Reviewed by USGSSolomon Islands88y ago
M7.8 earthquake 23 km SSE of Malango, Solomon Islands
Sunday, April 30, 1939, 02:55:30 UTC · 9.881°S, 159.829°E
A magnitude 7.8 earthquake struck 23 km SSE of Malango, Solomon Islands on Sunday, April 30, 1939, 02:55:30 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.8 on October 10, 1931.
- Magnitude
- 7.8
- Major · mw
- Depth
- 15 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VII
- Very strong (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
8.4 megatons of TNT
That is about 557 times the Hiroshima bomb. It released about 17,579 times the energy of a magnitude 5.0.
Tectonic setting
34 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
15 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 200 km
USGS lists 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M5.9 on May 6, 1939. 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 53 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 · 146 km E of this epicenter
- 7.8108 km SW of Kirakira, Solomon IslandsOctober 3, 1931 · 203 km SE of this epicenter
- 7.656 km W of Kirakira, Solomon IslandsDecember 15, 1935 · 181 km E of this epicenter
- 7.562 km SW of Malango, Solomon IslandsJanuary 25, 1926 · 63 km W of this epicenter
- 7.547 km ESE of Kirakira, Solomon IslandsDecember 10, 1910 · 284 km E of this epicenter
- 7.334 km WNW of Kirakira, Solomon IslandsApril 12, 1926 · 203 km E of this epicenter
- 7.341 km ESE of Malango, Solomon IslandsFebruary 19, 1906 · 23 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 7 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 62 recorded deaths. The most severe:
- 1931M7.8
San Cristobal Island
3 Oct 1931 · 175 km away
50 deathsSevere damage ($5–24M)tsunami
- 1939M7.9
Solomon Islands
30 Apr 1939 · 92 km away
12 deathsModerate damage ($1–5M)tsunami
- 1926M6.9
Solomon Islands
16 Sep 1926 · 41 km away
Moderate damage ($1–5M)tsunami
- 1926M7.5
Guadalcanal
25 Jan 1926 · 70 km away
Limited damage (under $1M)tsunami
- 1931M7.7
Solomon Islands
10 Oct 1931 · 150 km away
- 1935M7.6
Solomon Islands
15 Dec 1935 · 129 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.