M4.5 earthquake 75 km NE of Finschhafen, Papua New Guinea

Thursday, April 15, 1999, 00:02:26 UTC · 6.002°S, 148.238°E

A magnitude 4.5 earthquake struck 75 km NE of Finschhafen, Papua New Guinea on Thursday, April 15, 1999, 00:02:26 UTC, at a depth of 119.1 km (intermediate). It is the strongest earthquake within 300 km since an M6.0 on April 11, 1999.

Magnitude: 4.5; Light · mb
Depth: 119 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

144 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

119 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 M4.6 on May 14, 1999. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 920 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 23 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 137 recorded deaths. The most severe:

1988M4.3
Kaiapit (Landslide Generated)
6 Sep 1988 · 222 km away
74 deathsModerate damage ($1–5M)
1993M6.9
Eastern: Upper Markham Valley
13 Oct 1993 · 246 km away
60 deaths$5 million damage
1987M7.6
Huon Peninsula, Umboi Island
8 Feb 1987 · 61 km away · intensity VII
3 deaths$3 million damagetsunami
1906M8.0
New Britain
14 Sep 1906 · 139 km away
Severe damage ($5–24M)tsunami
1857M8.0
Bismarck Sea
17 Apr 1857 · 148 km away
Moderate damage ($1–5M)tsunami
1873M8.0
Maclay Coast
1873 · 254 km away · intensity IX
Moderate damage ($1–5M)tsunami

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

Nearby trackers