Magnitude 3.1, Fri Aug 25 2023 9:37 AM


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Origin


PublicID 2023p637570
UTC Time 2023-08-24T21:37:02Z
Latitude -37.20 (± 32.0 km)
Longitude 176.14 (± 38.1 km)
Depth 254 km (± 32 km)
Depth Type free
Earth Model iasp91
Used Phase Count 15
Used Station Count 9
Standard Error 0.55 (s)
Azimuthal Gap 303.54 (degrees)
Minimum Distance 1.31 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (MLv) 3.1 (± 0.5)  
MLv 3.1 (± 0.5) 6

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


-5.0-3.0-1.01.03.05.0residual (s)012345Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.04.05.0Magnitude234Distance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (MLv)


-2.0-1.00.01.02.0Residual234Distance (degrees)Magnitude Residuals (MLv)