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United States · Alaska

M6.4 Earthquake near Unorganized Borough, Alaska (United States)

UTC time: 2026-09-17 14:19:53 UTC Local time: —
Earthquake newsQuakeMap24
First published: Content updated:

Automatically generated from measurement data by QuakeMap24. Values may change after further analysis.

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M6.4 Earthquake near Unorganized Borough, Alaska (United States) · 2026-09-17 — Map showing the location of the epicenter
M6.4 Earthquake near Unorganized Borough, Alaska (United States) · 2026-09-17 — Map showing the location of the epicenter

About this earthquake

A magnitude M6.4 earthquake was recorded near Unorganized Borough, Alaska (United States) on September 17, 2026 at 14:19 UTC. The earthquake originated at an intermediate depth of about 115 km. Earthquakes of this magnitude can cause significant damage in populated areas.

The event was recorded by USGS. United States: 166 earthquakes were recorded in the past 24 hours, the strongest reaching M6.5.

Depth profile

Depth profile Depth: 114.8 km (Intermediate) Surface Shallow Intermediate Deep 0 km 70 km 300 km 700 km 114.8 km
Intermediate
114.8 km
114.8 km — deeper than the regional average (15.2 km)
Regional average: 15.2 km
Why depth matters

Intermediate-depth quakes are felt across a wider area but usually cause less surface damage.

Depth classes per USGS

Official USGS aftershock forecast

Probability of at least one aftershock at or above the specified magnitude during the entire stated time window. This does not predict an individual earthquake.

Issued: Sep 17, 2026, 2:49 PM UTC · Last checked: Sep 17, 2026, 3:00 PM UTC

Sep 17, 2026, 2:50 PM UTC – Sep 18, 2026, 2:50 PM UTC
MagnitudeProbability ≥ 1Count (95% interval)
M ≥ 3.099.02 %1–409
M ≥ 4.081.59 %0–41
M ≥ 5.034.10 %0–5
M ≥ 6.06.16 %0–1
M ≥ 7.00.70 %0–0
Sep 17, 2026, 2:50 PM UTC – Sep 24, 2026, 2:50 PM UTC
MagnitudeProbability ≥ 1Count (95% interval)
M ≥ 3.099.67 %3–733
M ≥ 4.089.48 %0–74
M ≥ 5.046.33 %0–8
M ≥ 6.010.12 %0–1
M ≥ 7.01.24 %0–0
Sep 17, 2026, 2:50 PM UTC – Oct 17, 2026, 2:50 PM UTC
MagnitudeProbability ≥ 1Count (95% interval)
M ≥ 3.099.84 %5–1,033
M ≥ 4.092.83 %0–104
M ≥ 5.053.97 %0–11
M ≥ 6.013.33 %0–2
M ≥ 7.01.72 %0–0
Sep 17, 2026, 2:50 PM UTC – Sep 17, 2027, 2:50 PM UTC
MagnitudeProbability ≥ 1Count (95% interval)
M ≥ 3.099.95 %8–1,690
M ≥ 4.096.16 %0–169
M ≥ 5.064.82 %0–18
M ≥ 6.019.26 %0–2
M ≥ 7.02.75 %0–1

The range is the 95% forecast interval for the number of earthquakes. Magnitude thresholds and time windows overlap: do not add the values. Windows already in progress still refer to the entire stated period.

Source: USGS — Operational Aftershock Forecast

Estimated impact

Green No or minimal impact expected.
5 Felt reports · max reported intensity 3.4

Ground shaking

V
Moderate · Intensity (MMI) V
Felt by all, slight damage possible.

Tectonic context

Located on the North America Plate.
Near the boundary North America ↔ Pacific · about 163 km away

Volcanoes nearby

  • Chagulak
    Distance: 4 km ·Stratovolcano ·Elevation: 1'028 m ·United States
  • Amukta
    Distance: 7 km ·Stratovolcano ·Elevation: 1'066 m ·Last eruption: 1996 ·United States
  • Yunaska
    Distance: 39 km ·Shield ·Elevation: 550 m ·Last eruption: 1937 ·United States
  • Herbert
    Distance: 76 km ·Stratovolcano ·Elevation: 1'280 m ·United States
  • Carlisle
    Distance: 86 km ·Stratovolcano ·Elevation: 1'620 m ·Last eruption: 1828 ·United States
  • Cleveland
    Distance: 89 km ·Stratovolcano ·Elevation: 1'730 m ·Last eruption: 2020 ·United States

Comparison of seismic sources

7 sources currently report magnitudes from M6.1 to M6.5.

Measurements can differ because agencies use different networks and calculation methods. Values may be revised.

SourceMagnitudeDepthPosition difference
SERBIA_RSZM6.310.0 km45.6 km
EMSCM6.435.0 km31.9 km
GFZM6.491.0 km42.6 km
RESIFM6.184.2 km45.0 km
SCEDCM6.5111.7 km25.6 km
USGSM6.383.0 km31.4 km
INGVM6.599.2 km25.9 km

Alaska

Context for this earthquake

17 Sep 2025 – 17 Sep 2026 · M ≥ 3.0 · 652 Catalogue entries

Sufficiently reliable matching data are not currently available for a direct comparison. The area profile shows the available records and their limitations.

Open seismic profile

Historical context nearby

Comparison with recorded earthquakes before this event within 250 km.

Magnitude rank#1
Earlier events M≥4199
Earlier events M≥587
Compared since2025-01-13

The QuakeMap24 comparison dataset begins on 2024-03-23. Earlier earthquakes may not be included.

Strongest earlier events

M6.32026-09-03 11:17:24 UTC144.4 km###.# km ( ###.# mi) WNW (az= 303.5) from Port Orford, OR M6.32026-02-23 05:11:49 UTC112.2 kmAlaska M6.22025-09-03 20:57:41 UTC183.1 km87 km SW of Nikolski, Alaska M6.12026-02-23 05:11:48 UTC112.2 km###.# km ( ###.# mi) WNW (az= 303.7) from Port Orford, OR M6.12026-02-23 05:11:48 UTC83.3 kmAlaska

Historic earthquake map · United States

Open history map
Explore recent and long-term earthquake activity in this country. Use filters to narrow down by magnitude, depth, and date range.

Country statistics · United States

Country overview
View earthquake KPIs, strongest and latest events, and averages for this country.

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