This Nicaraguan volcano, whose náhuatl name translates as “Great Boiling Summit”, is the only one that has not been renamed by the Spanish conquerers in reverence to some Saint or other. Folklore has it that when the priests were just about to baptize the mountain they had to abandon the ceremony when an eruption started. Momotombo was proud of his native name, and the famous French writer Victor Hugo referred to that legend in his “The Legend of the Ages“, XXVII, The Inquisition (in “Les raisons du Momotombo“). In this poem Hugo let Momotombo debate with a Spanish priest about why taking on a different name was not a good idea at all.
On 1 Dec. an explosion at Momotombo generated a gas-and-ash plume that rose 1 km above the crater, followed by three more explosions, all within one hour and ten minutes. This caused some excitement in the media, and of course in the nearby communities, as it was the first eruption since 1905. During 1-2 Dec. explosions ejected incandescent tephra, and slow-moving lava flew down its N flank. Ashfall was reported from nearby communities and some families began to self-evacuate. This activity continued through 10 Dec.. Later fieldwork revealed a small, incandescent, circular crater halfway up Momotombo’s E flank that was fuming during the morning on 6 Dec., and on 7 Dec. an explosion destroyed part of the crater. Since then, Momotombo has been more or less busy with occasional outbursts of ash; the crater, breached by a lava flow that was poured out on the north slope in 1905, is permanently steaming and displays a nice glow from the hot gasses in the crater every night these days.
Momotombo has long been emblematic to Nicaragua. Before WWI, it was a popular tourist destination and visitor numbers peaked in 1904 until it had an eruption in January 1905. Its image was printed on matchbooks and stamps and appeared on murals. – On a sad note, under the dictatorship of Anastasio Somoza Debayle, last dictator of that family clan up to 1979, it was used for a horrible crime: the bodies of people who were killed by secret police and National Guard were thrown into the crater of the Momotombo, where their remains were later discovered. – Today Momotombo is a tourist destination again, visited by local tourists and foreigners alike who revel in extreme adventure.
Momotombo, an andesitic-basaltic stratovolcano with the adjacent geothermal field, and his “little brother” Momotombito volcano in Lake Managua, are only about 4,500 years old. They have grown on the south-eastern edge of the caldera of a mainly collapsed ancient edifice – Monte Galán, a circular depression of 4 km in diameter and 200 m depth, invaded in part by lavas from Momotombo volcano.
Momotombo and Momotombito volcanoes are built upon ignimbrite deposits from the huge Malpaisillo caldera, which lies still further N. The location is on the NW shores of Lago de Managua (also known as Lago Xolotlán), near the city of León, and beside the old place of León, today the town of Puerto Momotombo.
Momotombo has erupted several times since the 16th century and had a particularly active period in the late 1800s, with 10 confirmed eruptions between 1858 and 1905. However, although there have been a VEI 3 eruption in 1524 and a VEI 4 in 1605, all following eruptions were VEI 2 or 1. After the 1905 eruption, it had always been obvious that Momotombo was not “sleeping”; swarms of volcanic earthquakes were recorded and the temperatures of the fumaroles went up at times to a maximum of 933°C.
Fumarole characteristics distinguish Momotombo from other volcanoes in Nicaragua: no other volcano exhibits high temperatures of ~700°C without displaying incandescence, but of course in times of the max temperatures the glow can be seen from far away.
From the 1970s on, a scientific interest in the volcanoes of Nicaragua lead to international research and better monitoring of Momotombo by INETER:
1980: Temperatures of 465-780°C were measured in summit crater fumaroles – 3/1982: Crater fumaroles were as high as 800°C; continuous vapor plume – 8/1982: Incandescence in the summit crater, T.max fumarole 825°C, tremor and small-magnitude discrete earthquakes. – 1983: T.max 855°C, magmatic movement recorded. – 1989: Numerous incandescent fumaroles at night with 40cm high, orange and blue flames from vents; large areas of hot ground >100°C. – 1994: Voluminous plume from summit crater, although fumarolic activity had declined – 1996: High seismicity and one black plume in the first half of April; – 2000: Seismic swarm incl. continuous tremor spells during May/June; T.max fumarole 933°C – 2003: Some seismic swarms and tornillos; – 2006: seismic swarms, one small summit gas explosion – 2011: elevated tremor during most of the year, high fumarole temperatures.
