M5.5 Earthquake 8 km SE of Quepos, Costa Rica — March 21, 2023
2023-03-21 01:44:13 UTC (2023-03-21) · approx. 7:44 PM UTC-6 local
Felt by 114 people across surrounding communities. Maximum shaking intensity MMI 4.4 (moderate).
On March 21, 2023 at 01:44 UTC, a magnitude 5.5 shallow crustal earthquake struck 8 km SE of Quepos, Costa Rica, at a depth of 35.0 km and coordinates 9.3707°, -84.1119°. The earthquake was reported felt by 114 peopleacross surrounding communities, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 4.4 (moderate). The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 211 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 532, placing it among routine seismic activity. The nearest populated place is Parrita (population 3,734).
Physical scale: An earthquake of magnitude 5.5 releases seismic energy equivalent to roughly 3 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 3.8 km — a useful intuition for the size of the slip patch on the fault.
Nearest Populated Places
What the Shaking Felt Like
At MMI 4.4 (moderate), people in the most strongly affected areas would have experienced: Mild shaking, similar to a passing truck. Hanging objects swing. Glasses and dishes may rattle. Not commonly felt outdoors.
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 114 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
Population exposure (USGS PAGER)
Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.
| Shaking intensity (MMI) | Description | Population exposed |
|---|---|---|
| MMI 3 | weak | 5,322,314 |
| MMI 4 | light | 464,564 |
Earthquake Details
-84.1119°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 5.5 earthquake near Quepos, Costa Rica?
The magnitude 5.5 earthquake that struck 8 km SE of Quepos, Costa Rica on March 21, 2023 at 01:44 UTC had a depth of 35.0 km. It was felt by 114 people with maximum shaking intensity of MMI 4.4 (moderate). For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at 9.3707°, -84.1119°, which is 8 km SE of Quepos, Costa Rica. The nearest populated place is Parrita (population 3,734).
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.5 earthquakes can continue for days to weeks and gradually diminish over time.
Authoritative source: USGS event page (event ID: us7000jlkb). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, March 21, 2023). M5.5 Earthquake 8 km SE of Quepos, Costa Rica — March 21, 2023. Retrieved October 9, 2024 from https://www.earthquaketracker.org/earthquakes/event/us7000jlkb/