M3.9 Earthquake 2 km SSE of Salitrillos, Costa Rica — July 20, 2021
2021-07-20 23:57:14 UTC (2021-07-20) · approx. 5:57 PM UTC-6 local
Felt by 32 people across nearby locations.
On July 20, 2021 at 23:57 UTC, a magnitude 3.9 shallow crustal earthquake struck 2 km SSE of Salitrillos, Costa Rica, at a depth of 8.9 km and coordinates 9.8321°, -84.0823°.
Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 11 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 296 m — a useful intuition for the size of the slip patch on the fault.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 32 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-84.0823°E
Technical Information
Common Questions
How strong was the magnitude 3.9 earthquake near Salitrillos, Costa Rica?
The magnitude 3.9 earthquake that struck 2 km SSE of Salitrillos, Costa Rica on July 20, 2021 at 23:57 UTC had a depth of 8.9 km. For context, this was a minor earthquake typically detected only by instruments.
Where did the earthquake occur?
The earthquake epicenter was located at 9.8321°, -84.0823°, which is 2 km SSE of Salitrillos, Costa Rica.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.9 earthquakes can continue for several days and gradually diminish over time.
Authoritative source: USGS event page (event ID: us6000exhn). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 20, 2021). M3.9 Earthquake 2 km SSE of Salitrillos, Costa Rica — July 20, 2021. Retrieved September 25, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000exhn/