QuakeIndex

quarry blast · reviewed by a seismologist

M 1.9ml

Oklahoma

No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.9 quarry blast was recorded in Oklahoma, 87 km (54 mi) ESE of Tulsa, OK, at 11:22 am CDT on 20 October 2020 (16:22 UTC), less than 1 km deep.

87 km (54 mi) ESE of Tulsa, OK

· 0.0 km deep · released about 20 lb of TNT

10 km30 km60 km120 km N Cherokee County 12 kmAdair County 36 kmMuskogee County 38 kmSequoyah County 42 kmWagoner County 47 kmMayes County 59 kmHaskell County 64 kmDelaware County 69 kmCrawford County 75 km
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
Oklahoma today
every earthquake in Oklahoma in the last 24 hours
Magnitude
M 1.9 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
Cherokee County, 12 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2213 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 20 km (12 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.

Earthquakes near other towns within 30 km: Park Hill, Tahlequah, Fort Gibson.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 20 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 760,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 540,000× the energy of this one
  3. Around the size people start to feel M 3.0 48× the energy of this one
  4. This earthquake M 1.9 about 20 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 35.8012, -95.0268. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Cherokee County, OK 12 km (7 mi) NNE earthquakes near Cherokee County
Adair County, OK 36 km (22 mi) ENE earthquakes near Adair County
Muskogee County, OK 38 km (24 mi) WSW earthquakes near Muskogee County
Sequoyah County, OK 42 km (26 mi) SE earthquakes near Sequoyah County
Wagoner County, OK 47 km (29 mi) WNW earthquakes near Wagoner County
Mayes County, OK 59 km (37 mi) NNW earthquakes near Mayes County

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. 1.6 2 km SW of Hulbert, Oklahoma
  2. 1.7 5 km NE of Porter, Oklahoma
  3. 1.5 3 km SW of Hulbert, Oklahoma
  4. 1.5 2 km SE of Zeb, Oklahoma
  5. 1.5 2 km NNE of Sams Corner, Oklahoma
  6. 1.7 4 km SW of Hulbert, Oklahoma
  7. 1.8 2 km SSW of Hulbert, Oklahoma
  8. 2.0 3 km SW of Hulbert, Oklahoma
  9. 1.5 3 km SW of Hulbert, Oklahoma
  10. 1.9 1 km ESE of Woodall, Oklahoma
  11. 1.6 1 km ENE of Zeb, Oklahoma
  12. 1.6 2 km SSW of Hulbert, Oklahoma
  13. 1.8 3 km SSW of Hulbert, Oklahoma
  14. 2.0 2 km SW of Hulbert, Oklahoma
  15. 1.6 1 km ESE of Zeb, Oklahoma

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.