QuakeIndex

ice quake · reviewed by a seismologist

M 1.6ml

125 km E of McCarthy, Alaska

No: USGS classifies this as a ice quake, not an earthquake. A magnitude 1.6 ice quake was recorded 125 km E of McCarthy, Alaska at 07:42 UTC on 2019-07-31, less than 1 km deep.

· 0.0 km deep · released about 7.6 lb 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 1.6 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2639 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 11 km (7 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.

USGS catalogues this as ice quake, not an earthquake.

How big was it?

This earthquake released about 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 lb of TNT

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 since 2016 was M 4.0 on 2017-11-05 — about 4,000 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.1 109 km E of McCarthy, Alaska · 32 km SW of this epicentre
  2. 5.7 152 km E of McCarthy, Alaska · 32 km SE of this epicentre
  3. 5.5 87 km ENE of McCarthy, Alaska · 42 km WNW of this epicentre
  4. 5.4 140 km SSE of Alcan Border, Alaska · 16 km E of this epicentre
  5. 5.4 136 km SSE of Alcan Border, Alaska · 26 km ENE 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 61.5008, -140.5671. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.9 97 km E of McCarthy, Alaska
  2. 1.5 144 km WNW of Haines Junction, Canada
  3. 1.8 129 km ESE of McCarthy, Alaska
  4. 1.9 99 km E of McCarthy, Alaska
  5. 1.6 121 km ESE of McCarthy, Alaska
  6. 1.9 120 km E of McCarthy, Alaska
  7. 2.5 144 km WNW of Haines Junction, Canada
  8. 2.9 143 km WNW of Haines Junction, Canada
  9. 2.0 144 km WNW of Haines Junction, Canada
  10. 2.1 144 km WNW of Haines Junction, Canada
  11. 3.2 144 km WNW of Haines Junction, Canada
  12. 1.7 129 km E of McCarthy, Alaska
  13. 1.7 Southern Yukon Territory, Canada
  14. 3.4 125 km E of McCarthy, Alaska
  15. 1.9 108 km E of McCarthy, 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.