M 6.4 Weber II Sun, May 13 1990

This earthquake was the second large shock to strike the Weber region in 1990, occurring 12 weeks after its predecessor.



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Origin


PublicID 125056
UTC Time 1990-05-13T04:23:10Z
Latitude -40.43 (± 0.0 km)
Longitude 176.47 (± 0.0 km)
Depth 30 km (± 1 km)
Depth Type free
Earth Model nz1dr
Used Phase Count 39
Used Station Count 37
Standard Error 0.11 (s)
Azimuthal Gap 90.00 (degrees)
Minimum Distance 0.24 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (Mw) 6.4  
ML 6.2 (± 0.2) 12
Mb 6.0 0
MS 6.4 0
Mw 6.4 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


-3.0-2.0-1.00.01.02.03.0residual (s)01234567Distance (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)