Bruce W. Christenson (Senior Researcher at GNS, Lower Hutt, New Zealand) is named CVL Secretary since December 2016, after New Zealand was elected as the exciting site of the next CVL10 Workshop, March 2019. Bruce is the most active among “lake pioneers” and his work and open view on Ruapehu, Tongariro, White Island, Raoul, and other lakes on Earth, is a strong fundament for many of us. Thank you, Bruce, for taking on this important task for CVL.
The second lake overturn within a week at an Italian volcanic lake was recorded last weekend (14-15 January 2017).
After fish kill was observed a week earlier at Lago Averno, located in the northern sector of the restless Campi Flegrei Caldera, north of Naples, Campania, the Monticchio Piccolo lake of Vulture volcano, Basilicata, Southern Italy, turned red, while its larger, but slightly shallower (35 vs 38 m depth) neighbour Monticchio Grande maintained its usual dark blue color.
Monticchio Piccolo turned red, not-coincidently contrasting with the white snow (Pictures by Diego Sabbatini).
Despite the ongoing unrest at Campi Flegrei, also recently highlighted in the Italian and international press, Giovanni Chiodini (INGV-Bologna, Italy) explained (in a divulgation post on his Facebook page) that the fish kill at Lago Averno was caused by lake overturn due to mixing of anoxic deep water layers with O2-rich shallow water layers… no changes in volcanic activity beneath Lago Averno are needed -nor happened- to cause this at-first-eye worrying event.
Lago Averno, Campi Flegrei, Naples, during “fish-kill quiescence” (Picture by Mauro Di Vito).
Similar fish kill events occured at Lago Averno in 2002, 2003 and 2005… always during the winter period! The graph below, from Caliro et al. (2008, JVGR), explains that lake overturn, and consequently fish kill, is density driven: water density is highest at 4°C, a temperature reached for surface water only during cold winters in southern Italy. As such, the cold and dense surface waters push down into the warmer and less dense deeper waters, leading to lake overturn.
Southern Italy is currently passing through and exceptionally cold winter, with near-freezing temperatures and snowfall, even at low elevations.
The Monticchio Grande and Monticchio Piccolo lakes were formed after the 140,000 a B.P. maar-forming eruptions, the last magmatic events of the rather poorly known Vulture complex stratovolcano (1,270 m a.s.l.), in Basilicata. Lake overturn at the Monticchio lakes, as paroxysms or more gentle events, has been documented in historical reports for the past 200+ years. Some have caused fish kill, as last week at Lago Averno. Caracausi et al. (2009, Terra Nova) discuss some triggering mechanisms of these overturn events at Vulture, besides providing the dissolved gas contents along the vertical profile of the maar lakes.
A red-colored Monticchio Piccolo at Vulture volcano, Basilicata (January 2017, picture by Diego Sabbatini).
The red color of the surface waters is almost surely caused by the oxidation of iron from bottom waters transported to the surface during lake roll-over… a yet classical mechanism, adopted from the “big brothers” Lake Nyos and Lake Monoun, Cameroon.
Although unfortunate for the fish, the two 2017 lake roll-over events at Lago Averno and Monticchio Piccolo are more comforting than worrying, in terms of volcanic risk assessment: periodical turnover during winter times of lakes in temperate regions is paired with the gentle release of gas (CO2 and CH4) stored in the bottom waters (Cabassi et al. 2013, Bull Volcanol), avoiding gas pressure build-up to supersaturation levels in deep water layers, possibly leading into more explosive gas releases. Nevertheless, both Lago Averno and Monticchio Piccolo (and Grande) are a lot smaller and less deep than Lakes Nyos and Monoun (Cameroon, 1986 and 1984 lethal gas bursts), and hence cannot store large amounts of gas to eventually convert them into Italian “killer lakes”.
Further research might be needed (CTD depth profiles, chemical and isotopic composition) to detail these particular events; operations that will probably support the above hypothesis based on simple surface observations and scientific experience.
Regarding volcanic risk reduction, let’s say that re-zeroing the “CO2-CH4 clock” at these shallow lakes is rather “good” than “bad”.
