Sequence · 2021-05-21

M 6.5 · Observed seismic cluster · 265 km SSE of Alo, Wallis and Futuna

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 cluster9
M6+1
Analysis radius260 km
Observation window14 days
Largest secondary eventM 5.3
Quake Pulse · Strong sequence

What the sequence shows

After the M 6.5 reference event, Quake Pulse counts 5 M4+ event(s) in the first 24 hours and 5 in the first 7 days. Fourteen-day M4.5+ activity is about 1.9× the average equivalent derived from the previous year. The largest secondary event is M 1.2 below the reference event.

64/100Sequence score
Events in the previous 24 h1
In the first hour1
In the first 24 hours5
In the first 7 days5
Within 14 days8
Peak one-hour count1

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 d111Average 14-day equivalent4.3Activity / baseline ratio1.9×

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 5.3Magnitude gapM 1.2Observed duration11.9 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.

265 km SSE of Alo, Wallis and Futuna · 260 kmInteractive 3D view of earthquakes within 260 km of 265 km SSE of Alo, Wallis and Futuna.265 km SSE of Alo, Wallis and FutunaM 4.5 · Fiji region · 4.6 kmM 4.7 · 266 km SSE of Alo, Wallis and Futuna · 17.8 kmM 4.5 · 263 km S of Alo, Wallis and Futuna · 29.6 kmM 4.6 · 115 km SW of Leava, Wallis and Futuna · 236.1 kmM 4.5 · 234 km E of Levuka, Fiji · 177.3 km
265 km SSE of Alo, Wallis and Futuna260 km5 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

5 Felt reports · PAGER GREEN · Tsunami indicator · Shallow

58/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 6.5265 km SSE of Alo, Wallis and Futuna10.0 km2021-05-21 22:13:18 UTCView event →
M 4.5Fiji region10.0 km2021-05-21 22:33:14 UTCView event →
M 4.7266 km SSE of Alo, Wallis and Futuna10.0 km2021-05-22 04:09:48 UTCView event →
M 4.5263 km S of Alo, Wallis and Futuna10.0 km2021-05-22 05:59:09 UTCView event →
M 4.6115 km SW of Leava, Wallis and Futuna395.2 km2021-05-22 14:24:47 UTCView event →
M 4.5234 km E of Levuka, Fiji549.7 km2021-05-22 21:32:57 UTCView event →
M 4.7224 km ENE of Levuka, Fiji547.1 km2021-05-28 23:34:29 UTCView event →
M 5.3265 km E of Levuka, Fiji520.8 km2021-05-30 03:55:14 UTCView event →
M 4.9229 km E of Levuka, Fiji593.6 km2021-06-02 20:36:23 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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