As most of us are aware, a lava lake appeared on the crater floor inside Santiago Crater on Nicaragua’s Volcan Masaya back in December 2015. This however wasn’t the first time Volcan Masaya hosted an active lava lake, Masaya has had a history of having a lava lake appear and disappear over the centuries and it goes back to the time of when the Spanish Conquistadors first conquered the land what is now today’s Nicaragua. The Spaniards having observed the lava lake activity had nicknamed it “La Boca del Infierno” or “The Mouth of Hell”. To give a brief geological background, Masaya Volcano is located within the El Ventarron or Masaya caldera built upon the Pleistocene pyroclastic shield volcano Las Sierras. There are four main craters, Nindiri, San Pedro, Santiago, and Masaya. Parasitic cones dot the flanks and a lava field is prominent towards Laguna de Masaya on the east flank of the volcano. Volcan Masaya is one of Nicaragua’s most active and unusual volcano which lies within the chain of volcanoes along the Central America subduction zone. This dominantly basaltic volcano has produced the odd explosive eruption as well as hosting lava lakes.
The early years of discovery
We go back to the year 1524 during the time the Spanish conquistadors had invaded The New World and at that time the Spaniards had witnessed volcanic activity from Masaya and Momotombo volcanoes. But it wasn’t until 1529 when the first known expedition to Volcan Masaya was conducted led by Gonzalo Fernandez de Oviedo y Valdez along with a local chieftain and three servants. They left Managua on horseback on 25th July 1529 and arrived at Laguna de Masaya before starting to climb at night where Gonzalo describes forcing his way through rough terrain, a reference to the lava fields on the east side of the Masaya caldera. Eventually, they reach the top and this is where Gonzalo Fernandez de Oviedo y Valdez describes a huge abyss which had a “plaza” so huge and round that “a hundred horses could play cañas in it” and a hole was present towards the south border of the plaza. Inside that hole was a lava lake, he just discovered where the source of the “glow on the mountain” came from. Gonzalo describes the lava lake at the bottom of the hole as “fire that was liquid and burning more fiercely than red hot coal” and further describes the behaviour as matter which was boiling in some parts and changing from one place to another and bubbles which reappeared here and there. From stories collected from the indigenous people it was suggested that the source of activity was previously located in the Masaya crater (now inactive), but when the Spaniards discovered Masaya Volcano it was in the Nindiri crater which was then the centre of volcanic activity.
Fray Blas del Castillo was the next person who conducted a significant expedition 9 years later, he described the crater containing the lava lake as being like “a bell turned upside down and getting narrower towards the bottom”. He then described the lava lake as having two main lava fountains with a lava spring towards the east-northeast wall with a dense cloud of smoke coming out from the cave towards the lava lake. He descended into the “plaza” on several occasions believing that the lava lake was molten gold or silver and wanted to extract samples of it. His first descent of the crater came on 13th April 1538 when he walked onto the crater floor full of ashes and basaltic rocks without technical support and holding only a wooden cross in one hand and a hammer in the other. Believing that the lava lake was molten gold and not wanting the rich to know about it, the expedition was carried out in secrecy among Fray Blas del Castillo and his companions. They spent months studying the site and the crater, and eventually brought along some equipment including chains, ropes, and containers in the hope of extracting what they thought was gold or silver. Blas del Castillo descended into the crater again in a basket and wore an iron helmet, he took with him a hammer, a flask of wine, and not forgetting his trusty wooden cross. On the ground and among some cracks emitting sulphurous fumes, he hammered away at the rocks collecting samples for over 3 hours and even hammered away at the bright crusts believing it to contain molten silver. The hole with the “molten gold” in it was in the middle of the “plaza” and it was bigger and deeper than what the party thought it was, so they were going to need more manpower and more equipment if they were going to extract the “gold”. Soon afterwards, men worked hard day and night to install pulleys and devices and they used a chain to lower the iron container into the crater to collect samples. At one point, the container got stuck and was difficult to get off but eventually they freed it with a semi melted sample. Tired, the expedition party decided to call it a day and returned to their respected places of residence and realised more chains would be needed. Word had eventually got around of the presence of the “molten gold” inside the crater and upon hearing the news, the Governor Rodrigo Contreras orders Fray Blas del Castillo to make another descent into the crater and he wanted to be present this time. On the 30th April 1538, the friar Blas del Castillo along with 7 other men descended into the crater and final managed to submerge the iron container into the melted matter after unsuccessful attempts and hauled it up full of scoria and so they managed to get their samples. Eventually, the iron container became glued to the melted matter on another attempt and the chains broke. Soon, the samples were studied and they were found not to be gold nor silver, much to the disappointment of the Governor Rodrigo Contreras who then banned Blas del Castillo from carrying out new prospectings. Fray Blas del Castillo later died upon his return to (what is now) Nicaragua from Spain after receiving authorisation from the king to find more potential gold. He was the first volcanologist of the New World.
