Magnitude 1.7, Tue Feb 21 2017 3:05 PM


Download Event Information


Origin


PublicID 2017p138072
UTC Time 2017-02-21T02:05:17Z
Latitude -39.07 (± 6.3 km)
Longitude 173.97 (± 6.9 km)
Depth 9 km (± 5 km)
Depth Type free
Earth Model nz3drx
Used Phase Count 11
Used Station Count 9
Standard Error 0.30 (s)
Azimuthal Gap 249.41 (degrees)
Minimum Distance 0.12 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (M) 1.7  
MLv 1.7 (± 0.3) 7
ML 2.0 (± 0.4) 7
M 1.7 7

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


-15.0-13.0-11.0-9.0-7.0-5.0-3.0-1.01.03.05.07.09.011.013.015.0residual (s)0123Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.0Magnitude1Distance (degrees)Station Magnitudes (MLv)

Station Magnitudes (ML)


0.01.02.03.0Magnitude1Distance (degrees)Station Magnitudes (ML)

Magnitude Residuals (MLv)


-1.00.01.0Residual1Distance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (ML)


-2.0-1.00.01.02.0Residual1Distance (degrees)Magnitude Residuals (ML)