Magnitude 6.7, Mon Dec 31 1984 10:36 AM


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Origin


PublicID 1566122
UTC Time 1984-12-30T21:36:54Z
Latitude -36.59 (± 0.1 km)
Longitude 177.55 (± 0.1 km)
Depth 12 km (± 0 km)
Depth Type operator assigned
Earth Model nz1d
Used Phase Count 12
Used Station Count 9
Standard Error 0.80 (s)
Azimuthal Gap 207.00 (degrees)
Minimum Distance 1.37 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (Mw) 6.7  
ML 6.3 (± 0.3) 10
MS 6.8 0
Mw 6.7 0

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


-2.0-1.00.01.02.0residual (s)012345Distance (degrees)Pick Residuals

Station Magnitudes (ML)


0.01.02.03.04.05.06.07.0Magnitude0Distance (degrees)Station Magnitudes (ML)

Magnitude Residuals (ML)


-1.00.01.0Residual0Distance (degrees)Magnitude Residuals (ML)