Despite the samples being discovered not to be of gold nor silver, this did not stop other people from believing the lava lake to be full of riches and having plans to exploit it. Juan Sanchez Portero who accompanied Blas del Castillo on the second descent into the crater obtained authorisation from the king in Spain but despite that, the governor wouldn’t allow him to carry out his plans. In 1551, the Dean of Leon Cathedral had big plans to use 200 slaves to dig a tunnel through the crater wall to drain it of the “gold” but was refused. In 1573, the friar Alonso de Molina got authorisation on condition that 1/5 of the riches will go to the king and in 1586, Benito Morales had authorisation but by then the lava lake had disappeared.
Not only was Volcan Masaya thought to contain riches, it was also associated with superstition from both the indigenous people and the Spaniards. Back then, the Spaniards were more religious than they are today because science in those days wasn’t understood well as it is during present day. It was thought to be “the mouth of hell” and it even prompted Fray Francisco de Bobadilla to climb the volcano in 1529 to erect a cross overlooking the crater in order to exorcise the demons and hell, a cross which still stands today. The indigenous people thought of the volcano as a god, they made offerings and also human sacrifices by throwing children and virgins into the lava lake, how charming! It is also said that a sorceress made an appearance inside the volcano when the local chiefs seeked advice.
So based on early accounts and information of Masaya Volcano, this indicates that only two craters existed back then which were the Masaya and Nindiri craters, the latter hosting a lava lake. The lava lake however wasn’t the only activity which was observed during the early years, Fray Bartolome de las Casas recalled that explosions occurred especially during rainy season when “the fire explodes with great fury”.
The lava flows and the emergence of Santiago crater
Fast forward to the year 1670, and the lava lake had progressively filled the Nindiri crater, it is said that it grew as wide as 1000m. Eventually, the lava overflowed the crater rim onto the north flank flowing for 2km and evidence of that can still be seen today. The location of the lava lake overflow of 1670 is just at the northeast point of today’s San Pedro crater.
In 1772, a fissure eruption occurred to the north of Masaya crater during the early hours of 16th March 1772 after being preceded by 2 hours of strong earthquakes. Lava flowed continuously for 8 days to the north eventually overflowing the caldera rim and parts of it branched out across the caldera walls, one branch flowed into Laguna de Masaya.
In 1852, further activity was observed in the Nindiri crater when lava was erupted onto the crater floor. Then in 1853-1859 saw the formation of two new pit craters, Santiago and San Pedro respectively. Santiago formed in 1853 with an initial diameter of 80 x 65m, later expanding to 600m wide during 1858-59. A column of “flames” and ashes was reported on 27th January 1859 and again on 27th March 1859. The Santiago crater later became the location of most recent activity on Volcan Masaya and it still goes on today.
Activity of modern times
The formation of the Santiago and San Pedro collapse pit craters exposed the alternating lava and tephra layers in the crater walls especially that of the formerly active Nindiri crater. Santiago crater often displays degassing activity and episodes of collapse events have occurred inside the crater whether it originated from the crater walls or on the crater floor. Sometimes collapses on the crater floor have revealed some incandescence or even a lava pool. These vents would sometimes display weak strombolian activity and sometimes these vents would eventually get blocked up again following a collapse inside the crater. In some cases, a collapse on the crater floor had progressed into an emergence of a lava lake and Volcan Masaya does have a history of lava lakes appearing and disappearing over the centuries. Ok, I won’t get into too much detail now so I will focus on the significant activity which occurred up to present day beginning with 1965.
In 1965, a lava lake formed inside Santiago crater which somehow was reduced to a small central spatter cone by 1969. However, effusive lava flow activity continued on the crater floor. In 1972, the spatter cone collapsed and a lava lake was visible until 1979.
