Sequence · 2015-05-30

M 7.8 · Observed seismic cluster · Bonin Islands, Japan region

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 radius468 km
Observation window14 days
Largest secondary eventM 6.2
Quake Pulse · Major sequence

What the sequence shows

After the M 7.8 reference event, Quake Pulse counts 3 M4+ event(s) in the first 24 hours and 6 in the first 7 days. Fourteen-day M4.5+ activity is about 1.0× the average equivalent derived from the previous year. The largest secondary event is M 1.6 below the reference event.

82/100Sequence score
Events in the previous 24 h1
In the first hour1
In the first 24 hours3
In the first 7 days6
Within 14 days6
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 d154Average 14-day equivalent5.9Activity / baseline ratio1.0×

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 6.2Magnitude gapM 1.6Observed duration5.4 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.

Bonin Islands, Japan region · 468 kmInteractive 3D view of earthquakes within 468 km of Bonin Islands, Japan region.Bonin Islands, Japan regionM 4.5 · Bonin Islands, Japan region · 11.7 kmM 4.8 · Volcano Islands, Japan region · 336.6 kmM 6.2 · Izu Islands, Japan region · 406.4 km
Bonin Islands, Japan region468 km3 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

360 Felt reports · PAGER GREEN · Tsunami indicator · Very deep

77/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 7.8Bonin Islands, Japan region664.0 km2015-05-30 11:23:02 UTCView event →
M 4.5Bonin Islands, Japan region683.4 km2015-05-30 12:10:13 UTCView event →
M 4.8Volcano Islands, Japan region137.5 km2015-05-30 17:22:39 UTCView event →
M 6.2Izu Islands, Japan region6.1 km2015-05-30 18:49:07 UTCView event →
M 4.9Bonin Islands, Japan region677.6 km2015-06-02 21:04:29 UTCView event →
M 4.8Izu Islands, Japan region10.0 km2015-06-03 08:16:06 UTCView event →
M 5.0Bonin Islands, Japan region8.5 km2015-06-04 21:46:19 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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