Roundup: Lava Flows, Pollen Grains and Village Projects

Hazards at Ice-Clad Volcanoes: Phenomena, Processes, and Examples From Mexico, Colombia, Ecuador, and Chile

Photo courtesy of the study
Photo courtesy of the study

“The interaction of volcanic activity with snow and ice bodies can cause serious hazards and risks[….] Case studies from Mexico, Colombia, Ecuador, and Chile are described. These descriptions depict the way in which the volcanic activity has interacted with ice bodies in recent volcanic crises (Popocatépetl, Mexico; Nevado del Huila, Columbia; Llaima and Villarica, Chile) and how the lahar processes have been generated. Reconstruction of historical events (Cotopaxi, Ecuador) or interpretation of events from the geological remains (Citlatépetl, Mexico) help to document past events that today could be disastrous for people and infrastructure now existing at the corresponding sites. A primary challenge for hazard prevention and risk reduction is the difficulty of making decisions based on imperfect information and a large degree of uncertainty. Successful assessments have resulted in the protection of lives in recent cases such as that at Nevado del Huila (Colombia).”

Read more about the study here.

 

Ancient pollen reveals droughts between Sierra Nevada glacier surges

The Sierra Nevada region.
The Sierra Nevada region. Courtesy of Wikipedia.

“Hidden below the surface of California’s Central Valley are pollen grains from the Pleistocene that are providing scientists with clues to the severity of droughts that struck the region between glacial periods.

The Pleistocene—the age of mammoths and mastodons—occurred between 1.8 million and 11,500 years ago. For this new study, scientists dug up Pleistocene sediment samples containing buried pollen from the Central Valley. They found that pollen samples dated from interglacial periods—years between surges in the mountain glaciers—predominantly came from desert plants. The same sediments lacked pollen from plants of wetter climates.”

To learn more about the new findings, click here.

 

Adapting in the Shadow of Annapurna: A Climate Tipping Point

02780771-35.3.cover“Rapid climate change in the Himalaya threatens the traditional livelihoods of remote mountain communities, challenges traditional systems of knowledge, and stresses existing socio-ecological systems. Through semi-structured interviews, participatory photography, and repeat photography focused on climate change and its impacts on traditional livelihoods, we aim to shed light on some of the socio-cultural implications of climate related change in Manang, a remote village in the Annapurna Conservation Area of Western Nepal…. Continued development of relevant, place-based adaptations to rapid Himalayan climate change depends on local peoples’ ability to understand the potential impacts of climate change and to adjust within complex, traditional socio-ecological systems.”

To learn more about the study and its findings, click here.

 

 

Ecuadorean Eruption Sparks Fears of Glacier Floods

Ash erupted from Ecuador’s glacier-covered Cotopaxi volcano last week after seventy quiet years. The debris shot five kilometres into the air, covering homes, cars, fields and roads as it descended, according to the Independent.

Patricio Ramon, of Ecuador’s Instituto Geofísico, said the eruption was phreatic, meaning that molten rock encountered water, creating a forceful release of steam.

“[I felt] in shock, not knowing what to do when I saw everything was moving. Then a strong smell of sulfur filled the mountain. Tourists were also concerned and wanted to leave as soon as possible,”  resident Franklin Varela told Ciudadana, an Ecuadorean radio station.

Cotopaxi, Ecuador’s second highest volcano, peaks at 5,897 metres and lies 45 kilometres from the capital, Quito. Its glacier, also named Cotopaxi, is considered to be of significant economic, social and environmental importance, according to reports of the United Nations Environment Programme. Meltwater from the glacier provides Quito with water and hydroelectric power, but in the last 40 years, the ice has thinned by more than 38 percent.  Most of this retreat is attributed to climate change, but eruptions can exacerbate glacial retreat by rapidly melting ice and triggering floods. Researchers from Instituto Geofísico told El Universal they considered Cotopaxi one of the most dangerous volcanoes in the world due to its potential for lahars, or mudflows, often triggered by glacial melt. When Cotopaxi erupted in 1877, lahars travelled as far as 100 kilometres from the volcano.  

