Magnitude 4.3, Sat Aug 21 2021 11:59 PM


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Origin


PublicID 2021p628380
UTC Time 2021-08-21T11:59:15Z
Latitude -26.56 (± 12.2 km)
Longitude -179.77 (± 33.9 km)
Depth 340 km (± 30 km)
Depth Type free
Earth Model iasp91
Used Phase Count 11
Used Station Count 8
Standard Error 0.89 (s)
Azimuthal Gap 297.27 (degrees)
Minimum Distance 3.15 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 4.3  
M 4.3 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


-10.0-8.0-6.0-4.0-2.00.02.04.06.08.010.0residual (s)02468101214Distance (degrees)Pick Residuals