On Saturday Afternoon a Shallow M5.5 Earthquake struck in the Bismarck Sea 127km from Kokopo (Papua New Guinea).

Written by Earthquakelist.org on November 18th, 2023. Last updated November 30th, 2023.

In the Bismarck Sea 127 kilometer from Kokopo, Papua New Guinea, a shallow and significant Magnitude 5.5 earthquake occurred in the early afternoon of Saturday November 18th, 2023. Shaking may have been felt by a total of 620 thousand people.

Earthquake Summary

This earthquake hit under water in the Bismarck Sea, 54 kilometers (34 mi) off the coast of Papua New Guinea, 127 kilometer west-northwest of Kokopo in East New Britain. The center of this earthquake had a very shallow depth of 10 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.

Date and Time:	Nov 18, 2023 13:01 (Port Moresby Time) - Nov 18, 2023 03:01 Universal Time.
Location:	127 km WNW of Kokopo, East New Britain, Papua New Guinea. Coordinates 3°46'28"S 151°16'15"E.
Map:	Map of area around epicenter. Click to open in Google Maps.
Magnitude:	MAG 5.5 Detected by 10 stations. Maximum Error Range ±0.098 .
Depth:	10 km (6 mi) A very shallow depth.
Max. Intensity:	V Moderate On the Modified Mercalli Scale.
Tsunami Risk:	Low tsunami risk Earthquakes under MAG-6.5 do not usually cause tsunami's. Always stay cautious - More info here.

Minimal impact predicted

Based on scientific estimates by the US Geographic Survey (USGS), the risk of high fatalities for this earthquake is classified at level GREEN (low). They expect an 65% likelyhood of between 0 and 1 fatalities, and a 96% chance that the number of fatalities falls no higher than 10.

The USGS classifies the economic impact of this earthquake at level GREEN (low). They expect an 65% likelyhood of between 0 and 1 million US Dollars in economic damage and impact, and a 96% chance that the economic impact of this earthquake falls no higher than 10 million USD.

Roughly 620 thousand people exposed to shaking

An estimated 620 thousand have been exposed to shaking (An MMI or Modified Mercalli Intensity level II or higher) as a result of this earthquake according scientific estimates published by the USGS.

An estimated 29,630 people were exposed to level IV. At this level, light shaking and likely no damage can be expected. Intensity level III was experienced by the majority of people (around 560 thousand). In their region, weak shaking and probably no damage can be expected. All exposure to shaking was within the borders of Papua New Guinea .

People	MMI Level	Shaking	Damage
0	I	Not noticable	None
29,980	II	Very weak	None
557,800	III	Weak	Probably none
29,630	IV	Light	Likely none
0	V	Moderate	Very light
0	VI	Strong	Light
0	VII	Very Strong	Moderate
0	VIII	Severe	Moderate to heavy
0	IX	Violent	Heavy
0	X	Extreme	Very heavy

Nearby towns and cities

This earthquake may have been felt in Papua New Guinea . The closest significant population center near the earthquake is Kokopo in East New Britain, Papua New Guinea. Kokopo is located 127 kilometer (79 mi) west-northwest of the epicenter. Kokopo experienced an earthquake intensity (MMI Scale) of roughly III. That level implies weak shaking and probably no damage.

Overview of nearby places

Cities and Towns around the epicenter of this earthquake.
Distance	Place	Intensity (MMI)
127 km (79 mi) ESE from epicenter	Kokopo East New Britain, Papua New Guinea.	III Weak
234 km (145 mi) SSW from epicenter	Kimbe West New Britain, Papua New Guinea.

Earthquake Intensity Map

The graph below overlays a map of the region around the epicenter with earthquake intensity data provided by the US Geographic Survey. The highest intensity level detected for this earthquake is IV.

I Not felt

II Weak

III Weak

IV Light

V Moderate

VI Strong

VII Very Strong

VIII Severe

IX Violent

X Extreme

Earthquake Intensity Map based on Shakemap Data provided by USGS.

Aftershocks detected

In the days before this main shock, 1 smaller foreshock was detected. Roughly 1 day before this earthquake, a foreshock measuring MAG-4.7 was detected nearby this earthquake.

Overview of foreshocks and aftershocks

Detected MAG2.5+ earthquakes within within 100km (62 mi), that occurred in the three days before and after the main shock.
Classification	Magnitude	When	Where
Foreshock	M 4.7	1 day earlier Nov 17, 2023 01:45 (Port Moresby Time)	48 km (30 mi) SSW from Main Shock.
Main Shock This Earthquake	M 5.5	Nov 18, 2023 13:01 (Port Moresby Time)	-

More earthquakes coming?

Aftershocks are usually at least 1 order of magnitude less strong than main shocks. The more time passes, the smaller the chance and likely strength of any potential aftershocks.

It's always adviced to be cautious of the risk of a larger shock following any significant earthquake, however this risk is fairly small. There is a roughly 94 percent change that no larger main shock will follow in the days following this earthquake.

Read: How to Stay Safe during an Earthquake (cdc.gov).

Earthquakes like this happen often in the region

Earthquakes of this strength are very common in the region. This is the strongest earthquake to hit since November 14th, 2023, when a 5.5 magnitude earthquake hit 43 km (27 mi) further southwest. An even stronger magnitude 7.9 earthquake struck on December 17th, 2016.

In total, 123 earthquakes with a magnitude of 5.5 or higher have been registered within 300km (186 mi) of this epicenter in the past 10 years. This comes down to an average of once every 30 days.

Low tsunami risk

DISCLAIMER: We strongly suggest to closely monitor advice from local authorities with regards to tsunami risks. Our analysis is based on automatically collected data from external sources, and these might contain mistakes. In addition, earthquakes can cause landslides that may lead to a tsunami, or be a followed by another, potentially stonger, earthquake.

Based on early data it appears this earthquake was not strong enough (lower than MAG-6.5) to be likely to cause destructive tsunami's. However this earthquake appeared to have hit at a shallow depth under sea, so stay cautious and monitor advice from local authorities.

Tsunami Risk Factors

Factor	Under Sea?	MAG-6.5 or stronger?	Shallow depth?
Explanation	Almost all tsunami's are caused by earthquakes with their epicenter under sea or very near the sea. However stay cautious in coastal areas as earthquakes on land may cause landslides into sea, potentially still causing a local tsunami.	Under MAG 6.5: Very unlikely to cause a tsunami. MAG 6.5 to 7.5: Destructive tsunami's do occur, but are uncommon. Likely to observe small sea level changes. MAG 7.6+: Earthquakes with these magnitudes might produce destructive tsunami's.	Most destructive tsunami's are caused by shallow earthquakes with a depth between 0 and 100km under the surface of the earth. Deeper tsunami's are unlikely to displace to ocean floor.
This Earthquake	This earthquake appears to have struck under the sea.	Not this earthquake. This earthquake had a magnitude of 5.5. Earthquakes of this strength are unlikely to trigger a tsunami.	This earthquake occurred at a depth of of 10 km (6 mi). Earthquakes this shallow could trigger a tsunami.

Sources

Last updated 30/11/23 03:28 (). This article contains currently available information about the earthquake and is automatically composed. We continue to update this article up to a few days after the earthquake occurred.