Magnitude 8.1, Fri Mar 5 2021 8:28 AM


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Origin


PublicID 2021p169764
UTC Time 2021-03-04T19:28:32Z
Latitude -29.73 (± 0.0 km)
Longitude -177.28 (± 0.0 km)
Depth 26 km (± 0 km)
Depth Type free
Earth Model
Used Phase Count 0
Used Station Count 0
Standard Error 7.99 (s)
Azimuthal Gap 0.00 (degrees)
Minimum Distance 0.00 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (Mw(mB)) 8.1 (± 0.4)  
Mw(mB) 8.1 (± 0.4) 5

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


-36.0-34.0-32.0-30.0-28.0-26.0-24.0-22.0-20.0-18.0-16.0-14.0-12.0-10.0-8.0-6.0-4.0-2.00.02.04.06.08.010.012.014.016.018.020.022.024.026.028.030.032.034.036.0residual (s)024681012141618202224262830323436384042444648Distance (degrees)Pick Residuals