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Sequence · 2009-03-19

M 7.6 · Observed seismic cluster · 191 km S of ‘Ohonua, 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 cluster65
M6+1
Analysis radius436 km
Observation window14 days
Largest secondary eventM 5.5
Quake Pulse · Major sequence

What the sequence shows

After the M 7.6 reference event, Quake Pulse counts 27 M4+ event(s) in the first 24 hours and 57 in the first 7 days. Fourteen-day M4.5+ activity is about 7.9× the average equivalent derived from the previous year. The largest secondary event is M 2.1 below the reference event.

88/100Sequence score
Events in the previous 24 h0
In the first hour7
In the first 24 hours27
In the first 7 days57
Within 14 days66
Peak one-hour count7

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 d217Average 14-day equivalent8.3Activity / baseline ratio7.9×

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 5.5Magnitude gapM 2.1Observed duration13.8 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.

1 hour24 hours7 days14 days
191 km S of ‘Ohonua, Tonga · 436 kmInteractive 3D view of earthquakes within 436 km of 191 km S of ‘Ohonua, Tonga.191 km S of ‘Ohonua, TongaM 4.9 · 234 km S of ‘Ohonua, Tonga · 42.9 kmM 4.5 · 252 km S of ‘Ohonua, Tonga · 61.6 kmM 4.6 · 159 km S of ‘Ohonua, Tonga · 50.1 kmM 4.7 · 183 km S of ‘Ohonua, Tonga · 17.0 kmM 4.6 · 223 km S of ‘Ohonua, Tonga · 31.7 kmM 4.7 · 220 km S of ‘Ohonua, Tonga · 29.1 kmM 4.8 · 175 km S of ‘Ohonua, Tonga · 49.4 kmM 5.0 · 193 km S of ‘Ohonua, Tonga · 32.9 kmM 4.7 · 201 km S of ‘Ohonua, Tonga · 13.9 kmM 4.7 · 190 km S of ‘Ohonua, Tonga · 20.4 kmM 4.6 · 115 km S of ‘Ohonua, Tonga · 83.5 kmM 4.8 · 130 km S of ‘Ohonua, Tonga · 64.7 kmM 4.9 · 244 km S of ‘Ohonua, Tonga · 53.1 kmM 5.3 · 196 km S of ‘Ohonua, Tonga · 5.6 kmM 4.9 · 216 km S of ‘Ohonua, Tonga · 25.0 kmM 4.9 · 168 km S of ‘Ohonua, Tonga · 26.2 kmM 4.5 · 273 km S of ‘Ohonua, Tonga · 82.5 kmM 4.7 · 293 km S of ‘Ohonua, Tonga · 126.1 kmM 4.9 · 274 km S of ‘Ohonua, Tonga · 114.7 kmM 4.7 · 270 km SSE of ‘Ohonua, Tonga · 83.6 kmM 4.6 · 209 km S of ‘Ohonua, Tonga · 49.3 kmM 4.8 · 238 km S of ‘Ohonua, Tonga · 59.9 kmM 5.4 · 189 km SSW of ‘Ohonua, Tonga · 66.9 kmM 4.8 · 153 km S of ‘Ohonua, Tonga · 64.7 kmM 4.9 · 184 km S of ‘Ohonua, Tonga · 59.8 kmM 4.8 · 171 km S of ‘Ohonua, Tonga · 61.7 kmM 5.0 · 202 km S of ‘Ohonua, Tonga · 10.5 km
191 km S of ‘Ohonua, Tonga436 km27 Recent earthquakes

