Magnitude4.5

Reviewed by USGS53y ago

M4.5 earthquake in Solomon Islands

Tuesday, March 12, 1974, 03:02:08 UTC · 7.343°S, 156.064°E

A magnitude 4.5 earthquake struck in Solomon Islands on Tuesday, March 12, 1974, 03:02:08 UTC, at a depth of 76.0 km (intermediate). It is the strongest earthquake within 300 km since an M5.3 on March 10, 1974.

Magnitude
4.5
Light · mb
Depth
76 km
Intermediate
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

85 tons of TNT

That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.

Tectonic setting

49 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: intermediate

76 km

Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.

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 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.4 on March 13, 1974. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M51h6h1d3d7d14d30dMainshock M4.5
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.7125 km NW of Gizo, Solomon Islands53y ago · 13 km SW of this epicenter
  2. 5.4114 km NW of Gizo, Solomon Islands53y ago · 6 km SE of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 235 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 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 5 recorded deaths. The most severe:

  1. 1939M7.7

    Bougainville Island

    30 Jan 1939 · 80 km away

    5 deathsModerate damage ($1–5M)tsunami

  2. 1959M7.3

    Solomon Islands

    17 Aug 1959 · 19 km away

    Severe damage ($5–24M)tsunami

  3. 1974M7.1

    Solomon Islands

    1 Feb 1974 · 52 km away · intensity VI

    Moderate damage ($1–5M)tsunami

  4. 1907M7.7

    New Britain

    4 May 1907 · 261 km away

  5. 1974M7.0

    Solomon Islands

    31 Jan 1974 · 25 km away

    tsunami

  6. 1955M6.5

    Fauro Island

    8 Sep 1955 · 64 km away

    tsunami

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

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