Magnitude 2.5, Wed Jun 21 2017 9:22 PM


Download Event Information


Origin


PublicID 2017p463218
UTC Time 2017-06-21T09:22:56Z
Latitude -42.67 (± 4.7 km)
Longitude 172.78 (± 3.6 km)
Depth 8 km (± 9 km)
Depth Type free
Earth Model iasp91
Used Phase Count 10
Used Station Count 6
Standard Error 0.21 (s)
Azimuthal Gap 113.18 (degrees)
Minimum Distance 0.35 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (ML) 2.5 (± 0.4)  
ML 2.5 (± 0.4) 11

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)01Distance (degrees)Pick Residuals

Station Magnitudes (ML)


0.01.02.03.0Magnitude1Distance (degrees)Station Magnitudes (ML)

Magnitude Residuals (ML)


-1.00.01.0Residual1Distance (degrees)Magnitude Residuals (ML)