Nestled amidst the rugged embrace of Guatemala’s towering volcanoes, Lake Atitlan emerges like a precious gem laying testament to natures majestic beauty. This pristine body of water captivates many a traveller to marvel upon its enchanting splendour each year. But how did it come to be renowned as one

of the most beautiful lakes on the planet by the great explorer and polymath Alexander von Humboldt? Well, let’s wind the geological clock back by 84,000 years where lake Atitlan’s story begins.

“the most beautiful lake in the world” Alexander Bon Humboldt

Google earth 2023

Lake Atitlan lies on a major fault zone known as the Motagua and Chixoy-Polochic fault complex between two converging tectonic plates. The dense oceanic Cocos plate and the lighter continental Caribbean plate. This makes it part of the Pacific Ring of Fire the most volcanically active region on Earth. As the Cocos and Caribbean plates converge the denser and heavier Cocos plate subducts (sinks) under the Caribbean plate, the region where this process occurs is called the subduction zone and this is where earthquakes occur. Subduction creates a huge amount of friction and pressures deep below the earth’s surface melting the solid crust into magma which rises to the surface triggering massive amounts of volcanism. As the oceanic plate descends into the mantle the overriding plate develops a belt of deformation, think of it as the earth folding and scrunching up like a sheet of paper or tin foil creating peaks and valleys in the form of volcanoes, valleys, and mountain ranges.

Now that we have established the geological context underpinning this region it’s time for the main event the caldera-forming Chocoyos supereruption. This gargantuan eruption ejected up to 300 km3 of tephra (unconsolidated volcanic material) decimating all life in Guatemala as it dispersed ash over 6,000,000 square kilometers. Analysis of deposits in geological layers and deep-sea cores reveal that the ash plumes composed of chlorine, sulfur, and bromine reached as far as Florida and Ecuador. The initial eruption reached magnitude 8, the highest ranking on the volcanic explosively index (VEI). The eruption was so massive that the magma chamber below the volcano collapsed leaving a crater in the earth. The geological evidence suggests that this eruption is likely to have been one of the greatest eruptions of the last 100,000 years.

Consecutive rainy seasons and water from the Panama bel and Quiscab rivers filled more than 300 metres of the caldera floor leaving just 300 meters between the water level and the peak of the caldera ridge forming the early Lake Atitlan.

After the eruption of Los Chocoyos, the continuation of volcanic activity created 3 volcanos in the caldera. Lake Atitlan which lies. On the southern edge of the caldera and the San Pedro and Toliman volcanoes which lie within the caldera. San Pedro is the oldest of the 3 volcanoes that fringe the lake.

“Lake Como, it seems to me, touches on the limit of permissibly picturesque, but Atitlán is Como with additional embellishments of several immense volcanoes. It really is too much of a good thing.” Aldous Huxley

The youngest of the 3 volcanoes Atitlan last erupted in 1853 developing almost completely in the last 10,000 years, it is also the only currently active volcano of the 3 with more than a dozen eruptions recorded between 1469 and 1853. Atitlan is part of the Central American volcanic arc a chain of volcanoes that stretches along Central America along the aforementioned subduction zone between the Cocos plate and Caribbean plate.

“El Lago de Atitlán es un ícono cultural y natural que inspira a cualquiera que lo visite.” Amigos del lago

In the shadow of the countries civil unrest Guatemala has developed a list of social issues to the detriment of the environment. This has introduced a host of ecological challenges to the lake. Population and human activity have led to increased agricultural Erosion and the inundation of raw sewage into the lake causing algal blooms and the deadly proliferation of Cyanobacteria that creates public health problems for the local community. More than 400, 000 Maya people live around around the lake and despite the contaminants they face they use the lake out of necessity.

There are around 14 waste treatment plants around the lake (2020) with 80 being needed to safely deal with the flow of wastewater. This demand is set to increase as the current population of 350, 000 is set to rise in the next 20-30 years.

In the 1950s the area around the lake became a national park unbeknownst to the rest of the world, Guatemala was seeking ways to increase tourism and boost the economy, and the introduction of the prized bass fish for sport and fishery seemed like the obvious answer to attract the anglers. As a result

deterioration of the lake’s ecosystem ensued as the bass ate through native species of fish and chicks and contributed to the extinction of the Atitlan grebe a rare bird endemic to Atitlan.

Lake Atitlan has been millions of years in the making and around 6000 years of human civilisation is threatening its very existence. In turn human civilisation will struggle as the symbiotic bond between humans and nature is weakened. This is why collectives such as Niños del lago are expending efforts to preserve and protect the lake that gave their ancestors life.

Whilst it’s great to visit places like lake Atitlan for their natural beauty it’s important to remember the negative impacts that humans can have when natural resources aren’t effectively managed. The Mayan’s where so entranced with the beauty and vibrancy of the lake that they named it the place where the rainbow gets its colour. And whilst we admire the like for what it has to offer us we are destroying it. The lake’s magic is so entrancing that one day if we continue to limitlessly exploit it the rainbow may well truly lose its colour.