Volcanoes

Guatemala City - Guatemalan authorities issued a danger warning on Wednesday in response to intensifying activity in the country's Fuego Volcano.The danger warning issued by the government was one step short of a declaration of emergency requiring evacuation of the communities around the volcano.




      
Volcano de Pacaya-Guatemala

     Pacaya, which in recent years has consistently erupted olivine-bearing high alumina basaltic lavas, erupted with remarkable violence on both 27 and 28 May 2010 with an explosion on the 27th lasting ~45 minutes. This was followed by a smaller explosion the next day that generated a plume assessed from satellite and meteorological data as reaching 13 km altitude. In this report we describe those events as explosions in order to distinguish them from the ongoing, decades-long, and often effusive eruption generally seen at Pacaya. The terms ‘explosion’ and ‘explosive’ appear warranted given such factors as the suddenness of escalation, the ~13 km plume altitude (~10 km over the summit when measured during the weaker explosion on the 28th, the density of projectiles, and the scale of the tephra fall. The term explosion seems consistent with common practice (Sparks, 1986; Fiske and others, 2009).
      Pacaya , which has a record of eruptions dating back over 1,600 years, has been erupting the majority of the time since 1961, often emitting rough-surfaced lavas but also occasionally discharging explosions. The centerpiece of the National Park of the same name, it is the most often climbed volcano in Guatemala. There have been 69 prior Smithsonian-published reports describing behavior from 1969 to early January 2010 (CSLP 03-70 to BGVN 34:12). REW (2013) ranked the 27 May explosions as sub-plinean and the associated lava emissions as the largest since similar events in 1961.

The 27 May 2010 explosion destroyed or damaged nearly 800 houses in nearby communities, forcing ~2,000 residents to evacuate and injuring 59 people. A high density of ballistics fell on nearby hamlets and villages, particularly those 2.5-3.5 km N of the MacKenny cone (El Cedro, San Francisco de Sales, and Calderas). The ballistics had sufficient mass and velocity to puncture roofs with a density on the order of one puncture per square meter in some places. Many more smaller ballistics bent but did not penetrate the corrugated sheet metal roofs common in many of the region's dwellings. Some of the ballistics were sufficiently hot to start fires.                                                                                                                                                    Ash caused widespread damage locally, and up to ~8 cm of ash fell on parts of metropolitan Guatemala City, the nation’s capital, centered ~35 km NNW of Pacaya. Up to 20 cm of tephra accumulated at and near Pacaya. According to available census data, the population within 10 km of Pacaya was 57,000 (John Ewert, USGS-CVO, personal communication).

Volcano de Fuego-Guatemala

Guatemala's Volcano of Fire erupted Saturday (Feb 25), spewing lava and sending up plumes of ash that rained down on nearby communities and could eventually reach the capital, civil protection authorities said.

      The Volcan de Fuego, one of the country's three active volcanos, is located about 45km southwest of the capital Guatemala City. It was the volcano's second eruption this year.

      David de Leon, spokesman for the National Coordinator for Disaster Reduction, said the volcanic activity later stabilised and fell within the normal range after an eruptive phase that lasted 13 hours.

       In addition to Fuego, the Central American country has two other active volcanos: Santiaguito in the west and Pacaya in the south, just 30km from the capital.

References: 

http://www.straitstimes.com/world/americas/guatemalas-volcano-of-fire-erupts

http://volcano.si.edu/volcano.cfm?vn=342110

Guatemala Seismicity and Prevention

CHALLENGE

Guatemala has been severely affected by natural hazards including volcanic activity, hurricanes, and landslides. The worst disaster was the 1976 earth- quake that killed over 23,000 people and resulted in economic damages estimated at 17.9 percent of gross domestic product (GDP). Over the last decades, further events caused additional human and economic losses, such as Hurricane Mitch (4.7 percent of GDP), the 2001 drought (0.1 percent), and Hurricane Stan (3.4 percent).

This high exposure to natural hazards has threat- ened the sustainability of social programs. Funding resources for social programs were repeatedly diverted to disaster response activities and the subsequent recovery process, without being replenished later. This resulted in an even worse situation for the underprivileged. 

SOLUTION

To address this challenge, the Guatemalan Government took significant steps towards a more proactive approach to disaster risk management and comprehensive disaster risk reduction and financing strategies. These efforts culminated in the adoption of the 2009-2011 National Program for Disaster Prevention and Mitigation (NPDPM). 

The Guatemala Disaster Risk Management Devel- opment Policy Loan with a Catastrophe Deferred Drawdown Option (CAT DDO) was designed to support the implementation of Guatemala’s national disaster risk management program and provide liquidity in the event of adverse natural events. Unlike traditional instruments to finance disaster response and recovery, the CAT DDO makes urgently needed resources available im- mediately after a declaration of emergency. This innovative mechanism allowed the Government to access $85 million to respond to the impacts. 

MOVING FORWARD

Guatemala recently developed a comprehensive National Strategy for Disaster Risk Reduction 2012-2017 and is positioned to start designing ex- ante Disaster Risk Finance and Insurance (DRFI) solutions. The Bank will support the Government in preparing and implementing a DRFI strategy tailored to its specific needs and capabilities. SEGEPLAN is expected to cooperate on issues related to incorporating and strengthening disaster risk management into land use plans and develop- ment plans. It will also identify legal instruments to ensure the application of disaster risk management at the municipal level and promote construction codes and standards.

