This non-uniform grid is based one the previous version defined here with the key differences:
- No longer using vs500 but instead using vs30 as a parameter
- The transfer function for scoring is: 1 for vs30 < 200; 0 for vs30 < 600; and linear in between
- total_score_domain = w_v*score_vs30 + w_p*score_population; w_v + w_p = 1.0
- w_v and w_p = 0.5
- The acceptance threshold for points to split were 0.7
The picture shows blue points: added points in the new grid. purple points: points in both grids and red points: points removed in the new grid
Number of stations in the grids proposed.
| 20170617 | 200<vs30<800 | 200<vs30<600 | 50:50 weighting 0.6 acceptance | 50:50 weighting 0.7 acceptance (18p6 final version) | |
|---|---|---|---|---|---|
| 400m | 39103 | 53177 | 53177 | 50106 | 47524 |
| 200m | 59687 | 97123 | (83000 - 91000) - estimate | 80922 | |
| 100m | 79510 | 140702 | (117000 - 132000) - estimate | 113682 |
Naming
The station *.ll files contain lines like the following
167.426710 -34.059020 0100001
The first digit is the level associated with it 0 is part of the base grid and level 4 is the finest resolution in the 100 m grid.
The second digit is a versioning number. This is just to make sure the 17p6 version has different names to the 18p6 version. This version has been coded as 1.
vs30 files
These have been generated using NZ_vs30_18p4. For stations that did not have a value a default of 500 m/s was used.
Real Stations
On hypocentre/kupe the non_uniform_whole_nz_with_real_stations* files have added 2164 stations.
There are 2242 unique stations as of 20180615.
Removing stations off the coast of NZ returns 2164
Removing stations that are closed and only keeping stations that are of the network: NZ, SM, SC, SB or SX. returns 385
(NZ (included per Brendon's advice
SM National strong motion network
SC Canterbury regional strong motion network
SB is included in http://info.geonet.org.nz/display/equip/Network+Location+Queries
operational strong motions stations XML file.
SX private sites strong motion.)
Future Changes
Wellington & Christchurch CBD overide / areas of high vs30 change
Varied level scoring thresholds
Plot for scores across NZ to visualize where scoring thresholds should be.
Selection of current Real Stations (instead of historic)
Finer grid than 5x smaller