With the striking of these winter lake roll-overs in southern Italy, a major concern now is to see if, and if so how, Lago Albano will “flip over ” this winter. Earlier research has demonstrated that Lago Albano, a large, 167 m deep crater lake of the active Colli Albani volcano (south of Rome) partially releases its CO2 each winter (Chiodini et al. 2010, Bull Volcanol), after being recharged with CO2 during a seismic swarm in the late 1980s.
Since the recent major tectonic earthquakes in Central Italy (August-October 2016) a depth survey has not yet been elaborated at Lago Albano.
Giovanni Chiodini and Dmitri Rouwet (INGV-Bologna) during the May 2010 Lago Albano survey.
After the voting for the site of the next CVL Workshop (CVL10-2019) NEW ZEALAND came out as the winner: NZ 50%, Italy 38%, Mexico 12%
Congratulations to Agnes Mazot and Bruce Christenson with their winning proposal.
Our commission will now support the organizing committee to make our tenth CVL Workshop an excellent event, in arguably the most spectacular setting of all our workshops so far: NEW ZEALAND
We will keep you updated through this webpage.
Some teasers for those who can’t wait till 2019! Welcome to New Zealand…
Rotorua. Picture by Eric Grosfils.
Ruapehu Crater Lake. Picture by Craig Miller.
Ruapehu Crater Lake. Picture by Veronica Chiarini.
Bruce Christenson, Steve Sherburn and Jean Vandemeulebrouck on Ruapehu Crater Lake, January 1991. Picture by Tony Hurst.
Phreatic eruption of Ruapehu in September 1995. Picture by Tony Hurst.
A degassing Ruapehu, September 1995. Picture by Tony Hurst.
Echosounding at Ruapehu Crater Lake, April 2010. Picture by Tony Hurst.
The Crater Lake on White Island volcano had shrunk to a few puddles on 21 December 2011. A sudden increase in lake level at the end of July 2011 was followed by a small eruption of ash and steam from a vent under the lake in August 2012. Picture by Tony Hurst.
Rupehu Crater Lake. Picture by Karoly Németh.
Ruapehu Crater Lake, after the September 2007 eruption. Picture by Karoly Németh.
Champagne Pool. Picture by Karoly Németh.
Frying Pan Lake. Picture by Karoly Németh.
Inferno Lake. Picture by Karoly Németh.
Lake Taupo. Picture by Karoly Németh.
Tongariro’s Emerald Lake. Picture by Victoria Smith.
On 8 September 2016 our beloved colleague and friend Bruno Capaccioni, Associate Professor in Geochemistry-Volcanology at the Università di Bologna, Italy, has left us too early.
A month after his leaving, our community is still in search of a new equilibrium.
Bruno was an active member of CVL, being the co-editor of the latest Special Volume on Volcanic Lakes in the Special Pubblications Series of the Geological Society of London. This volume will become the “Bruno issue”. Bruno animated the CVL8-2013 workshop in Japan, where he presented his original video footage on the Copahue 2012 unrest.
Bruno worked on the Argentinean crater lakes of Copahue and Peteroa volcanoes, El Chichón in Mexico, and on Costarican lakes Poás and Rincón de la Vieja. He supervised Mariano Agusto during his postdoc at Università di Bologna, and opened the doors of his lab to Dmitri Rouwet. Pioneering experiments in the lab on degassing from acidic lakes will certainly have a part II in the future.
The fluid lab at Università di Bologna will be dedicated to Bruno Capaccioni.
Besides his passion and commitment to volcanic lakes, Bruno was known as one of the most complete (fluid) geochemists, with studies ranging from gas to rock geochemistry (early work), and pure volcanology. Bruno is a pioneer of volatile organic compounds on volcanic systems. His recent work is on dissolved gases and hydrogeochemistry in wells in relation to seismic activity in Emilia-Romagna (near Bologna, Italy) after the May 2012 earthquakes, a project in which he mentored his PhD student Andrea Ricci.
By his students, Bruno will be remembered as an excellent, patient and dedicated teacher.
