Magnitude 1.5, Fri May 28 2021 4:49 PM


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Origin


PublicID 2021p397838
UTC Time 2021-05-28T04:49:00Z
Latitude -41.16 (± 13.3 km)
Longitude 172.60 (± 7.2 km)
Depth 109 km (± 14 km)
Depth Type free
Earth Model iasp91
Used Phase Count 14
Used Station Count 9
Standard Error 0.36 (s)
Azimuthal Gap 188.15 (degrees)
Minimum Distance 0.27 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (MLv) 1.5  
MLv 1.5 1
M 1.5 1

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)012Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.0MagnitudeDistance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (MLv)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (MLv)