M5.0 earthquake 116 km W of Gizo, Solomon Islands

Friday, August 5, 1977, 21:21:13 UTC · 7.922°S, 155.802°E

A magnitude 5.0 earthquake struck 116 km W of Gizo, Solomon Islands on Friday, August 5, 1977, 21:21:13 UTC, at a depth of 45.0 km (shallow). It is the strongest earthquake within 300 km since an M5.2 on August 1, 1977.

Magnitude: 5.0; Moderate · mb
Depth: 45 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 earthquake

In context

How big was it, and why here?

Energy released

477 tons of TNT

That is about 1/32 of the Hiroshima bomb. Each whole step in magnitude is about 32 times more energy.

Tectonic setting

20 km

from the nearest mapped plate boundary, between the Pacific and Woodlark plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

45 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 has not published any M2.5+ earthquake within 75 km in the 30 days after this event.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 404 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 5 recorded deaths. The most severe:

1939M7.7
Bougainville Island
30 Jan 1939 · 104 km away
5 deathsModerate damage ($1–5M)tsunami
1975M7.9
Bismarck Sea: Bougainville
20 Jul 1975 · 170 km away · intensity VIII
Severe damage ($5–24M)tsunami
1959M7.3
Solomon Islands
17 Aug 1959 · 52 km away
Severe damage ($5–24M)tsunami
1974M7.1
Solomon Islands
1 Feb 1974 · 62 km away · intensity VI
Moderate damage ($1–5M)tsunami
1907M7.7
New Britain
4 May 1907 · 236 km away
1975M7.7
Solomon Islands: Buin, Boku
20 Jul 1975 · 116 km away · intensity VII

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

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