Magnitude4.6

Reviewed by USGSPapua New Guinea34y ago

M4.6 earthquake 49 km NNW of Finschhafen, Papua New Guinea

Thursday, March 11, 1993, 21:04:16 UTC · 6.122°S, 147.730°E

A magnitude 4.6 earthquake struck 49 km NNW of Finschhafen, Papua New Guinea on Thursday, March 11, 1993, 21:04:16 UTC, at a depth of 73.2 km (intermediate). It is the strongest earthquake within 300 km since an M4.8 on March 11, 1993.

Magnitude
4.6
Light · mb
Depth
73 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

120 tons of TNT

That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.

Tectonic setting

104 km

from the nearest mapped plate boundary, between the South Bismarck and Woodlark plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: intermediate

73 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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M5.0 on March 27, 1993. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M51h6h1d3d7d14d30dMainshock M4.6
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 5.053 km NNE of Finschhafen, Papua New Guinea33y ago · 25 km E of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 737 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 24 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 155 recorded deaths. The most severe:

  1. 1988M4.3

    Kaiapit (Landslide Generated)

    6 Sep 1988 · 166 km away

    74 deathsModerate damage ($1–5M)

  2. 1993M6.9

    Eastern: Upper Markham Valley

    13 Oct 1993 · 191 km away

    60 deaths$5 million damage

  3. 1970M7.3

    Madang

    31 Oct 1970 · 284 km away · intensity VIII

    18 deaths$2 million damagetsunami

  4. 1987M7.6

    Huon Peninsula, Umboi Island

    8 Feb 1987 · 6 km away · intensity VII

    3 deaths$3 million damagetsunami

  5. 1906M8.0

    New Britain

    14 Sep 1906 · 171 km away

    Severe damage ($5–24M)tsunami

  6. 1857M8.0

    Bismarck Sea

    17 Apr 1857 · 106 km away

    Moderate damage ($1–5M)tsunami

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

Nearby trackers

Closest city pages