QuakeScout
Magnitude5.3

Reviewed by USGS45y ago

M5.3 earthquake off the west coast of the South Island of New Zealand

Wednesday, May 27, 1981, 18:57:21 UTC · 48.561°S, 164.047°E

A magnitude 5.3 earthquake struck off the west coast of the South Island of New Zealand on Wednesday, May 27, 1981, 18:57:21 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M7.6 on May 25, 1981.

Magnitude
5.3
Moderate · ms
Depth
33 km
Shallow
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: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

1 kilotons of TNT

That is about 1/11 of the Hiroshima bomb. It released about 3 times the energy of a magnitude 5.0.

Tectonic setting

13 km

from the nearest mapped plate boundary, between the Pacific and Australian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

33 km

Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.

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 75 km

USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.3 on June 15, 1981. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M51h6h1d3d7d14d30dMainshock M5.3
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 5.3off the west coast of the South Island of New Zealand45y ago · 49 km E of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 37 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 7.6off the west coast of the South Island of New ZealandMay 25, 1981 · 34 km SE of this epicenter
  2. 7.5173 km WSW of Riverton, New ZealandSeptember 1, 1945 · 225 km NE of this epicenter
  3. 7.4180 km W of Riverton, New ZealandOctober 12, 1979 · 244 km NE of this epicenter
  4. 7.0Auckland Islands, New Zealand regionSeptember 12, 1964 · 57 km SE of this epicenter
  5. 7.0Auckland Islands, New Zealand regionJanuary 5, 1955 · 189 km SW of this epicenter
  6. 7.0Auckland Islands, New Zealand regionFebruary 22, 1936 · 66 km S of this epicenter
  7. 6.8off the west coast of the South Island of New ZealandJanuary 12, 1954 · 65 km E of this epicenter
  8. 6.7Auckland Islands, New Zealand regionMarch 18, 1961 · 153 km S of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 3 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 1926M7.9

    Macquarie Island: North Of

    3 Oct 1926 · 229 km away

  2. 1981M7.6

    W Of North Island

    25 May 1981 · 34 km away

    tsunami

  3. 1979M7.5

    W Of North Island

    12 Oct 1979 · 244 km away · intensity V

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

Nearby trackers

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