This document describes an interactive web map of New Zealand earthquakes created by Harris Ohland. The map displays earthquake data from 1986 to 2016 with magnitudes of 4.0 or greater within 1750km of specified coordinates, obtained from the USGS earthquake archive. It also shows active fault data from New Zealand's GNS active fault shapefile. The map allows users to filter earthquakes by magnitude, depth, and year using slider filters and toggle the display of fault and plate boundary layers.

1. An Interactive Web Map of
New Zealand Earthquakes
BY HARRIS OHLAND

2. • Pacific plate subducts under Australian
plate to the North
• Australian plate subducts under Pacific
plate to the South
• Alpine fault zone in between (Australian
side moving North, Pacific side moving
South)
Source: https://upload.wikimedia.org/wikipedia/commons/8/8a/NZ_faults.png

3. USGS earthquake records (CSV) GNS Active Faults (shapefile)
All earthquakes within a 1750km of 41°16′15″S 173°17′2″E occuring from 1986 to
2016 with magnitudes 4.0 or greater and focal depths of 300km or less.

4. Demo

5. External scripts and stylesheets for
Mapbox and jQuery
Map container
Menu container and subcontainers

7. Mapbox access token
Global variables and map
Functions

8. • Add vector tileset source from Mapbox
Studio
• Set ‘mag’ variable and start ‘while’ loop that
will add one layer per unique magnitude
value
• Set circle radius based on magnitude value
and zoom level
• Set circle color based on magnitude
• Increment ‘mag’ variable by 0.1, add to
‘floats’ array, convert to float

9. • Set ‘mag’ variable, get min. and max.
values from the magnitude range
slider
• Use if/else statement to make layers
outside the specified range not visible

10. • Create new filter array using the
values from the ‘depth’ and ‘year’
range slider
• Update the filters for each layer

11. • Use if/else statement to set visibility
property for faults and plate
boundary when checked

12. • Create new filter array using the
values from the ‘depth’ and ‘year’
range slider
• Update the filters for each layer

14. Data Sources
Earthquakes
Institution: United States Geological Survey
Database: Earthquake Archive
URL: http://earthquake.usgs.gov/fdsnws/event/1/query.csv?starttime=1986-05-
15%2000:00:00&endtime=2016-05-15%2023:59:59&latitude=-
41.271&longitude=173.284&maxradiuskm=1750&minmagnitude=4&eventtype=earthquake
&orderby=time
Faults
Institution: New Zealand Institue of Geological and Nuclear Sciences
Database: Active Fault Database
URL: http://data.gns.cri.nz/af/exportShp.html

15. Special thanks to
• Kathleen Stewart
• Monica Lloyd
• Dave McLean
• Jim Verran
• Dr. Euan Smith