M 7.4 Hawke’s Bay Tue, Feb 3 1931

The 1931 Hawke’s Bay earthquake caused the largest loss of life and most extensive damage of any quake in New Zealand’s recorded history.



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Origin


PublicID 2178228
UTC Time 1931-02-02T22:47:00Z
Latitude -39.30 (± 0.0 km)
Longitude 177.00 (± 0.0 km)
Depth 20 km (± 0 km)
Depth Type operator assigned
Earth Model
Used Phase Count 0
Used Station Count 0
Standard Error 0.00 (s)
Azimuthal Gap 0.00 (degrees)
Minimum Distance 0.00 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (Mw) 7.4  
Mw 7.4 0
MS 7.8 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 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


residual (s)Distance (degrees)Pick Residuals