Sequence · 2019-11-04

M 6.6 · Observed seismic cluster · 136 km W of Neiafu, Tonga

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 cluster7
M6+2
Analysis radius276 km
Observation window14 days
Largest secondary eventM 6.2
Quake Pulse · Strong sequence

What the sequence shows

After the M 6.6 reference event, Quake Pulse counts 2 M4+ event(s) in the first 24 hours and 4 in the first 7 days. Fourteen-day M4.5+ activity is about 1.1× the average equivalent derived from the previous year. The largest secondary event is M 0.4 below the reference event.

71/100Sequence score
Events in the previous 24 h0
In the first hour1
In the first 24 hours2
In the first 7 days4
Within 14 days8
Peak one-hour count3

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 d188Average 14-day equivalent7.2Activity / baseline ratio1.1×

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 6.2Magnitude gapM 0.4Observed duration12.6 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.

136 km W of Neiafu, Tonga · 276 kmInteractive 3D view of earthquakes within 276 km of 136 km W of Neiafu, Tonga.136 km W of Neiafu, TongaM 5.5 · 181 km W of Neiafu, Tonga · 45.3 kmM 4.9 · 137 km W of Neiafu, Tonga · 3.3 km
136 km W of Neiafu, Tonga276 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

8 Felt reports · PAGER GREEN · Tsunami indicator · Shallow

57/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 6.6136 km W of Neiafu, Tonga10.0 km2019-11-04 22:43:32 UTCView event →
M 5.5181 km W of Neiafu, Tonga10.0 km2019-11-04 22:46:10 UTCView event →
M 4.9137 km W of Neiafu, Tonga10.0 km2019-11-05 00:05:30 UTCView event →
M 5.179 km NE of ‘Ohonua, Tonga10.0 km2019-11-06 23:37:23 UTCView event →
M 5.6155 km NW of Haveluloto, Tonga255.0 km2019-11-09 11:24:30 UTCView event →
M 4.5113 km WNW of Pangai, Tonga10.0 km2019-11-11 22:56:15 UTCView event →
M 5.5146 km W of Neiafu, Tonga10.0 km2019-11-11 23:00:21 UTCView event →
M 6.2147 km W of Neiafu, Tonga10.0 km2019-11-11 23:03:28 UTCView event →
M 5.8274 km W of Haveluloto, Tonga499.0 km2019-11-17 12:13:27 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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