Select a format below to download the complete technical data for this earthquake. [Succinct microcopy that describes what QUAKEML and STRONG is and that the open data in the current tab and do not download a file and that shaking layers is on an external site]
Calculated source location of the earthquake. It contains the parameters GeoNet's location software derived from seismic station observations.
| PublicID | 2012p662861 |
| UTC Time | 2012-09-02T06:12:21Z |
| Latitude | -44.58 (± 4.4 km) |
| Longitude | 168.26 (± 5.7 km) |
| Depth | 5 km (± 0 km) |
| Depth Type | operator assigned |
| Earth Model | nz3drx |
| Used Phase Count | 13 |
| Used Station Count | 8 |
| Standard Error | 0.77 (s) |
| Azimuthal Gap | 157.15 (degrees) |
| Minimum Distance | 0.25 (degrees) |
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.
The different magnitudes GeoNet uses to calculate the summary magnitude.
| Type | Magnitude | Station Count |
|---|---|---|
| Preferred (M) | 2.7 | |
| MLv | 2.7 (± 0.3) | 8 |
| ML | 2.8 (± 0.1) | 6 |
| M | 2.7 | 8 |
| Minimum distance | 0.25 (degree) |
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).
Observed arrival time at a seismic station compared to a predicted arrival time from a GeoNet's waveform propagation model (a given velocity model (1D-3D)). A residual of 0 s indicates that the observed seismic phase arrival time (typically P or S) matches the arrival time predicted by the GeoNet velocity model. Low residuals across multiple well-distributed stations increase confidence in the estimated event location and origin time. Large (brown) points are used to determine final solution, small (grey) points are not used in final solution.
MLv is the local (Richter) magnitude computed from amplitudes measured on the vertical component.
The individual magnitude estimates calculated from each seismic station using the ML (Local Magnitude) method. ML is the standard local (Richter) magnitude originally designed for Southern California by Richter (1935).
