M4.3 earthquake in South Island of New Zealand

Monday, October 4, 2010, 17:29:21 UTC · 43.620°S, 172.160°E

A magnitude 4.3 earthquake struck in South Island of New Zealand on Monday, October 4, 2010, 17:29:21 UTC, at a depth of 5.0 km (shallow).

Magnitude: 4.3; Light · ml
Depth: 5 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

43 tons of TNT

That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.

Tectonic setting

113 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

5 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 24 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.8 on October 18, 2010. 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 12 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 23 recorded deaths. The most severe:

1929M7.5
South Island
16 Jun 1929 · 208 km away
17 deathsModerate damage ($1–5M)tsunami
1968M7.1
South Island: Nw Coast
23 May 1968 · 214 km away
3 deaths$3 million damage
1848M6.0
Awatere River, Marlborough
18 Oct 1848 · 264 km away
3 deathstsunami
2010M7.0
Christchurch
3 Sep 2010 · 29 km away · intensity IX
$6.5 billion damage
1913M6.8
Tasman Sea
22 Feb 1913 · 209 km away · intensity VIII
Limited damage (under $1M)tsunami
1994M6.8
South Island: Christchurch
18 Jun 1994 · 84 km away · intensity VI
Limited damage (under $1M)

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

Nearby trackers