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 | 2021p201946 |
| UTC Time | 2021-03-16T17:15:54Z |
| Latitude | -33.53 (± 10.8 km) |
| Longitude | -179.02 (± 21.2 km) |
| Depth | 10 km (± 0 km) |
| Depth Type | operator assigned |
| Earth Model | iasp91 |
| Used Phase Count | 18 |
| Used Station Count | 11 |
| Standard Error | 1.18 (s) |
| Azimuthal Gap | 321.41 (degrees) |
| Minimum Distance | 4.57 (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.
| Type | Magnitude | Station Count |
|---|---|---|
| Preferred (M) | 4.1 | |
| M | 4.1 | 6 |
| Minimum distance | 4.57 (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 waveform propagation model (a given velocity model (1D or 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 the current solution, small (grey) points are observations not used.
