Reviewed by USGSNew Zealand17y ago
M4.7 earthquake 81 km WSW of Te Anau, New Zealand
Thursday, October 8, 2009, 10:16:29 UTC · 45.575°S, 166.704°E
A magnitude 4.7 earthquake struck 81 km WSW of Te Anau, New Zealand on Thursday, October 8, 2009, 10:16:29 UTC, at a depth of 8.0 km (shallow). It is the strongest earthquake within 300 km since an M4.7 on October 1, 2009.
- Magnitude
- 4.7
- Light · ml
- Depth
- 8 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
169 tons of TNT
That is about 1/89 of the Hiroshima bomb. A magnitude 5.0 releases about 3 times more energy.
Tectonic setting
24 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
8 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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.8 on October 8, 2009. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 101 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.897 km WSW of Te Anau, New ZealandJuly 15, 2009 · 24 km SW of this epicenter
- 7.5173 km WSW of Riverton, New ZealandSeptember 1, 1945 · 168 km S of this epicenter
- 7.4180 km W of Riverton, New ZealandOctober 12, 1979 · 144 km SW of this epicenter
- 7.256 km NW of Te Anau, New ZealandAugust 21, 2003 · 63 km NE of this epicenter
- 7.1255 km W of Riverton, New ZealandNovember 22, 2004 · 196 km SW of this epicenter
- 7.015 km WNW of Te Anau, New ZealandDecember 16, 1938 · 68 km E of this epicenter
- 7.063 km WNW of Te Anau, New ZealandAugust 10, 1993 · 37 km NE of this epicenter
- 6.870 km N of Te Anau, New ZealandOctober 15, 2007 · 109 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 2009M7.8
Off West Coast Of South Island
15 Jul 2009 · 24 km away
Limited damage (under $1M)tsunami
- 2003M7.2
Dunedin,Invercargill,Te Anau,Fiordland
21 Aug 2003 · 63 km away
Limited damage (under $1M)tsunami
- 2004M7.1
Invercargill, Southland, Otago
22 Nov 2004 · 196 km away
Limited damage (under $1M)tsunami
- 2007M6.8
South Island: Fiordland
15 Oct 2007 · 112 km away
Limited damage (under $1M)
- 1826M8.0
Fjordland
1826 · 30 km away
- 1979M7.5
W Of North Island
12 Oct 1979 · 144 km away · intensity V
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.