Detailed timeline

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

0 h24 h7 d14 d

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

42 Felt reports · Shallow

63/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 7.6191 km S of ‘Ohonua, Tonga31.0 km2009-03-19 18:17:40 UTCView event →
M 4.9234 km S of ‘Ohonua, Tonga35.0 km2009-03-19 18:45:28 UTCView event →
M 4.5252 km S of ‘Ohonua, Tonga35.0 km2009-03-19 18:55:06 UTCView event →
M 4.6159 km S of ‘Ohonua, Tonga35.0 km2009-03-19 18:59:34 UTCView event →
M 4.7183 km S of ‘Ohonua, Tonga35.0 km2009-03-19 19:00:07 UTCView event →
M 4.6223 km S of ‘Ohonua, Tonga35.0 km2009-03-19 19:01:03 UTCView event →
M 4.7220 km S of ‘Ohonua, Tonga35.0 km2009-03-19 19:06:03 UTCView event →
M 4.8175 km S of ‘Ohonua, Tonga35.0 km2009-03-19 19:13:15 UTCView event →
M 5.0193 km S of ‘Ohonua, Tonga35.4 km2009-03-19 19:27:03 UTCView event →
M 4.7201 km S of ‘Ohonua, Tonga35.0 km2009-03-19 19:33:19 UTCView event →
M 4.7190 km S of ‘Ohonua, Tonga35.0 km2009-03-19 19:40:21 UTCView event →
M 4.6115 km S of ‘Ohonua, Tonga35.0 km2009-03-19 19:47:06 UTCView event →
M 4.8130 km S of ‘Ohonua, Tonga35.0 km2009-03-19 20:29:26 UTCView event →
M 4.9244 km S of ‘Ohonua, Tonga35.0 km2009-03-19 20:30:14 UTCView event →
M 5.3196 km S of ‘Ohonua, Tonga35.0 km2009-03-19 20:33:59 UTCView event →
M 4.9216 km S of ‘Ohonua, Tonga38.4 km2009-03-19 23:15:52 UTCView event →
M 4.9168 km S of ‘Ohonua, Tonga35.0 km2009-03-20 02:10:38 UTCView event →
M 4.5273 km S of ‘Ohonua, Tonga35.0 km2009-03-20 04:23:15 UTCView event →
M 4.7293 km S of ‘Ohonua, Tonga35.0 km2009-03-20 05:20:32 UTCView event →
M 4.9274 km S of ‘Ohonua, Tonga35.0 km2009-03-20 05:22:01 UTCView event →
M 4.7270 km SSE of ‘Ohonua, Tonga35.0 km2009-03-20 06:00:56 UTCView event →
M 4.6209 km S of ‘Ohonua, Tonga35.0 km2009-03-20 06:38:32 UTCView event →
M 4.8238 km S of ‘Ohonua, Tonga35.0 km2009-03-20 07:02:52 UTCView event →
M 5.4189 km SSW of ‘Ohonua, Tonga48.0 km2009-03-20 11:23:39 UTCView event →
M 4.8153 km S of ‘Ohonua, Tonga35.0 km2009-03-20 11:26:24 UTCView event →
M 4.9184 km S of ‘Ohonua, Tonga35.0 km2009-03-20 13:29:16 UTCView event →
M 4.8171 km S of ‘Ohonua, Tonga37.4 km2009-03-20 14:00:05 UTCView event →
M 5.0202 km S of ‘Ohonua, Tonga35.0 km2009-03-20 15:54:42 UTCView event →
M 4.5214 km S of ‘Ohonua, Tonga35.0 km2009-03-20 18:46:33 UTCView event →
M 4.7206 km S of ‘Ohonua, Tonga37.1 km2009-03-20 21:41:29 UTCView event →
M 5.0217 km S of ‘Ohonua, Tonga35.0 km2009-03-21 01:18:35 UTCView event →
M 4.9225 km SSW of ‘Ohonua, Tonga35.0 km2009-03-21 01:27:58 UTCView event →
