Magnitude 2.1, Sat Mar 6 2021 5:30 AM


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Origin


PublicID 2021p172129
UTC Time 2021-03-05T16:30:53Z
Latitude -39.82 (± 4.0 km)
Longitude 176.75 (± 4.9 km)
Depth 16 km (± 10 km)
Depth Type free
Earth Model iasp91
Used Phase Count 13
Used Station Count 9
Standard Error 0.29 (s)
Azimuthal Gap 110.45 (degrees)
Minimum Distance 0.10 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 2.1  
M 2.1 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


-17.0-15.0-13.0-11.0-9.0-7.0-5.0-3.0-1.01.03.05.07.09.011.013.015.017.0residual (s)01Distance (degrees)Pick Residuals