The most recent ash eruptions led to the evacuation of hundreds of residents and livestock from El Pedregal, a community close to the volcano, reported La Hora. Farmers have expressed concerns that the ash that fell on their livestock feed will harm their animals.

Residents have been warned to avoid inhaling ash. Quito’s Mayor, Mauricio Rodas, told citizens he would hand out masks and told the city to remain calm.

Researchers continue to observe Cotopaxi’s activity as the volcano’s activity increases. On Saturday, Ecuador’s president, Rafael Correa, declared a state of emergency.

The president’s announcement comes the same week as a series of strikes against his government’s labor policies and changes to the constitution that would allow him to run for president at the end of his term. The army and police have been dispatched and civil guarantees are temporarily suspended.

“We declare a state of emergency due to the unusual activity of Mount Cotopaxi,” Correa said. “God willing, everything will go well and the volcano will not erupt.”

Volcanoes and Glaciers Shape Alaskan Landscape

Alaska's Pavlof Volcano, courtesy of NASA Goddard  Space Flight Center
Alaska’s Pavlof Volcano, courtesy of NASA Goddard Space Flight Center

Volcanic eruptions mark the beginnings of new landscapes. Ash and lava cover existing vegetation and map out a fresh terrain. Though researchers understand how volcanic landscapes evolve over centuries, there is little understanding of how volcanic eruptions have influenced the geomorphology, or the relationship between the Earth’s surface and geological structures, according to Christopher F. Waythomas, from the United States Geological Survey.

In a new review of historic volcanic eruptions, Waythomas laid the groundwork for interpreting the effects of volcanic eruptions on shaping the Alaskan landscape. He examined four volcanoes, Redoubt, Katmai, Pavlof and Kasatochi, and found that the volcanoes played a major – if not dominant – role in shaping the ecosystems and landscapes of southern and southwestern Alaska.

Alaska, especially the state’s Aleutian arc, experiences volcanic eruptions every one or two years. Most of the time, these eruptions affect the region’s extensive glaciers.

Following an eruption, melting glacier water can pick up debris and result in dangerous mudslides, or lahars. Lahars can be so powerful that they change the shape of the landscape they travel through, Waythomas found. They can also change sediment flux in the sea and create lahar blocked lakes.

Cleveland Volcano, Alaska, courtesy of NASA
Cleveland Volcano, Alaska, courtesy of NASA

“Given the significant magnitude of many Alaska eruptions and the high frequency of occurrence of eruptive activity, it is worthwhile to examine how eruptive activity and the products of this activity have affected the geomorphic evolution of landscapes throughout the Aleutian arc,” wrote Waythomas.”This task is practical and academic because of the obvious implications for hazards to people, infrastructure, and the environment and for understanding how volcanic systems evolve in an area that is as geologically dynamic as Alaska.” 

Because Alaska’s volcanoes erupt fairly frequently, they tend to be covered by a mantle of loose debris, which is easily dislodged by water flows following an eruption.

However, the varying nature of eruptions makes understanding the consequences of eruptions and lahars difficult. The state experiences both mild eruptions that spread ash across the surrounding areas and extreme events with heavy lava flow.

“The size, characteristics, and unpredictable occurrence of such flows present significant challenges for incorporating large lahars into conventional flood-hazard analyses,” wrote Waythomas.

By further studying the secondary effects of volcanic eruptions in Alaska, researchers will have a better understanding of how the events influence the hydrology, biology and form of the landscape, Waythomas added.

Calbuco Erupts a Third Time, with New Mudflows

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Summit view of current eruption (source:SERNAGEOMIN)

The glacier-covered volcano Calbuco in southern Chile has erupted for the third time today, after a few days of relative inactivity. It is sending forth a plume of ash 5 kilometers into the atmosphere, and it has created new mudslides, which are  associated with melting of glaciers as well as with recent rainfall.

