M7.1 Earthquake Near Constitución, Chile, Mar 25, 2012

Map

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

The earthquake

Magnitude: 7.1 (Mww, W-phase moment), major
Magnitude from: USGS National Earthquake Information Center
Local time: Sun, Mar 25, 2012, 7:37 PM GMT-3
UTC: 2012-03-25 22:37:06 UTC
Depth: 40.7 km (25.3 mi), shallow
Epicenter: 35.200° S, 72.217° W
Region: Chile
Felt reports: 1,122
Strongest shaking: VII, very strong 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
7.1	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed
7.12	Mw, moment	ISC-GEM global catalog	Final · ±0.1
6.96	Me, energy	Choy, USGS energy magnitude	Reviewed
7.1	Mww, W-phase moment	Duputel, W-phase inversion	Preliminary

Deaths and damage

From NOAA NCEI’s Significant Earthquake Database (record 9920), matched to this event by time and place.

Deaths: 1
Injuries: 14
Damage: $100 million
Houses damaged: Some (about 51 to 100)

Where the literature gives no number, NCEI records a description on a scale of 1 to 4, printed here in its words. Damage is in millions of US dollars of the year of the event, not adjusted for inflation.

NOAA’s full record of this earthquake

From Wikipedia

The 2012 Constitución earthquake was recorded on March 25, 2012, at 7:37 pm local time. It had a moment magnitude of 7.1 and its epicenter was located 23 km (14 mi) northeast of the city of Constitución, in the Maule Region, Chile. According to experts, it was a strong and late aftershock of the Great Chile earthquake of February 27, 2010.

The earthquake was felt from Coquimbo to the Los Lagos Region, with the Maule Region being the most affected and causing high commotion in the O'Higgins and Bio-bío regions, which were affected by the earthquake of 2010.

Text from Wikipedia, “2012 Constitución earthquake”, licensed CC BY-SA 4.0. Quoted as written; the full article has the rest.

The article is about the earthquake NOAA’s record describes, matched to this one by date, place and magnitude.

What happened

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

One person died from a heart attack at Parral, at least 11 people injured in the Santiago area and 3 injured in Bio-Bio. Some buildings damaged slightly at Santiago. Felt (VIII) at Cauquenes, Constitucion, Pelluhue and Talca; (VII) at Cobquecura, Linares, Molina, Parral, Pelarco, Rengo, Rio Claro and Villa Alegre. Felt strongly throughout south-central Chile. Felt (IV) at Mendoza and San Martin; (III) at Buenos Aires, San Juan and San Rafael, Argentina.

From the USGS event page for usp000jgsw. 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: VII, very strong shaking
Peak ground acceleration: 29.6% of gravity
Peak ground velocity: 3.3 cm/s
Map: Automatic

USGS ShakeMap: estimated shaking intensity around the epicenter — Estimated shaking intensity. Map: USGS ShakeMap.

Did you feel it?

1,122 people reported to the USGS what they felt; the strongest reported shaking was VIII, severe shaking.

Fault motion and ground failure

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

Faulting: Reverse (thrust)
Moment magnitude: 7.1 Mww
Nodal plane 1: Strike 182°, dip 72°, rake 85°
Nodal plane 2: Strike 17°, dip 17°, rake 104°

Tectonic setting

Why earthquakes happen here, from the USGS tectonic summary.

The March 25, 2012, M 7.1 Maule, Chile earthquake occurred as the result of shallow thrust faulting on or near the subduction interface between the Nazca and South America plates. At the location of this event, the Nazca plate moves east-northeast relative to South America at a velocity of about 74 mm/yr. The Nazca plate, oceanic in origin, subducts eastward beneath the South America plate at a shallow angle from the Peru-Chile Trench. It is seismically active to depths of approximately 200 km adjacent to the epicenter of the March 25th earthquake, though farther north seismicity continues to depths exceeding 600 km.

The March 25th earthquake occurred within the aftershock zone of the damaging M 8.8 Maule earthquake of February 27, 2010, and can also be considered an aftershock of that event. The subduction zone between the Nazca and South America plates has a long history of large megathrust earthquakes, including the largest event ever recorded, a M 9.5 earthquake in 1960, which ruptured a fault mostly to the south of the March 25th earthquake.

Hayes et al. (2016) Tectonic summaries of magnitude 7 and greater earthquakes from 2000 to 2015, USGS Open-File Report 2016-1192. (5.2 MB PDF)

From the USGS event page for usp000jgsw. U.S. Geological Survey text and figures are in the public domain.

USGS summary poster

How well it is located

Reviewed by a seismologist.

Station coverage gap: 15°
Stations used: 553

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Nearby

Within 100 km, magnitude 4.1 and up: 12 in the 60 days after this one and 7 in the 30 days before it.

After

Before

Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp000jgsw (also filed as usc0008pwq, choy20120325223706, duputel201203252237a, iscgem600841739, atlas20120325223706). Read Thu, Oct 1, 2026, 11:21 AM UTC.