M4.1 earthquake 59 km WNW of Te Anau, New Zealand

Thursday, November 20, 2003, 07:32:50 UTC · 45.310°S, 166.970°E

A magnitude 4.1 earthquake struck 59 km WNW of Te Anau, New Zealand on Thursday, November 20, 2003, 07:32:50 UTC, at a depth of 20.0 km (shallow).

Magnitude: 4.1; Light · 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

21 tons of TNT

That is about 1/707 of the Hiroshima bomb. A magnitude 5.0 releases about 22 times more energy.

Tectonic setting

23 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 20 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.8 on November 26, 2003. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 63 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

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:

2003M7.2
Dunedin,Invercargill,Te Anau,Fiordland
21 Aug 2003 · 27 km away
Limited damage (under $1M)tsunami
1826M8.0
Fjordland
1826 · 66 km away
1979M7.5
W Of North Island
12 Oct 1979 · 180 km away · intensity V

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

Nearby trackers