Sequence · 2023-05-21

M 6.8 · Observed seismic cluster · Prince Edward Islands 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 cluster4
M6+1
Analysis radius308 km
Observation window14 days
Largest secondary eventM 5.1
Quake Pulse · Strong sequence

What the sequence shows

After the M 6.8 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 8.0× the average equivalent derived from the previous year. The largest secondary event is M 1.7 below the reference event.

65/100Sequence score
Events in the previous 24 h0
In the first hour0
In the first 24 hours2
In the first 7 days4
Within 14 days4
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 d5Average 14-day equivalent0.2Activity / baseline ratio8.0×

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 5.1Magnitude gapM 1.7Observed duration5.3 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.

Prince Edward Islands region · 308 kmInteractive 3D view of earthquakes within 308 km of Prince Edward Islands region.Prince Edward Islands regionM 4.7 · Prince Edward Islands region · 18.7 kmM 5.1 · Prince Edward Islands region · 53.2 km
Prince Edward Islands region308 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

PAGER GREEN · Shallow

44/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 6.8Prince Edward Islands region28.0 km2023-05-21 14:56:48 UTCView event →
M 4.7Prince Edward Islands region10.0 km2023-05-21 16:36:49 UTCView event →
M 5.1Prince Edward Islands region10.0 km2023-05-21 17:23:20 UTCView event →
M 4.8Southwest Indian Ridge10.0 km2023-05-24 01:48:25 UTCView event →
M 5.0Prince Edward Islands region10.0 km2023-05-26 21:33:47 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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