Magnitude 6.1, Fri Aug 22 2003 2:12 AM


Download Event Information


Origin


PublicID 2169849
UTC Time 2003-08-21T14:12:27Z
Latitude -45.36 (± 0.0 km)
Longitude 166.82 (± 0.0 km)
Depth 24 km (± 2 km)
Depth Type free
Earth Model nz1dr
Used Phase Count 14
Used Station Count 9
Standard Error 0.21 (s)
Azimuthal Gap 279.00 (degrees)
Minimum Distance 0.36 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (Mw) 6.1  
ML 6.1 (± 0.2) 14
Mw 6.1 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)0123456789Distance (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)