4.5

M4.5 Earthquake 47 km NW of Ninilchik, AlaskaJuly 27, 2024

2024-07-27 18:12:14 UTC (2024-07-27) · approx. 8:12 AM UTC-10 local

Felt by 31 people across nearby locations.

MagnitudeM4.5(mww)
Time18:12 UTC8:12 AM UTC-10
Depth87.8 kmintermediate depth
Coordinates60.322°, -152.323°
Felt by31DYFI responses· max MMI 3.4
Status✓ Reviewed by USGS· Tsunami evaluation
Tsunami Warning Issued

On July 27, 2024 at 18:12 UTC, a magnitude 4.5 intermediate depth earthquake struck 47 km NW of Ninilchik, Alaska, at a depth of 87.8 km and coordinates 60.3222°, -152.3227°. The earthquake was reported felt by 31 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 3.4 (light).

Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 m — a useful intuition for the size of the slip patch on the fault.

The epicenter is located in Alaska, a region characterized by Pacific Plate subduction beneath the North American Plate, producing frequent megathrust and crustal earthquakes along the Aleutian arc. The nearest mapped fault system is the Aleutian megathrust. View all earthquakes in Alaska.

Learn more: Magnitude scale · Aftershock sequences

Map showing earthquake epicenter at 60.32°, -152.32°

ShakeMap — predicted shaking intensity

Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.

USGS ShakeMap intensity contours for the M4.5 earthquake near 47 km NW of Ninilchik, Alaska

Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 31 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.

USGS DYFI community-reported intensity map for the M4.5 earthquake near 47 km NW of Ninilchik, Alaska

Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report

Earthquake Details

Magnitude
4.5 mww
Depth
87.8 km
intermediate depth
Location
60.3222°N
-152.3227°E
Felt Reports
31
DYFI responses
Intensity (MMI)
3.4
light
Community Intensity
3.8
CDI from reports

Technical Information

Event ID
ak0249ly3xrw
Event Type
earthquake
Status
✓ Reviewed
Significance
323
RMS Residual
0.87 sec
Last Updated
2024-10-08 21:49:13 UTC

Common Questions

How strong was the magnitude 4.5 earthquake near Ninilchik, Alaska?

The magnitude 4.5 earthquake that struck 47 km NW of Ninilchik, Alaska on July 27, 2024 at 18:12 UTC had a depth of 87.8 km. It was felt by 31 people with maximum shaking intensity of MMI 3.4 (light). For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at 60.3222°, -152.3227°, which is 47 km NW of Ninilchik, Alaska. View all earthquakes in Alaska.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 earthquakes can continue for several days and gradually diminish over time.

Has Alaska had earthquakes this big before?

The largest recorded earthquake in Alaska was the M9.2 Great Alaska earthquake of March 27, 1964. Today's magnitude 4.5 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: ak0249ly3xrw). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2024, July 27, 2024). M4.5 Earthquake 47 km NW of Ninilchik, AlaskaJuly 27, 2024. Retrieved October 8, 2024 from https://www.earthquaketracker.org/earthquakes/event/ak0249ly3xrw/