Magnitude 4.8, Fri Jul 18 2025 9:19 PM


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Origin


PublicID 2025p536203
UTC Time 2025-07-18T09:19:13Z
Latitude 27.76 (± 0.0 km)
Longitude 139.62 (± 0.0 km)
Depth 503 km (± 0 km)
Depth Type operator assigned
Earth Model
Used Phase Count 0
Used Station Count 0
Standard Error 0.82 (s)
Azimuthal Gap 0.00 (degrees)
Minimum Distance 0.00 (degrees)

Magnitudes


Type Magnitude Station Count
Preferred (mB) 4.8 (± 0.1)  
mB 4.8 (± 0.1) 9
Mw(mB) 4.0 (± 0.4) 9
M 4.0 9

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


-2.0-1.00.01.02.0residual (s)024681012141618202224262830323436384042444648505254565860626466687072747678Distance (degrees)Pick Residuals

Station Magnitudes (mB)


0.01.02.03.04.05.06.0Magnitude76Distance (degrees)Station Magnitudes (mB)

Magnitude Residuals (mB)


-1.00.01.0Residual76Distance (degrees)Magnitude Residuals (mB)