Very strong shallow earthquake in Argentina

UPDATE 17:46 UTC : Director of Civil Defense from Tucuman Fernando Torres,  has confirmed that although no injuries have been reported, light damage has been noticed in the area around Ranchillos and Estacion Araoz.
The damage is however limited to cracks in walls, fallen plaster, broken moldings, etc. Due to the panic and the minor damage, we  have labeled this earthquake as  CatDat Orange This article will remain in this year's CatDat overview.

Light damaged area during the Tucuman February 21 2011 earthquake

UPDATE 15:13 UTC : People have felt the earthquake in the following cities Córdoba, Salta, San Luis, La Rioja, San Juan and Mendoza, making it the strongest earthquake in the area from the last several years.

UPDATE 14:02 UTC : Official statement from INPRES (National Seismological service of Argentina). ER: Note that the epicenter as located by INPRES is approx. 15 km more westward (closer to Tucuman, who also experienced the most forceful shaking).

"El último sísmo registrado se originó el 21/2/2011 a las 3:58 horas en la provincia de Tucumán ( El epicentro se ubicó a 45 Km. en dirección sur-sureste de la ciudad de San Miguel de Tucumán) a una profundidad de 27 Km. La intensidad del sismo en la escala Mercalli Modificada alcanzó el grado IV a V (cuatro a cinco) en la ciudad de San Miguel de Tucumán y en las Termas de Río Hondo en la provincia de Santiago del Estero, III (tres) en Santiago del Estero y San Fernando del Valle de Catamarca y II a III (dos a tres) en la ciudad de Salta ., y una magnitud de 5.9 en la escala de Richter .Al momento de emitir este parte no se han reportado daños ni víctimas como consecuencia de este evento."

UPDATE 13:41 UTC : The Power company delivering electricity to the greater epicenter area reported that the power cuts had NOTHING to do with the earthquake, but was originated in a malfunctioning of a transformer a few minutes prior to the earthquake. What a coincidence ... The power was restored 40 minutes after it was cut off.

A couple of videos from TV News channels talking to people in Tucuman (Spanish spoken).

UPDATE 12:49 UTC : People in the provinces of Tucuman and Santiago del Estero have to be ready for a number of aftershocks. Nobody can predict whether they will be weaker (the case in 98%) or even stronger (exceptional, but it happens sometimes).

UPDATE 12:44 UTC : Argentina Defensa Civil (Civil Defense) has surveyed the greater area of Santiago del Estero and did not find any damage themselves and did not received any phone call from people claiming damage on their houses..

UPDATE 10:18 UTC : The power cuts have been confirmed in Argentina. On top of all the panic there is currently heavy rain in the area.

UPDATE 10:14 UTC : A Brazilian source did report that the power was cut off for some time in some parts of the provinces Santiago del Estero and Tucuman.

UPDATE 10:12 UTC : So far we could not obtain information on which villages are located in the direct epicenter area (we think El Charco and Tacanas - based on the USGS data) nor have we any reports of this area. Shallow earthquakes are mostly dangerous directly near the epicenter.

UPDATE 9:42 UTC : Province of Santiago del Estero + the city of Tucuman : no reports of damage or injuries have been entered at this moment.

UPDATE 9:38 UTC : The way people are experience an earthquake can be very different from one village or town to another, even if they are the same distance from the epicenter.  Soil composition, direction of the tectonic movement are two very important factors during an earthquake.

UPDATE 9:27 UTC : EMSC changed his data again to : Magnitude 5.6 at a depth of 30 km. Based on the experiences of the people, the USGS numbers maybe closest.

UPDATE 9:15 UTC : Diario Panorama reports that the director of INPRES told them that the MMI values for Tucuman were V and Santiago del Estero III. No word so far of the situation in the epicenter villages.

UPDATE 9:08 UTC : Today's earthquake has been felt as by far the strongest of the last several years.

Landscape at San Augustin, Argentina, a village in the greater epicenter area - Panoramio image courtesy Juan Ullivarri - http://www.panoramio.com/photo/6502743

UPDATE 9:05 UTC : The population in the Tucuman - Santiago del Estero area is really frightened. Although it is still in the very early morning hours in the area, people are massively present on Twitter, Facebook and in the newspapers comments to talk about this very strong earthquake.

UPDATE 8:54 UTC : Argentina INPRES (Instituto Nacional de Prevencion Sismica) is showing as the last event still the February 18 tremor.

UPDATE 8:40 UTC : One of the side effects of this quake was that the cities were full with sirens coming from car alarm systems.

UPDATE 8:38 UTC : A lot of people have experienced today's earthquake a lot stronger than last year's massive 8.8 February 27 earthquake.

UPDATE 8:37 UTC : People in the earthquake area are reporting that the shaking lasted for about 20 seconds.

UPDATE 8:34 UTC : There was also a general panic in Santiago del Estero when the earth started shaking.
The earthquake did also scare people in Salta, Catamarca and Cordoba

UPDATE 8:30 UTC : EMSC reports a magnitude of Mb 6.1 at a depth of 30 km.

