Guerrero, Mexico Strong Aftershock

Very strong dangerous earthquake / aftershock in Guerrero, Mexico – severe shaking for 17,000 people

Last update: April 2, 2012 at 8:33 pm by By 

Most important Earthquake Data:
Magnitude : 6.3
UTC Time : Monday, April 02, 2012 at 17:36:43 UTC
Local time at epicenter : Monday, April 02, 2012 at 12:36:43 PM at epicenter
Depth (Hypocenter) : 12 km
Geo-location(s) :
27 km (17 miles) SSE (148°) from Ometepec, Guerrero, Mexico

Update 20:28 UTC :  The authorities in Puebla, one of the major Mexican cities and approx. 250 km from the epicenter,  have reported NO injures or damage. Good news which we expected at this distance. calls an area with a radius of about 35 km around the epicenter at high risk for additional damage (to the already damaged houses during the March 20 mainshock).

Update 19:44 UTC :  USGS has increased his intensity mapping prediction. The new estimate mention 17,000 people having felt a severe MMI VIII shaking (damaging environment), 180,000 people a VII MMI very strong shaking.
The new values are bad news and will make this aftershock almost certain a damaging one.
Until now we have No details yet on damage and injuries. As said earlier it will take another 2 to 6 hours to have see first serious assessments of the epicenter area

Update 19:42 UTC :  Intensity report in the most important cities in the greater epicenter area :
VII    Cuajinicuilapa    9,000 people
VII    San Juan Cacahuatepec    4,000  people
VII    Ometepec    18,000  people
VII    San Pedro Amuzgos    4,000  people
VI    San Pedro Jicayan    4,000  people
VI    Santiago Pinotepa Nacional    26,000  people
MMI VII : very strong shaking
MMI VI : strong shaking

Update 19:16 UTC :  Mexican authorities are reporting the strongest shaking in the Costa Chica region. Until now, we have no reports of damage, but we are almost sure that they will appear in 4 to 8 hours.

Update 18:38 UTC :  Helicopters were dispatched 5 MINUTES after the earthquake. The only damage seen was a billboard that fall causing NO injuries. (we are confirming the very swift reaction of the authorities in DF)

Update :  The Mexican seismological agency has increased his initial Magnitude to 6.0. Since the mainshock today, 2 aftershocks of resp. 4.6 and 4.7 have been listed (normal)

Update :  Read also the many felt reports at the bottom of this page

Update 18:29 UTC :  Last time, damage was only reported after several hours or even a couple of days in the epicenter area (one of the poorest areas in Mexico). Most houses are made from brick or in adobe in the greater epicenter area.

– Security secretary of Mexico City reports that there is NO damage.
– Communications are still working.
– Subway is still working.
Such reports are mostly based on the capital Mexico City or DF.

Update :  Intermediate report from Carlos Robles : Servicio Sismologico Nacional is upgrading the earthquake to 6.0. Saldo blanco (no deaths) is reported. There aren’t reports of damage.

Update 18:23 UTC :  There are NO Nuclear plants or Hydrodams in the greater epicenter area

Update :  EMSC (Seismology Europe) reports now a magnitude of 6.1 at a depth of 10 km

Update 18:18 UTC :  NO tsunami danger as the epicenter of the earthquake is below the Mexican mainland

Update :  Evacuation were held at Mexico city.It was felt strong in some parts of Mexico city.In Coyoacan there are only reports of scared people. (source : Carlos Robles)

I Have Felt It map courtesy USGS – blue lighter, yellow strong shaking

Update : USGS predicts a very strong shaking for 3,000 people in the epicentral area. 164,000 people will have experienced a strong MMI VI shaking and 289,000 people a moderate shaking. As this earthquake is also felt in DF,  the earthquake will have been noticed by millions of people.

Update : As this is an aftershock from the March 20 M 7.4 earthquake,  these aftershocks, even at the current magnitude are very normal !

Update : The president of DF is flying by helicopter over DF areas to overview the situation. He reports that so far no serious damage can be seen from the air

Update : The Mexican media including the local seismological agency are not reachable because of too many connections

for more information and updates, go to:

Guerrero, Oaxaca, Mexico 7.9 Earthquake

Earthquake in Guerrero – Oaxaca, Mexico – 500 houses severely damaged at least – but slight damage for such a quake

Last update: March 20, 2012 at 9:33 pm by By 

Most important Earthquake Data:
Magnitude :  7.9 (preliminary)
UTC Time : Tuesday, March 20, 2012 at 18:02:53 UTC
Local time at epicenter : Tuesday, March 20, 2012 at 12:02:53 PM at epicenter
Depth (Hypocenter) : 10 km
Geo-location(s) :
52 km (32 miles) NE (39°) from Ometepec, Guerrero, Mexico
53 km (33 miles) WSW (241°) from Tlaxiaco, Oaxaca, Mexico
193 km (120 miles) E (83°) from Acapulco, Guerrero, Mexico   

Update: 2 buildings in the historic center of Mexico city have also been reported damaged.

