Whakaari/White Island - Updates

Magnitude 4.5, Sun Nov 4 2018 10:32 PM

Download Event Information


PublicID 2018p830804
UTC Time 2018-11-04T09:32:40Z
Latitude -39.88 (± 2.3 km)
Longitude 176.83 (± 3.7 km)
Depth 18 km (± 3 km)
Depth Type free
Earth Model iasp91
Used Phase Count 30
Used Station Count 22
Standard Error 0.74 (s)
Azimuthal Gap 122.28 (degrees)
Minimum Distance 0.09 (degrees)


Type Magnitude Station Count
Preferred (M) 4.5  
ML 4.8 (± 0.4) 148
MLv 4.5 (± 0.4) 151
M 4.5 151

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

-5.0-3.0- (s)01234567Distance (degrees)Pick Residuals

Station Magnitudes (ML) (degrees)Station Magnitudes (ML)

Station Magnitudes (MLv) (degrees)Station Magnitudes (MLv)

Magnitude Residuals (ML)

- (degrees)Magnitude Residuals (ML)

Magnitude Residuals (MLv)

- (degrees)Magnitude Residuals (MLv)