UPDATE 8:30 UTC : USGS has changed its earthquake data into : Magnitude Mw 5.6 at a depth of 11 km.

UPDATE 8:17 UTC : So far we have only news from the major cities but not from the epicenter villages.  It is still dark in Argentina at this time.

UPDATE 8:16 UTC : The epicenter area is flat and is mainly used for farming.

UPDATE 8:09 UTC : Reports from Tucuman confirms that people jumped out of their bed when the shaking started and ran immediately on the street to join other people and told their experiences. This earthquake has been felt very strongly, contrary to some theoretical modeling data.
Tucuman is approx. 65 km from the epicenter.

UPDATE 8:06 UTC : GDACS population measurement for the epicenter area
696 people are living within a radius of 5 km around the epicenter
4,524 people are living within a radius of 10 km around the epicenter
18,233 people are living within a radius of 20 km around the epicenter
165,393 people are living within a radius of 50 km around the epicenter
1,908,440 people are living within a radius of 100 km around the epicenter

UPDATE 7:59 UTC : Based on present earthquake data,  light damage may be possible

UPDATE 7:57 UTC : Historic earthquakes in the greater epicenter area exclusively to the CATDAT Damaging Earthquakes Database (J. Daniell, 2003-2011) - references must be made when requoting.
1692 Tucuman earthquake was very close - Mag 7. (-28, -65)
Other similar size earthquakes have occurred:
- 17.11.1906 (-26.75, -65.7) Mag. 6, minor damage = I=7
- 11.08.1907 (-27.2, -65.5) Mag. 5.5, Caused significant damage in several locations in the province of Tucumán, especially Monteros and La Cocha.
06.11.1913 (-26.8, -65.1) depth 30km, Mag. 5.5 (I=6), felt with great intensity in San Miguel de Tucumán. Alarm and caused slight damage to that city.
03.04.1931 (-27, -65), depth 180km, Mag 6.3, Property damage was considerable, no deaths were reported. Tucuman, Argentina.
12.02.1933 (-26.6, -65.35), depth 30km, Mag 5.5Mb, (I=6) - minor damage
09.05.1981 (-26.482, -64.782), depth 16km, Mag 5.6UK, I=6, Minor damage occurred in the towns of Villa Burruyacú and Benjamin Arao
29.02.1992 (-26.68, -64.939); depth 23km, Mag 5.2, I=6, It caused slight damage to the town of Timbo Viejo, Tucumán province.
17.06.1997 (-27.662, -64.737); depth 28km, Mag 5.6, I=7, damaging.
28.05.2002 (-28.95, -66.74); depth 14km, Mag 6, I=8, Twenty-seven people injured and at least 40 houses destroyed at Aminga, Anillaco, Agua Blanca and Chuquis. Fifty percent of houses damaged in Castro Barros Department, La Rioja. Landslides occurred in the epicentral area. Felt strongly in Catamarca, Cordoba, San Juan, Santiago del Estero and Tucuman Provinces.

UPDATE 7:51UTC : USGS predicts a maximum MMI value of VI for 7,000 people (strong shaking).
136,000 will suffer a V moderate shaking and 2,119,000 people will have felt a light shaking.
A lot of Argentinians will have been waked-up by this earthquake

UPDATE 7:48 UTC : The epicenter is on the border of the Provinces of Tucuman and Santiago del Estero

UPDATE 7:43 UTC : GDACS published a GREEN earthquake alert for this earthquake = very limited chance on damage and/or injuries/ Earthquake-Report does not agree with this immediate positive outlook and based on the current data.

UPDATE 7:42 UTC : A witness report from Tucuman (65 km from the epicenter), talks about a strong shaking.

At 4 am in the night a very strong earthquake measuring 5.8 has struck in between Santiago del Estero and  Tucuman.
The earthquake occurred at a unusual shallow and dangerous depth of only 13 km (initial data)

Most important Earthquake Data:
Magnitude : 5.8 (afterwards modified into Mw 5.6)
UTC Time : Monday, February 21, 2011 at 06:58:36 UTC
Local time at epicenter : Monday, February 21, 2011 at 03:58:36 AM at epicenter
Depth (Hypocenter) : 13.5 km (afterwards modified into 10.6 km)
Send an "earthquake experience report" for this earthquake
Geo-location(s) :
Approx. 5 km from Tacanas and El Charco
65 km (40 miles) SE of San Miguel de Tucuman, Tuc., Argentina
80 km (50 miles) NW of Santiago del Estero, Argentina

Links to important maps
USGS Did You Feel It Map
Google satellite map of the area showing the kind of terrain the earthquake took place

3-dimensional view of the earthquake area (USGS epicenter location)
USGS Impact on population map
USGS historic earthquakes map
USGS Seismic hazard map

GDACS GREEN earthquake alert

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