Magnitude 1.5, Wed Dec 8 2021 12:11 PM


Download Event Information


Origin


PublicID 2021p921530
UTC Time 2021-12-07T23:11:15Z
Latitude -39.68 (± 4.2 km)
Longitude 176.95 (± 4.4 km)
Depth 17 km (± 7 km)
Depth Type free
Earth Model iasp91
Used Phase Count 13
Used Station Count 8
Standard Error 0.41 (s)
Azimuthal Gap 127.19 (degrees)
Minimum Distance 0.10 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (MLv) 1.5 (± 0.3)  
MLv 1.5 (± 0.3) 3

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


-1.00.01.0residual (s)0Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.0MagnitudeDistance (degrees)Station Magnitudes (MLv)

Magnitude Residuals (MLv)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (MLv)