QuakeScout
Magnitude4.3

Reviewed by USGS4y ago

M4.3 earthquake in South Sandwich Islands region

Saturday, July 23, 2022, 22:51:27 UTC · 58.375°S, 26.076°W

A magnitude 4.3 earthquake struck in South Sandwich Islands region on Saturday, July 23, 2022, 22:51:27 UTC, at a depth of 130.0 km (intermediate).

Magnitude
4.3
Light · mb
Depth
130 km
Intermediate
Felt reports
0
Did You Feel It?
Est. shaking
—
No ShakeMap
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeDashed circle: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

43 tons of TNT

That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.

Tectonic setting

128 km

from the nearest mapped plate boundary, between the Sandwich and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: intermediate

130 km

Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.

Did You Feel It?

Where it was felt

No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 50 km

USGS lists 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.2 on August 19, 2022. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M51h6h1d3d7d14d30dMainshock M4.3
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 5.2South Sandwich Islands region4y ago · 47 km NE of this epicenter
  2. 4.7South Sandwich Islands region4y ago · 50 km E of this epicenter
  3. 4.6South Sandwich Islands region4y ago · 47 km NE of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 1,817 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.12021 South Sandwich Islands EarthquakeAugust 12, 2021 · 47 km E of this epicenter
  2. 7.8South Sandwich Islands regionMay 26, 1964 · 247 km NW of this epicenter
  3. 7.5South Sandwich Islands regionAugust 12, 2021 · 109 km NE of this epicenter
  4. 7.5South Sandwich Islands regionAugust 28, 1933 · 216 km S of this epicenter
  5. 7.3South Sandwich Islands regionSeptember 1, 1961 · 108 km S of this epicenter
  6. 7.3South Sandwich Islands regionJuly 15, 2013 · 282 km S of this epicenter
  7. 7.2South Sandwich Islands regionNovember 15, 1910 · 148 km SE of this epicenter
  8. 7.2South Sandwich Islands regionDecember 27, 1991 · 265 km N of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 5 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 2021M8.1

    South Sandwich Islands

    12 Aug 2021 · 44 km away

    tsunami

  2. 1961M7.7

    South Sandwich Islands

    5 Sep 1961 · 68 km away

  3. 1961M7.7

    South Sandwich Islands

    8 Sep 1961 · 246 km away

  4. 1961M7.5

    South Sandwich Islands

    1 Sep 1961 · 143 km away

  5. 2021M7.5

    South Sandwich Islands

    12 Aug 2021 · 101 km away

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

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