Magnitude 3.9, Mon Oct 23 2023 12:21 PM


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Origin


PublicID 2023p797226
UTC Time 2023-10-22T23:21:07Z
Latitude -31.71 (± 21.1 km)
Longitude 179.63 (± 97.9 km)
Depth 33 km (± 0 km)
Depth Type operator assigned
Earth Model iasp91
Used Phase Count 8
Used Station Count 8
Standard Error 0.75 (s)
Azimuthal Gap 351.35 (degrees)
Minimum Distance 6.44 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (Mw(mB)) 3.9 (± 0.4)  
mB 4.7 (± 0.0) 2
Mw(mB) 3.9 (± 0.4) 2
ML 4.3 (± 0.2) 7
MLv 4.2 (± 0.3) 3
M 4.2 3

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


-64.0-62.0-60.0-58.0-56.0-54.0-52.0-50.0-48.0-46.0-44.0-42.0-40.0-38.0-36.0-34.0-32.0-30.0-28.0-26.0-24.0-22.0-20.0-18.0-16.0-14.0-12.0-10.0-8.0-6.0-4.0-2.00.02.04.06.08.010.012.014.016.018.020.022.024.026.028.030.032.034.036.038.040.042.044.046.048.050.052.054.056.058.060.062.064.0residual (s)012345678Distance (degrees)Pick Residuals

Station Magnitudes (mB)


0.01.02.03.04.05.0Magnitude7Distance (degrees)Station Magnitudes (mB)

Station Magnitudes (ML)


0.01.02.03.04.05.0Magnitude7Distance (degrees)Station Magnitudes (ML)

Station Magnitudes (MLv)


0.01.02.03.04.05.0Magnitude7Distance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (mB)


-1.00.01.0Residual7Distance (degrees)Magnitude Residuals (mB)

Magnitude Residuals (ML)


-1.00.01.0Residual7Distance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual7Distance (degrees)Magnitude Residuals (MLv)