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M5.1 earthquake Carlsberg Ridge

A magnitude 5.1 earthquake struck in the Carlsberg Ridge on Mon, Jul 21, 2003, 10:59 AM GMT+5 (05:59 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M5.4 Carlsberg Ridge. This one was a foreshock.

Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 5.1 (Mwc, centroid moment), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Mon, Jul 21, 2003, 10:59 AM GMT+5
UTC: 2003-07-21 05:59:43 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 1.242° S, 69.762° E
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
5.1	Mwc, centroid moment	USGS National Earthquake Information Center	Preferred · Reviewed
5.04	Mw, moment	ISC-GEM global catalog	Final · ±0.1
5.0	Mwc, centroid moment	Global CMT project	Preliminary

What happened

The USGS’s account of the effects of this earthquake.

no people dead or missing; no people injured; no buildings damaged or destroyed

From the USGS event page for usp000c302. U.S. Geological Survey text and figures are in the public domain.

Did you feel it?

No one has reported feeling this quake to the USGS.

Fault motion and ground failure

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Faulting: Oblique normal
Nodal plane 1: Strike 38°, dip 16°, rake -148°
Nodal plane 2: Strike 276°, dip 81°, rake -76°

How well it is located

Reviewed by a seismologist.

Depth from: OPERATOR_ASSIGNED
Station coverage gap: 56°
Stations used: 79

Nearby

Within 100 km, magnitude 2.1 and up: 6 in the 60 days after this one and 3 in the 30 days before it.

After

Before

Earthquakes today Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp000c302 (also filed as gcmtb072103a, gcmt20030721055943, iscgem7002910). Read Fri, Oct 2, 2026, 1:37 AM UTC.