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Magnitude 7.2

Monday October 19, 1868 - 12:14 AM, 55 km north-east of Collingwood

Download Event Information

Select a format below to download the complete technical data for this earthquake. [Succinct microcopy that describes what QUAKEML and STRONG is and that the open data in the current tab and do not download a file and that shaking layers is on an external site]

Origin data

Calculated source location of the earthquake. It contains the parameters GeoNet's location software derived from seismic station observations.

PublicID 2178062
UTC Time 1868-10-18T12:35:00Z
Latitude -40.20 (± 0.0 km)
Longitude 173.00 (± 0.0 km)
Depth 12 km (± 0 km)
Depth Type operator assigned
Earth Model
Used Phase Count 0
Used Station Count 0
Standard Error 0.00 (s)
Azimuthal Gap 0.00 (degrees)
Minimum Distance 0.00 (degrees)

Origin history map

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.

Magnitudes

The magnitudes calculated for this earthquake.

Type Magnitude Station Count
Preferred (Mw) 7.2  
Mw 7.2 0
Minimum distance (degree)  

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).

Pick Residuals

Observed arrival time at a seismic station compared to a predicted arrival time from a GeoNet waveform propagation model (a given velocity model (1D or 3D)). A residual of 0 s indicates that the observed seismic phase arrival time (typically P or S) matches the arrival time predicted by the GeoNet velocity model. Low residuals across multiple well-distributed stations increase confidence in the estimated event location and origin time. Large (brown) points are used to determine the current solution, small (grey) points are observations not used.

residual (s)Distance (degrees)Pick Residuals