– Update: No casualties have been reported from Omotopec which is good news given the damage.

– Update:  We have reports from Mexican radio (from Carlos) that 500 houses have been severely damaged or destroyed in Guerrero. As expected Omotopec has had a lot of this damage.

– Update: Currently only 60 houses are still being reported destroyed in the epicentral region with an extra 400 damaged.

– From Carlos Robles – our US/Mexico Earthquake correspondent:- A wall collapsed leaving one with serious injuries in Mexico City. Damage has been reported in Ciudad de Mexico like cracked roads, damaged buildings, and the bridge that collapsed in a bus with no casaulties.  Damage has been reported in Oaxaca with cracked roads and damaged buildings.

In Puebla the Palacio Municipal (Municipal palace, is a government building.) there were 2 cracked walls. Fissures in churches all over Mexico have been reported. Mobile phones were suspended due to overuse. The subway was suspended. The daughter of president Obama was in Oaxaca when the earthquake hit, she only felt the earthquake and has no injuries.

– A highway in Oaxaca has had a landslide cover a small section. It only caused slight damage in the form of a small car crash. Apart from that, other roads are all clear according to authorities.

– Earlier reports of a footbridge collapsing onto a bus in Mexico City were incorrect. In fact, it was the 10 meters of concrete guard rail of the footbridge which collapsed. No people were killed.

– Update : 1 person has been injured in Colonia Juarez – of a nervous breakdown. In addition a staircase collapsed in a police building and there are reports of minor injuries. Other than that only minor damage has been reported. Some bridges have been closed around Mexico as a precaution.

– Update : At least 60 houses have been destroyed in Guerrero. Most of these are expected to be old adobe houses. Omotopec is expected to have major damage. Damage will likely be in the tens of millions of US dollars.

2.5 million users have had outages in their electricity following the earthquake. After 90 minutes, 1.5 million users were restored to the grid. In the Eastern control area partial outages  in the cities of Poza Rica and Coatzacoalcos and parts of the states of Puebla, Tlaxcala and Morelos. CFE crews will continue working to restore power as quickly as possible in the affected areas.

– Update :  We notice, as expected, a lot of aftershocks, the strongest ones ranging from M 4.7  to M 5.3.

– Update :   – President Calderon has just confirmed that so far NO lives have been lost.
– Power plants are working normally
– The President has also declared that NO major damage was inflicted
– The Mexican Seismological service is maintaining a Magnitud of 7.8

– Update :  YouTube video of the shaking. The shaking we see on the video was more than 300 km from the epicenter! Swaying is more accentuated in high rise buildings.


I have felt it Map courtesy USGS

– Update :  At 13:52 local time (1 hour 50 minutes after the earthquake),  NO fatalities have been reported so far, a very good sign !

– Update :  New Intensity calculations(based on the M 7.4 Magnitude) are giving the following impact :
182,000 people MMI VII (very strong shaking)
596,000 people MMI VI (strong shaking)
2,736,000 people MMI V (moderate shaking)
32 million people MMI IV (light shaking)

– Update :  USGS has further decreased the Magnitude from 7.6 to 7.4, a lot weaker than the initially reported 7.9. The depth has been recalculated to 20 km. All this explains the lesser than originally expected intensity.

– Update :  GOOD preliminary news : Only light damage is currently reported out of the epicenter area. Based on our own experience, we think it is far too soon to have a final estimate, but after such an earthquake, we like to hear that the damage is not general.

– Update :  A concrete walkway bridge has collapsed on a microbus. No reports yet about victims. Some people have been hospitalized by a nervous breakdown.

– Update :  Everybody in the country could be found on the streets after evacuating houses and buildings. The situation on the roads of the bigger cities is simply chaotic. Everybody wants to drive back home.

GDACS another agency who calculates tsunami heights has calculated that a max. tsunami wave of 0.1 meter may have occurred, nothing to be scared of.

– Update :  the closest airports to the epicenter are Pinotepa Nacional (77km) and Ta Lo De Soto (71km)

– Update :  there are NO hydrodams or NO Nuclear Plants in the vicinity of the epicenter

– Update :  GDACS reports that the nearest populated places are: Coyul (16km), Putla de Guerrero (18km), Cuitlapa (15km), Laguna (3km). The closest civilian airport is Pinotepa Nacional (77km).

