Magnitude 2.4, Fri Feb 9 2018 10:57 AM


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Origin


PublicID 2018p105175
UTC Time 2018-02-08T21:57:18Z
Latitude -39.40 (± 9.5 km)
Longitude 174.02 (± 10.1 km)
Depth 18 km (± 18 km)
Depth Type free
Earth Model iasp91
Used Phase Count 14
Used Station Count 7
Standard Error 1.08 (s)
Azimuthal Gap 232.82 (degrees)
Minimum Distance 1.82 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 2.4  
MLv 2.4 (± 0.1) 3
ML 2.8 (± 0.2) 7
M 2.4 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


-8.0-6.0-4.0-2.00.02.04.06.08.0residual (s)0123Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.0Magnitude2Distance (degrees)Station Magnitudes (MLv)

Station Magnitudes (ML)


0.01.02.03.04.0Magnitude2Distance (degrees)Station Magnitudes (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual2Distance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (ML)


-1.00.01.0Residual2Distance (degrees)Magnitude Residuals (ML)