Magnitude 3.2, Mon Jan 18 2021 11:45 PM


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Origin


PublicID 2021p047157
UTC Time 2021-01-18T10:45:13Z
Latitude -35.47 (± 29.1 km)
Longitude 178.78 (± 33.0 km)
Depth 204 km (± 34 km)
Depth Type free
Earth Model iasp91
Used Phase Count 17
Used Station Count 9
Standard Error 0.56 (s)
Azimuthal Gap 341.83 (degrees)
Minimum Distance 2.12 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (MLv) 3.2 (± 0.3)  
ML 3.2 (± 0.2) 7
MLv 3.2 (± 0.3) 7
M 3.2 7

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).

Origin Map


Map of New Zealand.

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.

Pick Residuals


-2.0-1.00.01.02.0residual (s)0123Distance (degrees)Pick Residuals

Station Magnitudes (ML)


0.01.02.03.04.0Magnitude3Distance (degrees)Station Magnitudes (ML)

Station Magnitudes (MLv)


0.01.02.03.04.0Magnitude3Distance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (ML)


-1.00.01.0Residual3Distance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual3Distance (degrees)Magnitude Residuals (MLv)