Reviewed by USGSSolomon Islands35y ago
M5.6 earthquake 169 km SW of Buala, Solomon Islands
Wednesday, November 13, 1991, 02:14:53 UTC · 9.013°S, 158.320°E
A magnitude 5.6 earthquake struck 169 km SW of Buala, Solomon Islands on Wednesday, November 13, 1991, 02:14:53 UTC, at a depth of 29.0 km (shallow). It is the strongest earthquake within 300 km since an M6.1 on October 14, 1991.
- Magnitude
- 5.6
- Moderate · mw
- Depth
- 29 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
4 kilotons of TNT
That is about 1/4 of the Hiroshima bomb. It released about 8 times the energy of a magnitude 5.0.
Tectonic setting
38 km
from the nearest mapped plate boundary, between the Pacific and Australian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
29 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 2 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.2 on November 13, 1991. 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 288 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.823 km SSE of Malango, Solomon IslandsApril 30, 1939 · 192 km SE of this epicenter
- 7.685 km SE of Honiara, Solomon IslandsFebruary 7, 1984 · 261 km SE of this epicenter
- 7.5105 km ESE of Honiara, Solomon IslandsApril 20, 1977 · 290 km E of this epicenter
- 7.566 km SE of Honiara, Solomon IslandsApril 20, 1977 · 243 km SE of this epicenter
- 7.5103 km SE of Honiara, Solomon IslandsApril 21, 1977 · 285 km E of this epicenter
- 7.562 km SW of Malango, Solomon IslandsJanuary 25, 1926 · 157 km SE of this epicenter
- 7.341 km ESE of Malango, Solomon IslandsFebruary 19, 1906 · 213 km SE of this epicenter
- 7.361 km NW of Gizo, Solomon IslandsApril 19, 1936 · 250 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 14 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 64 recorded deaths. The most severe:
- 1977M6.8
Solomon Islands
20 Apr 1977 · 238 km away · intensity VI
34 deathsSevere damage ($5–24M)tsunami
- 1977M8.1
Solomon Islands
21 Apr 1977 · 285 km away · intensity VII
18 deathsSevere damage ($5–24M)tsunami
- 1939M7.9
Solomon Islands
30 Apr 1939 · 105 km away
12 deathsModerate damage ($1–5M)tsunami
- 1984M7.5
Guadalcanal
7 Feb 1984 · 261 km away · intensity VI
Moderate damage ($1–5M)
- 1926M6.9
Solomon Islands
16 Sep 1926 · 151 km away
Moderate damage ($1–5M)tsunami
- 1977M7.6
Solomon Islands
20 Apr 1977 · 243 km away · intensity VII
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.