The Commission on Volcanic Lakes (CVL) is a scientific, non-profit organization of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI), connecting researchers that seek to understand how volcanic lakes relate to volcanic activity and their hazards.
The citations below will soon convince you that there are innumerous reasons to deepen our knowledge on volcanic lakes, and… for the CVL community to exist.
“… are amongst the most spectacular natural features on the planet. These intersections of magmatic-hydrothermal systems and the Earth’s surface are, poetically speaking, ‘blue windows’ into the depth of a volcano.” (Christenson et al. 2015, Volcanic Lakes, Springer)
“… dot the landscape in many volcanic terrains. They range in size from tiny maar lakes to giant caldera lakes”. (Varekamp 2015, Volcanic Lakes, Springer)
“… are surface expressions of the hydrogeology of volcanic complexes.” (Mazza et al. 2015, Volcanic Lakes, Springer)
“… (are permanent when they) meet a combination of physical constraints: (i) the bottom of the lake should be protected against water seepage by physical sealing; (ii) the meteorological precipitation should be abundant (snowfall and its melt water, rainfall); (iii) the input of “volcanic” fluids should be sustained; and (iv) the heat input from the active volcano should be limited, to avoid drying out of the lake by evaporation (Brown et al. 1989, Pasternack and Varekamp 1997).” (Rouwet and Tassi 2011, Ann. Geophys. 54/2)
“… are classified into various groups according to their state of activity, based on their physical and chemical characteristics, such as low-activity to peak-activity lakes and no-activity lakes (Pasternack and Varekamp 1997), and CO2-dominated, quiescent and ‘active’ crater lakes (Varekamp et al. 2000).” (Rouwet and Tassi 2011, Ann. Geophys. 54/2)
“… are studied to monitor the activity of the underlying volcano or dangers associated with the lake itself; (they) provide insight into acid-water/rock interaction or (are) the shallow part of ore-depositing magmatic-hydrotermal systems. Ultimately, volcanic lakes are an expression of terrestrial degassing, and they provide clues to its magnitude.” (Pasternack and Varekamp 1997, Bull. Volcanol. 58)
“… are proto-type settings for (phreatic and phreatomagmatic) activity. Despite the fact that only 8% of the reported volcanic eruptions occurred in a subaqueous setting, they have caused 20% of fatalities (Mastin and Witter 2000). (…) A crater lake or liquid-dominated hydrothermal system, which are strong condensing media, are sensitive to sudden pressure drops when injected by gas-vapor batches, eventually leading to eruptions.” (Rouwet and Morrissey 2015, Volcanic Lakes, Springer)
“… derive their gases from four distinct sources: magmatic, hydrothermal, biospheric and atmospheric.” (Christenson and Tassi 2015, Volcanic Lakes, Springer)
“… provide the advantage to preserve eventual changes in fluid cycling with time, whereas such variations in fumarolic gases from volcano craters will be lost to the atmosphere as a ‘snapshot'”. (Rouwet and Ohba 2015, Volcanic Lakes, Springer)
“… are efficient traps of volcanic volatiles supplied from depth, and a lake’s water composition is considered as an indicator of the flux and composition of supplied volcanic fluids.” (Shinohara et al. 2015, Volcanic Lakes, Springer)
Lake Nyos, Cameroon. picture by D. Rouwet.
“… are known (cfr. Lake Nyos and Lake Monoun, Cameroon) for the dangerous accumulation of CO2 dissolved in stagnant bottom water, but the shallow waters that conceal this hazard are dilute and undergo seasonal changes similar to other deep crater lakes in the tropics.” (Kling et al. 2015, Volcanic Lakes, Springer)
“… can be ‘killer lakes’ (cfr. Lake Nyos and Lake Monoun, Cameroon) (… because they can kill) after a gas explosion or limnic eruption, a sudden release of carbon dioxide accumulated in deep water.” (Kusakabe 2015, Volcanic Lakes, Springer)
“… in the craters of active volcanoes and their related streams are often characterized by conditions considered extreme for life, such as high temperatures, low pH and very high concentrations of dissolved metals and minerals.” (Mapelli et al. 2015, Volcanic Lakes, Springer).