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United States · Alaska

M5.5 Earthquake near Matanuska-Susitna Borough, Alaska (United States)

UTC time: 2026-08-08 04:50:33 UTC Local time: —
Earthquake newsQuakeMap24
Archive record · original publication time was not recorded Content updated:

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

Magnitude
M5.5
Depth
0.2 km
Source
USGS

Alaska · Matanuska-Susitna Borough

Country overview

Map

M5.5 Earthquake near Matanuska-Susitna Borough, Alaska (United States) · 2026-08-08 — Map showing the location of the epicenter
M5.5 Earthquake near Matanuska-Susitna Borough, Alaska (United States) · 2026-08-08 — Map showing the location of the epicenter

About this earthquake

On August 8, 2026 at 04:50 UTC, a magnitude M5.5 earthquake occurred near Matanuska-Susitna Borough, Alaska (United States). With a focal depth of about 0 km, this was a shallow earthquake, whose shaking is usually felt more strongly at the surface. Events of this size can cause damage near the epicenter.

The data is provided by USGS and cross-checked across seismological networks. United States: over the past 24 hours, QuakeMap24 logged 186 earthquakes, the strongest at M4.0.

Depth profile

Depth profile Depth: 0.2 km (Shallow) Surface Shallow Intermediate Deep 0 km 70 km 300 km 700 km 0.2 km
Shallow
0.2 km
0.2 km — shallower than the regional average (15.2 km)
Regional average: 15.2 km
Why depth matters

Shallow quakes release energy near the surface — shaking is felt more strongly and damage potential is higher.

Depth classes per USGS

Felt reports

22felt reports at EMSC / LastQuake

Voluntary reports of feeling this earthquake. The count is not an intensity measurement and is not added to USGS DYFI reports.

Data updated: Aug 8, 2026, 9:44 AM UTC · Last checked: Sep 8, 2026, 12:07 AM UTC

Source: EMSC / LastQuake

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 19, 2026, 4:50 AM UTC · Last checked: Sep 22, 2026, 9:22 PM UTC

Sep 19, 2026, 5:00 AM UTC – Sep 20, 2026, 5:00 AM UTC · Expired
MagnitudeProbability ≥ 1Count (95% interval)
M ≥ 3.00.41 %0–0
M ≥ 4.00.04 %0–0
M ≥ 5.0< 0.01 %0–0
M ≥ 6.0< 0.01 %0–0
M ≥ 7.0< 0.01 %0–0
Sep 19, 2026, 5:00 AM UTC – Sep 26, 2026, 5:00 AM UTC
MagnitudeProbability ≥ 1Count (95% interval)
M ≥ 3.02.67 %0–1
M ≥ 4.00.27 %0–0
M ≥ 5.00.03 %0–0
M ≥ 6.0< 0.01 %0–0
M ≥ 7.0< 0.01 %0–0
Sep 19, 2026, 5:00 AM UTC – Oct 19, 2026, 5:00 AM UTC
MagnitudeProbability ≥ 1Count (95% interval)
M ≥ 3.08.91 %0–1
M ≥ 4.00.93 %0–0
M ≥ 5.00.09 %0–0
M ≥ 6.0< 0.01 %0–0
M ≥ 7.0< 0.01 %0–0
Sep 19, 2026, 5:00 AM UTC – Sep 19, 2027, 5:00 AM UTC
MagnitudeProbability ≥ 1Count (95% interval)
M ≥ 3.030.96 %0–2
M ≥ 4.03.68 %0–1
M ≥ 5.00.37 %0–0
M ≥ 6.00.04 %0–0
M ≥ 7.0< 0.01 %0–0

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

1'136 Felt reports · max reported intensity 5.4

Ground shaking

VI
Strong · Intensity (MMI) VI
Strongly felt, light building damage possible.

Tectonic context

Located on the North America Plate.
Near the boundary North America ↔ Pacific · about 490 km away

Nearby population centers

Distances are straight-line distances from the epicenter. Population data: GeoNames.

PlaceDistanceDirectionPopulation
Anchorage174.9 kmSE289'600

GeoNames · CC BY 4.0

Volcanoes nearby

  • Hayes
    Distance: 70 km ·Stratovolcano ·Elevation: 3'034 m ·Last eruption: 1200 ·United States
  • Spurr
    Distance: 108 km ·Stratovolcano ·Elevation: 3'374 m ·Last eruption: 1992 ·United States
  • Redoubt
    Distance: 199 km ·Stratovolcano ·Elevation: 3'108 m ·Last eruption: 2009 ·United States
  • Iliamna
    Distance: 252 km ·Stratovolcano ·Elevation: 3'053 m ·Last eruption: 1876 ·United States
  • Buzzard Creek
    Distance: 281 km ·Tuff ring(s) ·Elevation: 830 m ·Last eruption: -1050 ·United States
  • Augustine
    Distance: 328 km ·Lava dome(s) ·Elevation: 1'218 m ·Last eruption: 2006 ·United States

Subsequent earthquakes nearby

Events recorded after this earthquake within 150 km. They are not automatically classified as aftershocks.

First 6 hours14
First 24 hours23
First 72 hours45
Strongest subsequent eventM3.5
M3.22026-08-08 04:56:35 UTC8.0 kmMatanuska-Susitna Borough M2.42026-08-08 04:58:40 UTC4.1 kmMatanuska-Susitna Borough M2.42026-08-08 05:02:08 UTC1.6 kmMatanuska-Susitna Borough M1.32026-08-08 05:08:26 UTC2.0 kmMatanuska-Susitna Borough M1.92026-08-08 05:27:32 UTC2.8 kmMatanuska-Susitna Borough M2.42026-08-08 05:39:33 UTC3.8 kmMatanuska-Susitna Borough M2.12026-08-08 05:45:58 UTC2.1 kmMatanuska-Susitna Borough M2.12026-08-08 06:10:45 UTC3.6 kmMatanuska-Susitna Borough M3.42026-08-08 07:01:48 UTC2.2 kmMatanuska-Susitna Borough M1.32026-08-08 07:45:28 UTC2.2 kmMatanuska-Susitna Borough M1.62026-08-08 08:05:27 UTC20.0 kmMatanuska-Susitna Borough M2.02026-08-08 08:13:57 UTC2.5 kmMatanuska-Susitna Borough

Comparison of seismic sources

5 sources currently report magnitudes from M5.1 to M5.5.

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

SourceMagnitudeDepthPosition difference
USGSM5.50.2 km0.0 km
EMSCM5.55.0 km5.6 km
GFZM5.510.0 km16.0 km
SERBIA_RSZM5.410.0 km22.4 km
RESIFM5.110.0 km19.8 km

Alaska

Context for this earthquake

22 Sep 2025 – 22 Sep 2026 · M ≥ 3.0 · 655 Catalogue entries

Of 654 other entries for this area and period, 15 have a higher stored magnitude. Different magnitude types and reports not yet merged limit the comparison.

Open seismic profile

Historical context nearby

Comparison with recorded earthquakes before this event within 150 km.

Magnitude rank#7
Earlier events M≥436
Earlier events M≥514
Compared since2025-02-05

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

Strongest earlier events

M6.02025-11-27 17:11:17 UTC119.4 kmSouthern Alaska M6.02025-11-27 17:11:29 UTC115.1 km12 km WNW of Susitna, Alaska M6.02025-11-27 17:11:27 UTC110.8 kmSOUTHERN ALASKA M6.02025-11-27 17:11:26 UTC100.4 kmSouthern Alaska M5.92025-11-27 17:11:27 UTC111.2 kmSouthern Alaska, United States [Land: United States]

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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