Sequence · 2021-07-23

M 6.7 · Observed seismic cluster · 15 km S of Hukay, Philippines

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 radius292 km
Observation window14 days
Largest secondary eventM 5.8
Quake Pulse · Strong sequence

What the sequence shows

After the M 6.7 reference event, Quake Pulse counts 2 M4+ event(s) in the first 24 hours and 2 in the first 7 days. Fourteen-day M4.5+ activity is about 2.6× the average equivalent derived from the previous year. The largest secondary event is M 0.9 below the reference event.

69/100Sequence score
Events in the previous 24 h0
In the first hour1
In the first 24 hours2
In the first 7 days2
Within 14 days5
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 d50Average 14-day equivalent1.9Activity / baseline ratio2.6×

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 5.8Magnitude gapM 0.9Observed duration10.8 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.

15 km S of Hukay, Philippines · 292 kmInteractive 3D view of earthquakes within 292 km of 15 km S of Hukay, Philippines.15 km S of Hukay, PhilippinesM 5.8 · 6 km SE of Hukay, Philippines · 10.5 kmM 4.5 · 3 km E of Mabini, Philippines · 27.2 km
15 km S of Hukay, Philippines292 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

317 Felt reports · PAGER GREEN · Tsunami indicator · Intermediate

72/100
Impact and context →

M4.5+ events in cluster

MagnitudeLocationDepthTime
M 6.715 km S of Hukay, Philippines110.0 km2021-07-23 20:48:57 UTCView event →
M 5.86 km SE of Hukay, Philippines120.6 km2021-07-23 20:57:18 UTCView event →
M 4.53 km E of Mabini, Philippines121.9 km2021-07-24 09:43:35 UTCView event →
M 4.749 km WSW of San Nicolas, Philippines10.0 km2021-08-03 07:26:12 UTCView event →
M 4.630 km W of San Nicolas, Philippines35.0 km2021-08-03 12:58:45 UTCView event →
M 4.73 km E of Odala, Philippines91.5 km2021-08-03 16:20:17 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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