QuakeIndex

Earthquake · reviewed by a seismologist

M 4.9mb

58 km S of False Pass, Alaska

Yes. A magnitude 4.9 earthquake was recorded 58 km S of False Pass, Alaska, at 6:02 am AKDT on 9 May 2020 (14:02 UTC), 68 km deep. 1 person has reported feeling it to USGS.

· 68 km deep · released about 340 tons of TNT

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Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Magnitude
M 4.9 (mb)
Depth
68 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
Aleutians East Borough, 138 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2298 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 168 km (104 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 340 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 500× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 22× the energy of this one
  3. Magna, Utah 2020 M 5.7 16× the energy of this one
  4. This earthquake M 4.9 about 340 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 710× more

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km (31 mi) since our catalogue begins in 2016. The previous largest was M 4.8 on 2017-06-30.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 47 km SE of False Pass, Alaska · 45 km NE of this epicentre
  2. 6.5 79 km SW of False Pass, Alaska · 47 km W of this epicentre
  3. 6.0 96 km SSW of False Pass, Alaska · 41 km SSW of this epicentre
  4. 5.8 85 km SW of False Pass, Alaska · 49 km WSW of this epicentre
  5. 5.6 87 km SSW of False Pass, Alaska · 48 km WSW of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 54.3299, -163.4422. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aleutians East Borough, AK 138 km (86 mi) NE earthquakes near Aleutians East Borough

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

56 earthquakes have been recorded within 50 km since this one.

  1. 2.5 105 km SSW of False Pass, Alaska
  2. 2.0 57 km SSW of False Pass, Alaska
  3. 1.8 37 km SSE of False Pass, Alaska
  4. 2.3 25 km S of False Pass, Alaska
  5. 2.3 40 km S of False Pass, Alaska
  6. 1.9 25 km S of False Pass, Alaska
  7. 2.3 19 km SSW of False Pass, Alaska
  8. 1.7 52 km SSE of False Pass, Alaska
  9. 2.1 103 km S of False Pass, Alaska
  10. 1.9 91 km SSW of False Pass, Alaska
  11. 1.8 46 km S of False Pass, Alaska
  12. 1.8 22 km SSW of False Pass, Alaska
  13. 1.7 31 km SSE of False Pass, Alaska
  14. 1.7 74 km SSW of False Pass, Alaska
  15. 2.0 97 km SSW of False Pass, Alaska

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.