M4.9 Earthquake 31 km WSW of San Alejandro, Peru — March 28, 2024
2024-03-28 11:01:15 UTC (2024-03-28) · approx. 6:01 AM UTC-5 local
Aftershock of the M5.2 mainshock.
On March 28, 2024 at 11:01 UTC, a magnitude 4.9 shallow crustal earthquake struck 31 km WSW of San Alejandro, Peru, at a depth of 10.0 km and coordinates -8.8907°, -75.4944°. This earthquake was detected by 85 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 369, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 km — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.2 mainshock that occurred 6 days ago 66 km WNW of San Alejandro, Peru. Since the mainshock, the USGS has recorded 0 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
The epicenter is located in Peru, a region characterized by the northern Peru-Chile subduction zone, complicated by the subduction of the Nazca Ridge. The nearest mapped fault system is the Peru-Chile Trench. View all earthquakes in Peru.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
-75.4944°E
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Common Questions
How strong was the magnitude 4.9 earthquake near San Alejandro, Peru?
The magnitude 4.9 earthquake that struck 31 km WSW of San Alejandro, Peru on March 28, 2024 at 11:01 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -8.8907°, -75.4944°, which is 31 km WSW of San Alejandro, Peru. View all earthquakes in Peru.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.2 one earlier?
No. This magnitude 4.9 earthquake is an aftershock of the larger magnitude 5.2 mainshock that occurred earlier 66 km WNW of San Alejandro, Peru. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Has Peru had earthquakes this big before?
The largest recorded earthquake in Peru was the M8.0 Arequipa earthquake of June 23, 2001. Today's magnitude 4.9 event is significantly smaller than that historical record.
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Authoritative source: USGS event page (event ID: us7000m8id). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2024, March 28, 2024). M4.9 Earthquake 31 km WSW of San Alejandro, Peru — March 28, 2024. Retrieved June 1, 2024 from https://www.earthquaketracker.org/earthquakes/event/us7000m8id/