The 2010 Guatemala City sinkhole was a disaster on 30May2010, in which an area approximately across and deep collapsed in Guatemala City's Zona 2, swallowing a three-story factory. The sinkhole occurred for a combination of reasons, including

Tropical Storm Agatha Tropical Storm Agatha was a weak but deadly tropical cyclone that brought widespread floods to much of Central America, and was the deadliest tropical cyclone in the eastern Pacific since Hurricane Pauline in 1997. The first storm of the 2010 Pa ...

, the Pacaya Volcano eruption, and leakage from sewer pipes.

Background

Overall, the risk of sinkholes occurring in Guatemala City is very high and unpredictable. One recent, similar sinkhole had collapsed in 2007, forming a pit deep.Waltham, T., 2008
''Sinkhole hazard case histories in karst terrains.''
Quarterly Journal of Engineering Geology and Hydrogeology. vol. 41 no. 3, pp.. 291-300.Halliday, W. R., 2007, ''Pseudokarst in the 21st century.'' Journal of Cave and Karst Studies. vol. 69, no. 1, p. 103–113. The 2007 Guatemala City sinkhole was formed by fluid from a sewer eroding uncemented volcanic ash,

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

, and other pyroclastic deposits underlying Guatemala City. The hazards around the pipe have since then been mitigated, by improved handling of the city's wastewater and runoff. Several rainstorms also contributed to the sinkhole's collapse, as stormwater percolated into the ground, further dissolving the rocks beneath Guatemala City. The 2010 sinkhole was formed for similar reasons.

Formation

Sewage pipes

Tropical Storm Agatha Guatemala Flooding

The sinkhole formed due to volcanic pumice deposits, upon which Guatemala City is built. These deposits were unconsolidated and of low density, allowing easy

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...

. According to Sam Bonis, a geologist at

Dartmouth College Dartmouth College (; ) is a private research university in Hanover, New Hampshire. Established in 1769 by Eleazar Wheelock, it is one of the nine colonial colleges chartered before the American Revolution. Although founded to educate Native ...

, leaking pipes went unfixed long enough to create the conditions necessary for sinkhole formation because of lax city zoning regulations and building codes. Bonis also says that the Guatemala City sinkhole is a misnomer: sinkholes have natural causes, but this one was mainly artificial. In addition, according to Bonis, sinkholes are usually formed from

but there is no limestone hundreds of metres underneath Guatemala City. Bonis proposes that the sinkhole be renamed a piping feature.

Tropical Storm Agatha

Tropical Storm Agatha was first identified as a trough of

low pressure In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...

of the western coast of Costa Rica on 24May2010. On May 29, the depression intensified into a tropical storm and was given the name Agatha. Later that day, the system intensified slightly before making

landfall Landfall is the event of a storm moving over land after being over water. More broadly, and in relation to human travel, it refers to 'the first land that is reached or seen at the end of a journey across the sea or through the air, or the fact ...

near the

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

- Guatemala border with winds of . By the morning of 30May, the center of Agatha moved over the highest terrain in

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

, resulting in the dissipation of the low-level circulation. Torrential rains from the storm widened the cavity, eventually causing the collapse of the sinkhole.

Pacaya volcano eruption

On 27May, three days before Agatha became a tropical depression, the Pacaya volcano, located about south of Guatemala City, erupted, killing at least one person and blanketing nearby areas with layers of ash. The eruption prompted officials to shut down the country's international airport. Upon the formation of Agatha, people feared that excessive rainfall from the storm could exacerbate the situation and trigger

lahars A lahar (, from jv, ꦮ꧀ꦭꦲꦂ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley. Lahars are extremel ...

. This had the effect of clogging the underground pipes with

soot Soot ( ) is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolysed ...

, increasing the chances of pipe rupture.

Collapse and aftermath

Mariela Castañón, a reporter for the daily newspaper ''La Hora'', reported that the ground collapsed suddenly, taking a three-story house that was used as a factory, and possibly a security guard, along with it. Electricity poles were also sucked in. Authorities said they could not confirm the security guard's death. Because of the role played by sewage pipes in the sinkhole's collapse, Sam Bonis, along with other geologists, has demanded that the

government A government is the system or group of people governing an organized community, generally a state. In the case of its broad associative definition, government normally consists of legislature, executive, and judiciary. Government is ...

inspect the sewer system more regularly. According to officials, the sinkhole had similarities with another Guatemalan sinkhole which collapsed in 2007, which may also have been formed by ruptured sewage pipes. On a wider scale, immediately following reports of fatalities due to Agatha, a state of emergency was declared for Guatemala. On 31May, the government started to deploy national aid, and donation centers for victims of the storm were opened across the country. According to the

Office for the Coordination of Humanitarian Affairs The United Nations Office for the Coordination of Humanitarian Affairs (OCHA) is a United Nations (UN) body established in December 1991 by the General Assembly to strengthen the international response to complex emergencies and natural disaster ...

(OCHA), schools in Guatemala were to be closed until at least 4June.

Filling in the sinkhole

Immediately after the sinkhole's collapse, there were plans to fill it in with a soil cement made from cement,

, and

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

known locally as ''lodocreto'' ("mudcrete"). This substance was also used to fill in the 2007 Guatemala City sinkhole. However, another technique, which geologists call the graded-filter technique, in which the sinkhole is filled with successive layers of boulders, smaller rocks, and gravel, could possibly be a better solution. This is because filling the hole in with cement diverts water runoff to other areas, potentially increasing the risk of sinkholes occurring in other parts of the city. The graded-filter technique, on the other hand, allows water to seep through.

References

{{Guatemala topics 2010 natural disasters 21st century in Guatemala City 21st-century sinkholes 2010 in Guatemala Natural disasters in Guatemala Sinkholes of North America Landforms of Guatemala