Reviewed by USGSSolomon Islands43y ago
M4.7 earthquake 97 km WNW of Kirakira, Solomon Islands
Saturday, February 11, 1984, 21:48:45 UTC · 10.240°S, 161.060°E
A magnitude 4.7 earthquake struck 97 km WNW of Kirakira, Solomon Islands on Saturday, February 11, 1984, 21:48:45 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M4.9 on February 11, 1984.
- Magnitude
- 4.7
- 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
169 tons of TNT
That is about 1/89 of the Hiroshima bomb. A magnitude 5.0 releases about 3 times more energy.
Tectonic setting
71 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 M4.2 on February 17, 1984. 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 356 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.8116 km NW of Kirakira, Solomon IslandsOctober 10, 1931 · 57 km N of this epicenter
- 7.823 km SSE of Malango, Solomon IslandsApril 30, 1939 · 141 km W of this epicenter
- 7.8108 km SW of Kirakira, Solomon IslandsOctober 3, 1931 · 99 km S of this epicenter
- 7.656 km W of Kirakira, Solomon IslandsDecember 15, 1935 · 41 km E of this epicenter
- 7.685 km SE of Honiara, Solomon IslandsFebruary 7, 1984 · 69 km W of this epicenter
- 7.5105 km ESE of Honiara, Solomon IslandsApril 20, 1977 · 51 km NW of this epicenter
- 7.566 km SE of Honiara, Solomon IslandsApril 20, 1977 · 87 km NW of this epicenter
- 7.5103 km SE of Honiara, Solomon IslandsApril 21, 1977 · 47 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 15 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 114 recorded deaths. The most severe:
- 1931M7.8
San Cristobal Island
3 Oct 1931 · 77 km away
50 deathsSevere damage ($5–24M)tsunami
- 1977M6.8
Solomon Islands
20 Apr 1977 · 93 km away · intensity VI
34 deathsSevere damage ($5–24M)tsunami
- 1977M8.1
Solomon Islands
21 Apr 1977 · 47 km away · intensity VII
18 deathsSevere damage ($5–24M)tsunami
- 1939M7.9
Solomon Islands
30 Apr 1939 · 226 km away
12 deathsModerate damage ($1–5M)tsunami
- 1984M7.5
Guadalcanal
7 Feb 1984 · 69 km away · intensity VI
Moderate damage ($1–5M)
- 1926M6.9
Solomon Islands
16 Sep 1926 · 180 km away
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.