6.7

M6.7 Earthquake 15 km S of Hukay, Philippines — July 23, 2021

2021-07-23 20:48:57 UTC (2021-07-23) · approx. 4:48 AM UTC+8 local

Felt by 317 people across surrounding communities. Maximum shaking intensity MMI 5.0 (strong).

MagnitudeM6.7(mww)
Time20:48 UTC≈ 4:48 AM UTC+8
Depth110.0 kmintermediate depth
Coordinates13.705°, 120.726°
Felt by317DYFI responses· max MMI 5.0
Status✓ Reviewed by USGS· Tsunami evaluation· green PAGER
green Alert— no significant casualties or damage expected
Tsunami Warning Issued

On July 23, 2021 at 20:48 UTC, a magnitude 6.7 intermediate depth earthquake struck 15 km S of Hukay, Philippines, at a depth of 110.0 km and coordinates 13.7047°, 120.7259°. The earthquake was reported felt by 317 peopleacross surrounding communities, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 5.0 (strong). The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. The nearest populated place is Balitoc (population 3,121).

Physical scale: An earthquake of magnitude 6.7 releases seismic energy equivalent to roughly 169 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 25 km — a useful intuition for the size of the slip patch on the fault.

The epicenter is located in Philippines, a region characterized by the Manila Trench and Philippine Trench subduction systems, where the Philippine Sea Plate overrides the Eurasian Plate. The nearest mapped fault system is the Philippine Fault. View all earthquakes in Philippines.

Learn more: Magnitude scale · Aftershock sequences

Nearest Populated Places

Balitocpop. 3,121
MMI 5.0 (moderate)
Lucsuhinpop. 4,240
MMI 5.0 (moderate)
Gulodpop. 2,705
MMI 5.0 (moderate)
Bigapop. 3,096
MMI 5.0 (moderate)
Calataganpop. 16,110
MMI 4.9 (moderate)
Wawapop. 4,881
MMI 4.9 (moderate)

What the Shaking Felt Like

At MMI 5.0 (strong), people in the most strongly affected areas would have experienced: Moderate shaking that everyone in the area would feel. Sleeping people are awakened. Dishes and windows may break. Unstable objects may be knocked over.

Map showing earthquake epicenter at 13.70°, 120.73°

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 M6.7 earthquake near 15 km S of Hukay, Philippines

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

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 317 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 M6.7 earthquake near 15 km S of Hukay, Philippines

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

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)DescriptionPopulation exposed
MMI 3weak23,798,592
MMI 4light43,204,600
MMI 5moderate3,220,306

Earthquake Details

Magnitude
6.7 mww
Depth
110.0 km
intermediate depth
Location
13.7047°N
120.7259°E
Felt Reports
317
DYFI responses
Intensity (MMI)
5.0
strong
Community Intensity
7.7
CDI from reports

Technical Information

Event ID
us6000eyfk
Event Type
earthquake
Status
✓ Reviewed
Significance
935
Azimuthal Gap
12.0°
Min Station Distance
8.139°
RMS Residual
0.98 sec
Last Updated
2025-12-22 19:04:48 UTC

Nearby Earthquakes (Last 7 Days)

4.6
19 km ENE of Nailong, Philippines
4 days ago · 10.0 km deep

Common Questions

How strong was the magnitude 6.7 earthquake near Hukay, Philippines?

The magnitude 6.7 earthquake that struck 15 km S of Hukay, Philippines on July 23, 2021 at 20:48 UTC had a depth of 110.0 km. It was felt by 317 people with maximum shaking intensity of MMI 5.0 (strong). For context, this was a strong earthquake capable of causing significant damage.

Where did the earthquake occur?

The earthquake epicenter was located at 13.7047°, 120.7259°, which is 15 km S of Hukay, Philippines. The nearest populated place is Balitoc (population 3,121). View all earthquakes in Philippines.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 6.7 earthquakes can continue for weeks to months and gradually diminish over time.

Has Philippines had earthquakes this big before?

The largest recorded earthquake in Philippines was the M8.0 Mindanao earthquake of August 17, 1976. Today's magnitude 6.7 event is significantly smaller than that historical record.

Actions

View on USGSDid You Feel It?

Location

Philippines
View all Philippines earthquakes

Authoritative source: USGS event page (event ID: us6000eyfk). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, July 23, 2021). M6.7 Earthquake 15 km S of Hukay, Philippines — July 23, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000eyfk/