As in its first eruption, seismic activity resumed only briefly before the eruption itself, just after 1pm local time. Though this eruption is, at least at present, smaller than the previous ones on 22 and 23 April, it is still sizable. And it has elicited a stronger reaction, including a public announcement by President Michelle Bachelet within hours of the event. She stated, “All measures are being taken. We are committed not to rest in our efforts to attend to this emergency as quickly as possible.”

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Police directing evacuation near Calbuco. (source: YouTube/M.Klebek)

Both the National Service of Geology and Mines and the National Emergency Office have issued a red alert, the highest level. 6600 local residents have been evacuated, a larger number than for the previous recent eruptions of the volcano. Non-residents have been prohibited from entering the area near the volcano as well. National police have been instructed to enforce this restriction.

The new ash fall, and other volcanic debris, are likely to cause additional damage in southern Chile, which has not yet fully recovered from the ash falls of last week. The Washington Post quotes one local resident as saying,  “We were working, cleaning the ash and sand from our homes when this third eruption took place. I feel so much anger and impotence it just breaks me apart.”

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Aerial view of current eruption (source: Chilean Air Force)

Meanwhile, the European MetOp satellites have been tracing the plume of aerosols from the earlier eruptions of Calbuco. As this animation shows, the aerosols have now crossed the Atlantic Ocean and have reached South Africa, where dramatic sunsets are now expected.

The webcams of the National Service of Geology and Mines have images which are a bit grainy, but are striking nonetheless.

For further details about the current eruption, read Erik Klemetti’s recent post  in WIRED.

 

Eruption in Glacier-covered Volcano in Chile

One of South America’s most active volcanoes, Villarrica, erupted Tuesday, 3 March 2015,  around 3 a.m. local time in Chile, creating a danger that lava would interact with the large ice cap on the mountain. The volcano spewed a lava fountain 1.5 kilometers into the air, and the pillar of smoke and ash reached 6-8 kilometers in height. Fortunately, the National Emergency Office issued a red alert and ensured the evacuation of roughly 3300 people from the volcano’s vicinity, especially residents from the town of Pucón. This area experienced  many moderate to large eruptions, including events in  1640 and 1948 which appear in the historical record, and earlier ones attested to by indigenous populations of the area and by geological evidence.

The upper reaches of the volcano are covered by an ice cap about 40 square kilometers in area, including the Pichillancahue-Turbio Glacier. This 2840 meter-high mountain is a popular destination for hikers, who are fond of peering inside of the volcano. What differentiates Villarrica from many  other volcanoes is that it contains an intermittent lava lake within its crater. In fact, Villarrica volcano is composed of layers of hardened lava and volcanic ash from previous eruptions. It is capable of erupting explosively  due to high pressure that results from the release of dissolved gas as magma rises to the surface. These explosions are often accompanied by loud sounds that can be heard over great distances.

The eruption can be seen in this dramatic time-lapse video, which starts in black and white, and then shifts to color.

There are three major interrelated concerns about this eruption.  Firstly, the lava could melt the glacier ice and snow on the sides of the volcano, causing massive lahars (mud and debris flows), much like the ones that occurred during the eruptions of 1964 and 1971. Secondly, the noxious volcanic ashes could pervade in the air. During the 1971 eruption of Villarrica, at least 15 fatalities from the inhalation of toxic gasses were reported. Finally, there is a somewhat lower risk of a large releases of volcanic ash, which could affect human health, damage power transmission lines, and harm vegetation.  Previous eruptions of Villarrica have released smaller amounts of ash; paradoxically, these have protected the glaciers by insulating them and protecting them from incoming solar radiation.

Eruption of Villarrica, 3 March 2015 (source: Kalvicio de las Nieves)
Eruption of Villarrica, 3 March 2015 (source: Kalvicio de las Nieves)

At the time of posting, the volcanic activity is diminished, with much reduced lava emissions and lesser seismic activity. Alerts remain at the orange level for the present.

For other stories on volcanic eruptions near glaciers, look here and here