Magnitude 4.1, Thu May 6 2021 4:59 PM


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Origin


PublicID 2021p338401
UTC Time 2021-05-06T04:59:28Z
Latitude -32.95 (± 47.1 km)
Longitude -179.04 (± 55.7 km)
Depth 294 km (± 79 km)
Depth Type free
Earth Model tab
Used Phase Count 11
Used Station Count 7
Standard Error 0.88 (s)
Azimuthal Gap 342.39 (degrees)
Minimum Distance 5.09 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 4.1  
ML 3.9 (± 0.4) 5
MLv 4.2 (± 0.6) 4
mB 4.2 (± 0.3) 3
Mw(mB) 3.2 (± 0.4) 3
M 4.1 4

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


-4.0-3.0-2.0-1.00.01.02.03.04.0residual (s)012345678Distance (degrees)Pick Residuals

Station Magnitudes (ML)


0.01.02.03.04.05.0Magnitude67Distance (degrees)Station Magnitudes (ML)

Station Magnitudes (MLv)


0.01.02.03.04.05.06.0Magnitude67Distance (degrees)Station Magnitudes (MLv)

Station Magnitudes (mB)


0.01.02.03.04.05.0Magnitude6Distance (degrees)Station Magnitudes (mB)

Magnitude Residuals (ML)


-1.00.01.0Residual67Distance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual67Distance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (mB)


-1.00.01.0Residual6Distance (degrees)Magnitude Residuals (mB)