QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9mb_lg

4 km SW of Center Sandwich, New Hampshire

· 8.3 km deep · released about 680 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Carroll County 24 kmBelknap County 29 kmGrafton County 33 kmMerrimack County 56 kmStrafford County 65 kmOrange County 75 kmSullivan County 76 kmYork County 76 kmCaledonia County 92 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
Magnitude
M 2.9 (mb_lg)
Depth
8.3 km below the surface
Felt
207 reports · strongest reported intensity IV
Nearest
Carroll County, 24 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1174 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 207 people have reported feeling it to USGS.

How big was it?

This earthquake released about 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.4× the energy of this one
  4. This earthquake M 2.9 about 680 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.

Where

Epicentre 43.7796, -71.4803. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Carroll County, NH 24 km (15 mi) WSW of here earthquakes near Carroll County
Belknap County, NH 29 km (18 mi) N of here earthquakes near Belknap County
Grafton County, NH 33 km (21 mi) ESE of here earthquakes near Grafton County
Merrimack County, NH 56 km (35 mi) NNE of here earthquakes near Merrimack County
Strafford County, NH 65 km (40 mi) NNW of here earthquakes near Strafford County
Orange County, VT 75 km (47 mi) ESE of here earthquakes near Orange County

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

Aftershocks so far

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

  1. 1.6 2 km SW of Center Sandwich, New Hampshire
  2. 1.9 4 km ESE of Northfield, New Hampshire
  3. 1.5 6 km SE of New Hampton, New Hampshire
  4. 2.0 5 km S of Alton, New Hampshire
  5. 2.2 4 km NW of Gilford, New Hampshire
  6. 2.2 1 km W of Andover, New Hampshire
  7. 1.8 3 km SW of Center Sandwich, New Hampshire

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.