M5.6 earthquake 27 km NNW of Claveria, Philippines
A magnitude 5.6 earthquake struck 27 km NNW of Claveria, Philippines on Thu, Aug 11, 1983, 8:02 PM GMT+8 (12:02 UTC), 15 km (9 mi) below the surface.
A larger quake followed: M6.5 16 km ENE of Piddig, Philippines. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.6 (mb, body-wave), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1983-08-11 12:02:58 UTC
- Depth
- 14.8 km (9.2 mi), shallow
- Epicenter
- 18.828° N, 120.957° E
- Region
- Philippines
- Strongest shaking
- IV, light shaking
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Magnitude estimates
Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.
| Mag. | Scale | Computed by | Notes |
|---|---|---|---|
| 5.6 | mb, body-wave | USGS National Earthquake Information Center | Preferred · Reviewed · 68 stations |
| 5.81 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.8 | Mwc, centroid moment | Global CMT project | Preliminary |
What happened
The USGS’s account of the effects of this earthquake.
Slight damage in the Laoag area. Felt (V RF) at Pasuquin. CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME B081183A DATA USED: GDSN L.P. BODY WAVES: 16S, 40C, T=45 CENTROID LOCATION: ORIGIN TIME 12: 3: 3.3 0.3 LAT 18.63N 0.03;LON 120.72E 0.05 DEP 20.2 2.5;HALF-DURATION 3.1 MOMENT TENSOR; SCALE 10**24 D-CM MRR=-3.23 0.23; MTT=4.24 0.22 MFF=-1.01 0.38; MRT=-1.65 0.47 MRF=-0.51 0.40; MTF=-5.58 0.19 PRINCIPAL AXES: 1.(T) VAL=7.90;PLG=6;AZM=212 2.(N) -2.51; 57; 113 3.(P) -5.39; 33; 306 BEST DOUBLE COUPLE:M0=6.6*10**24 NP1:STRIKE=344;DIP=63;SLIP=-20 NP2:Strike=83;Dip=72;Slip=-152
From the USGS event page for usp0001xkv. U.S. Geological Survey text and figures are in the public domain.
Shaking
The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.
- Strongest estimated
- IV, light shaking
- Peak ground acceleration
- 5.8% of gravity
- Peak ground velocity
- 1.2 cm/s
- Map
- Automatic
Did you feel it?
No one has reported feeling this quake to the USGS.
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.6 and up: 12 in the 60 days after this one and 4 in the 30 days before it.
After
- 6.516 km ENE of Piddig, Philippines · 15754 days ago · 29 km deep · 67 km away
- 4.711 km ESE of Pagudpud, Philippines · 15754 days ago · 33 km deep · 36 km away
- 4.919 km NE of Piddig, Philippines · 15754 days ago · 33 km deep · 60 km away
- 4.728 km NE of Solsona, Philippines · 15752 days ago · 52 km deep · 62 km away
- 4.611 km NNE of Piddig, Philippines · 15752 days ago · 33 km deep · 67 km away
- 3.831 km NW of Pagudpud, Philippines · 15752 days ago · 33 km deep · 39 km away
- 3.937 km NNE of Pagudpud, Philippines · 15744 days ago · 33 km deep · 11 km away
- 4.116 km SSE of Bangui, Philippines · 15742 days ago · 15 km deep · 51 km away
- 4.71 km NW of Pasuquin, Philippines · 15738 days ago · 33 km deep · 65 km away
- 5.68 km S of Padong, Philippines · 15724 days ago · 33 km deep · 97 km away
- 5.027 km SE of Bangui, Philippines · 15717 days ago · 36 km deep · 51 km away
- 4.621 km SE of Bangui, Philippines · 15717 days ago · 33 km deep · 51 km away
Before
- 5.016 km NW of Claveria, Philippines · 15761 days ago · 28 km deep · 12 km away
- 4.740 km N of Pagudpud, Philippines · 15763 days ago · 41 km deep · 17 km away
- 4.567 km N of Namuac, Philippines · 15766 days ago · 33 km deep · 52 km away
- 4.758 km N of Namuac, Philippines · 15781 days ago · 33 km deep · 44 km away
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Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0001xkv (also filed as gcmtb081183a, gcmt19830811120301, atlas19830811120302, iscgem570057). Read Sun, Oct 4, 2026, 6:23 PM UTC.