This severe earthquake generated over 200 landslides and several small-scale tsunami on the South Island's west coast.
| PublicID | 2103645 |
| UTC Time | 2003-08-21T12:12:49Z |
| Latitude | -45.19 (± 0.0 km) |
| Longitude | 166.83 (± 0.1 km) |
| Depth | 24 km (± 2 km) |
| Depth Type | free |
| Earth Model | nz1dr |
| Used Phase Count | 12 |
| Used Station Count | 10 |
| Standard Error | 0.19 (s) |
| Azimuthal Gap | 270.00 (degrees) |
| Minimum Distance | 0.46 (degrees) |
| Type | Magnitude | Station Count |
| Preferred (Mw) | 7.1 | |
| ML | 7.0 (± 0.2) | 10 |
| Mw | 7.1 | 0 |
GeoNet combines magnitudes into a summary magnitude, M, which consists of a weighted average of the individual magnitudes and attempts to be a best possible compromise between all magnitudes for a range of earthquake sizes.
Summary magnitude for GeoNet is then defined as:
M = (2 * MLv + (0.4 * number_of stations(Mw(mB)) - 1) * Mw(mB)) / (2 + (0.4 * number_of_stations(Mw(mB)) - 1))
Where MLv is local magnitude calculated on the vertical component and Mw(mB) is a Mw estimation based of mB by Bormann and Saul (2008).
Map showing stations with picks used to locate the earthquake. Stations with picks that have a zero weight in the solution are shown as small grey circles. Those with a higher weight are shown as larger circles. The quake is shown by the largest circle.