A very strong earthquake measuring M 6.6 struck Guatemala/Mexico border region on September 7, 2013 at 00:13 UTC. USGS measured depth at 67 km (41.6 miles), EMSC at 114 km. Three aftershocks were recorded by USGS. Magnitude 5.4 hit seven minutes after the main event. M 4.1 struck at 03:08 UTC and 07:30 UTC. All four earthquakes had hypocenter at approximately the same depth of 65 - 70 km according to USGS. It was late afternoon, 18:13 local time in Guatemala, when the main event occurred.
Epicenter was located 5 km (3 miles) ESE of Ciudad Tecun Uman, Guatemala, and 15 km (9 miles) NE of Suchiate, Mexico. Metropolitan Guatemala City, with population of about 1 million, is approximately 171 km (106 miles) W from epicenter and the quake was felt strongly there. It caused blackouts in some areas, but authorities have not reported any immediate injuries or damage.
There are about 4 240 545 people living within 100 km radius.
The population in epicenter region resides in structures that are vulnerable to earthquake shaking, though some resistant structures exist. The predominant vulnerable building types are mud wall and concrete/cinder block masonry construction. Recent earthquakes in this area have caused secondary hazards such as landslides and fires that might have contributed to losses.
Guatemala's fire department issued a statement saying a few poorly-built homes were destroyed in the town of Patzicia, located between the epicenter and the capital.
Nation's natural disaster agency said a major highway was blocked by a landslide.
The earthquake occurred in the Middle American trench, at or near the interface between the Cocos and North America plates. The style of faulting based on the W-phase source mechanism indicates slip likely occurred on a shallow thrust fault consistent with the subduction interface. At the latitude of this event, the Cocos plate moves towards the north-northeast with respect to the North American plate at a rate of 78 mm/yr.
ER reader from Guatemala City said: Felt strong shaking for about 45 seconds , it built up to very strong in in middle of that time, then slowly eased off.
By the morning of September 8th (UTC) 30 people were reportedly injured when they fled from they houses and fell or caused traffic accidents. They all were carried to hospitals.
Unfortunately one woman from Coatepeque area suffered a heart attack due to the earthquake and died.
More than 40 people in different parts of Guatemala suffered a nervous breakdown or other kinds of shocks. The local fire fighters care for them. At least 11 people were injured by the direct shaking effects (falling debris, etc), among them a pregnant woman.
There were reports of several collapsed houses and many damaged. Damage was reported all over Guatemala.
This was one of the strongest earthquakes in Guatemala since a massive M 7.4 last November killed 50 people. That one was the strongest in 36 years and left thousands of people homeless and without electricity or water.
The broad scale tectonics of the western and southwestern coast of Central America are dominated by the northeastward subduction of the Cocos oceanic plate beneath the North America plate. Thrust- and normal-type earthquakes are a common occurrence along this plate boundary and the Guatemala region, with events occurring both within the subduction zone and in the overriding plate. Over the past 40 years, 27 events of Mw6.0 or greater have occurred within 300km of the September 2013 event. Events of note in this region include earthquakes on November 2012 Mw7.4 offshore of Guatemala, which killed 39 people; September 1993 Mw7.2 offshore of Chiapas, Mexico, which killed one person; and December 1983 Mw7.0 offshore of Guatemala. Other early 20th century earthquakes in the Guatemala region include August 1942 Mw7.9, which killed 38 and April 1902 M7.5, which killed more than 5000 people.
Featured image: USGS