Magnitude 6.4, Fri Apr 28 2023 3:13 PM


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Origin


PublicID 2023p316582
UTC Time 2023-04-28T03:13:43Z
Latitude -25.11 (± 0.0 km)
Longitude 178.46 (± 0.0 km)
Depth 576 km (± 0 km)
Depth Type free
Earth Model
Used Phase Count 0
Used Station Count 0
Standard Error 2.84 (s)
Azimuthal Gap 0.00 (degrees)
Minimum Distance 0.00 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (mB) 6.4 (± 0.2)  
mB 6.4 (± 0.2) 53
Mw(mB) 6.1 (± 0.4) 134
MLv 7.3 (± 0.5) 3
M 6.2 134

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


-7.0-5.0-3.0-1.01.03.05.07.0residual (s)02468101214161820222426Distance (degrees)Pick Residuals

Station Magnitudes (mB)


0.01.02.03.04.05.06.07.08.0Magnitude02468101214161820222426Distance (degrees)Station Magnitudes (mB)

Station Magnitudes (MLv)


0.01.02.03.04.05.06.07.08.0Magnitude67Distance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (mB)


-2.0-1.00.01.02.0Residual02468101214161820222426Distance (degrees)Magnitude Residuals (mB)

Magnitude Residuals (MLv)


-1.00.01.0Residual67Distance (degrees)Magnitude Residuals (MLv)