Momotombo geothermal field power plant
Nicaragua has the lowest electricity generation in Central America, and the lowest percentage of population with access to electricity. However, it does have a large geothermal potential thanks to the volcanoes of the Marribios range along the Pacific Coast. The country is still very far from exploiting this natural resource efficiently. The larger of two operating geothermal plants is the Momotombo geothermal project, whose commercial exploitation started in 1983, when the first unit of 35MW was put in operation. The second unit of 35MW was installed in 1989. Unfortunately, the strategy adopted by the National Electricity Company for the development of Momotombo neglected reinjection and focused exclusively on exploitation. Among others, over-exploitation of the reservoir and a lack of a proper field development strategy, resulted in a steep decline of power output from 69 MW in 1990 down to 9 MW in 1999. While the present company running the plant has implemented modern technologies for a sustainable environmentally responsible scheme including full reinjection, it can not supply steam for more than 23-24 MW of power output from one 35 MW turbine at the current project (2008).
GRABENS, ARCS and TRENCHES
Since the late Cretaceous the Central American Volcanic Arc (CAVA) has been built by subduction of the Cocos plate beneath the Caribbean plate with a rate of ~8 cm/a. This process is responsible for the widespread Tertiary and Quaternary volcanism in the area and the intense seismic activity. The contact between the two plates is marked by the ‘‘Middle American Trench”, extending NW-SE from Mexico to Costa Rica. The Teuantepec Ridge divides the trench into two blocks characterized by different rates of movement.
One interesting geological feature is the Nicaragua depression, a 70–80 km wide tectonic graben that runs parallel to the Middle American Trench for about 300 km. It probably began to subside in the Late Miocene. The graben (or rather a half-graben) is filled with ~6 km of volcaniclastic and marine sediments and contains the two major Lakes L. Managua and L. Nicaragua were the depression is deepest. Along its western side stretches the NW-SE-trending Nicaraguan volcanic front, which comprises at least 12 major volcanic complexes that have been active during the Holocene, including the 6 presently active volcanoes.
Cordillera de Maribios (or Cordillera de Marrabios), a mountain range in León and Chinandega departments, is a volcanic range containing San Cristóbal 1745 m, Pilas 983 m, Telica 1060 m, Cerro Negro 450 m, and Momotombo 1258 m. From Momotombo’s crater rim you can see a unique and spectacular view: the Pacific Ocean, the volcanic complex of Masaya , Lake Nicaragua and in the center of this, the island of Ometepe with its two volcanoes.
This 40-km-long (N–S direction) and 25-km-wide part of the Managua graben is the site of considerable seismic and volcano-tectonic activity; its western boundary is marked by the Mateare fault. Volcanic activity started about 100 ka ago in the inland plateau, and shifted westwards during the Quaternary due to a change in the angle of slope of the subducting slab of Cocos Plate.
The Nicaragua volcanic arc is divided into two parallel segments by the Nejapa-Miraflores secondary line (N–S direction): The NW volcanic chain extends for about 175 km, from the Cosiguina volcano in the Fonseca Gulf on the border with Honduras to the Momotombo volcano and the small Apoyeque caldera; the SW volcanic chain extends for 215 km from Masaya volcano to Madera volcano and Conception volcano, which formed Ometepe Island in Nicaragua lake.
From LEÓN VIEJO (OLD LEÓN) to Santiago de los Caballeros de LEÓN (NEW)
Morphological changes in the volcano – really?
“And in the same government of Nicaragua in the province of Nagrando, a league or two from the city of Leon, there is a high mountain summit which always has several chimneys smoke”
Juan Lopez de Velasco writes around 1580 that the City was two leagues* from the Momotombo volcano, which agrees fairly with the real distance to the ruins. He also notes the distance to the top of the cone of the volcano, which however did not meet modern measurements. On the “León Viejo” website I read that: Here the evolution of the volcano through the last four hundred years must be taken into account – in those times it had five craters! The chronicler had added a drawing, and a disparity between this and the later state of the cone was already noticed by Ephraim George Squier around 1850. So, León Viejo was probably founded when Momotombo had its last and definitive morphological changes, which formed the modern topography.
Backstage, I talked this through with agimarc… it might well be that Momo at that time was a Somma volcano with its central cone sitting in an earlier crater but, if the artist has not hopelessly exaggerated (which he sure has anyway), we think no, it would not be possible that such a deeply divided volcanic complex would grow into a flawlessly conical mountain within a few hundred years.
