Magnitude 5.5, Sat May 31 2025 9:30 AM


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Origin


PublicID 2025p405133
UTC Time 2025-05-30T21:30:33Z
Latitude -21.18 (± 9.5 km)
Longitude -175.16 (± 7.4 km)
Depth 100 km (± 0 km)
Depth Type operator assigned
Earth Model iasp91
Used Phase Count 7
Used Station Count 6
Standard Error 1.25 (s)
Azimuthal Gap 130.99 (degrees)
Minimum Distance 5.34 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (mB) 5.5 (± 0.5)  
MLv 5.5 (± 0.4) 2
mB 5.5 (± 0.5) 2
Mw(mB) 4.9 (± 0.5) 2
M 5.5 2

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


-6.0-4.0-2.00.02.04.06.0residual (s)0246810121416182022Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.04.05.06.0Magnitude67Distance (degrees)Station Magnitudes (MLv)

Station Magnitudes (mB)


0.01.02.03.04.05.06.0Magnitude6810121416182022Distance (degrees)Station Magnitudes (mB)

Magnitude Residuals (MLv)


-1.00.01.0Residual67Distance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (mB)


-1.00.01.0Residual6810121416182022Distance (degrees)Magnitude Residuals (mB)