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Sequence · 2025-12-08

M 6.6 · Observed seismic cluster · 129 km S of Honchō, Japan

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 cluster33
M6+2
Analysis radius276 km
Observation window14 days
Largest secondary eventM 6.7
Quake Pulse · Major sequence

What the sequence shows

After the M 6.6 reference event, Quake Pulse counts 6 M4+ event(s) in the first 24 hours and 25 in the first 7 days. Fourteen-day M4.5+ activity is about 6.1× the average equivalent derived from the previous year. The largest secondary event is M 0.0 below the reference event.

77/100Sequence score
Events in the previous 24 h7
In the first hour1
In the first 24 hours6
In the first 7 days25
Within 14 days35
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 d150Average 14-day equivalent5.8Activity / baseline ratio6.1×

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 6.7Magnitude gapM 0.0Observed duration12.2 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
129 km S of Honchō, Japan · 276 kmInteractive 3D view of earthquakes within 276 km of 129 km S of Honchō, Japan.129 km S of Honchō, JapanM 5.0 · 112 km S of Honchō, Japan · 19.3 kmM 5.6 · 109 km NE of Kuji, Japan · 36.9 kmM 4.9 · 76 km E of Yokohama, Japan · 88.2 kmM 4.6 · 88 km S of Honchō, Japan · 48.0 kmM 5.0 · 89 km E of Mutsu, Japan · 81.5 kmM 4.5 · 106 km S of Honchō, Japan · 27.1 km
129 km S of Honchō, Japan276 km6 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

4 Felt reports · PAGER GREEN · Shallow

47/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 6.6129 km S of Honchō, Japan19.0 km2025-12-08 21:52:41 UTCView event →
M 5.0112 km S of Honchō, Japan49.6 km2025-12-08 22:07:18 UTCView event →
M 5.6109 km NE of Kuji, Japan47.8 km2025-12-08 23:59:06 UTCView event →
M 4.976 km E of Yokohama, Japan54.9 km2025-12-09 00:18:27 UTCView event →
M 4.688 km S of Honchō, Japan52.9 km2025-12-09 05:15:51 UTCView event →
M 5.089 km E of Mutsu, Japan60.1 km2025-12-09 09:09:47 UTCView event →
M 4.5106 km S of Honchō, Japan43.5 km2025-12-09 09:20:03 UTCView event →
M 4.5119 km ENE of Hachinohe, Japan49.3 km2025-12-09 22:20:05 UTCView event →
M 4.698 km ENE of Yokohama, Japan53.8 km2025-12-09 23:04:36 UTCView event →
M 4.5113 km ENE of Misawa, Japan51.6 km2025-12-10 06:23:49 UTCView event →
M 4.7142 km E of Yamada, Japan10.0 km2025-12-10 10:55:12 UTCView event →
M 4.597 km E of Yokohama, Japan50.8 km2025-12-10 14:01:30 UTCView event →
M 5.7108 km ENE of Hachinohe, Japan33.0 km2025-12-10 14:52:24 UTCView event →
M 4.5131 km NE of Kuji, Japan42.8 km2025-12-11 01:22:57 UTCView event →
M 4.898 km SSW of Honchō, Japan43.1 km2025-12-11 18:11:05 UTCView event →
M 5.0111 km S of Honchō, Japan29.0 km2025-12-11 22:09:19 UTCView event →
M 6.7117 km NE of Kuji, Japan19.0 km2025-12-12 02:44:12 UTCView event →
M 4.6126 km NE of Kuji, Japan35.0 km2025-12-12 03:06:35 UTCView event →
M 5.3125 km S of Honchō, Japan32.6 km2025-12-12 03:21:39 UTCView event →
M 4.7131 km S of Honchō, Japan38.9 km2025-12-12 03:26:12 UTCView event →
M 4.6126 km NE of Kuji, Japan35.0 km2025-12-12 04:58:22 UTCView event →
M 4.6106 km E of Yokohama, Japan60.7 km2025-12-12 07:55:43 UTCView event →
M 4.676 km ENE of Misawa, Japan66.8 km2025-12-13 05:59:44 UTCView event →
M 4.5166 km ENE of Noda, Japan31.8 km2025-12-13 21:49:37 UTCView event →
M 5.0145 km E of Miyako, Japan10.0 km2025-12-14 07:58:11 UTCView event →
M 4.7106 km SSW of Honchō, Japan45.7 km2025-12-14 18:09:28 UTCView event →
M 4.529 km S of Ōfunato, Japan94.3 km2025-12-16 02:45:35 UTCView event →
M 5.1133 km S of Honchō, Japan35.0 km2025-12-16 05:38:51 UTCView event →
M 5.094 km E of Mutsu, Japan52.0 km2025-12-17 09:50:18 UTCView event →
M 4.696 km ENE of Miyako, Japan42.2 km2025-12-18 00:50:42 UTCView event →
M 4.6100 km E of Miyako, Japan41.6 km2025-12-18 05:20:11 UTCView event →
M 4.7113 km E of Miyako, Japan36.2 km2025-12-19 21:40:07 UTCView event →
M 5.278 km SSE of Nemuro, Japan10.0 km2025-12-20 12:30:27 UTCView event →
M 4.875 km SE of Nemuro, Japan30.4 km2025-12-20 12:33:54 UTCView event →
M 5.270 km SSE of Nemuro, Japan35.0 km2025-12-20 12:58:54 UTCView event →
M 5.457 km ENE of Misawa, Japan57.2 km2025-12-21 01:29:03 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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