Reviewed by USGSSolomon Islands35y ago
M4.3 earthquake 150 km ESE of Gizo, Solomon Islands
Tuesday, October 15, 1991, 04:26:29 UTC · 8.812°S, 158.011°E
A magnitude 4.3 earthquake struck 150 km ESE of Gizo, Solomon Islands on Tuesday, October 15, 1991, 04:26:29 UTC, at a depth of 33.0 km (shallow).
- Magnitude
- 4.3
- Light · mb
- Depth
- 33 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
43 tons of TNT
That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.
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
33 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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M5.6 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 291 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 · 232 km SE of this epicenter
- 7.566 km SE of Honiara, Solomon IslandsApril 20, 1977 · 283 km SE of this epicenter
- 7.562 km SW of Malango, Solomon IslandsJanuary 25, 1926 · 197 km SE of this epicenter
- 7.341 km ESE of Malango, Solomon IslandsFebruary 19, 1906 · 253 km SE of this epicenter
- 7.361 km NW of Gizo, Solomon IslandsApril 19, 1936 · 209 km NW of this epicenter
- 7.358 km SSE of Malango, Solomon IslandsAugust 18, 1968 · 259 km SE of this epicenter
- 7.2143 km W of Gizo, Solomon IslandsJuly 29, 1977 · 286 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 12 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 46 recorded deaths. The most severe:
- 1977M6.8
Solomon Islands
20 Apr 1977 · 278 km away · intensity VI
34 deathsSevere damage ($5–24M)tsunami
- 1939M7.9
Solomon Islands
30 Apr 1939 · 145 km away
12 deathsModerate damage ($1–5M)tsunami
- 1959M7.3
Solomon Islands
17 Aug 1959 · 265 km away
Severe damage ($5–24M)tsunami
- 1926M6.9
Solomon Islands
16 Sep 1926 · 191 km away
Moderate damage ($1–5M)tsunami
- 1977M7.6
Solomon Islands
20 Apr 1977 · 283 km away · intensity VII
Limited damage (under $1M)tsunami
- 1926M7.5
Guadalcanal
25 Jan 1926 · 192 km away
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.