Magnitude 3.8, Mon Jan 30 2023 5:44 AM


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Origin


PublicID 2023p077563
UTC Time 2023-01-29T16:44:31Z
Latitude -31.56 (± 37.1 km)
Longitude 179.41 (± 74.7 km)
Depth 408 km (± 102 km)
Depth Type free
Earth Model iasp91
Used Phase Count 12
Used Station Count 8
Standard Error 1.01 (s)
Azimuthal Gap 352.07 (degrees)
Minimum Distance 6.30 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (mB) 3.8 (± 0.1)  
MLv 4.5 1
ML 4.2 1
mB 3.8 (± 0.1) 3
Mw(mB) 2.8 (± 0.4) 3
M 4.3 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


-3.0-2.0-1.00.01.02.03.0residual (s)01234567Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.04.05.0MagnitudeDistance (degrees)Station Magnitudes (MLv)

Station Magnitudes (ML)


0.01.02.03.04.05.0MagnitudeDistance (degrees)Station Magnitudes (ML)

Station Magnitudes (mB)


0.01.02.03.04.0Magnitude7Distance (degrees)Station Magnitudes (mB)

Magnitude Residuals (MLv)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (ML)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (mB)


-1.00.01.0Residual7Distance (degrees)Magnitude Residuals (mB)