Magnitude 3.1, Mon Jan 15 2018 9:51 AM


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Origin


PublicID 2018p037484
UTC Time 2018-01-14T20:51:38Z
Latitude -42.26 (± 3.4 km)
Longitude 173.56 (± 2.4 km)
Depth 5 km (± 5 km)
Depth Type free
Earth Model nz3drx
Used Phase Count 15
Used Station Count 8
Standard Error 0.35 (s)
Azimuthal Gap 108.35 (degrees)
Minimum Distance 0.15 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 3.1  
MLv 3.1 (± 0.3) 6
ML 3.3 (± 0.2) 6
M 3.1 6

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


-6.0-4.0-2.00.02.04.06.0residual (s)01234Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.04.0MagnitudeDistance (degrees)Station Magnitudes (MLv)

Station Magnitudes (ML)


0.01.02.03.04.0MagnitudeDistance (degrees)Station Magnitudes (ML)

Magnitude Residuals (MLv)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (ML)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (ML)