QuakeScout
Magnitude3.8

Reviewed by USGSNew Zealand23y ago

M3.8 earthquake 61 km WNW of Te Anau, New Zealand

Wednesday, January 21, 2004, 02:34:31 UTC · 45.250°S, 166.970°E

A magnitude 3.8 earthquake struck 61 km WNW of Te Anau, New Zealand on Wednesday, January 21, 2004, 02:34:31 UTC, at a depth of 20.0 km (shallow).

Magnitude
3.8
Minor · ml
Depth
20 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: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

8 tons of TNT

That is about 1/1,992 of the Hiroshima bomb. A magnitude 5.0 releases about 63 times more energy.

Tectonic setting

19 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

20 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 50 km

USGS lists 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.2 on February 3, 2004. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M41h6h1d3d7d14d30dMainshock M3.8
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 3.839 km WSW of Te Anau, New Zealand22y ago · 37 km SE of this epicenter
  2. 4.248 km WSW of Te Anau, New Zealand22y ago · 40 km S of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 66 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 7.5173 km WSW of Riverton, New ZealandSeptember 1, 1945 · 209 km S of this epicenter
  2. 7.4180 km W of Riverton, New ZealandOctober 12, 1979 · 186 km SW of this epicenter
  3. 7.256 km NW of Te Anau, New ZealandAugust 21, 2003 · 21 km NE of this epicenter
  4. 7.015 km WNW of Te Anau, New ZealandDecember 16, 1938 · 46 km E of this epicenter
  5. 7.063 km WNW of Te Anau, New ZealandAugust 10, 1993 · 5 km SW of this epicenter
  6. 6.762 km WNW of Te Anau, New ZealandAugust 2, 1943 · 1 km NW of this epicenter
  7. 6.746 km NNW of Te Anau, New ZealandJune 3, 1988 · 56 km NE of this epicenter
  8. 6.686 km N of Te Anau, New ZealandMay 4, 1976 · 83 km NE of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 4 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 2003M7.2

    Dunedin,Invercargill,Te Anau,Fiordland

    21 Aug 2003 · 21 km away

    Limited damage (under $1M)tsunami

  2. 2004M7.1

    Invercargill, Southland, Otago

    22 Nov 2004 · 235 km away

    Limited damage (under $1M)tsunami

  3. 1826M8.0

    Fjordland

    1826 · 71 km away

  4. 1979M7.5

    W Of North Island

    12 Oct 1979 · 186 km away · intensity V

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

Nearby trackers

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