Magnitude 4.7, Mon Mar 2 2020 4:40 PM


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Origin


PublicID 2020p165286
UTC Time 2020-03-02T03:40:21Z
Latitude -31.10 (± 6.6 km)
Longitude -177.76 (± 26.6 km)
Depth 12 km (± 0 km)
Depth Type operator assigned
Earth Model iasp91
Used Phase Count 11
Used Station Count 9
Standard Error 3.54 (s)
Azimuthal Gap 208.44 (degrees)
Minimum Distance 1.84 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 4.7  
ML 4.6 (± 0.3) 3
MLv 4.7 (± 0.3) 2
M 4.7 2

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


-9.0-7.0-5.0-3.0-1.01.03.05.07.09.0residual (s)0123456789Distance (degrees)Pick Residuals

Station Magnitudes (ML)


0.01.02.03.04.05.0Magnitude234567Distance (degrees)Station Magnitudes (ML)

Station Magnitudes (MLv)


0.01.02.03.04.05.0Magnitude234567Distance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (ML)


-1.00.01.0Residual234567Distance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual234567Distance (degrees)Magnitude Residuals (MLv)