Sequence · 2021-05-21

M 7.3 · Observed seismic cluster · Southern Qinghai, China

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 cluster27
M6+1
Analysis radius388 km
Observation window14 days
Largest secondary eventM 5.5
Quake Pulse · Major sequence

What the sequence shows

After the M 7.3 reference event, Quake Pulse counts 19 M4+ event(s) in the first 24 hours and 22 in the first 7 days. Fourteen-day M4.5+ activity is about 52.0× the average equivalent derived from the previous year. The largest secondary event is M 1.8 below the reference event.

94/100Sequence score
Events in the previous 24 h0
In the first hour9
In the first 24 hours19
In the first 7 days22
Within 14 days26
Peak one-hour count9

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 d3Average 14-day equivalent0.1Activity / baseline ratio52.0×

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 5.5Magnitude gapM 1.8Observed duration12.5 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.

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

28 Felt reports · PAGER ORANGE · Shallow

77/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 7.3Southern Qinghai, China10.0 km2021-05-21 18:04:13 UTCView event →
M 5.2Southern Qinghai, China10.0 km2021-05-21 18:10:41 UTCView event →
M 5.5Southern Qinghai, China10.0 km2021-05-21 18:12:15 UTCView event →
M 5.5189 km W of Oula Xiuma, China10.0 km2021-05-21 18:13:01 UTCView event →
M 4.9Southern Qinghai, China10.0 km2021-05-21 18:15:10 UTCView event →
M 4.6Southern Qinghai, China10.0 km2021-05-21 18:22:21 UTCView event →
M 4.7Southern Qinghai, China10.0 km2021-05-21 18:25:05 UTCView event →
M 4.5Southern Qinghai, China10.0 km2021-05-21 18:30:32 UTCView event →
M 4.6Southern Qinghai, China10.0 km2021-05-21 18:36:02 UTCView event →
M 4.9Southern Qinghai, China10.0 km2021-05-21 19:03:08 UTCView event →
M 4.5Southern Qinghai, China10.0 km2021-05-21 19:09:18 UTCView event →
M 4.6Southern Qinghai, China10.0 km2021-05-21 19:49:14 UTCView event →
M 4.5Southern Qinghai, China10.0 km2021-05-21 20:04:30 UTCView event →
M 4.6Southern Qinghai, China10.0 km2021-05-21 21:59:36 UTCView event →
M 5.1Southern Qinghai, China10.0 km2021-05-22 02:29:37 UTCView event →
M 5.1Southern Qinghai, China10.0 km2021-05-22 02:38:45 UTCView event →
M 4.5Southern Qinghai, China10.0 km2021-05-22 03:16:13 UTCView event →
M 5.2Southern Qinghai, China10.0 km2021-05-22 03:21:18 UTCView event →
M 4.7261 km SW of Linxia Chengguanzhen, China10.0 km2021-05-22 03:30:47 UTCView event →
M 4.9Southern Qinghai, China10.0 km2021-05-22 07:06:23 UTCView event →
M 4.7Southern Qinghai, China10.0 km2021-05-24 14:15:21 UTCView event →
M 4.6Southern Qinghai, China10.0 km2021-05-24 23:00:22 UTCView event →
M 5.1Southern Qinghai, China10.0 km2021-05-27 13:06:07 UTCView event →
M 5.1Southern Qinghai, China10.0 km2021-05-30 04:50:09 UTCView event →
M 5.0Southern Qinghai, China10.0 km2021-05-30 06:55:15 UTCView event →
M 4.5Southern Qinghai, China12.4 km2021-05-31 00:12:12 UTCView event →
M 5.0Southern Qinghai, China10.0 km2021-06-03 05:55:18 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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