Reviewed by USGSNew Zealand98y ago
M5.5 earthquake 38 km ESE of Westport, New Zealand
Wednesday, June 19, 1929, 03:25:30 UTC · 41.861°S, 172.044°E
A magnitude 5.5 earthquake struck 38 km ESE of Westport, New Zealand on Wednesday, June 19, 1929, 03:25:30 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.3 on June 16, 1929.
- Magnitude
- 5.5
- Moderate · mw
- Depth
- 15 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
3 kilotons of TNT
That is about 1/6 of the Hiroshima bomb. It released about 5 times the energy of a magnitude 5.0.
Tectonic setting
78 km
from the nearest mapped plate boundary, between the Australian and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
15 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 75 km
USGS lists 3 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M6.5 on June 22, 1929. 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 3 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 7 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 · 21 km away
17 deathsModerate damage ($1–5M)tsunami
- 1848M6.0
Awatere River, Marlborough
18 Oct 1848 · 164 km away
3 deathstsunami
- 1855M8.0
Wellington,Waiouru,Wanganui,Otaki
23 Jan 1855 · 255 km away
Severe damage ($5–24M)tsunami
- 1848M7.9
N.
15 Oct 1848 · 214 km away
Limited damage (under $1M)tsunami
- 1913M6.8
Tasman Sea
22 Feb 1913 · 46 km away · intensity VIII
Limited damage (under $1M)tsunami
- 1868M7.6
Tasman Sea
18 Oct 1868 · 201 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.