Magnitude 6.5, Wed Sep 20 2017 1:43 PM


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Origin


PublicID 2017p708304
UTC Time 2017-09-20T01:43:32Z
Latitude -50.49 (± 18.9 km)
Longitude 163.20 (± 21.3 km)
Depth 33 km (± 0 km)
Depth Type operator assigned
Earth Model iasp91
Used Phase Count 15
Used Station Count 9
Standard Error 0.81 (s)
Azimuthal Gap 340.72 (degrees)
Minimum Distance 4.84 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 6.5  
MLv 6.8 (± 0.2) 10
ML 6.9 (± 0.1) 7
mB 6.3 (± 0.1) 6
Mw(mB) 6.0 (± 0.4) 6
M 6.5 10

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)02468101214Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.04.05.06.07.08.0Magnitude567Distance (degrees)Station Magnitudes (MLv)

Station Magnitudes (ML)


0.01.02.03.04.05.06.07.08.0Magnitude56Distance (degrees)Station Magnitudes (ML)

Station Magnitudes (mB)


0.01.02.03.04.05.06.07.0Magnitude6Distance (degrees)Station Magnitudes (mB)

Magnitude Residuals (MLv)


-1.00.01.0Residual567Distance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (ML)


-2.0-1.00.01.02.0Residual56Distance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (mB)


-1.00.01.0Residual6Distance (degrees)Magnitude Residuals (mB)