M5.7 Earthquake 172 km WSW of Merizo Village, Guam — October 20, 2023
2023-10-20 00:04:22 UTC (2023-10-20) · approx. 10:04 AM UTC+10 local
On October 20, 2023 at 00:04 UTC, a magnitude 5.7 shallow crustal earthquake struck 172 km WSW of Merizo Village, Guam, at a depth of 16.8 km and coordinates 12.4144°, 143.3404°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 130 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 500, placing it among routine seismic activity. The nearest populated place is Merizo Village (population 2,152).
Physical scale: An earthquake of magnitude 5.7 releases seismic energy equivalent to roughly 5 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 5.2 km — a useful intuition for the size of the slip patch on the fault.
Nearest Populated Places
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.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Population exposure (USGS PAGER)
Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.
| Shaking intensity (MMI) | Description | Population exposed |
|---|---|---|
| MMI 3 | weak | 180,245 |
Earthquake Details
143.3404°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 5.7 earthquake near Merizo Village, Guam?
The magnitude 5.7 earthquake that struck 172 km WSW of Merizo Village, Guam on October 20, 2023 at 00:04 UTC had a depth of 16.8 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at 12.4144°, 143.3404°, which is 172 km WSW of Merizo Village, Guam. The nearest populated place is Merizo Village (population 2,152).
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.7 earthquakes can continue for days to weeks and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us6000lgrt). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, October 20, 2023). M5.7 Earthquake 172 km WSW of Merizo Village, Guam — October 20, 2023. Retrieved October 5, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000lgrt/