Magnitude 5.5, Sat Aug 23 2003 9:13 PM


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Origin


PublicID 2281164
UTC Time 2003-08-23T09:13:54Z
Latitude -45.31 (± 0.0 km)
Longitude 166.92 (± 0.0 km)
Depth 28 km (± 1 km)
Depth Type free
Earth Model nz1dr
Used Phase Count 18
Used Station Count 7
Standard Error 0.28 (s)
Azimuthal Gap 208.00 (degrees)
Minimum Distance 0.09 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (Mw) 5.5  
ML 5.5 (± 0.2) 13
Mw 5.5 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)0Distance (degrees)Pick Residuals

Station Magnitudes (ML)


0.01.02.03.04.05.06.0Magnitude0Distance (degrees)Station Magnitudes (ML)

Magnitude Residuals (ML)


-1.00.01.0Residual0Distance (degrees)Magnitude Residuals (ML)