Welcome back Laguna Caliente

OVSICORI-UNA reports the return of Laguna Caliente, the hyper-acidic crater lake of Poás volcano, Costa Rica, as shown in the web-cam view below (top picture, http://www.ovsicori.una.ac.cr/index.php/vulcanologia/camaras-volcanes/crater-v-poas).

The crater lake had disappeared after culmination of the 2006-2016 phreatic eruption cycle into phreatomagmatic and magmatic eruptions, activity that started in April 2017. The southern part of the basin of Laguna Caliente (front of the top picture below) was newly formed after the 2017 magmatic eruptions that destroyed the dome, emplaced during the last major magmatic eruption cycle of 1953-1955 (lower picture).

It is no surprise that Laguna Caliente reformed, as the large volume magmatic-hydrothermal system underlying the lake was probably only temporarily and partially disturbed by the magmatic eruptions in 2017.

A recent paper by Terada and Hashimoto (2017) (Variety and sustainability of volcanic lakes: Response to subaqueous thermal activity predicted by a numerical model, J Geophys Res Solid Earth 122.doi:10.1002/2017JB14387) explains that neither a high rate of precipitation nor an impermeable layer at the lake bottom are necessary constraints to sustain/reform an active crater lake; a sufficiently high ratio between input rate at the lake bottom of a high enthalpy fluid and the lake surface can cause the re-appearance of a crater lake.

The adequate lake basin, abundant rain fall, and high fluid input from below are all factors favoring lake formation. As such, the Poás crater has returned to its most characteristic “wet” nature, hosting Laguna Caliente. The new peanut-shaped “window” into the magmatic-hydrothermal will be a useful tool for future monitoring efforts. OVSICORI and RSN-UCR will follow up the monitoring of Laguna Caliente with remote sensing techniques, direct measurements and lake and fumarole sampling, following internal safety protocols.

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20 January 2018 (OVSICORI web-cam: http://www.ovsicori.una.ac.cr/index.php/vulcanologia/camaras-volcanes/crater-v-poas)


poas febrero 15 001

April 2007 (D. Rouwet)    

The state of activity during the past year can be tracked on http://www.ovsicori.una.ac.cr/index.php/vulcanologia/grafica-de-los-volcanes, or http://www.rsn.ucr.ac.cr/actividad-volcanica/reportes-volcanicos#

FURTHER READING on arguably the most studied crater lake on Earth:

Recent publications on the 2006-2016 phreatic eruption cycle are:

  • de Moor JM, Aiuppa A, Pacheco J, Avard G, Kern C, Liuzzo M, Martínez M, Giudice G, Fischer TP (2016) Short-period volcanic gas precursors to phreatic eruptions: Insights from Poás Volcano, Costa Rica. Earth Planet Sci Lett 442:218-227.doi:10.1016/J.epsl.2016-02-056
  • Fischer TP, Ramírez C, Mora-Amador RA, Hilton DR, Barnes JD, Sharp ZD, de Moor JM, Barry PH, Füri E, Shaw AM (2015) Temporal variations in fumarole gas chemistry at Poás volcano, Costa Rica. J Volcanol Geotherm Res 294:56-70.doi:10.1016/j.volgeores.2015.02.002
  • Rouwet D, Mora-Amador R, Ramírez CJ, González G, Inguaggiato S (2016) Dynamic fluid recycling at Laguna Caliente (Poás, Costa Rica) before and during the 2006-ongoing phreatic eruption cuycle. Geological Society of London Special Publications 437, Geochemistry and Geophysics of Volcanic Lakes. Eds. Caudron C, Capaccioni B, Ohba T.doi:10.1144/SP437.11


Poás’ Laguna Caliente on 22 January 2018 (picture by Carlos Cordero).

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.


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



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.


“Wet volcanoes” session at IAVCEI_Portland 2017


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

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.


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