Global Seismic Activity

Assessing worldwide seismic energy release

Last 24 hours Calculated at 19:15 UTC (Every 15 min)
Seismic activity index (0–100)
1013
Joules
Energy released (24h)
Calm Normal Elevated High Very high
Seismic activity index (0–100)
Energy released (24h)
1013 Joules
log10(E): 13.55
Ranked vs last 365 days
17th percentile
Higher than 17% of days
Strongest event (24h)
M5.3
111 events with M≥3

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
We filter earthquake events from the last 24 hours using a magnitude threshold of M≥3.0 and a rolling UTC window.
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
We sum energies across all events to obtain E24h and compare today’s value against the previous 365 days. The index shown (0–100) is the percentile rank.

FAQ

What does the seismic activity index score mean?
The 0–100 score is a percentile rank of today’s 24-hour released energy compared to the distribution of the previous 365 days. A score of 76 means today’s activity is higher than about 76% of all days in that reference period. It is a measure of observed global activity, not a forecast.
Why is the calculation based on logarithmic energy release?
Earthquake magnitude is logarithmic: an increase by 1.0 magnitude corresponds to roughly 10× amplitude and ~31.6× energy. An energy-based index therefore reflects physics much better than simply counting events. This prevents many small quakes from outweighing one genuinely large release of energy.
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?
We maintain a history of snapshots. The percentile rank is computed as the fraction of historical log10(E24h) values that are less than or equal to today’s log10(E24h), multiplied by 100. This yields a reproducible, comparable index where 50 is typical (median) and 90 indicates unusually high activity compared to the last year.
Why use a magnitude threshold (M≥3.0)?
Global detection and reporting completeness varies for very small events, and different networks detect microquakes differently. Using M≥3.0 reduces sensitivity to local detection differences and focuses on events more consistently reported worldwide. This improves reproducibility and reduces noise.
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?
QuakeMap24 aggregates real-time earthquake data from more than 25 international seismological institutes and data centers worldwide. These include national and regional providers such as the USGS Earthquake Hazards Program, the European-Mediterranean Seismological Centre (EMSC), ETH Zurich, INGV, IRIS and many others. All incoming events are deduplicated and harmonized before being used in the global activity index. The complete and continuously updated list of data providers is available here: https://quakemap24.com/en/page/source.