Reviewed by USGSTonga39y ago
M5.9 earthquake 115 km SSW of Hihifo, Tonga
Tuesday, November 24, 1987, 15:06:09 UTC · 16.976°S, 174.026°W
A magnitude 5.9 earthquake struck 115 km SSW of Hihifo, Tonga on Tuesday, November 24, 1987, 15:06:09 UTC, at a depth of 143.2 km (intermediate). It is the strongest earthquake within 300 km since an M6.2 on November 3, 1987.
- Magnitude
- 5.9
- Moderate · mw
- Depth
- 143 km
- Intermediate
- 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
11 kilotons of TNT
That is about the energy of the Hiroshima bomb. It released about 22 times the energy of a magnitude 5.0.
Tectonic setting
53 km
from the nearest mapped plate boundary, between the Tonga and Niuafo'ou plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: intermediate
143 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M4.4 on November 28, 1987. 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 840 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11919 Tonga EarthquakeApril 30, 1919 · 225 km SE of this epicenter
- 8.0The 1917 Samoa-Tonga EarthquakeJune 26, 1917 · 235 km N of this epicenter
- 7.8146 km ESE of Hihifo, TongaDecember 26, 1975 · 184 km NE of this epicenter
- 7.7133 km NE of Hihifo, TongaSeptember 1, 1981 · 246 km NE of this epicenter
- 7.6199 km ESE of Hihifo, TongaApril 2, 1977 · 208 km E of this epicenter
- 7.4103 km ESE of Neiafu, TongaFebruary 27, 1921 · 239 km SE of this epicenter
- 7.385 km ESE of Neiafu, TongaJanuary 2, 1907 · 245 km S of this epicenter
- 7.3201 km ENE of Neiafu, TongaOctober 6, 1987 · 219 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 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 · 197 km away
2 deathsModerate damage ($1–5M)tsunami
- 1919M8.1
Tonga Islands
30 Apr 1919 · 221 km away
Limited damage (under $1M)tsunami
- 1865M8.0
Tonga Islands
18 Nov 1865 · 286 km away
Limited damage (under $1M)tsunami
- 1981M7.7
Apia; American Samoa: Pago Pago
1 Sep 1981 · 246 km away · intensity VI
Limited damage (under $1M)tsunami
- 1977M7.6
Apia
2 Apr 1977 · 208 km away · intensity VI
Limited damage (under $1M)tsunami
- 1975M7.8
Samoa Islands
26 Dec 1975 · 184 km away · intensity V
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.