Magnitude 4.7, Tue Sep 30 2025 9:24 AM


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Origin


PublicID 2025p734741
UTC Time 2025-09-29T20:24:59Z
Latitude -27.96 (± 6.0 km)
Longitude -177.91 (± 12.3 km)
Depth 100 km (± 0 km)
Depth Type operator assigned
Earth Model iasp91
Used Phase Count 9
Used Station Count 9
Standard Error 0.79 (s)
Azimuthal Gap 155.39 (degrees)
Minimum Distance 10.09 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (mB) 4.7 (± 0.5)  
mB 4.7 (± 0.5) 2
Mw(mB) 3.9 (± 0.5) 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


-23.0-21.0-19.0-17.0-15.0-13.0-11.0-9.0-7.0-5.0-3.0-1.01.03.05.07.09.011.013.015.017.019.021.023.0residual (s)0246810121416Distance (degrees)Pick Residuals

Station Magnitudes (mB)


0.01.02.03.04.05.0Magnitude111315Distance (degrees)Station Magnitudes (mB)

Magnitude Residuals (mB)


-1.00.01.0Residual111315Distance (degrees)Magnitude Residuals (mB)