LAKE SESSION: 7th International Maar Conference, Olot, Catalonia, Spain (21-25 May 2018)

I would like to draw your attention on the upcoming 7th Maar Conference in Olot, Catalonia, Spain (21-25 May 2018).

A Circular with details can be downloaded here.

The Commission on Volcanic Lakes will be represented in the Scientific Committee of the Conference, and a multi-disciplinary “lake session” will be organized:

Session 3. Lakes in maar volcanoes: the sedimentary record of paleontology, climate change and hydrochemistry

Abstract submission deadline: 15 December 2017.

We hope to meet you on the cosy town of Olot, near Barcelona, in the Garrotxa Volcanic Field, foothills of the Pyrenees.

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Olot, Catalonia, Spain

 

Two fascinating Conferences in 2018

I would like to draw your attention on two fascinating conferences during the European spring of 2018 in Spain and Sweden. CVL aims to be present with a Scientific Sesssion. Please check here and on the specific websites of the conferences for further deadlines and details.

7th Maar Conference, Olot, Catalunya-Spain, 21-25 May 2018

http://maar2018.com/

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Olot, Catalunya, capital of the Garrotxa Volcanic Zone.

 

The FIRST joint meeting of the International Paleolimnology Association and the International Association of Limnogeology, Stockholm, Sweden, 18-21 June 2018.

http://ipa-ial.geo.su.se/

“Wet volcanoes” session at IAVCEI_Portland 2017

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III.5 Wet volcanoes: aquifers and lakes and their related hazards

Conveners:
Audray Delcamp, Vrije Universiteit Brussel; delcampa@tcd.ie
Jessica Ball, USGS; jlball@usgs.gov
Engielle Mae Paguican-Fabbro, Vrije Universiteit Brussel; engiellepaguican@gmail.com
Benjamin van Wyk de Vries, Laboratoire Magmas et Volcans; B.vanwyk@opgc.fr
Dmitri Rouwet, Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, Italy; dmitri.rouwet@ingv.it
Agnes Mazot, GNS-Wairakei, New Zealand; a.mazot@gns.cri.nz
Corentin Caudron, University of Cambridge, UK; corentin.caudron@gmail.com
Johan C. Varekamp, Wesleyan University, USA; jvarekamp@wesleyan.edu
Haruhisa Nakamichi, Sakurajima Volcano Research Center, Disaster Prevention Research Institute, Kyoto University, Japan; nakamiti@svo.dpri.kyoto-u.ac.jp

Volcanoes store large amounts of water in their porous layers, cracks, and cavities, whereas crater lakes can be subaerial exposures of underlying hydrothermal systems or direct receptacles of volcanic gases. “Wet volcanoes” can have phreatic and magmatic eruptions, and variations in composition and temperature of the aqueous fluids, and the level of seismicity can be used to monitor such activities. Unrest at wet volcanoes often culminates into phreatic eruptions, which are generally hard to predict. The “hydrocells” themselves also pose dangers, be it limnic eruptions or rupturing of the system with toxic floods. Similarly, ground water can play a major role during collapse by changing the volcano’s rheology. Modelling the hydrogeological system of volcanic aquifers is difficult since the environment is constantly changing and geophysical data and boreholes are limited.
We invite contributions that involve studies on wet volcanoes and active crater lake systems, using water and gas chemistry or geophysical surveys, hydrogeology with focus on water storage, migration, drainage, evolution with time, and contributions on the influence of water before and during landslides. In addition, work on numerical, conceptual and analogue modeling of fluid flow as well as eruption mechanisms of these volcanoes are welcome.

Deadline for abstract submissions is March 17, 2017. Click here to start your submission.

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Portland, Oregon. The Hawthorne Bridge over Willamette River (picture D. Rouwet, 2010) .

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Bruce W. Christenson named CVL Secretary

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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.

Italian lakes “flipping over” this winter

Dmitri Rouwet (INGV-Bologna, Italy) – 17/01/2017

 

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.

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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.

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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.

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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.

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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.

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Giovanni Chiodini and Dmitri Rouwet (INGV-Bologna) during the May 2010 Lago Albano survey.