Magnitude 3.1, Tue Nov 7 2017 11:41 PM



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Origin


PublicID 2017p839041
UTC Time 2017-11-07T10:41:22Z
Latitude -42.31 (± 4.2 km)
Longitude 173.69 (± 6.5 km)
Depth 10 km (± 6 km)
Depth Type free
Earth Model iasp91
Used Phase Count 15
Used Station Count 9
Standard Error 0.32 (s)
Azimuthal Gap 146.34 (degrees)
Minimum Distance 0.12 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 3.1  
MLv 3.1 (± 0.1) 13
ML 3.2 (± 0.1) 6
M 3.1 13

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


-4.0-3.0-2.0-1.00.01.02.03.04.0residual (s)01234Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.04.0Magnitude01Distance (degrees)Station Magnitudes (MLv)

Station Magnitudes (ML)


0.01.02.03.04.0Magnitude0Distance (degrees)Station Magnitudes (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual01Distance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (ML)


-1.00.01.0Residual0Distance (degrees)Magnitude Residuals (ML)