Magnitude 4.1, Wed Aug 2 2017 12:04 PM


Download Event Information


Origin


PublicID 2017p575683
UTC Time 2017-08-02T00:04:06Z
Latitude -49.02 (± 15.7 km)
Longitude 164.98 (± 15.5 km)
Depth 33 km (± 0 km)
Depth Type operator assigned
Earth Model iasp91
Used Phase Count 13
Used Station Count 7
Standard Error 0.42 (s)
Azimuthal Gap 332.57 (degrees)
Minimum Distance 2.98 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 4.1  
MLv 4.1 (± 0.4) 2
ML 4.1 (± 0.1) 7
M 4.1 2

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)012345Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.04.05.0Magnitude3Distance (degrees)Station Magnitudes (MLv)

Station Magnitudes (ML)


0.01.02.03.04.05.0Magnitude34Distance (degrees)Station Magnitudes (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual3Distance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (ML)


-1.00.01.0Residual34Distance (degrees)Magnitude Residuals (ML)