M 4.7215 km S of ‘Ohonua, Tonga35.0 km2009-03-21 02:41:43 UTCView event →
M 4.8251 km S of ‘Ohonua, Tonga35.0 km2009-03-21 03:25:27 UTCView event →
M 4.6138 km SSW of ‘Ohonua, Tonga35.0 km2009-03-21 03:33:21 UTCView event →
M 4.6151 km S of ‘Ohonua, Tonga35.0 km2009-03-21 04:09:35 UTCView event →
M 4.8206 km SSW of ‘Ohonua, Tonga35.0 km2009-03-21 04:31:40 UTCView event →
M 4.8225 km SSW of ‘Ohonua, Tonga35.0 km2009-03-21 04:50:19 UTCView event →
M 4.9229 km S of ‘Ohonua, Tonga35.0 km2009-03-21 05:37:30 UTCView event →
M 4.6206 km SW of Vaini, Tonga127.4 km2009-03-21 06:08:02 UTCView event →
M 4.7231 km S of ‘Ohonua, Tonga35.0 km2009-03-21 10:22:00 UTCView event →
M 4.7Tonga region35.0 km2009-03-21 11:33:40 UTCView event →
M 4.5Fiji region573.7 km2009-03-21 12:07:48 UTCView event →
M 4.6217 km S of ‘Ohonua, Tonga35.0 km2009-03-21 12:14:52 UTCView event →
M 4.8202 km SSE of ‘Ohonua, Tonga20.2 km2009-03-21 13:59:13 UTCView event →
M 5.0234 km S of ‘Ohonua, Tonga35.0 km2009-03-21 17:38:39 UTCView event →
M 4.7166 km S of ‘Ohonua, Tonga35.0 km2009-03-21 20:09:21 UTCView event →
M 4.6192 km SSW of ‘Ohonua, Tonga35.0 km2009-03-21 20:49:22 UTCView event →
M 4.8175 km S of ‘Ohonua, Tonga35.0 km2009-03-22 01:54:48 UTCView event →
M 4.9259 km SSE of ‘Ohonua, Tonga35.0 km2009-03-22 10:27:46 UTCView event →
M 4.7228 km S of ‘Ohonua, Tonga35.0 km2009-03-22 10:42:12 UTCView event →
M 4.6147 km S of ‘Ohonua, Tonga35.0 km2009-03-22 11:48:28 UTCView event →
M 4.8223 km S of ‘Ohonua, Tonga35.0 km2009-03-22 19:52:15 UTCView event →
M 5.1167 km S of ‘Ohonua, Tonga36.3 km2009-03-23 04:43:34 UTCView event →
M 4.8244 km S of ‘Ohonua, Tonga35.0 km2009-03-24 03:58:44 UTCView event →
M 5.5271 km SSW of ‘Ohonua, Tonga59.1 km2009-03-25 21:46:00 UTCView event →
M 4.8292 km SSW of ‘Ohonua, Tonga59.6 km2009-03-26 01:41:00 UTCView event →
M 5.2192 km S of ‘Ohonua, Tonga42.3 km2009-03-26 10:00:30 UTCView event →
M 5.0223 km S of ‘Ohonua, Tonga57.5 km2009-03-28 05:07:01 UTCView event →
M 4.7279 km W of Haveluloto, Tonga125.1 km2009-03-28 15:58:22 UTCView event →
M 4.9201 km S of ‘Ohonua, Tonga55.0 km2009-03-28 21:05:45 UTCView event →
M 5.1196 km S of ‘Ohonua, Tonga58.5 km2009-03-28 22:06:50 UTCView event →
M 4.6241 km S of ‘Ohonua, Tonga35.0 km2009-03-30 19:56:53 UTCView event →
M 4.9241 km S of ‘Ohonua, Tonga44.1 km2009-03-31 00:05:07 UTCView event →
M 4.5211 km S of ‘Ohonua, Tonga82.7 km2009-03-31 01:16:48 UTCView event →
M 4.681 km SE of Neiafu, Tonga35.0 km2009-03-31 07:34:01 UTCView event →
M 4.5193 km S of ‘Ohonua, Tonga50.1 km2009-04-02 13:05:01 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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