During the 1980s, the activity predominately consisted of gas emissions. Collapse events had also occurred inside the crater and incandescence was observed. The odd small explosive eruptions had also occurred, one of the largest came in 7th October 1982 when ejecta and tephra covered an area of 150,000 square metres which killed a few trees and animals that were near the summit and also melted parts of asphalt on a road. During February 1989, a lava lake had emerged in a new collapse pit but then apparently disappeared in March 1989.
A lava lake once again appeared inside Santiago crater in 1993 but had gradually cooled by 1994 and was reduced to an incandescent vent on the crater floor. Strombolian explosions had occurred in 1993-94 and again in 1997-98.
On the 23rd April 2001, an unexpected larger than normal explosion had occurred catching a group of tourists by surprise. Fortunately, there were no fatalities and only minor injuries were sustained but vehicles were damaged by ejecta. In one incident, a volcanic bomb penetrated the roof of a bus landing in an unoccupied seat and in another incident, a bomb embedded itself in the bonnet of a car. The grass close to the car park caught fire. Ashfall was reported near the village of Ticuantepe.
During 2003-05, incandescence was observed in the crater again while intermittent ash explosions and collapse events were also observed. A landslide event during the night of 2nd March 2005 may have blocked the active vent which caused the gas plume to diminish. Explosions occurred in 2006 and again in 2008, and a new vent on the crater floor of Santiago was reported in 2006. Degassing continued.
Moving on to more recent years now and incandescence was observed inside the crater in 2010, and during 2011 crater wall collapses occurred causing the active vent to be blocked by the debris which in turn prompted the brief closure of the national park. In 2012, around 68 explosions occurred between 30th April and 17th May of that year. The initial explosion on 30th April 2012 ejected blocks and a column of ash up to 1000m above the summit and smaller explosions which followed ejected material up to 500m. Hot blocks which fell on bushes started fires which prompted staff at the national park to close the park following hazardous conditions. Incandescence inside the crater briefly appeared during April 2013.
During December 2015, INETER reported that magma had risen to the crater floor resulting in the formation of two incandescent vents which marked the beginning of the current volcanic activity on Volcan Masaya. By January 2016 the vents expanded revealing two lava lakes at the bottom of the crater floor before a third lava lake emerged during early February 2016. The lava lakes grew in size into February 2016 and the odd small explosions had also occurred during January and February. By March 2016 the lava lakes had merged into one and had risen in level by then, and the lava lake activity is still going on now during the time of this writing. During the activity of March 2016 a torrent of lava was observed pouring into the lava lake and was caught on camera.
After reading about the early accounts of the early expeditions to Masaya Volcano I’ve gained admiration for the Spanish friar Blas del Castillo, a brave man who knew he was taking risks by daring to venture inside the crater and extracting what he thought must’ve been molten gold or silver which turns out it wasn’t. As far as volcanic activity on Masaya goes, the activity predominately consists of gas emissions and also lava lake activity (when there is one). Small strombolian explosions occasionally occurs but as history tells us, Masaya is also capable of producing larger explosions ejecting blocks outside of the crater. Fissure eruptions are possible but very rarely does that happen. The 2016 lava lake may eventually disappear in the long run but I’m sure lava lakes will keep re-appearing during our lifetime. According to data by GVP, a population of about 989,888 lives within 10km of the volcano as there are quite a few settlements scattered around the Volcan Masaya area. The local population are prone to health hazards if a sulphur dioxide plume is blown in their direction and crop damage also occurs.
Video 1 – Drone footage of the landscape around the summit craters (prior to the current lava lake). Video credit: Chris Mayorga.
Video 2 – Lavafall cascading into the lava lake during March 2016. Video credit: Richard Guevara.
Video 3 – The current lava lake activity on Masaya Volcano. Video credit: Marc Szeglat.
Masaya, the “Mouth of Hell”, Nicaragua: Volcanological interpretation of the myths, legends and anecdotes – Jose G. Viramonte and Jaime Incer-Barquero.
Pit crater structure and processes governing persistent activity at Masaya Volcano, Nicaragua – H. Rymer, B. Van Wyk de Vries, J. Stix, and G. Williams-Jones.
Global Volcanism Program