4.3

M4.3 Earthquake 26 km ESE of Bobon, PhilippinesJuly 21, 2023

2023-07-21 19:24:48 UTC (2023-07-21) · approx. 3:24 AM UTC+8 local

MagnitudeM4.3(mb)
Time19:24 UTC3:24 AM UTC+8
Depth74.3 kmintermediate depth
Coordinates6.744°, 126.538°
Felt byNo felt reports
Status✓ Reviewed by USGS

On July 21, 2023 at 19:24 UTC, a magnitude 4.3 intermediate depth earthquake struck 26 km ESE of Bobon, Philippines, at a depth of 74.3 km and coordinates 6.7437°, 126.5384°.

Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 m — 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 5.0 mainshock that occurred 5 days ago 45 km SE of Lukatan, Philippines. 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.

Map showing earthquake epicenter at 6.74°, 126.54°

Earthquake Details

Magnitude
4.3 mb
Depth
74.3 km
intermediate depth
Location
6.7437°N
126.5384°E

Technical Information

Event ID
us7000khh5
Event Type
earthquake
Status
✓ Reviewed
Significance
284
Stations Used
53
Azimuthal Gap
116.0°
Min Station Distance
1.006°
RMS Residual
0.95 sec
Last Updated
2023-09-28 21:34:04 UTC

Common Questions

How strong was the magnitude 4.3 earthquake near Bobon, Philippines?

The magnitude 4.3 earthquake that struck 26 km ESE of Bobon, Philippines on July 21, 2023 at 19:24 UTC had a depth of 74.3 km. For context, this was a light earthquake commonly felt near the epicenter.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.3 earthquakes can continue for several days and gradually diminish over time.

Is this the same earthquake as the M5.0 one earlier?

No. This magnitude 4.3 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 45 km SE of Lukatan, Philippines. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

Understanding This Data

Magnitude 4.3 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000khh5). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, July 21, 2023). M4.3 Earthquake 26 km ESE of Bobon, PhilippinesJuly 21, 2023. Retrieved September 28, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000khh5/