Magnitude 1.8, Sat Jun 23 2018 7:37 PM


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Origin


PublicID 2018p468425
UTC Time 2018-06-23T07:37:11Z
Latitude -40.33 (± 4.3 km)
Longitude 176.63 (± 5.7 km)
Depth 19 km (± 8 km)
Depth Type free
Earth Model iasp91
Used Phase Count 14
Used Station Count 7
Standard Error 0.26 (s)
Azimuthal Gap 189.42 (degrees)
Minimum Distance 0.03 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 1.8  
ML 2.2 (± 0.1) 5
MLv 1.8 (± 0.2) 4
M 1.8 4

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


-7.0-5.0-3.0-1.01.03.05.07.0residual (s)0123456Distance (degrees)Pick Residuals

Station Magnitudes (ML)


0.01.02.03.0MagnitudeDistance (degrees)Station Magnitudes (ML)

Station Magnitudes (MLv)


0.01.02.0MagnitudeDistance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (ML)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (MLv)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (MLv)