use of geospatial data and techniques to map Tsunami inundation at Gawader, Pakistan
Reference for lab exercise: Coastal Flood Mapping in ArcGIS 2 2

3. Reading Material
Study and numerical modeling of 1945 Makran tsunami due to a probable submarine landslide merical_modeling_of_1945_Makran_tsunami_due_to_a_probable_su bmarine_landslide
International Centre for Water Hazard and Risk Management

4. DATASET
DEM
Study area shapefile
Tsunami simulated wave height

5. STUDY AREA Along subduction zone of Makran (MSZ)
MSZ has a potential of triggering future tsunami
Coastal communities in Pakistan are at a high risk
Gawadar, Pasni and Omara, with their fast growing population, are the most vulnerable cities due to their locations near MSZ

7. Numerical Simulation of Tsunami
Done by Pakistan Meteorological Department (PMD) using Nakamura software
For tsunami generation due to a possible future M8.5 earthquake scenario
Observation Point
Arrival Time (sec)
Tsunami Height (m) amsl
Karachi
7,200
2.8
Ormara
2,200
9.3
Pasni
2,900
8.5
Gawadar
1,550
8.8
Jiwani
1,100
8.9

10. Problem? To Identify Inundated Area
Identify Gawadar city area that will be inundated (God forbid) due to the simulated height of the tsunami wave

11. PROCESSING STEPS Download Digital Elevation Model (DEM)
Clip DEM with study area boundary shapefile

13. PROCESSING STEPS ArcMap tools Map algebra  Raster Calculator
new raster will be created with 1, 0

14. PROCESSING STEPS
Reclass  Reclassify
0 = Nodata, 1= 1

15. PROCESSING STEPS
Remove areas that are not hydrologically connected to the coastline
Convert reclassified raster DEM into vector data

16. PROCESSING STEPS Use selection tool
Select by location –spatial selection method … = are crossed by the outline of the source layer feature
Save selected features as new layer
Calculate Area
Add field in attribute table
Calculate geometry  area (select units)

17. PROCESSING STEPS Use selection tool
Select by location –spatial selection method … = are crossed by the outline of the source layer feature
Save selected features as new layer

18. PROCESSING STEPS Calculate percent inundation
Calculate area of study site (use boundary shapefile)
Divide inundation area by study area and multiply with 100

19. Inundation Layout

20. Risk and Damage Assessment
Acquire or digitize GIS layers of element at risk
Buildings
Roads
Utilities
Other sites
Overlay inundation extent on these layers
Identify risk areas

21. Identify Safe Evacuation Routes
How?

22. Thank you