Magnitude 4.5, Sun Aug 27 2017 9:24 AM


Download Event Information


Origin


PublicID 2017p642957
UTC Time 2017-08-26T21:24:36Z
Latitude -23.18 (± 0.0 km)
Longitude -177.12 (± 0.0 km)
Depth 207 km (± 0 km)
Depth Type free
Earth Model
Used Phase Count 0
Used Station Count 0
Standard Error 2.88 (s)
Azimuthal Gap 0.00 (degrees)
Minimum Distance 0.00 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (mB) 4.5  
MLv 5.9 1
mB 4.5 1
Mw(mB) 3.7 (± 0.4) 1
M 5.9 1

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


-8.0-6.0-4.0-2.00.02.04.06.08.0residual (s)0246810121416Distance (degrees)Pick Residuals

Station Magnitudes (MLv)


0.01.02.03.04.05.06.0MagnitudeDistance (degrees)Station Magnitudes (MLv)

Station Magnitudes (mB)


0.01.02.03.04.05.0MagnitudeDistance (degrees)Station Magnitudes (mB)

Magnitude Residuals (MLv)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (mB)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (mB)