Magnitude 2.7, Fri May 28 2021 3:03 AM


Download Event Information


Origin


PublicID 2021p396289
UTC Time 2021-05-27T15:03:07Z
Latitude -37.43 (± 22.4 km)
Longitude -179.93 (± 23.4 km)
Depth 20 km (± 42 km)
Depth Type free
Earth Model iasp91
Used Phase Count 16
Used Station Count 9
Standard Error 0.46 (s)
Azimuthal Gap 334.71 (degrees)
Minimum Distance 1.37 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 2.7  
ML 2.8 (± 0.1) 7
MLv 2.7 (± 0.2) 6
M 2.7 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


-2.0-1.00.01.02.0residual (s)0123Distance (degrees)Pick Residuals

Station Magnitudes (ML)


0.01.02.03.04.0Magnitude2Distance (degrees)Station Magnitudes (ML)

Station Magnitudes (MLv)


0.01.02.03.04.0Magnitude2Distance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (ML)


-1.00.01.0Residual2Distance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual2Distance (degrees)Magnitude Residuals (MLv)