Magnitude 6.0, Tue Jan 18 1977 6:41 PM


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Origin


PublicID 1558224
UTC Time 1977-01-18T05:41:48Z
Latitude -41.84 (± 0.0 km)
Longitude 174.58 (± 0.1 km)
Depth 33 km (± 0 km)
Depth Type operator assigned
Earth Model nz1d
Used Phase Count 10
Used Station Count 9
Standard Error 0.80 (s)
Azimuthal Gap 164.00 (degrees)
Minimum Distance 0.58 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (Mw) 6.0  
ML 6.0 (± 0.2) 4
MS 5.9 0
Mw 6.0 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)012Distance (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)