More likely it was the view he had from a very low standpoint on the shore of (or a boat on) Lake Managua, E of Momo. It appears that he drew the double chute that is still obvious today on the cone (it might have been further east at that the time). That would make his central mountain the actual Momotombo cone, and the surrounding “cones” the foothills to the east, in front of Momo. It also explains why, in his view, old “León” appears directly to the left of the mountains. Those foothills must be the Malpaisillo ignimbrites, or perhaps remnants of the Monte Galán caldera/eruptions. And Momotombo rising above them might well have had the same shape it has now, a big even cone. – Remains the question of the “several chimneys smoke“… As we have seen above, in the reports about this last eruption (“…fieldwork revealed a small, incandescent, circular crater halfway up Momotombo’s E flank that was fuming during the morning on 6 Dec.”), this volcano seems to be in a habit of forming additional flank craters. These appear where magma exploits paths of weaker rock structure or poor consolidation and erupts on places other than the summit. Sometimes they persist and grow tall cones of their own, but often they erupt just once and the little heap is eroded or covered by more material from the summit very soon. So, could it be that the “several chimneys” were flank craters of which there might occur a higher number in bigger eruptions? Keep in mind that Momo is a very young volcano, with its materials not well consolidated yet, where magma might find ways to break through at any place of the cone.
*A Spanish league was officially equivalent to 4180 meters (2.6 miles) before the legua was abolished by Philip II in 1568. Today Leon Viejo is 9 km from the Momotombo summit.
Relocation of León
Momotombo was in eruption when the Spaniards arrived in the area but, notwithstanding the threats from the volcano, they founded their capital nearby on the shores of Lake Xolotlán. The first city named León in Nicaragua was built in 1524 under Francisco Hernández de Córdoba about 30 kilometres (20 mi) east of the present site. In 1610 several earthquakes rattled the town and caused severe damage to the infrastructure. Now the settlers held a referendum and decided to relocate the city to its present location. The old city was then gradually buried by the continuous expulsions of ash and volcanic rocks from Momotombo and by lake sediments. – After searching for decades between forests and thickets around the Momotombo Volcano and Lake Managua, the place could be rediscovered in the 1960s and 16 ruins have been excavated and partially restored. León Viejo is the only 16th-century, colonial city in America that has never suffered city-planning alterations during its history. This fact was the main argument in a request to the UNESCO and the place was consequently declared a World Heritage Site in 2000, part of the town now named Puerto Momotombo.
THE VOLCANIC POWER OF A STAMP
The first attempt to construct a navigable link between the Caribbean Sea and the Pacific Ocean, by the great French engineer Ferdinand de Lesseps in 1882, was stymied by landslides, malaria and yellow fever. Together, these caused the deaths of almost 22,000 workers in Panama. When the United States took up the challenge, its Canal Commission initially recommended a different route, through Nicaragua. But one man thought this would present even greater dangers, from volcanic activity and earthquakes. Philippe Bunau-Varilla, a French soldier and engineer who was a veteran of the de Lesseps project, was convinced that the terrain of Nicaragua was far too hostile for a canal, and set out to lobby the US Congress in favour of the Panama route. It was a natural event that swung matters in his favour. In the spring of 1902, Nicaragua’s Mount Momotombo erupted, causing extensive destruction along the proposed course of the canal. The country’s government tried desperately to suppress details of this, but Bunau-Varilla was on the case. His break came when he spotted on his correspondence a Nicaragua stamp from two years earlier. Prophetically, it depicted the mighty Momotombo crater, smoking angrily behind Lake Nicaragua. From a stamp dealer in Washington, Bunau-Varilla purchased 90 copies of the design, which had been used on a set of 14 values from 1-centavo to 5-pesos. He mounted the stamps individually, below the caption ‘An official witness to volcanic activity in Nicaragua’, on sheets of paper which were posted individually to every US Senator. When voting took place the next day, it was 42 to 32 in favour of Panama over Nicaragua. Then Bunau-Varilla journeyed to a New York stamp dealer, from whom he purchased 500 more copies of the stamp, to send to members of the House of Representatives. This time the result was a runaway victory for Panama, with only eight dissenting votes. Work began in 1904, and in 10 years the most challenging engineering project in history had been completed. Thanks to the lobbying power of a simple postage stamp, we know it as the Panama Canal and not the Nicaragua Canal. (Cited from “Stamp Magazine“, John Winchester)
– This was all true at the time… Today the world does talk of a “Canal de Nicaragua”. It was proposed and decided that by the end of 2015 work should begin on a 259.4 km long canal from Brito at the Pacific Ocean to the Rio Punta Gorda valley to meet the Caribbean Sea. So far, apparently, not much has been done yet and the project has been postponed for a year.
Enjoy – GRANYIA
SOURCES & FURTHER READING
– GVP, Momotombo
– The origin of the Nicaraguan depression (1964, paywalled)
– Cenozoic tectonics of the Nicaraguan depression… (2009, paywalled)
– Four Momotombo volcano webcams
– Momotombo on Wikipedia
– Leon Viejo, the first capital of Nicaragua
– Sarah & Duncan travel
– Adventures in Travel
– Twenty five Years of Production History at the Momotombo … (2008, PDF)