Magnitude 4.6, Wed Aug 2 2023 1:30 PM


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Origin


PublicID 2023p575851
UTC Time 2023-08-02T01:30:08Z
Latitude -32.93 (± 6.8 km)
Longitude -177.56 (± 22.1 km)
Depth 33 km (± 0 km)
Depth Type operator assigned
Earth Model tab
Used Phase Count 9
Used Station Count 8
Standard Error 2.06 (s)
Azimuthal Gap 215.29 (degrees)
Minimum Distance 3.67 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (Mw(mB)) 4.6 (± 0.4)  
mB 5.2 (± 0.1) 4
Mw(mB) 4.6 (± 0.4) 3
ML 4.8 (± 0.1) 7
MLv 4.9 (± 0.1) 5
M 4.8 5

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


-11.0-9.0-7.0-5.0-3.0-1.01.03.05.07.09.011.0residual (s)0123456789Distance (degrees)Pick Residuals

Station Magnitudes (mB)


0.01.02.03.04.05.06.0Magnitude7Distance (degrees)Station Magnitudes (mB)

Station Magnitudes (ML)


0.01.02.03.04.05.06.0Magnitude4567Distance (degrees)Station Magnitudes (ML)

Station Magnitudes (MLv)


0.01.02.03.04.05.06.0Magnitude4567Distance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (mB)


-1.00.01.0Residual7Distance (degrees)Magnitude Residuals (mB)

Magnitude Residuals (ML)


-1.00.01.0Residual4567Distance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual4567Distance (degrees)Magnitude Residuals (MLv)