Reviewed by USGSTonga29y ago
M4.9 earthquake 188 km WSW of Haveluloto, Tonga
Friday, November 7, 1997, 13:41:01 UTC · 21.917°S, 176.840°W
A magnitude 4.9 earthquake struck 188 km WSW of Haveluloto, Tonga on Friday, November 7, 1997, 13:41:01 UTC, at a depth of 172.2 km (intermediate). It is the strongest earthquake within 300 km since an M5.6 on November 4, 1997.
- Magnitude
- 4.9
- Light · mb
- Depth
- 172 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
338 tons of TNT
That is about 1/45 of the Hiroshima bomb. A magnitude 5.0 releases about 1 times more energy.
Tectonic setting
27 km
from the nearest mapped plate boundary, between the Tonga and Australian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: intermediate
172 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 50 km
USGS lists 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.6 on December 7, 1997. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.6164 km WSW of Haveluloto, Tonga29y ago · 28 km NE of this epicenter
- 3.1195 km WSW of Haveluloto, Tonga29y ago · 22 km NW of this epicenter
- 4.5211 km WSW of Haveluloto, Tonga29y ago · 24 km W of this epicenter
- 4.6142 km WSW of Haveluloto, Tonga29y ago · 46 km NE of this epicenter
- 4.6168 km WSW of Haveluloto, Tonga29y ago · 29 km N of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 1,383 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.0TongaJanuary 4, 1903 · 286 km NE of this epicenter
- 7.8159 km W of Pangai, TongaDecember 14, 1950 · 266 km N of this epicenter
- 7.8192 km WSW of Haveluloto, TongaOctober 14, 1997 · 22 km S of this epicenter
- 7.5262 km WNW of Haveluloto, TongaMay 21, 1962 · 213 km N of this epicenter
- 7.4Fiji regionSeptember 28, 1957 · 219 km NW of this epicenter
- 7.4Fiji regionAugust 5, 1996 · 204 km NW of this epicenter
- 7.3227 km WNW of Haveluloto, TongaApril 16, 1937 · 155 km N of this epicenter
- 7.3Fiji regionMay 25, 1944 · 271 km W 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 1 recorded deaths. The most severe:
- 1977M7.2
Tonga Trench
22 Jun 1977 · 144 km away · intensity IV
1 death$1 million damagetsunami
- 1937M8.1
Fiji Islands
16 Apr 1937 · 49 km away
- 1903M8.0
Tonga Islands
4 Jan 1903 · 286 km away
- 1950M7.7
Tonga Islands
14 Dec 1950 · 283 km away · intensity VI
- 1982M7.7
Tonga Trench
19 Dec 1982 · 266 km away
tsunami
- 1997M7.7
Tonga Islands
14 Oct 1997 · 22 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.