Reviewed by USGSNew Zealand16y ago
M4.1 earthquake 7 km NW of Ashburton, New Zealand
Thursday, September 30, 2010, 16:53:26 UTC · 43.857°S, 171.655°E
A magnitude 4.1 earthquake struck 7 km NW of Ashburton, New Zealand on Thursday, September 30, 2010, 16:53:26 UTC, at a depth of 18.4 km (shallow).
- Magnitude
- 4.1
- Light · ml
- Depth
- 18 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
115 km
from the nearest mapped plate boundary, between the Australian and Pacific plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
18 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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.3 on October 4, 2010. 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 57 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.368 km S of Wakefield, New ZealandJune 16, 1929 · 242 km NE of this epicenter
- 7.138 km E of Westport, New ZealandMay 23, 1968 · 239 km N of this epicenter
- 7.030 km NW of Amberley, New ZealandMarch 9, 1929 · 116 km NE of this epicenter
- 7.019 km NE of Methven, New ZealandSeptember 3, 2010 · 40 km N of this epicenter
- 6.856 km NW of Oxford, New ZealandJune 18, 1994 · 99 km N of this epicenter
- 6.535 km NNW of Methven, New ZealandJune 26, 1946 · 59 km N of this epicenter
- 6.558 km SW of Wakefield, New ZealandJune 22, 1929 · 240 km N of this epicenter
- 6.471 km NNE of Amberley, New ZealandMay 22, 1948 · 183 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 20 recorded deaths. The most severe:
- 1929M7.5
South Island
16 Jun 1929 · 239 km away
17 deathsModerate damage ($1–5M)tsunami
- 1968M7.1
South Island: Nw Coast
23 May 1968 · 241 km away
3 deaths$3 million damage
- 2010M7.0
Christchurch
3 Sep 2010 · 40 km away · intensity IX
$6.5 billion damage
- 1913M6.8
Tasman Sea
22 Feb 1913 · 229 km away · intensity VIII
Limited damage (under $1M)tsunami
- 1994M6.8
South Island: Christchurch
18 Jun 1994 · 99 km away · intensity VI
Limited damage (under $1M)
- 2010M5.0
South Island: Christchurch
6 Sep 2010 · 67 km away · intensity V
Limited damage (under $1M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.