Earthquakes - There's more than just Shaking

This will be the first of several posts for our GIS Applications class. Our first few weeks will be on  on Natural Disasters.  Earthquakes is our first topic.    The first map is of NewMadrid.   It's an usual series of quakes in the middle of the US.   We concentrated on the vulnerable RailRoads.

The next three maps are a study of the Northridge, California quake in 1994.
We looked at the geology underneath the quake and surrounding area.
We compared the Velocity and Acceleration of the ground area based on recording stations data. Then we studied the aftershocks.

Lastly, we are to include the Process Summary describing our steps to the end.

Process:  Part I -

1)      Made copy of original NewMadrid.mxd  as ORG_NewMadrid.mxd before any analysis undertaken. 

2)      Viewing largest earthquakes on map- Identify 4:  SC-1886; AK- 1811 & MI- 1812 (2).

3)      Examining urban areas- Memphis, Tennessee could be wiped off map sitting in MMI zones IX & X, then St.Louis, Missouri in Zone VIII would sustain substantial damages.

4)      Set up “intersect” for urban areas in NewMadrid layer. 91 cities identified. In Urban Areas layer created summarized table: S:\...\EqHuman\NewMadrid\NewMadrid.mdb as UrbanRisk. Summary on selected records only.

5)      Calculated population density of the counties by ad ding field to layer (type Double)>Pop_Density (field highlighted)> field calculator > expression [POP2001]/[Shape_Area]  equates to  “based on population of 2001 census” per area of county   X number of persons per sq meter (linear unit).  Field was populated.

6)      Estimated population In the MMI zones: arctoolbox>analysis tools>overlay>intersect used layers ‘counties’ and NewMadrid MMi- output in NewMadrid.mdb/County_MMI (added as Data layer file)

7)      Created population summary table in county MMI zones. In County_MMI layer created new field POP2001ADJ- (with type-long integer)  field calculator – [pop_densisty]*[shape_area]     then on same field created summary table in NewMadrid.mdb called PopMMI.  Table shows MMI zone, counties in each zone and total population in each zone. Using stats on the sum field total affected people (60,088,587).

8)      Created graph of Population in MMI zones.  Used graph wizard.  (in TOC-create graph)

9)      Step 7. Identified vulnerable interstates. Using NewMadridMMI layer, added field MMI-num (type short integer) In edit mode, populated field showing numbers for each MMI roman numeral zone.  Made separate layer for zones 8-10 to use for clipping. (MMI_8to10).

10)  Clipped interstates to MMI_8to10.   Clipped railroads zone 10, created new layer- Railrisk.

11)  Step 9. Used layer MMI_8to10 to select by location all dams completely within it. Made new layer Dams_risk.  Saved this new map as Earthqk_1lab_NewMadrid.mxd. 

12)  In Catalog cleaned up file directory deleting unnecessary layers.

13)  New layers created & kept: County_MMI; MMI_8to10; Dams_Risk; 1stRD_risk; RailRisk

14)  Polished assignment with final jpeg map.  S:\GISApps\....\MyData\Earthqk_1lab_NewMadrid.mxd.

                                                                                                                                          

Part 2 Summary- Building Damage, Northridge

1)      Opened Map Northridge1.mxd, made copy of original to work with.  In building status layer, set up properties for unsafe & limited entry as suggested.   Created new layer  in main map for only unsafe & limited entry.  Source for GCS same- Nad 1927 UTM Zone 11N, Transverse Mercator projection, GCS   North American 1927, Clark 1866 spheroid Changed colors to RED for unsafe and lavender for limited entry.  Too many other layers in map had yellow base colors which made viewing structures too confusing.

2)      Using spatial analysis>Kernel Density>input building status (red/yellow only)> output DmgPat_REDYEL>search radius 5000>popfield none>outputcell 100; created damage analysis of buildings. Saved this new layer as …Eqhuman\MyData\DmgPat_REDYEL.lyr (renamed to building damage density)

3)      Created new layer: Building Damage Centerline, using the building damage density centers as baseline.  Named bldDmgLINE.shp, coupled it with Major Faults as source for comparison analysis.

4)       When creating my map, I saw the need to highlight the quaternary geological layer. Through select by attributes, I created a new shapefile layer in the Northridge file (GeoQuat.shp).

5)      Finally visuals clicked & created maps for delivery.

Part 4- Process Summary- Distribution of Aftershocks, Base Map-Northridge3.mxd

11)      Created graph of Aftershocks, showing number per day and number of days after main shock.  Saved graph as Noh3AFTMaxSH.shp (It showed 11949 aftershocks up to 522 days after main one). 

22)      The Main shock was already a feature on the map with its own attribute table.

33)      Created separate layer with aftershocks magnitude >=3.0, saved shapefile as Quakes>3.

Exported as new layer to map.

44)      Saved new map as FinalNRidge3_AftSHK.mxd to give it clearer definition in map directory.  Prepared output as a final map for delivery.

55)      Realized after completing Part 4 that I had page 3 of Part III in my instructions. 

66)      Performed a kernel density on the aftershocks used>cellsize 100>search 3000> sqkm; saved file as AftSHK_DEN.   Showed aftershocks were not near the main shock. Makes one wonder if a new fault was developing when we put the PGA & PGV together.

77)      Put graphs on separate new map to import them as jpegs to dropbox. Main summary table was saved as Noh3AFTMaxSUM. 

Part 3- Process Summary

1)                  After realizing I had pages mixed up, I was able to get started. Imported NorthridgeAfter.csv.  Changed projection (but not clear as to why). Did not have warning box. Created shapefile as needed.

2)                  Already had main shock on my map.  Created new shapefile Quakes>3. Went into properties, quantities>classification>manual for new labels 4, 5 & 6.

3)                  Made map of aftershocks saved as FinalNRidge3_AftSHK.jpeg.