M5.6 Earthquake 11 km SW of Álftanes, Iceland — October 20, 2020
2020-10-20 13:43:17 UTC (2020-10-20) · approx. 12:43 PM UTC-1 local
Felt by 91 people across nearby locations. Maximum shaking intensity MMI 6.9 (very strong).
On October 20, 2020 at 13:43 UTC, a magnitude 5.6 shallow crustal earthquake struck 11 km SW of Álftanes, Iceland, at a depth of 10.0 km and coordinates 64.0134°, -22.1508°. The earthquake was reported felt by 91 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 6.9 (very strong). The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. The nearest populated place is Alftanes (population 2,392).
Physical scale: An earthquake of magnitude 5.6 releases seismic energy equivalent to roughly 4 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 4.4 km — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in Iceland, a region characterized by the Mid-Atlantic Ridge, where the North American and Eurasian plates diverge at 18-25 mm per year, amplified by the Iceland mantle plume. The nearest mapped fault system is the Mid-Atlantic Ridge. View all earthquakes in Iceland.
Learn more: Magnitude scale · Aftershock sequences
Nearest Populated Places
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 91 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 | 23,568 |
| MMI 4 | light | 211,500 |
| MMI 5 | moderate | 55,568 |
| MMI 6 | strong | 1,985 |
| MMI 7 | very strong | 106 |
Earthquake Details
-22.1508°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 5.6 earthquake near Álftanes, Iceland?
The magnitude 5.6 earthquake that struck 11 km SW of Álftanes, Iceland on October 20, 2020 at 13:43 UTC had a depth of 10.0 km. It was felt by 91 people with maximum shaking intensity of MMI 6.9 (very strong). For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at 64.0134°, -22.1508°, which is 11 km SW of Álftanes, Iceland. The nearest populated place is Alftanes (population 2,392). View all earthquakes in Iceland.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.6 earthquakes can continue for days to weeks and gradually diminish over time.
Has Iceland had earthquakes this big before?
The largest recorded earthquake in Iceland was the M6.6 South Iceland earthquake of June 17, 2000. Today's magnitude 5.6 event is within one magnitude unit of that historical record.
Authoritative source: USGS event page (event ID: us6000ca0k). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, October 20, 2020). M5.6 Earthquake 11 km SW of Álftanes, Iceland — October 20, 2020. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000ca0k/