Magnitude 4.0, Fri May 1 2020 2:13 PM


Download Event Information


Origin


PublicID 2020p327278
UTC Time 2020-05-01T02:13:10Z
Latitude -31.83 (± 76.8 km)
Longitude 179.02 (± 120.3 km)
Depth 447 km (± 132 km)
Depth Type free
Earth Model iasp91
Used Phase Count 9
Used Station Count 9
Standard Error 0.65 (s)
Azimuthal Gap 216.36 (degrees)
Minimum Distance 3.68 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (mB) 4.0 (± 0.1)  
ML 3.8 (± 0.1) 7
MLv 4.0 (± 0.1) 3
mB 4.0 (± 0.1) 4
Mw(mB) 3.1 (± 0.4) 4
M 3.8 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


-3.0-2.0-1.00.01.02.03.0residual (s)0123456789Distance (degrees)Pick Residuals

Station Magnitudes (ML)


0.01.02.03.04.05.0Magnitude6Distance (degrees)Station Magnitudes (ML)

Station Magnitudes (MLv)


0.01.02.03.04.05.0MagnitudeDistance (degrees)Station Magnitudes (MLv)

Station Magnitudes (mB)


0.01.02.03.04.05.0MagnitudeDistance (degrees)Station Magnitudes (mB)

Magnitude Residuals (ML)


-1.00.01.0Residual6Distance (degrees)Magnitude Residuals (ML)

Magnitude Residuals (MLv)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (MLv)

Magnitude Residuals (mB)


-1.00.01.0ResidualDistance (degrees)Magnitude Residuals (mB)