– Update :  The area has currently a lot of aftershocks as could be expected. These aftershocks will go on for many hours and even days. Gradually they will get weaker but sometimes even M 6.x can be reached.  People in the epicenter area will have to spend the night on the streets out of fear for aftershocks.

– Update :  This earthquake is a subduction earthquake, which means that the Oceanic plate is gliging below the North American plate and often hangs for a while. When the accumulated energy is suddenly freed a massive earthquake is generated.

for more information and updates, go to:


Strong Earthquake – Iguala, Mexico

Very strong earthquake near Iguala, Mexico – 2 people killed, 4 injured and 50 houses damaged in Guerrero

Last update: December 11, 2011 at 5:38 pm by By 

Earthquake overview :  A very strong earthquake occurred near Iguala Mexico at 07:47 PM local time. Luckily the hypocenter was at a depth of 64.7 km.

image copyright and courtesy

Update 11/12 – 17:23 UTC
– The Civil Defense undersecretary from the Guerrero province has declared that the official death toll is 2(updated from 3), 4 people have been injured  and 50 houses have been damaged.

Update 11/12 – 13:23 UTC
– As could be expected after such a powerful earthquake, a number of aftershocks have been reported so far
– The picture at right shows the damaged van of the unlucky driver who lost his live during this earthquake. We do not know the exact circumstances but it looks that he was hit by one of the heavy stones on the ground. 2 woman inside the van were more lucky as the far heavier stones where blocked by the roof of the van. The woman were injured.

Update 11/12 – 12:06 UTC
The death toll remains at 3 and will probably and hopefully not increase anymore.
All the fatalities have been reported in Guerrero state.
The Mexico City DF (Federal district) has reported a SALDO BLANCO, which means that there were NO injuries and/or fatalities
– At least 13.2 million people must have Felt the earthquake
– The deep hypocenter or focal depth  is the main reason why this very strong earthquake did not made more victims.
– Based on what we know right now, we can call it a lucky escape.
– The video below shows the shaking while a TV soap was being recorded. We think that this video was recorded in Mexico City, at least 150 km from the epicenter. The video shows very well the length of the shaking (official reports are mentioning 47 seconds, but this might have been the case closer to the epicenter).

Update 09:06 UTC : 
A third death has occurred in the northern region of Guerrero, where a rock fell onto a driver.
Thus we have had 1 death via structural failure, and 2 via rockfalls.
In Chilpancingo, several houses and businesses were damaged, while the Cathedral of the Assumption of Mary has a serious crack in one of the towers.
Civil Protection has continued monitoring of damage, mainly in Zumpango del Rio, where the epicenter occurred. Helicopters are flying over for more reports, as people gradually have returned inside their buildings in a city that is ready to receive thousands of pilgrims for the annual celebration of the feast of Our Lady of Guadalupe.

Update 08:34 UTC : 
The death toll from this earthquake remains at 2. An 11 year old boy was killed when the roof of his house fell on him, and a rock fall caused the death of a motorist. As yet these are the only reports of deaths. Injuries have occurred in many locations from falling structures, objects and landslides.

I Have Felt It map – courtesy USGS

Update 08:34 UTC : 
The epicentral region has been hit by many earthquakes in the past 110 years according to CATDAT – here are just some of the damaging earthquakes within 100km of the epicenter. Chilpancingo has had damage on average every 30 years.
Date Magnitude Lat/Long No. of fatalities
1899 7.5Ml 17.1,-100.5 Chilpancingo damage
16/01/1902 7.3Ml 17.6,-99.5 300
6/10/1937 6.5Ml 17.3,-99.3 0
10/01/1944 7Ml 18.1,-100.6 0
11/05/1962 7.3Mw 17.18,-99.642 4
19/05/1962 6.7Ms 17.009,-99.763 30
30/11/1962 5.1Ml 17.6,-99.7 1
6/07/1964 7.2mB 18.193,-100.509 78
2/07/1968 5.7mB 17.519,-100.259 1
7/06/1976 6.4Mw 17.378,-100.691 0
13/04/2007 6Ml 17.302,-100.198 0

Update 08:11 UTC : 
From such an earthquake, the shaking in the soft soil (clay basin) of Mexico City, can sometimes be amplified many times, and could be the reason why we have seen damaged buildings in Mexico City despite expected low ground accelerations due to the distance from the epicenter. Mexico City was built on a lake originally, and hence the soft alluvial soils that magnify ground motion.

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