Major Historic Earthquakes in Guatemala

The USGS list of historic earthquakes indicates that Guatemala has experienced at least three ≥M7.0 in recorded history: the same organisation’s map of historic seismicity, however, shows many more large-scale events. And, given the fact that earthquakes are no respecters of national boundaries, it is worth noting that the country has also been affected by large tremors occurring along the length of the subduction zone.

Seismic activity characterises such tectonically dynamic belts and in 2012 alone the Cocos subduction zone has seen a number of significant earthquakes, including two of M7.4 and M6.4 off the coast of Mexico and two of M7.4 and M7.6 off Costa Rica, the latter occurring within the previous two months. Smaller earthquakes have also abounded, as the map of seismicity for the year demonstrates.

Resources:

http://www.worldbank.org/en/results/2013/10/08/promoting-proactive-disaster-risk-management-in-Guatemala

https://www.decodedscience.org/m7-4-earthquake-guatemala-november-7-2012/19953

Week 2: Guatemala on the Plate Tectonic Map

Guatemala is located on the North American Plate as well as the Caribbean Plate. 

The North American Plate as well as the Caribbean plate are classified as convergent (subduction) boundary. Convergent boundaries occur where plates move toward each other (Natural Hazards, Keller, DeVecchio).

In some areas the plates move toward each other. This is called convergence. At convergent plate boundaries (also called destructive plate boundaries), crustal plates collide in super slow motion causing earthquakes, folding and volcanic activity. It is estimated that about three quarters of all earthquakes occur along convergent plate boundaries.

The earth has two kinds of crust. The continents are mostly made of thick granite. When continents pull apart, the gap is filled by thin crust made of basalt. In plate tectonics, a continent is any piece of continental crust surrounded by oceanic crust or plate boundaries. Greenland is a continent. When North America and Europe began to pull apart about 80 million years ago, Greenland originally moved as part of Europe for about 20 million years. Then the crust broke on the east side of Greenland, leaving it attached to the North American Plate.
The North American plate’s interactions with other plates generate various geologic features on its surface, from mountain belts to faults. The Motagua Fault (also, Motagua Fault Zone) is a major, active left lateral-moving transform fault which cuts across Guatemala, continuing offshore along the southern Pacific coast of Mexico, returning onshore along the southernmost tip of Oaxaca, then continuing offshore until it merges with the Middle America Trench near Acapulco. It forms part of the tectonic boundary between the North American Plate and the Caribbean Plate. It is considered the onshore continuation of the Cayman Trench which runs under the Caribbean Sea.

The Motagua Fault is regarded by some geologists as part of a system of faults designated the "Motagua-Polochic system" rather than as a discrete single boundary. The Polochic fault (also referred to as the Chixoy-Polochic Fault) lies north and parallel to the Motagua Fault and shares some of the motion between the North American and Caribbean Plates.

The Motagua Fault has been responsible for several major earthquakes in Guatemala's history, including the 7.5 M_w Guatemala 1976 earthquake.^[1]

The Caribbean Plate is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off the north coast of South America.

Roughly 3.2 million square kilometers (1.2 million square miles) in area, the Caribbean Plate borders the North American Plate, the South American Plate, the Nazca Plate and the Cocos Plate. These borders are regions of intense seismic activity, including frequent earthquakes, occasional tsunamis,^[2] and volcanic eruptions

The northern boundary with the North American plate is a transform or strike-slip boundary which runs from the border area of Belize, Guatemala (Motagua Fault), and Honduras in Central America, eastward through the Cayman trough on south of the southeast coast of Cuba, and just north of Hispaniola, Puerto Rico, and the Virgin Islands. Part of the Puerto Rico Trench, the deepest part of the Atlantic Ocean (roughly 8,400 meters), lies along this border. The Puerto Rico trench is at a complex transition from the subduction boundary to the south and the transform boundary to the west.

Santa Maria Volcano: Plate Tectonic Setting

Santa María is located in the volcanic highlands of Guatemala, which parallel the Pacific coast of the country. The highlands were formed by the subduction of the Cocos plate under the Caribbean plate, which resulted in the formation of a line of stratovolcanoes that stretches along much of the Pacific coast of Central America. In Guatemala, these volcanoes overlie a basement of carbonate as well as igneous and metamorphic rocks; many xenoliths ("foreign" rock fragments) found in lavas erupted from the stratovolcanoes are composed of limestone, granite, and gneiss



References:
https://en.wikipedia.org/wiki/Caribbean_Plate
http://geology.com/volcanoes/santa-maria/
https://www.uwgb.edu/dutchs/GeolColBk/NAmerPlate.HTM
https://en.wikipedia.org/wiki/Motagua_Fault
http://www.geoforcxc.com/our-planet/plate-tectonics/

Week 1: Earth’s disasters, catastrophes and hazards

Earths disasters, catastrophes and hazards can occur at any given time and at any given place.

A natural disaster is a major adverse event resulting from natural processes of the Earth; examples include floods, hurricanes, tornadoes, volcanic eruptions, earthquakes, tsunamis, and other geologic processes. When 10 or more people are killed, 100 or more individuals are affected, a state of emergency is declared, is also considered a disaster. 

A catastrophe is a massive disaster that requires a lot of money and time to help the people and the area to recover and possibly rebuild from the hazard.

A hazard is a natural process that threatens human life or property.