Sequence · 2018-12-11

M 7.1 · Observed seismic cluster · South Sandwich 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 cluster6
M6+1
Analysis radius356 km
Observation window14 days
Largest secondary eventM 5.2
Quake Pulse · Strong sequence

What the sequence shows

After the M 7.1 reference event, Quake Pulse counts 1 M4+ event(s) in the first 24 hours and 3 in the first 7 days. Fourteen-day M4.5+ activity is about 0.7× the average equivalent derived from the previous year. The largest secondary event is M 1.8 below the reference event.

68/100Sequence score
Events in the previous 24 h0
In the first hour0
In the first 24 hours1
In the first 7 days3
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 d210Average 14-day equivalent8.1Activity / baseline ratio0.7×

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 5.3Magnitude gapM 1.8Observed duration13.1 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.

South Sandwich Islands region · 356 kmInteractive 3D view of earthquakes within 356 km of South Sandwich Islands region.South Sandwich Islands regionM 4.6 · South Sandwich Islands region · 184.4 km
South Sandwich Islands region356 km1 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 · Tsunami indicator · Intermediate

62/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 7.1South Sandwich Islands region133.0 km2018-12-11 02:26:29 UTCView event →
M 4.6South Sandwich Islands region43.6 km2018-12-11 17:47:12 UTCView event →
M 5.3South Sandwich Islands region13.1 km2018-12-12 09:14:25 UTCView event →
M 4.5South Sandwich Islands region98.8 km2018-12-16 18:30:51 UTCView event →
M 5.2South Sandwich Islands region44.1 km2018-12-21 20:46:14 UTCView event →
M 4.5South Sandwich Islands region45.3 km2018-12-23 12:31:23 UTCView event →
M 4.5South Sandwich Islands region45.6 km2018-12-24 05:16:39 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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