Reviewed by USGSTonga31y ago
M4.2 earthquake 96 km NNE of Hihifo, Tonga
Saturday, April 22, 1995, 09:33:17 UTC · 15.168°S, 173.405°W
A magnitude 4.2 earthquake struck 96 km NNE of Hihifo, Tonga on Saturday, April 22, 1995, 09:33:17 UTC, at a depth of 10.0 km (shallow).
- Magnitude
- 4.2
- Light · mb
- Depth
- 10 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
30 tons of TNT
That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.
Tectonic setting
52 km
from the nearest mapped plate boundary, between the Tonga and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
10 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 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M6.0 on May 7, 1995. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.989 km N of Hihifo, Tonga31y ago · 25 km W of this epicenter
- 4.5109 km NNE of Hihifo, Tonga31y ago · 13 km NE of this epicenter
- 6.082 km NE of Hihifo, Tonga31y ago · 32 km SE of this epicenter
- 5.087 km NNE of Hihifo, Tonga31y ago · 13 km S of this epicenter
- 4.6104 km N of Hihifo, Tonga31y ago · 32 km NW of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 860 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.0The 1917 Samoa-Tonga EarthquakeJune 26, 1917 · 24 km NE of this epicenter
- 7.8146 km ESE of Hihifo, TongaDecember 26, 1975 · 158 km SE of this epicenter
- 7.7133 km NE of Hihifo, TongaSeptember 1, 1981 · 41 km NE of this epicenter
- 7.6199 km ESE of Hihifo, TongaApril 2, 1977 · 220 km SE of this epicenter
- 7.488 km NNE of Hihifo, TongaApril 7, 1995 · 14 km W of this epicenter
- 7.219 km ENE of Hihifo, TongaOctober 15, 1984 · 81 km S of this epicenter
- 7.1112 km NNE of Hihifo, TongaApril 14, 1957 · 17 km N of this epicenter
- 7.0206 km SE of Hihifo, TongaJune 17, 1978 · 247 km SE 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, which together caused about 2 recorded deaths. The most severe:
- 1917M8.3
Samoa Islands
26 Jun 1917 · 57 km away
2 deathsModerate damage ($1–5M)tsunami
- 1981M7.7
Apia; American Samoa: Pago Pago
1 Sep 1981 · 41 km away · intensity VI
Limited damage (under $1M)tsunami
- 1977M7.6
Apia
2 Apr 1977 · 220 km away · intensity VI
Limited damage (under $1M)tsunami
- 1975M7.8
Samoa Islands
26 Dec 1975 · 158 km away · intensity V
tsunami
- 1957M7.5
Samoa Islands
14 Apr 1957 · 57 km away
- 1995M7.4
Apia; American Samoa: Pago Pago; Niue
7 Apr 1995 · 14 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.