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Light mag. 4.2 earthquake - Bering Sea, 169 mi southwest of Unalaska, Aleutians West, Alaska, USA, on Thursday, Mar 16, 2023 at 6:33 pm (GMT -9) -

Light magnitude 4.2 earthquake at 45 km depth

17 Mar 04:05 UTC: First to report: USGS after 32 minutes.

Update Fri, 17 Mar 2023, 04:12

Moderate magnitude 4.2 earthquake 54 miles southwest of Nikolski, Alaska, United States

4.2 quake 16 Mar 6:33 pm (GMT -9)

A magnitude 4.2 earthquake near Nikolski, Aleutians West, Alaska, USA, was reported 39 minutes ago by the United States Geological Survey, considered the key international and national agency that monitors seismic activity in the US. The earthquake occurred at a moderately shallow depth of 28 miles beneath the epicenter early evening on Thursday, March 16th, 2023, at 6:33 pm local time. Magnitude and other quake parameters can still change in the coming hours as the agency continues to process seismic data.
A second report was later issued by The Incorporated Research Institutions for Seismology (IRIS), which listed it as a magnitude 4.2 earthquake as well. A third agency, the citizen-seismograph network of RaspberryShake, reported the same quake at magnitude 4.2.
Towns or cities near the epicenter where the quake might have been felt as very weak shaking include Nikolski (pop. 18) located 54 miles from the epicenter.

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Earthquake details

Date & time	Mar 17, 2023 03:33:15 UTC -
Local time at epicenter	Thursday, Mar 16, 2023 at 6:33 pm (GMT -9)
Status	Confirmed
Magnitude	4.2
Depth	44.8 km
Epicenter latitude / longitude	52.5639°N / 169.9892°W (Bering Sea, Alaska, United States)
Antipode	52.564°S / 10.011°E
Shaking intensity	Weak shaking near epicenter
Felt	0 reports
Primary data source	USGS (United States Geological Survey)
Nearest volcano	Herbert (21 km / 13 mi)
Nearby towns and cities	87 km (54 mi) WSW of Nikolski (pop: 18) \| Show on map \| Quakes nearby 272 km (169 mi) WSW of Unalaska (pop: 4,490) \| Show on map \| Quakes nearby 273 km (169 mi) WSW of Dutch Harbor (pop: 4,380) \| Show on map \| Quakes nearby
Weather at epicenter at time of quake	Overcast Clouds -0.2°C (32 F), humidity: 56%, wind: 11 m/s (22 kts) from N
Estimated seismic energy released	1.3 x 10¹¹ joules (35 megawatt hours, equivalent to 30.1 tons of TNT) \| about seismic energy

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Data for the same earthquake reported by different agencies

Info: The more agencies report about the same quake and post similar data, the more confidence you can have in the data. It takes normally up to a few hours until earthquake parameters are calculated with near-optimum precision.

Mag.	Depth	Location	Source
4.2	45 km	86 Km WSW of Nikolski, Alaska	USGS
4.2	45 km	Fox Islands, Aleutian Islands	RaspberryShake
4.2	10 km	Fox Islands, Aleutian Islands	IRIS
4.2	45 km	FOX ISLANDS, ALEUTIAN ISLANDS	EMSC

Most recent quakes Top 20 past 24 hrs Quakes in the US Alaska

Seismograms

Seismic station: Cone F, Okmok Caldera, Alaska (OKCF/AV network) | Distance from quake: 155 km / 96 mi | Show on map | Station Info

Seismic station Cone F, Okmok Caldera, Alaska: vertical movement plot around time of quake (source: IRIS/BUD)

Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Bandpass filter applied: 0.2-10.0 Hz. Source: IRIS Buffer of Uniform Data (BUD) webtool

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Seismic station Cone F, Okmok Caldera, Alaska: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station Cone F, Okmok Caldera, Alaska: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake, showing horizontal E-W and N-S ground movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station: Pakushin Southeast, Makushin Volcano, Alaska (MAPS/AV network) | Distance from quake: 246 km / 153 mi | Show on map | Station Info

Seismic station Pakushin Southeast, Makushin Volcano, Alaska: vertical movement plot around time of quake (source: IRIS/BUD)

Seismic station Pakushin Southeast, Makushin Volcano, Alaska: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station Pakushin Southeast, Makushin Volcano, Alaska: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake.
Top: vertical movement, bottom: horizontal (E-W and N-S) movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station: Westdahl Peak, Westdahl Peak, Alaska (WESP/AV network) | Distance from quake: 409 km / 254 mi | Show on map | Station Info

Seismic station Westdahl Peak, Westdahl Peak, Alaska: vertical movement plot around time of quake (source: IRIS/BUD)

Seismic station Westdahl Peak, Westdahl Peak, Alaska: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station Westdahl Peak, Westdahl Peak, Alaska: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake.
Top: vertical movement, bottom: horizontal (E-W and N-S) movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station: Dolgoi Island, Mount Dutton, Alaska (DOL/AV network) | Distance from quake: 605 km / 376 mi | Show on map | Station Info

Seismic station Dolgoi Island, Mount Dutton, Alaska: vertical movement plot around time of quake (source: IRIS/BUD)

Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Bandpass filter applied: 0.2-5.0 Hz. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station Dolgoi Island, Mount Dutton, Alaska: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station Dolgoi Island, Mount Dutton, Alaska: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake.
Top: vertical movement, bottom: horizontal (E-W and N-S) movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station: Pilot Point, AK, USA (R16K/AK network) | Distance from quake: 964 km / 599 mi | Show on map | Station Info

Seismic station Pilot Point, AK, USA: vertical movement plot around time of quake (source: IRIS/BUD)

Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Bandpass filter applied: 0.2-5.0 Hz. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station Pilot Point, AK, USA: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station Pilot Point, AK, USA: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake.
Top: vertical movement, bottom: horizontal (E-W and N-S) movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

User reports for this quake

User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.

There are no user reports for this quake.

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