Magnitude 3.8, Fri Mar 15 2019 5:17 PM


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Origin


PublicID 2019p197780
UTC Time 2019-03-15T04:17:38Z
Latitude -31.13 (± 5.5 km)
Longitude -177.32 (± 27.1 km)
Depth 33 km (± 0 km)
Depth Type operator assigned
Earth Model iasp91
Used Phase Count 11
Used Station Count 6
Standard Error 0.94 (s)
Azimuthal Gap 221.92 (degrees)
Minimum Distance 1.93 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 3.8  
MLv 3.8 1
ML 4.5 (± 0.3) 3
M 3.8 1

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)012345678Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.04.0MagnitudeDistance (degrees)Station Magnitudes (MLv)

Station Magnitudes (ML)


0.01.02.03.04.05.0Magnitude234567Distance (degrees)Station Magnitudes (ML)

Magnitude Residuals (MLv)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (ML)


-1.00.01.0Residual234567Distance (degrees)Magnitude Residuals (ML)