Global Seismic Activity

Assessing worldwide seismic energy release

Last 24 hours Calculated at 2026-10-17 22:00:00 UTC (Every 15 min)
Estimated energy (24 h)
8.10 × 1013
Joules
Last 24 hours
Calm Normal Elevated High Very high
Seismic activity index (0–100)
Estimated energy (24 h)
8.10 × 1013 Joules
log10(E): 13.91
Ranked vs last 365 days
36th percentile
36% of earlier 24-hour windows had an equal or lower value.
Strongest event (24h)
M5.8
132 events with M≥3

Reference: 34819 earlier windows · 2025-10-17 22:00:00 to 2026-10-17 21:45:00 UTC.

Methodology and Calculation

The global seismic activity index estimates the total seismic energy released in the last 24 hours (Joule) and indicates how unusual this activity level is compared to historical trends.

1
Collecting data
Reports sharing an event ID are grouped. We select one preferred source per event, then filter M≥3 in the rolling UTC interval [start, end).
2
Estimating energy
For each event we estimate released energy E using a classical approximation: log10(E) = 1.5M + 4.8 (E in Joule).
3
Ranking activity
Energies are summed and compared with earlier 24-hour windows from the preceding 365 days. Windows are sampled every 15 minutes. The current window and future values are excluded.

Energy is an approximation based on mixed magnitude types. Reports may arrive late or be revised. History is recalculated daily from the current catalogue, so past values may change. This index is not an earthquake prediction or a measure of local hazard. USGS: E = 10^(1.5M + 4.8) · USGS: Mw / Mb / Ml

FAQ

What does the seismic activity index score mean?
The 0–100 value is a relative rank. At 76, about 76% of earlier reference windows had an equal or lower energy value. Windows overlap; this is neither a fraction of independent days nor a probability of danger.
Why is the calculation based on logarithmic energy release?
One magnitude unit represents roughly 31.6 times more energy in this approximation. Large events therefore strongly influence the total. Energy is summed linearly; magnitudes are not added.
How exactly is energy computed and aggregated?
For each earthquake with magnitude M we compute E = 10^(1.5M + 4.8) Joule (a widely used practical approximation). We then sum energies across all events in the rolling 24-hour UTC window to obtain E24h. Because E24h spans orders of magnitude, we also display log10(E24h) for stability and interpretability.
How is the percentile (0–100) computed?
Rank = 100 × number of earlier values ≤ the current value / number of earlier values, rounded to an integer. Only previous windows using the same calculation version, M≥3 and 24 hours within the preceding 365 days are included. The actual reference count is displayed.
Why use a magnitude threshold (M≥3.0)?
M≥3 is a filter choice, not a guarantee of global completeness. Small earthquakes are recorded unevenly between regions; gaps remain above M3. Changes to sources and monitoring networks can influence the index.
Does the index indicate risk or predict earthquakes?
No. The index summarizes observed global activity in the past 24 hours. It does not model tectonic stress, fault loading, aftershock probability, or local hazard. A high score means the last 24 hours were unusually active compared to the last year, not that a major earthquake is imminent.
What are the main limitations and uncertainties?
Uncertainties include: mixed magnitude types (Mw/Mb/Ml) depending on source; reporting delays, later revisions and re-locations; uneven detection completeness across regions; and the fact that the energy relation is an approximation. QuakeMap24 uses a deduplicated multi-source catalog to reduce duplicates, but differences across agencies can still occur.
Which data sources are used for the global seismic activity index?
Events come from the QuakeMap24 earthquake catalogue. Reports sharing an event ID count once. Preferred sources follow the same priority as event lists, starting with USGS and EMSC. The Source page lists the providers.