Magnitude 4.4, Thu Oct 22 2015 10:43 PM

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PublicID 2015p795690
UTC Time 2015-10-22T09:43:59Z
Latitude -41.20 (± 0.9 km)
Longitude 175.08 (± 1.3 km)
Depth 6 km (± 2 km)
Depth Type free
Earth Model nz3drx
Used Phase Count 52
Used Station Count 46
Standard Error 0.80 (s)
Azimuthal Gap 55.14 (degrees)
Minimum Distance 0.06 (degrees)


Type Magnitude Station Count
Preferred (M) 4.4  
MLv 4.4 (± 0.3) 155
ML 4.6 (± 0.2) 18
M 4.4 155

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- (s)0123456Distance (degrees)Pick Residuals

Station Magnitudes (MLv) (degrees)Station Magnitudes (MLv)

Station Magnitudes (ML) (degrees)Station Magnitudes (ML)

Magnitude Residuals (MLv)

- (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (ML)

- (degrees)Magnitude Residuals (ML)