Sequence · 2004-12-23

M 8.1 · Observed seismic cluster · 2004 Tasman Sea Earthquake

Explore clusters of M4.5+ events observed around significant earthquakes. These clusters are descriptive and are not presented as earthquake predictions.

M4.5+ events in cluster21
M6+2
Analysis radius516 km
Observation window14 days
Largest secondary eventM 6.1
Quake Pulse · Major sequence

What the sequence shows

After the M 8.1 reference event, Quake Pulse counts 15 M4+ event(s) in the first 24 hours and 19 in the first 7 days. Fourteen-day M4.5+ activity is about 40.0× the average equivalent derived from the previous year. The largest secondary event is M 2.0 below the reference event.

94/100Sequence score
Events in the previous 24 h0
In the first hour2
In the first 24 hours15
In the first 7 days19
Within 14 days20
Peak one-hour count5

Local historical context

Descriptive comparison with M4.5+ events observed in the same radius during the 365 days before the sequence.

M4.5+ events / 365 d11Average 14-day equivalent0.4Activity / baseline ratio40.0×

A ratio above 1 means denser M4.5+ activity than the average equivalent derived from the previous 365 days. It is not a risk measure or a forecast.

Reference event

Largest secondary eventM 6.1Magnitude gapM 2.0Observed duration11.1 d

Earlier events are shown as context only. They are not labelled precursors and should not be interpreted as predictive signals.

Evolving sequence map

Shows M4+ cluster events according to elapsed time after the reference event.

2004 Tasman Sea Earthquake · 516 kmInteractive 3D view of earthquakes within 516 km of 2004 Tasman Sea Earthquake.2004 Tasman Sea EarthquakeM 5.0 · north of Macquarie Island · 22.4 kmM 5.3 · north of Macquarie Island · 23.6 km
2004 Tasman Sea Earthquake516 km2 Recent earthquakes

Detailed timeline

Dots represent M4+ events retained by the sequence detector. Dot size depends on magnitude.

Sequences are descriptive groupings based on spatial and temporal proximity. Quake Pulse does not establish a causal link between every event here and does not provide earthquake forecasts.

Quake Pulse

Main-event impact

Shallow

55/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 8.12004 Tasman Sea Earthquake10.0 km2004-12-23 14:59:04 UTCView event →
M 5.0north of Macquarie Island10.0 km2004-12-23 15:16:32 UTCView event →
M 5.3north of Macquarie Island10.0 km2004-12-23 15:48:21 UTCView event →
M 4.8north of Macquarie Island10.0 km2004-12-23 15:59:59 UTCView event →
M 4.9north of Macquarie Island10.0 km2004-12-23 16:07:38 UTCView event →
M 4.9north of Macquarie Island10.0 km2004-12-23 16:16:33 UTCView event →
M 4.8north of Macquarie Island10.0 km2004-12-23 16:22:19 UTCView event →
M 4.7north of Macquarie Island10.0 km2004-12-23 16:26:30 UTCView event →
M 5.0north of Macquarie Island10.0 km2004-12-23 19:05:35 UTCView event →
M 5.6north of Macquarie Island10.0 km2004-12-23 19:50:05 UTCView event →
M 4.6north of Macquarie Island10.0 km2004-12-23 20:00:37 UTCView event →
M 4.7north of Macquarie Island10.0 km2004-12-24 01:30:43 UTCView event →
M 4.7north of Macquarie Island10.0 km2004-12-24 03:28:45 UTCView event →
M 5.4north of Macquarie Island10.0 km2004-12-24 05:31:48 UTCView event →
M 4.7north of Macquarie Island10.0 km2004-12-24 10:24:04 UTCView event →
M 4.8north of Macquarie Island10.0 km2004-12-24 14:29:29 UTCView event →
M 4.8north of Macquarie Island10.0 km2004-12-24 20:14:20 UTCView event →
M 4.6north of Macquarie Island10.0 km2004-12-24 21:56:02 UTCView event →
M 4.9north of Macquarie Island10.0 km2004-12-24 22:34:39 UTCView event →
M 4.8north of Macquarie Island10.0 km2004-12-25 02:43:33 UTCView event →
M 6.1north of Macquarie Island10.0 km2005-01-03 17:59:28 UTCView event →

Interpretation

Explore clusters of M4.5+ events observed around significant earthquakes. These clusters are descriptive and are not presented as earthquake predictions. Historical small-earthquake detection varies through time. Long-term comparisons are most robust at higher magnitude thresholds.

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